Search results
Results from the WOW.Com Content Network
The Flory theory of rubber elasticity suggests that rubber elasticity has primarily entropic origins. By using the following basic equations for Helmholtz free energy and its discussion about entropy, the force generated from the deformation of a rubber chain from its original unstretched conformation can be derived.
The Gent hyperelastic material model [1] is a phenomenological model of rubber elasticity that is based on the concept of limiting chain extensibility. In this model, the strain energy density function is designed such that it has a singularity when the first invariant of the left Cauchy-Green deformation tensor reaches a limiting value .
The Yeoh model for incompressible rubber is a function only of . For compressible rubbers, a dependence on I 3 {\displaystyle I_{3}} is added on. Since a polynomial form of the strain energy density function is used but all the three invariants of the left Cauchy-Green deformation tensor are not, the Yeoh model is also called the reduced ...
In continuum mechanics, an Arruda–Boyce model [1] is a hyperelastic constitutive model used to describe the mechanical behavior of rubber and other polymeric substances. This model is based on the statistical mechanics of a material with a cubic representative volume element containing eight chains along the diagonal directions.
Many viscoelastic materials exhibit rubber like behavior explained by the thermodynamic theory of polymer elasticity. Some examples of viscoelastic materials are amorphous polymers, semicrystalline polymers, biopolymers, metals at very high temperatures, and bitumen materials.
Elasticity theory primarily develops formalisms for the mechanics of solid bodies and materials. [1] (Note however, the work done by a stretched rubber band is not an example of elastic energy. [citation needed] It is an example of entropic elasticity.)
Elastic response of rubber-like materials are often modeled based on the Mooney–Rivlin model. The constants , are determined by fitting the predicted stress from the above equations to the experimental data. The recommended tests are uniaxial tension, equibiaxial compression, equibiaxial tension, uniaxial compression, and for shear, planar ...
The free energy expression derived from the Neohookean model of rubber elasticity is in terms of free energy change due to deformation per unit volume of the sample. The strand concentration, v, is the number of strands over the volume which does not depend on the overall size and shape of the elastomer. [ 4 ]