Acoustoelastic and acoustoplastic effects of polymethylmethacrylate measured by V(f,z) defocusing measurement system

This paper applies a lensless line-focus poly(vinylidenefluoride) (PVDF) ultrasound transducer along with a V(f,z) defocusing measurement system to determine the acoustoelastic and acoustoplastic effects of polymethylmethacrylate (PMMA). Different strains are formed in PMMA samples using a uniaxial tensile loading mechanism. The velocity changes of leaky surface-skimming longitudinal waves under different strains are measured along various directions relative to the loading direction. The acoustoelastic coefficients are calculated from measurement results. Finally, the acoustoplastic effects of PMMA are also measured and determined. The results of acoustoelastic and acoustoplastic effects and the measurement system provide an efficient way for estimating applied and residual stresses in PMMA nondestructively.