一、概述疲劳问题是承受动荷载结构的重要研究课题。承受动荷载的结构有桥梁、地震区的厂房及建筑结构、海上输油管道、压力容器、船体结构、飞机结构等。作用在结构上的动荷载包括使用期间的运营荷载,如在桥梁上的列车、海上结构承受的风浪、船舶结构承受的负荷和水的浮力,压力容器中的内压力变化,还有风力,地震力以及其它原因产生的荷载。结构钢材及其连接在承受变应力时,它承受的最大应力虽然低于强度规定值,但会产生低应力的疲劳破坏,这种现象,很 First, an overview of the fatigue problem is to bear the dynamic load structure of an important research topic. Bear dynamic load structure of the bridge, the earthquake area of ​​the plant and building structures, offshore oil pipelines, pressure vessels, hull structures, aircraft structures. Dynamic loads acting on the structure include operational loads during use, such as trains on bridges, storm waves borne by offshore structures, loads borne by ship structures and buoyancy of water, changes in internal pressure in pressure vessels, and wind, earthquakes Force and other causes of the load. Structural steel and its connection to withstand the stress, it withstands the maximum stress although lower than the intensity of the specified value, but will produce low-stress fatigue damage, this phenomenon is very