Hygrothermal expansion coefficients of composite materials studied by a simple statistical approach

In this article, an investigation of the coefficients of hygrothermal expan sion for a general class of randomly-oriented composite laminate is present ed. A simple random statistical analysis has been used to demonstrate that under certain conditions, for instance, a laminate with 40 plies or more, t he mean values of the coefficients of hygrothermal expansion in the randoml y-oriented laminate are close to those values evaluated from the classical hygrothermal-elastic lamination theory. Also, the influence of the various lamina material properties E-2/E-1, G(12)/E-1 and nu(12) as well as the lam ina hygrothermal expansion coefficients alpha(1)/alpha(2) and beta(1)/beta( 2) to the coefficients of hygrothermal expansion of the laminate are invest igated. The results from this statistical analysis provide a set of general guidelines for designing the coefficients of hygrothermal expansion of the composite laminates to meet different environmental conditions in engineer ing application.