Computing Stresses from Measured In-plane Strains in Viscoelastic Body under Plane Stress Condition

抄録

This study proposes a method for computing stresses from measured values of in-plane strains in viscoelastic body under plane stress condition. Since Poisson's ratio depends on time and temperature, it is difficult to calculate stresses from in-plane strains unless Poisson's ratio is treated as a constant. This research focuses on pseudoelasticity in the linear viscoelasticity and the stresses are computed using a numerical Laplace transformation. Since the relation between a through-thickness strain and in-plane strains is expressed in Laplace domain, Poisson's ratio can be treated as time-and temperature-dependence. The Laplace transformation is performed numerically using a fast Fourier transformation. Therefore, the computational nature of FFT affects the process of calculating the stress of the viscoelastic body. Appropriate values can be calculated by increasing the number of input data using the numerical Laplace transformation. The effectiveness of the proposed method is demonstrated by computing stresses from strains. Results show that stresses can be evaluated from in-plane strains even if Poisson's ratio exhibits time-and temperature-dependence.