RELIABILITY OF TRANSMISSION STRUCTURES INCLUDING NONLINEAR EFFECTS

Some transmission structures exhibit important geometric and material nonlinearities that should be considered in their analysis and design. Unless simplifying assumptions are made, reliability analysis of thes e structures is complex and can be very computer-time intensive. This paper describes an approximate method to conduct reliability analysis of nonlinear transmission structures. It is shown that for most transm ission structures, the design point is close to the 50-year return per iod loads. Using this result, approximate g-functions for nonlinear pr oblems are obtained with minimum computational effort. It is also show n that when the material strengths are highly correlated, g-functions that include interaction of axial load and bending moments may be redu ced to g-functions with no interaction. These simplifying results are implemented in a microcomputer program, RELIAB, which can handle compl ex transmission structures such as large latticed structures, tension- only structures, or structures that exhibit nonlinearities. RELIAB's a ccuracy is ascertained by comparing results with another computer prog ram, TRANSREL, which accounts for the residual strength of latticed to wers following progressive failure of one or more components.