Constitutive modeling of polycarbonate over a wide range of strain rates and temperatures

摘要

The mechanical behavior of polycarbonate was experimentally investigated over a wide range of strain rates (10(-4) to 5 x 10(3) s(-1)) and temperatures (293 to 353 K). Compression tests under these conditions were performed using a SHIMADZU universal testing machine and a split Hopkinson pressure bar. Falling weight impact testing was carried out on an Instron Dynatup 9200 drop tower system. The rate- and temperature-dependent deformation behavior of polycarbonate was discussed in detail. Dynamic mechanical analysis (DMA) tests were utilized to observe the glass (alpha) transition and the secondary (beta) transition of polycarbonate. The DMA results indicate that the alpha and beta transitions have a dramatic influence on the mechanical behavior of polycarbonate. The decompose/shift/reconstruct (DSR) method was utilized to decompose the storage modulus into the a and beta components and extrapolate the entire modulus, the alpha-component modulus and the beta-component modulus. Based on three previous models, namely, Mulliken-Boyce, G'Sell-Jonas and DSGZ, an adiabatic model is proposed to predict the mechanical behavior of polycarbonate. The model considers the contributions of both the alpha and beta transitions to the mechanical behavior, and it has been implemented in ABAQUS/Explicit through a user material subroutine VUMAT. The model predictions are proven to essentially coincide with the experimental results during compression testing and falling weight impact testing.