Finite strain behavior of polyurea for a wide range of strain rates

[摘要] (cont.) The device is composed of a hydraulic piston along with nylon input and output bars. A finite strain constitutive model of polyurea is presented in order to predict the hysteresis and rate-sensitivity behavior. The 1-D rheological concept of two Maxwell elements in parallel is employed within the framework of the multiplicative decomposition of the deformation gradient. Model parameters are calibrated based on the uniaxial compressive tests at various rates. The corresponding algorithms is implemented as a user-defined material subroutine VUMAT for ABAQUS/Explicit, and used to predict the response of polyurea. The proposed constitutive model reasonably captures the experimentally observed asymmetric rate-sensitivity and stress-relaxation behavior: strong rate-sensitivity and large amount of stress relaxation during loading phase, but weak rate-sensitivity and smaller amount of stress relaxation during unloading phase. In order to validate the proposed model, various dynamic punching tests are performed, and their results are well compared with the model predictions during loading although the prediction of unloading behavior can be further improved.

[发布机构] Massachusetts Institute of Technology