Abstract
Buried pipelines are subjected to very large cyclic soil displacement due to an earthquake. Especially pipe bends are bent by those cyclic soil movement. After 1995 Hyogoken-Nambu earthquake, it has been focused that reliability of structures under large displacement due to great earthquake. Considering the safety of pipe bend subjected to cyclic soil displacement, the low cycle fatigue strength is very important material property.
However, a few studies have been carried out on the low cycle fatigue strength in the region of life less thar 100 cycles. Furthermore, the method which can estimate the low cycle strength under variable amplitude displacement such as seismic wave motion has not been precisely investigated.
Therefore, the low cycle fatigue strength of steel pipe bend was experimentally investigated both under constant and variable amplitude displacement conditions. And numerical analysis for simulating the deformation of pipe bend subjected to cyclic displacement was carried out.
The applicability of linear cumulative damage low on the fatigue strength of pipe bend in the region of life less than 100 cycles is discussed.
