An Improved Unique Fatigue Crack Growth Rate Curve Model and Determination of the Model Shape Exponents  

一种改进的裂纹扩展率单一曲线模型及模型指数确定

作　　者：Li Sun Yingcai Huang Xiaoping Huang 孙力;黄瀛偲;黄小平(State Key Lab of Ocean Engineering,Shanghai JiaoTong University,Shanghai,200240,China;ShanghaiWaigaoqiao Shipbuilding Co.,LTD.,Shanghai 200137,China)

机构地区：[1]State Key Lab of Ocean Engineering,Shanghai JiaoTong University,Shanghai,200240,China [2]ShanghaiWaigaoqiao Shipbuilding Co.,LTD.,Shanghai 200137,China

出　　处：《Journal of Marine Science and Application》2022年第4期104-115,共12页船舶与海洋工程学报（英文版）

摘　　要：It is essential to precisely predict the crack growth,especially the near-threshold regime crack growth under different stress ratios,for most engineering structures consume their fatigue lives in this regime under random loading.In this paper,an improved unique curve model is proposed based on the unique curve model,and the determination of the shape exponents of this model is provided.The crack growth rate curves of some materials taken from the literature are evaluated using the improved model,and the results indicate that the improved model can accurately predict the crack growth rate in the nearthreshold and Paris regimes.The improved unique curve model can solve the problems about the shape exponents determination and weak ability around the near-threshold regime meet in the unique curve model.In addition,the shape exponents in the improved model at negative stress ratios are discussed,which can directly adopt that in the unique curve model.

关 键 词：Near-threshold regime Crack growth rate Stress ratio Improved unique curve model Shape exponents 

分 类 号：P75[天文地球—海洋科学]