Abstract:

The uniaxial-compresgion stress strain curves of loading-and-unloading cycle in the ranges of T= - 40-40℃ and ε_t = 1.0 × 10_-4-1.0×10_-1s_-1 for an aeropautical per-spex-PMMA liave been experimentally measured. A non-linear and rate-dependent thermoviscoelastic-plastic constitutive model, i. e. an activation dashpot which is used to consider the plastic deformation in series couple with on equivalent standard linear solid or an equivalent Maxwell body which is used to consider the viscoelastic deformation, is suggested. The effects of both temperature and strain rate can be considered in our model. The comprehensive constitutive relations both in differential and integral forms are worked out. While using these relations to fit the stress-strain curves measured experimentally, the agreement shows veasonably good with the correlation coefficients greater than 99%.

Key words: aeronautical perspex （PMMA）, non-linear constitutive relation, viscoelastic deformation, plastic deformation