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

The Importance of the Mare in Anton Chekhov’s Misery Essay -- Anton Ch

The Importance of the Mare in Misery  Ã‚     Ã‚  Ã‚   Iona Potapov, the main character in Anton Chekhov’s short story, "Misery," is yearning for someone to listen to his woes. Every human he comes in contact with blatantly ignores his badly-needed-to-tell-story by either shunning him or falling asleep. There is, however, one character in this story that would willingly listen to Iona, a character who is with Iona through almost the entire story. This character is his mare. Renato Poggioli describes the story as being built "around two motionless figures, an animal and a man" (316). Iona and the mare are very much alike. They appear to be each other’s only companion, and they also act a lot alike. When Iona sits quietly, covered in snow that has recently fallen on him, his little mare is described as "white and motionless too" (17). Neither man nor mare cares move; both are still, frozen in time, waiting. Another example of the similar behavior between the two occurs when "the sledge driver clicks to the horse, cranes his neck like a swan. The mare cranes her neck, too" (18). As the story opens Iona sits in his sleigh desperately waiting for his first fare, and when that fare arrives he immediately starts to talk of his son’s death (18). Although his best possible friend – the mare – is already present to listen to his story, Iona does not come to this realization until much later in the story. At the beginning, he still believes that what he needs, and will be able to find, is another human being with whom to share his woes. The fare’s response to Iona’s story is, "have you gone cracked, you old dog? Look where you are going" (18). Iona, upset at this, continues to look around at the fare, in hopes of starting his story o... ... no longer keep silence about the death of his son. He speaks to the air, and the mare is listening. She doesn’t shun him, abuse him, or ignore him. She just listens, as any good animal would do. Works Cited Beck, Alan, M., and Aaron Honoria Katcher. "Animal Companions: More Companion Than Animal." Man and Beast Revisited. Ed. Michael H. Robinson and Lionel Tiger. Washington: Smithsonian P, 1991. 265-66. Chekhov, Anton. "Misery." The Harper Anthology of Fiction. Ed. Sylvan Barnet. New York: HarperCollins, 1991. 17-21. Hildebrandt, Sherri. "Another Kind of Grief." St. Paul Pioneer Press 13 Sept. 1998: 1-4. Poggioli, Renato. "Storytelling in a Double Key." Anton Chekhov’s Short Stories. Ed. Ralph E. Matlaw. New York: W.W. Norton & Co., 1979. 316-317. Royal Bank of Canada. "Pets and Human Beings." Montreal: Royal Bank Letter, July/Aug. 1989.   

Mass Customization and Global Logistics :: Economics Business Custom Essays

"Mass Customisation is - the customisation and personalisation of products and services - for individual customers at a mass production price. So, what does mass customisation mean for manufacturers and retailers? Simply this, that there’s money to be made and customer satisfaction to be achieved by allowing the buyer to customise his or her own purchases by choosing the size, colour and style from a predetermined, often extensive, list of ‘options’. The ultimate goal is to manufacture on a mass scale, retain or improve the margins associated with mass production, and supply a final product that meets each buyer’s individual desires. Apparel captures a major share of mass-customised products, but the concept stretches far beyond a single industry — to furniture, automobiles, eyeglasses, aeronautics, Barbie dolls, computers and so on. For the manufacturer, mass customisation offers an advantage because it differentiates his product from that of his competitors. It enables him to charge a premium for allowing his customer the ‘privilege’ to specify the final details of his purchase. Moreover, it allows the consumer to ‘buy in’ emotionally to the purchase, thereby reducing the risk that he will return the product he’s purchased — forcing the manufacturer to restock or mark down, or even worse scrap, the item. Success in mass customisation is achieved by producing items quickly; therefore it is critical for the manufacturer to find ways to reduce product development cycles whenever possible. In 2002. Fortune Magazine, and many other worldwide publications, proclaim: "You will have it your way". Mass customisation has come full circle. Allow us to provide our definition of mass customisation. It is the opportunity created by taking an otherwise standard product or service and modifying it to meet the unique requirements and choices of a single individual. Mass customisation provides uniqueness and freedom of choice; perfect fit with multiple options; fair, competitive cost; single-piece production; timeliness; quick-to-market; and, very importantly, the consumer is involved throughout the process. A compelling aspect of mass customisation is that it meets diverse objectives. The customer desires uniqueness; freedom of choice; perfect fit or form; fair, competitive cost. The manufactures want to differentiate from their competitors, to improve profit margins and to reduce risk and returns. Retailers want to sell products at higher profit margins, to provide product variety and choice for the customer and to minimise the inventory risk. Today’s customer for mass customisation tends to address the desires of more affluent people, those, for example, who can afford a custom-built yacht, expensive vehicle or a special item of clothing, but that situation is changing fast. Tomorrow’s opportunity for mass customisation will, in my view, be quite literally everybody for everyone; whether rich or poor, the desire for choice and

Marketing scenario Essay

Introduction Positioned as an premium offering focused to lowest overall cost to end users through superior overall performance. Leader in quality , performance and technological innovation Product lines Carton sealing and industrial tapes Specialized adhesives Other packaging products K2 tape – Manufactured using patented technology and a brand name for pressure sensitive carton sealing tape Very high tensile strength and sheer resistance Positioning High Price K2 Products Low Quality High Quality Ipack Tensile New Product Low Price Problem Statement †¢ K2 tape competed against inferior economy grade products in carton sealing type †¢ IPACK offered 25-35% lesser price †¢ Revenue of K2- $68.6 million IPACK – $28.5 million in 2012 †¢ Tensile – a new competitor had $2.7 million dollar sale with one sales representative Should PST stay with high quality product or enter the economy grade segment ? Option 1: Enter the economy grade segment under the same brand PROS Access to the economy segment Defend market share against competition Diversification of product portfolio CONS Dilution of the brand image as a maker of  technological superior product Cannibalization of its own product offering Cluttered product line Option 2: Enter the economy grade segment under different brand Implications for: PROS CONS Customer †¢ Ability to fulfill need of price sensitive  customers †¢ Possibility of change in perception of  being a quality leader Distributor †¢ Possibility to offer a low end PST  product †¢ Even wider product range; Limited  sales force Sales Force †¢ Ability to offer more variety in terms of  price levels †¢ More effort to explain product  differences Brand †¢ No positive impact †¢ Negative impact on brand image Option 2: Stay with high-quality products Implications for: PROS CONS Customer †¢ Maintaining image of quality Leader †¢ Loss of Market share; Not targeting  price sensitive consumers Distributor †¢ No need for adjustment in  distribution policy †¢ Low-price offer only from competitor not from PST Sales Force †¢ Consistent and easy product  quality †¢ No ability to offer solution for price  sensitive customer Brand †¢ Consistent overall brand image †¢ No negative impact Recommendation PST should enter the economy grade segment NEW BRAND †¢ New name (unrelated to PST) to avoid negative impact on brand image †¢ Marketed completely independent PRODUCT LAUNCH †¢ Development and launch of two new products to compete with Tensile †¢ Competitive pricing strategy (similar to Tensile) ENTER MARKET †¢ Make use of well established distribution network †¢ Offer economy equivalents for RD-48 & RDS-72 SUCCESS FACTORS †¢ There is a projected growth in demand (e.g. packaging segment 2.2%) †¢ PST has an established sales force and distribution network in the tape market †¢ There is a lack of brand loyalty of price sensitive customers (switching to PSTs new brand) †¢ There was suitable equipment and capacity for quick production Distribution Plan †¢ Distribution through existing network for faster brand growth †¢ Hire more sales people to increase service quality & sales in PSTs tape business

Sounds and Imagery of Human Emotion

Sounds and Imagery of Human Emotion In Marge Piercy’s â€Å"The Secretary Chant†, the author uses images and sound to both dehumanize and mechanize the female speaker, while John Updike uses imagery and sounds to make the â€Å"Player Piano† come to life. Piercy uses images of the speaker, connected with various office equipment to give a vision to the reader of a woman living her life through the office equipment that is part of her very being. Piercy uses personification in reverse and other metaphors, such as metonymy, and paradox, to give an actual picture of the office machines actually performing their functions.And also through the operation of the office equipment attached to the speaker showing her only purpose in life. Sounds are important in â€Å"The Secretary Chant as onomatopoeia, alliteration, and the descriptions that show the speaker little by little becoming more mechanized until filed away for another day. Updike also uses personification to m ake the â€Å"Player Piano† come alive. Through rhyme, alliteration, consonance, cacophony, diction, and meter the poem sounds like music. The images that the speaker brings forth when the poem is read out loud, is melodic.The perfectly played â€Å"Payer Piano† only works within the constraints of the human-made machine. John Updike’s poem, â€Å"Player Piano† and Marge Piercy’s â€Å"The Secretary Chant â€Å"convey through sound and imagery the personification and dehumanization of mechanical speakers, with Updike doing a better job by saying that people are irreplaceable because of emotion. The title of Piercy’s â€Å"The Secretary Chant† gives a good indication of the list of statements that begin with: â€Å"My hips are a desk. From my ears hang / chains of paper clips† (lines 1-3), metaphors that make the reader visualize that the speaker is only a place where office machines connect together to form her purpose at the firm, as an object to perform tasks. The first six lines, as well as, lines eight through thirteen vividly describe in detail where each office supply and machine connects. And, there are, of course, as in any office, a list of things that the speaker would be commanded to do. Would you get me a cup of coffee? Make a copy of this report, please. Have you typed that letter up for my signature?To me the speaker states a list of things she is comprised of, just like the boss gives her a list of things to perform. And the list continues on and on and on. In the first line the speaker gives the reader a vision that her hips are just a place to put things, when no other work is being performed. The lines paint a picture of the frustration and the monotony the speaker’s body parts have become. Even when the speaker complains: â€Å"From my mouth issue canceled reams† (16). The paradoxical complaint falls on deaf ears as if any one would listen to a machine that needs to get back to performing its tasks.The speaker has become one with her desk, supplies, and office equipment. This goes on to reinforce the theme that the speaker’s only usefulness is to perform the tasks that are asked for the speaker as an object, and as the office machines. Marge Piercy’s â€Å"The Secretary Chant â€Å"conveys through sound and imagery the dehumanization, while doing a good job of showing emotional frustration with the performance of tasks in the office. Piercy uses sound in two lines â€Å"The Secretary Chant† by using onomatopoeia to give the reader’s imagination of the speaker becoming a machine through words that sound like what machines sound like: â€Å"Buzz.Click† (7). And also the cash register sound of: â€Å"Zing. Tinkle† (14). The sound of the speaker’s brain frying on overload can be felt through the explicit mental image in the lines: â€Å"My head is a switchboard / where crossed lines crackle. † ( 9-10). Piercy uses alliteration, To drive home the point, in the last four lines of â€Å"The Secretary Chant† in which the speaker breaks down in a hopeless heap of printed emotion copied and delivered from herself saying: File me under W because I wonce was a woman. (21-24)Piercy visually shows the last true part of the speaker giving up her emotion and placing it only where the reader can find out about by looking somewhere else in the office machine that takes over. Marge Piercy’s â€Å"The Secretary Chant† uses sounds to show that human emotion can be filed away and replaced. In John Updike’s â€Å"Player Piano† personification is used to wake up an inhuman piano that plays itself, sort of like the poem itself does when read aloud. Updike uses assonance and consonance in the first couple of lines to give musicality to the lines.The devices are first used with a repetition of â€Å"-ick† sounds to mimic the keys on the piano. Onomatopoei a is used throughout the poem to as words make the sounds musically and mimic the â€Å"Player Piano. † The author follows those sounds with a repetition of â€Å"-uck† sounds. There are a lot of sound going on in the first stanza, including alliteration internal rhymes, diction and meter with all coming together with the smooth â€Å"s† sounds a pleasant melody. Updike uses a connotation for life when the speaker says: â€Å"Light-footed, my steel feelers flicker† (line 3).The connotation of the word flicker means life, as long as the flame is burning and the denotation means to move with a fast or jerky motion. The combination of the two meanings gives the feeling that the piano is alive. John Updike’s poem, â€Å"Player Piano† shows through sound and images that the personification of the mechanical speaker is alive and lively. In the second and third stanza build on the personification with the â€Å"Player Piano† speaker says: â €Å"My paper can caper; abandon (5).An internal rhyme that suggests that the paper can leap and jump about like it is alive, followed by abandon which adds to the unrestrained movement like someone young and full of energy. Updike uses onomatopoeia, alliteration, internal rhyme and assonance when describing lines five through eight. But there is a little change in the tone when the reader says: â€Å"Is broadcast by dint of my din, / And no man or band has a hand in / The tones I turn on from within† (6-8). Dint means force or effort; the speaker’s power of a jumble of loud, discordant sounds, followed by what I think the poem means perfect alone on his own.This is irony at its best, because the piano was created by a man, the music played, composed by a human. Then, through the speaker saying in the last two lines: â€Å"But never my numb plucker fumbles, / Misstrums me, or tries a new tune† (11-12). Cacophony is used on line eleven, lines that are discordant and difficult for a human to pronounce the piano does so with ease and perfection, But it can’t compose anything new, teach itself how to play a new song, play with feeling and emotion. And it is this very human thing that it cannot replace.John Updike’s poem, â€Å"Player Piano† conveys through sound and images the personification of the mechanical speaker is alive, but explains that a machine cannot replace human emotion. In Marge Piercy’s â€Å"The Secretary Chant†, the author uses images and sound to both dehumanize and mechanize the female speaker, while John Updike uses imagery and sounds to make the â€Å"Player Piano† come alive. Piercy uses images visualizing the speaker’s dehumanization to make some valid thoughts of only being viewed as an object, and only being good at tasks the speaker is hired to perform.Piercy through sound and description, with vivid detail, became just another task only good for what the job descripti on entailed. The speaker by giving up, because no one listened, showed that humans with emotions can be replaced. â€Å"Player Piano† through rhyme, alliteration, consonance, cacophony, diction, and meter make the poem sound and read like music. The images that Updike’s speaker brings forth when the poem is read out loud are melodic and, a perfectly played piano only works within the constraints of the human-made machine.The best use of sound and imagery goes to John Updike’s â€Å"Player Piano. † Updike through sound and imagery, and the musical feeling shown through the personification of the speaker, conveys that humans with emotion cannot be replaced.Works Cited Pierce, Marge. â€Å"The Secretary Chant. †The Compact Bedford Introduction to Literature. Ed. Michael Meyer. 9th ed. Boston: Bedford/St. Martin’s, 2012. 550. Print. Updike, John. â€Å"Player Piano. †The Compact Bedford Introduction to Literature. Ed. Michael Meyer. 9th e d. Boston: Bedford/St. Martin’s, 2012. 708. Print.

With the on-going war against terror, now is not the time for the Essay

With the on-going war against terror, now is not the time for the government to reduce the size of the Air Force - Essay Example According to current plans, the American Air Force is set to be reduced in size by 20,000 personnel. Such a reduction would mean a decrease of almost 30% in numeric strength and weaken the Air Force considerably. The war we are fighting today means having the ability to drop soldiers into combat hot zones, provide them with terrain information, air cover and bring them back home once an operation is complete (Wikipedia, 2006). All these functions demand that we keep a capable and strong Air Force which would be very difficult to have with a third of the Air Force seeking jobs elsewhere. It can be said that a reduction in the armed forces overall would be good for peace and prosperity of the nation as a whole, but it is not correct to say that now is the right time to take such actions. The concept of war is indeed a concept of suffering and there is no argument on the point that when we are at peace we would have little need for a huge Air Force. However, at the present moment, we are not at peace therefore a reduction in the Air Force is simply illogical. Additionally, the war we are fighting is different from any other in our history and we have to develop new tools as well as techniques to take on a hidden enemy who strikes from the shadows. Without our Air Force at full strength, such a task would be difficult if not impossible. After the end of the cold war and the collapse of the Soviet Union, America barely had time to enjoy its status as the sole superpower in the world because of the changing geopolitical scenarios. In fact, the current situation shows that America is more involved in protecting its foreign interests than it has been at any point in history (Wikipedia, 2006). However, to expect that America can offer protection to its allies and friends by simply exerting diplomatic force is unrealistic. War is often inevitable and small

Strategy Plan for American Airlines Co Research Paper

Strategy Plan for American Airlines Co - Research Paper Example The company’s top priority is to meet or exceed the needs and expectations of their customers by giving them the best travel experience upon boarding, on-board, and upon arrival. This could be done through route network optimization, competitive pricing, cost structuring, safety and security, and many more. The main trust of this paper is to provide a strategy plan for American Airlines Inc. This plan would incorporate competitive strategy that would help the company become the market share leader and largest air carrier in the world. 2. American Airlines, Inc. A. Business Overview i. Company history. American Airways was founded last 1930 through the consolidation of 85 subsidiaries airlines of The Aviation Corporation. American Airways was renamed to its current American Airlines Inc. under the appointment of the new CEO, C.R. Smith; the airline is headquartered in Fort Worth, Texas. For several years, AA had managed to introduce improvements in terms of technology, fliers p rogram, quality service, etc. making AA the largest in passenger miles and passenger fleet size. AA had maintained its strong presence particularly in the U.S. domestic market, and in 2009, â€Å"about 38.85 of Americans flying were international- Latin America and Caribbean, 18.7%; Europe, 15.6%; and Pacific, 4.5%† (â€Å"AMR Corporation,† 2010). Since then, AA had been successful and considered to be one of the biggest global airlines that served one-third of the U.S. population (85.7million) and more than 300,000 tons of cargo in a year. On a daily basis, the carrier transported an approximately 275,000 passengers between nearly 250 cities in over 40 countries with average daily flights of 3,400. ii. Worldwide operator. AA is one of the largest operators worldwide with a total of 623 active aircrafts as of 2010 and the largest number of international destinations. The carrier has scheduled domestic flights throughout North America, South America, Central America, an d other extensive international network in East and South Asia, and Europe. It has been more successful and gain competitive advancement after combining network fleet with AmericanConnection and American Eagle as its regional affiliates. B. Organizational Structure i. 655 Aircrafts/ 260 Destinations/ Dallas Hub AA is wholly owned subsidiary of AMR Corporation which is a publicly-traded company. The accountability and responsibility structure of AA is often disseminated in the organization through the board of directors and a chief executive officer. A large commercial airline like AA has hundreds of smaller stations to points all over the world, and hub airports that include: Chicago, Miami, New York, Los Angeles, and Dallas/Fort Worth International Airport - the largest hub. To send passengers to these hubs, AA employed various aircrafts such as Boeing, and ATR, ERJ, Bombardier for American Eagle. Currently, AA has 623 aircrafts with more than 621 fleet size and 250 destinations ac ross 40 countries around the world. C. Business Segments i. Domestic (U.S.). The U.S. domestic market is dominated by AA with a market share of 13.7%. The regional carriers of AA, American Eagle and AmericanConnection served as an advantage to the company as the affiliation acquired 7.5% of the total domestic market (Vasigh, Fleming, & Tacker, 2008, p. 14).