SN-Paris全寿命综合模型

Improving Pugno's Generalized Paris′ Law and Applying it to Calculating Whole Fatigue Life of Structure

基于SN材料疲劳寿命曲线和Paris裂纹扩展公式,发展了一种进行结构全寿命分析的模型,称为SN-Paris全寿命综合模型。SN-Paris全寿命综合模型是在经典损伤容限Paris公式的基础上,引入裂纹长度影响因子aS,结合SN试验曲线,得到一个可以进行结构全寿命分析的裂纹扩展寿命分析模型。裂纹长度影响因子分析中考虑了结构构型因子β的影响,因而该综合模型可以进行一般结构的全寿命分析。该模型分析结果在裂纹长度趋近于零时与结构疲劳寿命SN曲线吻合很好,在长裂纹时与结构裂纹扩展寿命Paris结果完全一致,模型合理,且具有很好的工程使用精度。模型所用参数都是现有的材料试验常数,没有引入新的材料常数,工程的应用简便。

Aim. In Pugno＇s generalized Paris＇ law, he introduced a fracture quantum as. In our opinion, in order to apply Pugno＇s generalized Paris＇ law to calculating the whole fatigue life of a structure, the dependency of as on the type of a structure should be investigated. In the full paper, we explain in detail how to calculate an as that takes into account the type of structure and then how to apply the improved Pugno＇s generalized Paris＇ law to calculating the whole fatigue life of structure. In this abstract, we just add some pertinent remarks to listing the three topics of explanation. The first topic is. the basic equation of fatigue crack propagation. The second topic is： SN-Paris model for whole fatigue life. In topic two, we give a detailed derivation of the formula for calculating as that takes into consideration its dependency on the type of structure. The third topic is： a numerical example. In topic three, there is one figure summarizing the numerical results obtained. As compared with the whole fatigue life values taken from Ref. 12 edited by Wu, a well-known Chinese handbook on engineering fatigue, our improved Pugno＇s generalized Paris＇ law for fatigue crack growth can give results that are quite satisfactory; so our improved Pugno＇s generalized Paris＇ law can give results of whole fatigue life of a structure that are accurate and reasonable for practical use.