Estimation of residual strength under multi-level loads

Aiming at the deficiencies of existing methods in estimating residual strength under multi-levelloads, based on Schaff's residual strength model, an equivalent damage ratio model is put forward, and is applied to estimate residual strength under multi-level loads. Finally a run-of-mill formula is given. Using the given formula it is convenient to estimate residual strength through recursive computation. As a result of equivalent damage ratio model, it can be applied to an arbitrary load history, so it has a wider applicable range than the original Schaff model.