Small time behavior of hygrothermal stresses in axisymmetric double-layer cylinders

This article presents an analytical approach for an axisymmetric double-lay er annular cylinder subjected to hygrothermal loading for a small time. The coupled equations are first decoupled and divided into two general initial and boundary value problems for each layer. The boundary values at the int erface are currently unknown and can be determined by the interfacial condi tions. The Laplace transform method is implemented to solve these problems, and an asymptotic expansion for a large value of the transformed variable is used to obtain the transformed solutions. Generally, they can be numeric ally inverted to obtain the time domain response. However analytical forms can be found from a table of inverse Laplace transforms for some special ca ses. The results are in agreement with the cases that have exact solutions or analytical solutions obtained by the alternative method. It is determine d that the computing time required for the calculations is only about 1/5 c ompared with that by the alternative analytical approach for t* = 0.02; and the shorter the time, the smaller the ratio of computing time. Moreover, t he present method has a great advantage in obtaining the maximum stresses a t the surfaces, which are very important for structural design.