Battle of Raymond in the Civil War

Battle of Raymond in the Civil War Battle of Raymond - Conflict Dates: The Battle of Raymond was fought May 12, 1863, during the American Civil War (1861-1865). Armies Commanders Union Major General James B. McPherson12,000 men Confederate Brigadier General John Gregg4,400 men Battle of Raymond - Background: In late 1862, Major General Ulysses S. Grant began efforts to capture the key Confederate bastion of Vicksburg, MS. Located high on the bluffs above the Mississippi, the city was key to controlling the river below. After several false starts, Grant elected to move south through Louisiana and cross the river south of Vicksburg. He was aided in this effort by Rear Admiral David D. Porters gunboats. On April 30, 1863, Grants Army of the Tennessee began crossing the Mississippi at Bruinsburg, MS. Sweeping aside Confederate defenders at Port Gibson, Grant moved inland. With Union forces to the south, the Confederate commander at Vicksburg, Lieutenant General John Pemberton, began organizing a defense outside of the city and calling for reinforcements from General Joseph E. Johnston. The bulk of these were directed to Jackson, MS though their transit to the city was hampered by damage inflicted to the railroads by Colonel Benjamin Griersons cavalry raid in April. With Grant advancing northeast, Pemberton expected the Union troops to directly drive on Vicksburg and began pulling back towards the city. Successfully keeping the enemy off balance, Grant instead set his sights on Jackson and cutting the Southern Railroad which connected the two cities. Using the Big Black River to cover his left flank, Grant advanced with Major General James B. McPhersons XVII Corps on the right with orders to proceed through Raymond to strike the railroad at Bolton. To McPhersons left, Major General John McClernands XIII Corps was to sever the Southern at Edwards while Major General William T. Shermans XV Corps was to attack between Edwards and Bolton at Midway (Map). Battle of Raymond - Gregg Arrives: In an effort to halt Grants advance towards Jackson, Pemberton directed that all reinforcements reaching the capital be sent twenty miles southwest to Raymond. Here he hoped to form a defensive line behind Fourteen Mile Creek. The first troops to arrive in Raymond were those of Brigadier General John Greggs over-strength brigade. Entering the town on May 11 with his tired men, Gregg found that local cavalry units had not properly posted guards on the area roads. Making camp, Gregg was unaware that McPhersons corps was approaching from the southwest. As the Confederates were resting, Grant ordered McPherson to push two divisions into Raymond by noon on May 12. To comply with this request, he directed Major General John Logans Third Division to lead the advance. Battle of Raymond - First Shots: Screened by Union cavalry, Logans men pushed towards Fourteen Mile Creek early on May 12. Learning from locals that a large Confederate force was ahead, Logan deployed the 20th Ohio into a long skirmish line and sent them towards the creek. Hampered by rough terrain and vegetation, the 20th Ohio moved slowly. Shortening the line, Logan pushed Brigadier General Elias Dennis Second Brigade forward into a field along the west bank of the creek. In Raymond, Gregg had recently received intelligence which implied that Grants main body was south of Edwards. As a result, when reports arrived of Union troops near the creek, he believed them to be part of a small raiding party. Marching his men from the town, Gregg concealed them on the hills overlooking the creek. Seeking to lure the Federals into a trap, he sent a small guard detachment to the bridge over the creek in the hope that the enemy would attack. Once the Union men were across the bridge, Gregg intended to overwhelm them. Around 10:00 AM, Union skirmishers pushed towards the bridge but halted in a nearby tree line rather than attacking. Then, to Greggs surprise, they brought forward artillery and began firing on the Confederates near the bridge. This development led Gregg to conclude he was facing a full brigade rather than a raiding force. Undeterred, he altered his plan and shifted his command to the left while preparing for a larger ambush. Once the enemy was across the creek, he intended to attack while also sending two regiments through the trees to strike the Union artillery. Battle of Raymond - Gregg Surprised: Across the creek, McPherson suspected a trap and directed the remainder of Logans division to move up. While one brigade was held in reserve, Brigadier General John E. Smiths brigade was quietly deployed on Dennis right. Ordering his troops to advance, Logans men moved slowly through the vegetation towards the deep banks of the creek. Due to a bend in the creek, the first across was the 23rd Indiana. Reaching the far bank, they came under heavy attack from Confederate forces. Hearing the enemy yell, Colonel Manning Force led his 20th Ohio to the 23rd Indianas aid. Coming under fire, the Ohioans used the creek bed for cover. From this position they engaged the 7th Texas and 3rd Tennessee. Hard pressed, Force requested the 20th Illinois to advance to his regiments aid (Map). Surging past the 20th Ohio, the Confederates pushed forward and soon encountered Logans main body which was in a nearby tree line. As the two sides exchanged fire, the Union troops at the creek began falling back to join their comrades. In an effort to better understand the situation, McPherson and Logan directed Union forces to withdraw a short distance back to a fence line. Establishing a new position, they were pursued by the two Confederate regiments who believed the enemy was fleeing. Encountering the new Union line, they began to take heavy losses. Their situation quickly worsened when the 31st Illinois, which had been posted on Logans right began attacking their flank. Battle of Raymond - Union Victory: On the Confederate left, the two regiments that Gregg had ordered to get into the enemys rear, the 50th Tennessee and consolidated 10th/30th Tennessee, pushed forward and scattered the Union cavalry screen. Seeing his cavalry retreating, Logan became concerned about his right flank. Racing around the field, he pulled two regiments from Brigadier General John Stevensons reserve brigade to plug holes in the line and dispatched two more, the 7th Missouri and 32nd Ohio, to cover the Union right. These troops were later joined by additional regiments from Brigadier General Marcellus Crockers division. As the 50th and 10th/30th Tennessees emerged from the trees and saw the Union troops, it quickly became clear to Gregg that he was not engaging an enemy brigade, but rather an entire division. As the 50th and 10th/30th Tennessees pulled back into the trees, the 3rd Tennessee began to crumble as the flanking fire from the 31st Illinois took its toll. As the Tennessee regiment disintegrated, the 7th Texas came under fire from the entire Union line. Attacked by the 8th Illinois, the Texans finally broke and fled back across the creek with Union forces in pursuit. Seeking new instructions, Colonel Randal McGavock of the 10th/30th Tennessee dispatched an aide to Gregg. Unable to find their commander, the aide returned and informed McGavock of the Confederate collapse to their right. Without informing the 50th Tennessee, McGavock advanced his men on an angle to attack the Union pursuers. Charging forward, they began to slow Logans advance until they were taken in the flank by the 31st Illinois. Sustaining heavy losses, including McGavock, the regiment began a fighting withdrawal to a nearby hill. Here they were joined by Greggs reserve, the 41st Tennessee, as well as remnants of other shattered regiments. Pausing to reform their men, McPherson and Logan began firing on the hill. This continued as the day passed. Frantically attempting to restore order to his command, Gregg saw McPhersons line moving to flank his position on the hill. Lacking the resources to contest this, he began retreating towards Jackson. Fighting a delaying action to cover the withdrawal, Greggs troops took growing losses from Union artillery before fully disengaging. Battle of Raymond - Aftermath: In the fighting at the Battle of Raymond, McPhersons corps sustained 68 killed, 341 wounded, and 37 missing while Gregg lost 100 killed, 305 wounded, and 415 captured. As Gregg and arriving Confederate reinforcements were concentrating at Jackson, Grant decided to mount a major effort against the city. Winning the Battle of Jackson on May 14, he captured the Mississippi capital and destroyed its rail connections to Vicksburg. Turning west to deal with Pemberton, Grant defeated the Confederate commander at Champion Hill (May 16) and Big Black River Bridge (May 17). Falling back to the Vicksburg defenses, Pemberton turned back two Union assaults but ultimately lost the city after a siege which ended on July 4. Selected Sources Civil War Trust: Battle of RaymondBattle of RaymondNational Park Service: Battle of Raymond

3 Types of Quotation Errors

3 Types of Quotation Errors 3 Types of Quotation Errors 3 Types of Quotation Errors By Mark Nichol In the following sentences, something about the treatment of a quotation interferes with comprehension. Discussion of the error, and a revision of the sentence, follows each example. 1. â€Å"We are seeing our efforts having some effect on their financial flows. And it’s difficult to get a handle on just how much because of the different illicit ways in which they are handling their finances, but you’ve seen the efforts that our military has taken to take out cash-storage sites, and I think it is our hope and expectation that that will have demonstrable effects. On what order of magnitude, I think it’s difficult to say,† said Lisa Monaco, President Barack Obama’s counterterrorism adviser. It is not until the end of this seventy-seven-word statement that we learn who said it. Attribution of a speaker or writer should occur much sooner, preferably at the end of the first of two or more sentences, or even interrupting two independent clauses within the first sentence: â€Å"We are seeing our efforts having some effect on their financial flows,† said Lisa Monaco, President Barack Obama’s counterterrorism adviser. â€Å"And it’s difficult . . . .† 2. At times, I would succumb to a, â€Å"I’m not sure they’re going to make it† mind-set. When a quotation that represents a categorical statement follows the article a/an or the, no punctuation should precede the quotation: â€Å"At times, I would succumb to a ‘I’m not sure they’re going to make it’ mind-set.† (The phrase can also be written without quotation marks but linked by hyphens: â€Å"At times, I would succumb to a I’m-not-sure-they’re-going-to-make-it mind-set.† However, because that extended phrasal adjective could conceivably be spoken, and it is cumbersome as a hyphenated phrase, the format treating it as a quotation is preferable.) 3. She rallied the crowd by crying â€Å"shame on you, John.† The verb that precedes this quotation should be followed by a comma, and the first word should be capitalized. Also, a cry is a loudly delivered statement, so an exclamation point is appropriate: â€Å"She rallied the crowd by crying, ‘Shame on you, John!’† Want to improve your English in five minutes a day? Get a subscription and start receiving our writing tips and exercises daily! Keep learning! Browse the Punctuation category, check our popular posts, or choose a related post below:12 Types of LanguageWhat is Dative Case?35 Synonyms for Rain and Snow

4 page essay Example | Topics and Well Written Essays - 1000 words

4 page - Essay Example An example is given where the regulators never reacted to the extra ordinary increase in the financial institutions leverage. this never reacted to the movement of assets worth trillions of dollars from banks balance sheet. This shows how the regulators did not do their work. Increasing the regulators power without checking the problem and trying to regulate it helps in solving nothing. Barth, Caprio and Levine studied that the governance of financial regulation the system that is supposed to design, implement and reform financial policies contributed highly to the crisis faced in the United States. The senior most officials are blamed for repeatedly designing implementing and maintaining policies that destabilized the financial markets. The Financial Guardians maintained the same policies even after learning that these policies were increasing the instability of the financial system in the country. Also, even after the authorities had discovered about what was happening, the regulators did not adjust their policies even when they had the time and power this came to one conclusion that the regulators never worked ii the interest of the public but their own. The group indicated in their book that the failures of the respective governments in the governance of the financial regulations played a crucial role in crisis by being part of the destructive policies created and maintained by the regulatory agencies. The proposals laid out by the institutions have not addressed the weighty issues including their weaknesses with governing financial regulation. The public is also not involved in the process as there is no mechanism laid down through which people can obtain well laid informed assessment of the financial institution. Since the public are the ones affected by these policies, it is highly recommended they get involved with the process. It is hard

Korean War Annotated Bibliography Example | Topics and Well Written Essays - 500 words

Korean War - Annotated Bibliography Example As a result, the Korean Peninsula was divided into half along the 38th parallel. The Russians occupied area north of the line, while the United States of America occupied the south. In this book, the tensions and the political environments leading up to the war are described in detail. Both the North and the South were under dictatorial rule. In the South, there was the anti-communist dictator Syngman Rhee, while in the North, there was the communist dictator Kim Il Sung. It is observed that neither of the dictators was content to remain on his side of the 38th parallel and border disputes were rampant as a result. The connection of this invasion of the South by the North and the rising conflict thereof and the ongoing cold war is given in this piece. The war is said to have come as a surprise to the U.S. who considered it malicious and more than a mere border dispute. To them, nonintervention in the dispute was never on the table as they regarded it as a deliberate offensive in a communist campaign to take over the world. The Gays give more in-depth analysis of the situation between the United States and Russia particularly, prior to this war and the inevitability of these two nations’ role in the dispute. The warring nations are differently backed by two quarreling nations and so, when one invades the other, there is bound to be suspicion of a wider play. The stands taken by America and the Soviet Union are discussed in greater details. In April 1950, a National Security Council report known as the NSC-68 recommends the US to use military force to counter communist expansion anywhere it was perceived to be occurring. As a result, then US President Harry Truman is quoted as saying that if they let Korea down, the Soviets will keep on going and swallowing up one place after another. Lee talks about the difficulties and the armies of the war. North Korean army is seen as

Perforation of Composite Sandwich Panels

Perforation of Composite Sandwich Panels CHAPTER 1 INTRODUCTION 1.1 Introduction The use of sandwich structures has been increasing in recent years because of their lightweight and high stiffness. Commonly, the naval industry and transportation uses the E-glass fibers while the aerospace industry uses composite structures such as carbon fiber. The use of sandwich panels with composite facesheet in the naval industry is particularly appealing because they have better corrosion and environmental resistance and reduced magnetic signatures when compared to double-hull construction steel ships. On the other hand, composite sandwich panels are easily susceptible to damage by a strange object impact. The damage may be visible, penetration or perforation, or invisible, internal delamination and debonding. Both types of damages will result in stiffness and strength reduction. It is then important to study the impact behavior of composite sandwich panels. Failure in composite structures can be caused by low, high and extremely high or localized impact. An impact caused by a foreign body initiates two waves from impact point in a panel: a through-thickness wave and a transverse shear wave. Whether or not these waves play an important role in the impact response of the panel depends on the actual contact duration between the projectile and panel and the time it takes the transverse shear wave to reach the panel boundary. Figures 1.1 (a)-(c) show three-impact scenarios: low-velocity, high-velocity and ballistic impact. In low-velocity impact, the contact force duration is long compared to the time it takes the transverse shear wave travel to reach the plate boundary. Many waves reflect back and forth across the side dimension of the panel. In high-velocity impact, the contact force duration is much shorter than the transverse shear wave travel time through the panel. Usually high-velocity impact is the same with perforation and localized damage of the panel. Ballistic impact deals only with through-thickness wave propagation. During ballistic impact, there is complete perforation of the panel with little or no panel deformation. The contact force duration is approximately the wave travel time through the panel thickness. Ballistic impact usually involves the study of penetration mechanics. Low-velocity High-velocity Ballistic Impact The projectile to panel mass ratio will control whether wave propagation effect dominates the panel impact response and then suggested that a mass ratio be use as a parameter to determine impact response. It was shown that small mass impacts produce more damage than high-mass impacts having same kinetic energy. While small-mass impacts were defined by wave-controlled response, large mass impacts were defined by boundary-controlled response. Common examples of low-velocity impact are of bird strikes, collision with floating object, and dropped tools, may cause damage. Underwater blast or debris from a faraway explosion and air was considered as a high-velocity impact situation. Examples of ballistic impact would be a bullet or fragments from a nearby explosion hitting the panel. Another important factor governing the impact on composite structures is the ballistic limit. The ballistic limit is defined as the highest velocity of the projectile to cause perforation. When the residual velocity (exit) of the projectile is zero, then the initial velocity of the projectile that causes perforation is the ballistic limit of the sandwich panel. The ballistic limit may be calculate analytically or determined experimentally. In the experimental method, sandwich panels are shoot with projectiles over narrow range of velocities to either just cause penetration or to just perforate the panel. There exists a striking velocity at which 50% of the panels are completely perforate above this value and remaining 50% are partly penetrate below this value. This striking velocity is expresse as V50, which is the ballistic limit of the panel. In the analytical approach, the ballistic limit is determined by the conservation of energy principle. The approach is complex because it inc ludes a variety of factors like core thickness, facesheet thickness, shape of the projectile, core crushing stress, and so on. 1.2 Problem Statement This topic was an expansion of the Wan Awis research. He has done only an experimental work. For impact application, we need to predict skin and core material thickness. Since impact phenomena depend on numerous parameters such as material properties or projectile geometry, a numerical model, validated experimentally, is necessary to allow the study of the influence of several parameters without making costly experimental tests. This will definitely enhance the development of our military technology and achievements in the future because of the ability of this software to cut production cost and time consuming of the experimental work. The numerical figures have been compared to modal test results aiming mainly to validate the studies. Simulation based on finite element analysis (FEA) must not exceed  ± 15% error or this simulation could be claimed not acceptable. 1.3 Objective To simulate the damage of composite sandwich structures subjected to high-velocity impact using finite element analysis. To determine the energy absorption capability of the components on the behavior of the sandwich panel under impact load using ANSYS AUTODYN 13.0 To validate a numerical model with actual experiment. 1.4 Scope of Works To characterize a mechanical behavior of carbon fiber panel by using tensile and determine the fiber volume force and density. Design and validate the numerical model. Conduct a ballistic impact test simulation. Using the experiments data to calculate the energy absorption on the impact. CHAPTER 2 LITERATURE REVIEW 2.1 Introduction A great deal of research has been conducted in the area of impact of composite structures. In this chapter, previous work done on the impact response of laminated composite plates and composite sandwich panels will be reviewed. 2.2 Impact of Composite Laminates A detail study of impact of composite laminates in the three impact regimes ballistic impact, low-velocity and high-velocity is presented in this section. 2.2.1 Low-velocity Impact Abrate, 1998 give a specific review on different analytical models of impact on composite laminates. He classified impact models into four groups: impact on infinite plate model, energy balance models, spring-mass models, and complete models. In the energy balance model, the initial kinetic energy of the projectile is used to calculate the deformation of the composite laminate. The velocity of the projectile reaches zero at the maximum deflection of the composite laminate. At this point, all of the kinetic energy of the projectile is converted to strain energy needed to deform the composite laminate. Energy balance model assumes that the structure behaves in quasi-static manner. The time history of force and deflection are obtained using the spring-mass model representing the composite laminate. The model shown in Figure 2.1 consists of nonlinear contact stiffness (K), one spring representing the linear stiffness of the structure (Kbs), another spring for the nonlinear membrane stiff ness (Km), effective mass of the structure (M2) as well as the mass of the projectile (M1). Equations of motion are written from a free body diagram. The infinite plate model is used when the deformation wavefront has not reached the boundary but if the wave reaches the plate boundary then this model is not an appropriate one to use. In the complete model, the dynamics of the structure and projectile are taken into explanation. Appropriate plate theory has to be selected and used. In many cases the classical plate theory can be used but when transverse shear deformations become significant, higher-order theories must be used. One of the earliest studies on the impact of composite laminates was by Goldsmith et al, 1995, who conducted high-velocity and quasi-static impact tests on carbon-fiber laminates by using a cylindro-conical projectile. Three different specimen of varying thickness were considered. Energy balance principle was used to predict the dynamic penetration energy, static penetration energy, and also the ballistic limit of the composite laminate. The fiber failure accounted for most of the energy absorbed. The predicted theoretical energy was in good agreement with measured energy for thin laminates but not for the thick laminates. This was approved to the fact that transverse shear deformation played an important responsibility in thick laminates subjected to low-velocity impact. The effect of transverse shear deformation was not dominant due to its quick occurrence in the high-velocity impact of laminates. Therefore, the predicted energy in the dynamic case was always close to but less than the measured energy for the thin and thick laminates. The predicted ballistic limit was less than measured values due to the nonlinear factors. Cantwell, 2007 studied the influence of target geometry in the low-velocity impact of composite laminate. The tests were performed on GFRP plates with hemispherical indenter on either circular or square supports. He used energy-balance model to predict the plate deflection and the delamination area of the laminated structure. His study stated that there is little or no influence of target geometry on the failure modes. It also suggested that delamination was dependent on interlaminar shear stress and increasing the plate diameter required more energy for damage initiation. Hou et al., 2000 predicted impact damage in composite laminates using LSDYNA 3D. The numerical results were compared to experimental results on low-velocity impact on composite laminate with an initial velocity of 7.08 m/s The Chang-Chang failure criteria was modified taking the shear stress into consideration and the model was implemented in DYNA 3D. 2.2.2 High-velocity Impact In 1988, Cantwell performed high-velocity impact tests of CFRP laminates with 6 mm diameter, 1g steel ball as the projectile. The influence of fiber stacking sequence and target geometry was study. The experiments reveal that varying the target geometry had no significance on initial damage caused. While the damage initiated in the distal facesheet in thin laminates, however, in thick laminates it initiated from incident facesheet. Zhao et al., 2007 investigated the failure modes in composite laminates subjected to high-velocity impact. Three different laminates were subject to impact by hemispherical projectile in the range of 10-300 m/s. An energy balance was considered and equations for residual velocity for the laminates were given in terms of the mass of the projectile and striking velocity. The thickness and stacking sequence were finding to play an important role in the energy absorption. Cheng et al., 2007 developed an analytical model based on the spring-mass model for high-velocity impact of a blunt ended and a sharp-ended projectile on thick composite laminates. They considered the effect of moving boundary due to the propagation of shear wave. The analysis was modeled using series of quasi-static events. At the end of each quasi-static step, the failed layers were remove based on punch shear damage and fiber damage criteria, and the wave front was moved outwards. While the first spring stiffness constant was measure based on the penetration depth of the projectile, the second spring stiffness constant was measured based on the bottom node of the plate. 2.2.3 Ballistic Impact Silva et al., 2005 performed numerical simulations of ballistic impact on thin Kevlar 29 composite laminates using a fragment-simulating projectile. The laminate material model was simulating using AUTODYN and the projectile was modeled using Johnson-Cook strength model. Finite element mesh for both laminate and projectile was generating using True Grid. Accurate predictions of ballistic limit (V50) and the failure modes were made. Ballistic limit is the minimum velocity of impact at which a given projectile just perforates a given target. On occasion, the term is also used to identify the maximum impact velocity at which the projectile can penetrate into the target with perforation. It is often defined statistically as the impact velocity for which the projectile has a 50% probability of perforating the target; it is then denoted by V50. Guild et al., 2007 conducted numerical simulations of ballistic impact on composite laminates and compared them with experimental results. The laminates were made of E-glass/vinyl ester resin with varying thickness and ball bearings of varying mass were use as projectiles. The damage modes included fiber failure, matrix failure, penetration, and delamination. Hashin failure criteria was use to determine the damage mode. Delamination was modeled using an interface between the two plies. As the force increased between two nodes above the specified value, the nodes were untied and the delamination increased. The ballistic limit from experiments was in good agreement with numerical results Naik et al., 2008 studied the ballistic impact behavior of thick composites. E-glass/epoxy laminates of varying thickness were subject to high-velocity impact. The effects of projectile diameter, projectile mass and laminate thickness on the ballistic limit were studied. Wave theory and an energy balance were use to predict the ballistic limit of the laminate. The contact duration of the projectile with the laminate was maximum when the initial velocity was equal to ballistic limit and decreased when the initial velocity increased beyond the ballistic limit. Deka et al., 2008 conducted ballisitic impact on E-glass/polypropylene composite laminates with cylinder-shaped projectiles. The experimental results were validating with numerical analysis using LS-DYNA. Although the laminate was modeling in Hypermesh, LS-DYNA was used to analyze failure mechanisms. The analytical model was base on energy conservation and failure in the numerical analysis was predicted based on Hashins failure criteria. 2.3 Impact of Composite Sandwich Panels In this section, a detail study of impact of composite sandwich panels in the three impact regimes low-velocity, high-velocity and ballistic impact is presented. 2.3.1 Low-velocity Impact Mines et al., 1998 investigated quasi-static loading and low-velocity impact behavior on two different composite sandwich panels. While the first panel was made up of E-glass/vinyl ester skin and Coremat ® core, the second panel was made of Eglass/epoxy skin and aluminium honeycomb core. The first panel with Coremat ® core had failed in the sequence of core shear, debonding, and distal facesheet damage and incident facesheet failure. The second panel failed by core shear, debonding, incident facesheet failure and then distal facesheet failure later. In the low-velocity impact tests, the failure pattern remained the same in both the panels as of the quasi-static tests. The core properties and impact velocity govern the energy absorption capability of the sandwich panel. Wen et al., 1998 investigated the penetration and perforation of composite laminates and sandwich panels under quasi-static, drop-weight and ballistic impact tests by flat-faced, hemispherical-ended and conical-nosed indenters/projectiles. They categorized the impact on laminates and sandwich panels into low-velocity impact and wave-dominated (high-velocity/ballistic impact) response. It was also stated in the research that sandwich panels subjected to low-velocity impact have similar load-displacement characteristics as of quasi-static loading case. The perforation energy required by flat faced projectile was more than hemispherical-ended and conical shaped projectiles in high-velocity impact. Schubel et al., 2005 investigated quasi-static and low-velocity impact behavior of sandwich panels with woven carbon/epoxy facesheets and PVC foam. The low-velocity impact model behaved similar to quasi-static loading case when loads and strain levels were same. The static indentation response was compared to the numerical results obtained using ABAQUS and were in good agreement. A membrane solution, assuming membrane in the core affected region and plate on elastic foundation in the rest of sandwich panel was in poor agreement with the numerical results. Hoo Fatt et al., 2001, developed static and dynamic models of sandwich panels subjected to low-velocity impact. They investigated the behavior of sandwich panels having carbon/epoxy skins and a Nomex honeycomb core with a hemispherical indenter under various support conditions such as simply supported, fully clamped, and rigidly supported. Spring-mass models were considered to determine the load-displacement curve. They also investigated the damage initiation of sandwich panels under low-velocity impact loading. The initial mode of damage depended upon the panel support conditions, projectile nose shape, geometry of the specimens, and material properties of the facesheet and core. Various failure patterns were studied and solutions based on them were derived separately. The analytical solution for the ballistic limit was also found and results for thick laminates were in better agreement than thin laminates. Suvorov et al., 2005 performed numerical analysis on sandwich panels with foam core and studied the effect of interlayer in between the top facesheet and foam core. The foam core was modeled as crushable foam in ABAQUS. While the polyurethane (PUR) interlayer reduced the deformations in both the core and the composite facesheets, the elastomeric foam (EF) interlayer offered a better protection for the foam core alone. Besant et al., 2001 performed numerical analysis on sandwich panels with aluminium honeycomb core. The metal honeycomb core was modeled as elastic perfectly plastic material. A quadratic yield criterion was proposed for the core material, which included both normal and transverse shear stresses. The importance of core plasticity in finite element analysis was explained. 2.3.2 High-velocity Impact A great deal of work has been done in the area of low-velocity impact of laminates and sandwich panels and high-velocity impact of laminates but limited work has been presented in the domain of high-velocity and ballistic impact of sandwich panels. The following describes some recent studies on the high-velocity impact of composite sandwich panels Velmurugan et al., 2006 studied the projectile impact on composite sandwich panels in the range of 30-100 m/s. The sandwich models in this study were not the typical sandwich panels in the conventional sense. They had a core height comparable to the facesheet thickness and acted as a bonding agent between the facesheets. Energy-balance model was used to determine the ballistic limit of three different sandwich panels. They assumed the sandwich panel as a single plate since the foam layer was thin and comparable to facesheet thickness. Also uniform failure mechanism along the through thickness direction was assumed in their model. Skvortsov et al., 2003 developed an analytical model using energy-balance principle to determine the ballistic limit of composite sandwich panels subjected to high velocity impact. Two different sandwich panels were subjected to high velocity impact using three different projectiles. These tests were conducted on simply supported and rigidly supported boundary conditions, and the initial velocity was varied in the range of 70-95 m/s. The predicted panel energy was close to the experimental values and the error was due to the strain-rate effects, plastic behavior, and hardening phenomena, which are not consider in the analysis. 2.3.3 Ballistic Impact Kepler et al., 2007 conducted ballistic impact on sandwich panels consisting of GFRP plates and Divinycell H80 core, with three different projectiles. Lumped spring mass model was use to calculate force histories and panel response. Concentric rings connected by shear springs represented the sandwich panel. In this model, core shear deformation was assumed as the single significant contributor to the sandwich panel stiffness. The facesheet orthotropic was neglected in the panel response. Four different force histories: constant force, triangular force, sine series, and combination of sine and triangular force were used to calculate the energy loss in the panel. Of these, triangular and combined force gave results in better agreement with experimental results. 2.4 Aluminium Honeycomb For design and construction of lightweight transportation systems such as satellites, aircraft, high-speed trains and fast ferries, structural weight saving is one of the major considerations. To meet this requirement, sandwich construction is frequently use instead of increasing material thickness. This type of construction consists of thin two facing layers separated by a core material. Potential materials for sandwich facings are aluminium alloys, high tensile steels, titanium, and composites depending on the specific mission requirement. Several types of core shapes and core material are been applied to the construction of sandwich structures. Among them, the honeycomb core that consists of very thin foils in the form of hexagonal cells perpendicular to the facings is the most popular. A sandwich construction provides excellent structural efficiency, i.e., with high ratio of strength to weight. Other advantages offered by sandwich construction are elimination of welding, superior insulating qualities and design versatility. Even if the concept of sandwich construction is not very new, it has primarily been adopt for non-strength part of structures in the last decade. This is because there are a variety of problem areas to be overcome when the sandwich construction is applied to design of dynamically loaded structures. Other investigators have previously carried out noteworthy theoretical and experimental studies on linear elastic and nonlinear behavior of aluminium sandwich panels. Kelsey et al., 1985 derived simple theoretical expressions of the shear modulus of honeycomb sandwich cores. Witherell, 1977 performed an extensive theoretical study for structural design of an air cushion vehicle hull structure using aluminium honeycomb sandwich panels. Okuto et al., 1991 showed the validity of the so-called equivalent plate thickness method in which a honeycomb sandwich panel subjected to inplane loads is approximately replaced by a single skin panel with equivalent plate thickness. Kobayashi et al., 1994, studied Elasto plastic bending behavior of sandwich panels. An experimental study was undertaken by Yeh et al., 1991 to investigate the buckling strength characteristics of aluminium honeycomb sandwich panels in axial compression. Kunimo et al., 1989 both, have studied the characteristics of the energy absorption capacity of bare honeycomb cores under lateral crushing loads theoretically and experimentally. 2.5 Ballistic Limit The ballistic limit may also be defined as the maximum velocity at which a particular projectile is expected to consistently fail to penetrate armor of given thickness and physical properties at a specified angle of obliquity. Because of the expense of firing tests and the impossibility of controlling striking velocity precisely, plus the existence of a zone of mixed results in which a projectile may completely penetrate or only partially penetrate under apparently identical conditions, statistical approaches are necessary, based upon limited firings. Certain approaches lead to approximation of the V50 Point, that is, the velocity at which complete penetration and incomplete penetration are equally likely to occur. Other methods attempt to approximate the V0 Point, that is, the maximum velocity at which no complete penetration will occur 2.6 Energy Absorption Mechanism of Composite Materials The research was done by Naik and Shrirao at 2004. Impact loads can be categorized into three categories which is low-velocity impact, high-velocity impact and hyper-velocity impact. This classification is made because of change in projectiles velocity will result in different mechanisms in terms of energy transfer between projectile and target, energy dissipation and damage propagation mechanism. Basically, ballistic impact is considered as low-mass high velocity impact. In this impact event, a low-mass projectile is launched by source into target at high velocity. It is unlike low-velocity impact that involved high-mass impactor impacting a target at low velocity. In view of the fact that ballistic impact is high velocity event, the effect is localized and near to impact location. According to Naik et al. (2006), seven possible energy absorbing mechanisms occur at the target during ballistic impact. Those mechanisms are cone formation at the back face of the target, deformation of secondary yarns, tension in primary yarns/fibres, delamination, matrix cracking, shear plugging and friction between the projectile and the target. Then, the researchers formulated all these energies into equation whereby the total energy absorbed by the target is summation of kinetic energy of moving cone EKE, shear plugging ESP, deformation of secondary yarns ED, tensile failure of primary yarns ETF, delamination EDL, matrix cracking EMC and friction energy EF. ETOTALi = EKEi + ESPi + EDi + ETFi + EDLi + EMCi + EFi Mines et al. (1999) identified three modes of energy absorption when analysed the ballistic perforation of composites with different shape of projectile. These energy absorptions are local perforation, delamination and friction between the missile and the target. However, the contribution of friction between the missile and the target in energy absorption is low compared to the other two. In terms of local perforation, three through-thickness regimes can be identified, namely: I shear failure, II tensile failure and III tensile failure and delamination. Out of these three regimes, the through-thickness perforation failure is dominated by shear failure. Similar observation has been made by other researcher for thick graphite epoxy laminates whereby the perforation failure is dominated by shear failure. The third main energy absorption mechanism is delamination. Delamination can propagate under Mode I (tensile) and Mode II (shear) loading and each mode can dominate each other depend ing on structural configuration of the composite as well as material properties. Therefore, it can be predicted that the total perforation energy is a summation of energy absorption due to local perforation, delamination and friction between the missile and the target. Epred = Ef + Esh + Edl where Ef = friction between the missile and the target; Esh = local perforation; Edl = delamination Apart from that, Morye et al. (2000) has studied energy absorption mechanism in thermoplastic fibre reinforced composites through experimental and analytical prediction. They considered three mechanisms that involved in absorbing energy by composite materials upon ballistic impact. The three energy absorption mechanisms are tensile failure of primary yarns, elastic deformation of secondary yarns and the third mechanism is kinetic energy of cone formed at back face of composite materials. They concluded that kinetic energy of the moving cone had a dominant effect as energy absorption mechanism for composite materials. However, they neglected a delamination as one of the factor contributed to the failure of composite materials during ballistic impact. 2.7 Kinetic Energy Equation Kinetic energy (KE) attack is a penetration of the residual energy of a projectile. A projectile can give a certain amount of energy to attack and damage a vehicle if the projectile sufficient residual energy when it arrive at the target. This residual is very important to overmatch the capability and strength of the target material to resist penetration, and then it will penetrate. Kinetic energy shot can be presented with the simple law of physic. K.E =  ½ Mprojectile Vprojectile2 Increasing the mass (Mprojectile) of the shot increases its energy, but the real payoff comes from increasing its velocity (Vprojectile). If the diameter of the shot fills the whole gun barrel, the projectile becomes heavier and difficult to accelerate to required velocity with the length of the barrel. Additionally, a large diameter solid shot will provide more energy to penetrate the armour plate compared to a projectile which has the same mass but a smaller diameter. Consequently, the larger shot is not only less effective at the target but it is difficult to give it the necessary velocity. According to Chang et al., 1990, depth of penetration at the target will depend not only on residual energy, but also on shape and size of the projectile. The curve shape at the projectile head is more important, as it must not only able to pierce the armour but the shoulders of the shot must also support the remainder so that it does not break up on its way through the armour. If for given mass the diameter of the shot is reduced and is length increased, then for the same residual energy the shot will penetrate further, as it is working on a smaller cross section area of armour. The ratio of length-to-diameter is called slenderness ratio. Any projectile with ratio in excess of 7:1 cannot be spin stabilized it is not until they reach a ratio approximately 20:1 that they can call long rod. So, based on those discussions above, we can conclude that energy absorption can be performed by this relation Eabsor = Ein Eout = [ ½ Mprojectile Vin2] [ ½ Mprojectile Vout2] =  ½ Mprojectile (Vin2 Vout2) So, Eabsorbed =  ½ Mprojectile (Vin2 Vout2) 2.8 Tsai-Hill Failure Criterion Hill, 1950 proposed a yield criterion for orthotropic materials: G+HÏÆ'12+F+HÏÆ'22+F+GÏÆ'32-2HÏÆ'1ÏÆ'2-2GÏÆ'1ÏÆ'3-2FÏÆ'2ÏÆ'3+2LÏ„232+2MÏ„132+2NÏ„122=1 This orthotropic yield criterion will be used as an orthotropic strength or failure criterion in the spirit of both criteria being limits of linear elastic behavior. Thus, Hills yield stresses F, G, H, L, M and N will be regarded as failure strengths. Hills criterion is an extension of von Mises yield criterion. The von Mises criterion, in turn, can be related to the amount of energy that is used to distort the isotropic body rather than to change its volume. However, distortion cannot be separated from dilatation in orthotropic materials, so Equation 2.8 is not related to distortional energy. Unfortunately, some authors still mistakenly call the criterion of Tsai-Hill a distortional energy failure criterion. The failure strength parameters F, G, H, L, M and N were related to the usual failure strength X, Y, and S for a lamina by Tsai. If only Ï„12 acts on the body, then, because its maximum value is S, 2N=1S2 Similarly, if only ÏÆ'1 acts on the body, then G+H=1X2 And if only ÏÆ'2 acts, then F+H=1Y2 If the strength in the 3-direction is denoted by Z and only ÏÆ'3 acts, then F+G=1Z2 Then, upon combination of Equations (2.10), (2.11) and (2.12), the following relations between F, G, H and X, Y, Z result: 2F=1Y2+1Z2-1X2 2G=1X2+1Z2-1Y2 2H=1X2+1Y2-1Z2 For plane stress in the 1-2 plane of a unidirectional lamina with fibers in the 1-direction, ÏÆ'3 = Ï„13 = Ï„23 = 0. However, from the cross sectional of such a lamina in Figure 2.3, Y = Z from the obvious geometrical symmetry of the material construction. Thus, Equation (2.8) leads to ÏÆ'12X2-ÏÆ'1ÏÆ'2X2+ÏÆ'22Y2+Ï„122S2=1 as the governing

Porters Force Analysis On Leisure Cruise Industry

The universe economic system has been engulfed by strong international competition. Porter has argued that scheme equates how any steadfast competes against others in its concern. He argued that scheme is non merely a series of theoretical accounts at the corporate degree of scheme. The scheme includes analysing possible entrants, providers, purchasers, replacements and rivals. He describes the competitory forces determining an industry in his six forces theoretical account of industrial competition. By analysing the forces, one assesses the forces driving competition in an industry and evaluates the odds of a house successfully come ining and viing in an industry. The forces are includes: possible entrants with their menace of entry, providers with their bargaining power, purchasers with their bargaining power, industry rivals with their competition among existing houses, and replacements with their menace of utility service or merchandise and. Government engagement is another force that affects any industry[ I ]. The full leisure industry is composed of bomber industries including gambling, sail, lodging, athleticss installations, travel and touristry and vocational ownership. Cruise is one of the fastest turning sectors in the leisure industry which ensures that people basking their holidaies get conveyance installations. Under this sector, the companies which largely operate are transporting companies which transport people in leisure from one topographic point to another. The companies include AIDA Cruises, Celebrity Cruise, Cunard line, Disney Cruise Line, Holland American Line, Ocean Village, Princes Cruises, Royal Caribbea International and Seabourn Curise Line. All these named operate in Florida under the umbrella organic structure Florida-Carebbean Cruise Association ( Maya, 2010 )[ two ]. This is an industry of merriment characterized monolithic investings. Taking Ocean Village as an illustration of companies stand foring the full industry, this research paper will analyse the six po rter forces that affect the industry[ three ]. Buyers and dickering power In the industry, purchasers are traveler traveling for vocational Tourss, leisure activities and all that pertains to fun. Buyer power is the capableness of purchasers, their agents, and clients of the industry to act upon the monetary value charged and footings of purchase. If purchasers ‘ power is high, so the net income borders of the houses runing in the industry tends to be low. If the purchasers are organized and are few, so their power is high. The industry whose purchaser power is high tends to be unattractive to new investors since the realized net incomes are usually low ( Peng, 2009, p. 42 ) . In this sail sector of the leisure industry, purchasers are few and be given to be organized. Therefore, Ocean Village Company feels the force per unit area of good organized purchasers who have high-bargaining powers. The industry represents purchasers from higher economic and societal category who can form and inquire for their rights in the industry. They are willing to pass their money for leisure services therefore do non see much impact on pricing every bit long as they get choice services. Ocean Village Company has tried to include some other services to do any ocean trip successful and pull more clients. These include the wellness installations provided within the company and adjustment characteristics offered to travellers. Potential entrants and entry barriers When a company and industry in general, is doing net incomes, other investors think of embarking into that industry so that they enjoy the net incomes realized. This creates a inquiry of how the incumbent houses within the industry attempt to make barriers for new entrants. The executives of the industry attempt to make barriers even if it means passing some money on the same undertaking[ four ]. If the current houses in the industry can maintain possible entrants at bay, the full topic of competition and its impacts on the incumbent houses ‘ net incomes become moot. The menace of new houses to come in an industry is low if the incumbent houses have high powers to act upon monetary values, control resources and determine the nature of competition within the industry. In Florida, the industry has organized its houses and formed an association to cover with such affairs. The association, Florida-Caribbean Cruise Association, protect the houses from any external entrants every bit much as possible. It has partnered with the authorities to put high criterions for any house that wish to come in into the industry. This makes possible investors be scared off from come ining such a market hence the industry can be classified as basking the powers to protect its current signifiers from the possible entrants. Suppliers and their bargaining power Supplier power is the capableness of sellers to make up one's mind the monetary values and footings of supply. Suppliers include sellers of labour, natural stuffs, and capital goods. If their power is high, so the net income borders of the incumbent houses tend to be low. Such low net income borders make an industry unattractive to possible entrants. The being of many providers indicates low provider power, and frailty versa. Firms in the industry rely on many supplier classs to carry through its services. The major providers of the industry are those that supply fuel to houses in the industry. Shell Company[ V ]is the chief provider of fuel in the industry but there are other possible companies which can provide. Ocean Village Company has entered into understanding its providers on footings of sale which are non altered till the understanding period expires. Substitute merchandises and services The handiness of replacements for an industry ‘s merchandises and services alters the power of the incumbent houses. As the handiness of replacement merchandises and services rises and the easy of replacement additions, the power of incumbent houses to command monetary values and footings of concern diminutions. In the instance of this industry, the replacement might be air hose conveyance, rail and route. However, they do non supply the intended services the purchaser wants when taking. Cruise industry provides diversion installations, good environment in H2O and others that a individual on leisure activities needs. This makes the industry enjoy limited replacement merchandises and services. The power of the houses runing in the industry is hence high. Rivals and competition Competitive competition is the extent to which houses respond to competitory moves of other houses in the same industry. In some industries like sail industry, â€Å" gentleman ‘s understanding † exists whereby houses respect one another ‘s market niches and follow a â€Å" unrecorded and allow unrecorded † scheme ( Ireland et al, 2008, p. 82 ) . The industry has formed an association which deals with such issues as competition and unwanted behaviours within the industry. This reduces competition and competition within the industry doing the companies operated in a friendly mode. They are associated to supply better and quality clients to leisure clients and there is no demand to vie in the disbursal of the industry and consumers. In other sectors within the larger leisure industry, a â€Å" dog eat Canis familiaris †[ six ]thought prevails, cutthroat competition is the regulation and competitory moves are smartly encountered. This happens in hotel bo mber industry since many houses exist here. Government engagement This is another force, although non normally talked as, which influences any industry. It is a demand for the houses in any industry to follow with all authorities ordinances including enrollment, paying revenue enhancements and be responsible to the environment. Government engagement determines the profitableness of an industry. Sometimes, the authorities comes in to protect its consumers from development by houses in any industry[ seven ]. They can make up one's mind to command monetary values and quality of services offered. The sum of revenue enhancement charged besides reduces the company operating in that industry ‘s net incomes. It can be realized that in Florida, the authorities ensures that the safety of crewmans is maximal and the quality of services offered is optimum. Since the house operates in H2O, it is supposed to keep high criterions to protect the environment, H2O in this instance. Harmonizing to Kassing ( 2006 )[ eight ], Government provides substructure for all commercial diversion and touristry endeavors. However, the authorities engagement in this industry is minimum. This is because the industry does non offer basic trade goods which would do the authorities intervene to command monetary values. The company enjoys authorities protection from sea challengers. The demands the authorities has put in footings of new entrants are excessively affecting doing the industry one of those that are difficult to come in into by new companies. Decision The forces determine profitableness of any industry as they influence the costs, monetary values, and needed investing of houses in that peculiar industry. Buyers power influence the monetary values Ocean Village Company and any other company can bear down. It besides has an influence on investing cost since sceptered purchasers asks for expensive services. Supplier ‘s bargaining powers influences input costs like fuel. The competition influences monetary values and viing costs. On the other manus, entry menace bounds monetary value charged and makes incumbent houses invest to avoid it ( porter, 1985, p. 7 ) . The Florida based companies runing in the sail industry formed an association, Florida-Caribbean Cruise Association, which has changed the industry construction. They agree on how to carry on concerns, how to make entry barriers and common characteristics to follow so as to fulfill their clients in Leisure-Cruise industry. It is a strong association of houses that have ma de the industry one of the popular in Florida and profitable.

Propaganda For The World War I - 1650 Words

Imagine a powerful tool someone could use in order to reach and influence the masses, from even a small community to a whole nation or even multiple nations. Something that can be used to spread awareness and information, whether it be true or false, used to paint a picture and influence masses to a single viewpoint. Propaganda: â€Å"ideas or statements that are often false or exaggerated and that are spread in order to benefit a cause, a political leader, a government, etc.† Could there be a more perfect tool used to influence millions of people; whether it be promoting or bashing a person, and idea, or a nation? Something as innocent as a poster on wall seen by a passerby, but with a sentimental message that urges attention. People have†¦show more content†¦Nations attacked the dignity and eroded any humanistic view that other nations might have had. Occasionally time was of the essence, and they needed something quick to get the people’s attention and imme diate support and so propaganda was the answer. From the 19th century to the early 20th century, the United States was still largely isolationists; focusing more on domestic affairs and trying to stay out of European affairs. In the United States, President Woodrow Wilson was very opposed to going to war and publically made so aware to the people. Even with tensions building up to the First World War, the U.S. did not want to get involved in European affairs. In his speech of acceptance, President Wilson said â€Å"We have been neutral not only because it was the fixed and traditional policy of the United States to stand aloof from the politics of Europe† but because the United States â€Å"had no part† to play in the war. He portrays the war in a very negative manner, describing it as an â€Å"infection of conflict† and as the â€Å"extension of the fires of hate and desolation.† He also states that our role was to â€Å"serve mankind by reserving our strength and our resources for the difficult day s of restoration and healing.† The U.S. couldn’t turn a blind eye for long though. With a series of events including the Zimmerman Telegram, the attack on the Lusitania, and Germany’s declaration of unrestricted submarine warfare, they were edged on to join. Allied