Experimental and theoretical description of the plastic behaviour of semicrystalline polymers
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Kontou, E
(EN)
Spathis, G
(EN)
In this work, a new experimental technique, based on a non-contact method of strain measurement, has been applied in the case of semicrystalline polymers, where yielding occurs through inhomogeneous deformation (necking). It was then possible to construct the true stress-strain curves at various crosshead speeds tested. Furthermore, a constitutive model for the description of this behaviour has been introduced, grounded on a plasticity theory, which has been developed and initially applied on plastic behaviour of crystalline metals. This theoretical model was proved to predict satisfactorily the experimental results. Moreover, the rate effect and the post yield phenomena, as possible strain softening and strain hardening have also been described in terms of molecular parameters connected with the material tested. (C) 1997 Elsevier Science Ltd.
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