Coupled Processes of Deformation and Long-Term Damage of Physically Nonlinear Laminated Materials

A theory of long-term damage of laminated materials with physically nonlinear components is proposed. The damage of components is modeled by random micropores. The damage criterion for a microvolume is characterized by its stress-rupture strength. It is determined by the dependence of the time to brittle failure on the difference between the equivalent stress and its critical value, which is the tensile strength, according to the Huber–Mises criterion, and assumed to be a random function of coordinates. An equation of damage (porosity) balance in the components at an arbitrary time is formulated. Algorithms of calculating the time dependence of microdamage and macrostresses are developed and respective curves are plotted. The influence of the nonlinearity of the matrix on the macrostress–macrostrain and damage curves is studied