Mechanics of a rate-dependent polymer network |
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Authors: | Q Yu |
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Institution: | Department of Aeronautics and Astronautics , Stanford University , Durand Building, 496 Lomita Mall, Stanford, CA 94305-4035, USA |
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Abstract: | Pure rubber-like materials usually have little or no rate-dependency during finite straining. In contrast, polymeric materials can exhibit rate-dependent rubber-like responses in the large-strain range. A thermodynamic analysis points to the existence of rate-effects for an elastic network. The presence of reversible crystallization with a rate-dependent feature changes the conformation mobility of the network structure and, subsequently, contributes to the alterations in its elasticity. The internal energy of an elastic polymer network, however, exhibits a step-wise dependence on the applied strain-rates; it alters only at discrete values of strain-rates, every pair of which differs with a unique value that can be described as a sensitivity parameter. At loading rates lower than this parameter, the rate-effects of the polymeric network are absent. |
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