一、引言近年来许多研究者从不同角度研究尺寸效应的影响因素,并从微观机制和物理模型来解释其尺寸效应,以提出在工程上估算疲劳裂纹扩展寿命的有效方法。尺寸效应不仅取决于试样的宽度、厚度、有效的长度,还和材料的屈服强度、应力比 R、应力状态、载荷历程、环 I. INTRODUCTION In recent years, many researchers have studied the influential factors of size effect from different angles and explained its size effect from the micro mechanism and the physical model to propose an effective method to estimate the fatigue crack growth life span in engineering. The size effect depends not only on the specimen width, thickness, effective length, but also on the yield strength of the material, the stress ratio R, the stress state, the loading history, the ring