The stress strain curve can be represented by an ideal elasto plastic material with properties of steel in compression and tension same. An elastic material is one that will return to its original shape when the force applied to it is taken away. Plastic deformation of materials covers the fundamental properties and characterization of materials, ranging from simple solids to complex heterophase systems. The concepts of elastic and plastic deformation will be covered. Mechanical properties of metals western university. They, like other polymeric materials, exhibit viscoelastic behaviour where, as the name suggests, the material response has both elastic and viscous components. To minimize deformation, select a material with a large elastic modulus e or g.
This reversible behavior often shows a linear relation between stress and strain. As shown in the figure below, a parallel line offset by 0. The traditional analysis of structures is based on the linear elastic behaviour of materials, implying that the material follows hookes law. The behaviour of a material subjected to a tensile pulling or compressive pushing force can be described as either elastic or plastic a material is elastic if it returns to its original shape and size when the force is removed. When stress application ceases, the body regains its original shape and size. One of the most important subjects for any student of engineering or materials to master is the behaviour of materials and structures under load. Understanding of the elasticplastic behaviour of fibrous composites is important from the. Class 11 physics applications of elastic behaviour of. Elastic deformation the recovery of the original dimensions of a deformed body when the load is removed is known as elastic deformation.
When a sufficient load is applied to a metal or other structural material, it will cause the material to change shape. For a perfect plastic material the stress cannot rise above the yield stress and strain can continue to accumulate without any change is. Class 11 physics applications of elastic behaviour of materials mbd alchemie. The study of the elastic behavior of a material is of much importance. Evaluating elasticplastic behaviour of rock materials.
Plastic analysis version ii 35 1 plastic analysis 1. Different materials show different elastic behavior. This difference in the behaviour of the material is based on their elastic and plastic nature. A balanced mechanics materials approach and coverage of the latest developments in biomaterials and electronic materials, the new edition of this popular text is the most thorough and modern book available for upperlevel undergraduate courses on the. This region is that part of the element over which significant inelastic behavior is expected to occur. Manual for the calculation of elasticplastic materials. This method of design limits the structural usefulness of the material upto a certain allowable. Almost every engineering design requires knowledge of the elastic behavior of materials.
They describe the attributes of materials such as rubber, plastic, metal, etc. E youngs modulus e extension onedimensional strain. In physics, when an external force is applied to the surface of any material or a body, the material undergoes a. Chapter outline mechanical properties of metals how do. Elastic and anelastic behavior of materials in small. Reverse loadings into the plastic range, therefore, are seldom allowed, and only under carefully controlled conditions. In the 1600s, a scientist called robert hooke discovered a law for elastic materials. An introduction to mechanics of elastic and plastic deformation of. Engineering and manufacturing elasticity research elasticity mechanics failure mode and. Whats the difference between elastic and plastic deformation. The structure and characteristics of most typical rubber and thermoplastic elastomers will be. Elasticity is the ability of a body to resist any permanent changes to it when stress is applied. At the same time, incorporating fibres into metal or ceramic matrix yields a material with new elasticplastic properties. Mechanical behavior of materials materials science and.
Elasticplastic behavior an overview sciencedirect topics. For example, a solid piece of metal being bent or pounded into a new shape displays plasticity as permanent changes occur within the material itself. The hookes law states that for the elastic range of the material, applied stress is equal to the product of the youngs modulus and the strain of the material. From material to cross section to critical region to structure. The elasticplastic transition of metals article pdf available in international journal of plasticity 83 april 2016 with 1,466 reads how we measure reads. The exponent druckerprager is a more complex elastic plastic model, which is better able to describe behaviour under stress states in which there is a high component of hydrostatic tension. Generally, the terms plastic and elastic are, physical properties, used to describe an object. For contact under normal load only, it has been shown by a recent finite element analysis kogut and etsion, 2003 that. Elasticity is the ability of a body to resist any permanent change to it when stress is applied.
Effect of defects on elastic plastic behavior of cellular materials. Apply a freebody analysis on each component to determine the. Materials commonly known as plastics are not plastic in the sense described here. Predicting and modelling this plastic deformation is the topic of this section.
The limiting load beyond which the material no longer behaves elastically is the. This will then lead to a discussion of the microstructure of materials and a physical explanation of what is happening to a polycrystalline material as it is loaded to failure. Report by journal of civil engineering and management. Such a material iselastic accordingtothedescription ofelasticity given earlier immediate response,fullrecovery, andit is also linear in its relation between stress and strain or equivalently, force and deformation.
Find materials for this course in the pages linked along the left. Difference between plastic and elastic plastic vs elastic. This variability is related to the behavior of dislocations in the material, chapter 7. In the first part of this lesson, we work through a hierarchy of behavior from material, to crosssection, to critical region, and, finally, to the entire structure. Elastic and plastic behavior the recovery of the original dimensions of a deformed body when the load is removed is known as. A temporary shape change that is selfreversing after the force is removed, so that the object returns to its original shape, is called elastic deformation. We will cover elastic and plastic deformation, creep, and fracture of materials including crystalline and amorphous metals, ceramics, and biopolymers, and will focus on the design and processing of materials from the atomic to the macroscale to achieve desired mechanical behavior. A high elastic modulus is typical for materials that are hard to deform.
Elasticity, ability of a deformed material body to return to its original shape and size when the forces causing the deformation are removed. The degree of viscoelasticity is strongly dependent upon the temperature of test and the rate at which the polymer is deformed, as well as such structural variables. Different materials show different elastic behaviour. Elastic properties of materials most materials will get narrow when stretched and thicken when compressed this behaviour is qualified by poissons ratio, which is defined as the ratio of lateral and axial strain z y z poisson s ratio x. Solid objects will deform when adequate forces are applied to them. If the material is elastic, the object will return to its initial shape and size when these forces are removed. The uniaxial tension test is a convenient method to indicate plastic behaviours of a. Structures and materials section 4 behaviour of materials. Figure 27 represents an elemental free body similar to that shown in fig. The elastic deformation of a solid is a reversible process, when the applied stress is removed the solid returns to its original state. Therefore a hookean material is linear elastic, and materials engineers use these descriptors interchangeably. It is important to keep in mind that not all elastic materials are linear rubber is. Elastic behavior versus viscoelastic behavior the difference between elastic materials and viscoelastic materials is that viscoelastic materials have a viscosity factor and the elastic ones dont. The difference between elastic materials and viscoelastic.
Plastic behaviour is sometimes called inelastic behaviour. In practice, it is difficult to identify the exact point at which a material moves from the elastic region to the plastic region. Check out for more free engineering tutorials and math lessons. In this slide, the critical region coincides with the flexural plastic hinging of a beam. The two parameters that determine the elasticity of a material are its elastic modulus and its elastic limit. Typical reactions for chain assembling are polyaddition continuous or step wise and condensation polymerization polycondensation 1 figure 1. But elastic moduli are relatively insensitive to these effects. The section will cover the behaviour of materials by introducing the stressstrain curve. Elastic and anelastic behavior of materials in small dimensions volume 27 issue 1 shefford p. The book presents articles on the low temperature of deformation of bcc metals and their solidsolution alloys.
Evaluating elasticplastic behaviour of rock materials using hoekbrown failure criterion. In the construction of various structures like bridges, columns, pillars, beams, etc. Thus, the plasticity index is a good indicator of the relative amounts of elastic and plastic deformation. For example, the deflection at the free end of a cantilever carrying an endpointload is. This chapter is concerned with deformation of a structural member under axial.
Mechanical properties refers to the behavior of material when external forces. The taylor impact behavior of the model hyperelastic rubbery and elasticplastic glassy polymers was examined in terms of energy dissipation and resilience features of. Topic 06 inelastic behavior of materials and structures. Because viscoelastic materials have the viscosity factor, they have a strain rate dependent on time. This permanent deformation behavior occurs when the tensile or compressive uniaxial stress reaches y. In fact solid polymers show a combination of elastic and viscous behaviour known as viscoelasticity. Plastic strain is the permanent change in shape or size of a body without fracture, accumulated over time by a sustained stress beyond the elastic limit yield point of the material. The material has now moved into the region referred to as plastic deformation. Such situations occur in the strengthening of damaged.
To a greater or lesser extent, most solid materials exhibit elastic behaviour, but there. Stressstrain behavior elastic plastic stress strain elastic deformation reversible. For a perfect plastic material the stress cannot rise above the yield stress and strain can continue to accumulate without any change is stress. If the material is a metal, the deformation remains elastic up to a certain. In physics and materials science, plasticity, also known as plastic deformation, is the ability of a solid material to undergo permanent deformation, a nonreversible change of shape in response to applied forces. Due to their viscosity, their response is, unlike the plastic materials, ratedependent. For the most part, in this section, the material will be assumed to be perfectly plastic, that is, there is no work hardening. Even a concrete floor changes shape as you walk across it. Idealized inelastic behavior to critical region and member. All three of these factors favour elastic rather than plastic behaviour. A property of various metals that describes their ability to undergo permanent stains is called plasticity. The idea of this part of the virtual education in rubber technology course is to give students an extensive overview of elastomeric materials.
Pdf effect of defects on elasticplastic behavior of. For engineering purposes the limit of usable elastic behavior is described by the. Basic principles of elasticity and plasticity plastic range plastic range. Difference between elastic and plastic deformation.