Abstract: In dealing with the heat conduction problem of the tightly compressed adjacent plane plates with different constant thermal conduction coefficients, we conventionally solve it layer by layer requiring to fulfill two requirements of equal temperature and equal heat flux at every two directly contacting intermediate surfaces.In this paper, we consider only such a case that the adjacent plane plates possess a gradually varying thermal conduction coefficients in order to offer a chance to solve such problem once for all instead of pursuiting the old tedious and time-consuming procedure, i.e., by solving the sproblem layer by layer.

Key words: K-type tubular joints, random fatigue, surface crack, life of propagation, fracture mechanics