考虑分级加载的连续非线性Chaboche-Paris全寿命模型.pdfVIP

学兔兔 第50卷第2期 机 械 工 程 学 报 VO1．5O NO．2 2014年 1月 JOURNAL OF MECHANICAL ENGINEERING Jan． 2014 DoI：l0．3901／JME．2014．O2．187 考虑分级加载的连续非线性Chaboche．Paris 全寿命模型木 张俊红 杨 硕 林杰威 马 梁 (天津大学内燃机燃烧学国家重点实验室 天津 300072) 摘要：结构疲劳全寿命可分为裂纹萌生和裂纹扩展两个阶段，裂纹萌生寿命和裂纹扩展寿命的预测通常分开进行，很少有理 论能将两者合二为一。结合CHABOCHE提出的非线性损伤理论，对Paris公式进行修正，将其扩展至全寿命阶段；建立损 伤累积与裂纹长度关系模型，分析分级加载对损伤累积的影响。计算结果表明，提出的Chaboche-Paris全寿命模型对无初始 裂纹结构的寿命预测结果与其s．N疲劳试验数据结果一致，对具有宏观可见裂纹结构的寿命预测结果与Paris公式计算结果 一 致，验证提出的全寿命模型在全寿命预测和裂纹扩展寿命预测两个阶段的可用性和正确性：分级加载时，Chaboche．Paris 模型可以体现出加载顺序对疲劳损伤累积的影响，当外载为低．高加载时，循环比之和大于 1，当外载为高一低加载时，循环 比之和小于1，与试验结果吻合。 关键词：寿命预测；分级加载；全寿命；裂纹扩展；非线性连续损伤 中图分类号：V215 Chaboche--Paris Full--life Prediction Model Considering Multi--level Loading and Non-linear Continuum Damage ZHANG Junhong YANG Shuo LIN Jiewei MA Liang (State Key Laboratory of Engines，Tianjin University,Tianjin 300072) Abstract：Structural fatigue life contains crack initiation stage and crack propagation stage．Generally,crack initiation life and crack propagation life are calculated separately．Extended Paris model to a whole life prediction model based on Chaboche non-linear damage model，and build a relational model between nonlinear dam age accumulation and crack length to analyze how a multi-level loading affect the dam age accumulation．The results show that：When there iS no initia1 crack．the Chaboche-Paris model analysis results are in good agreement with the S-N experimental results；when there is a macroscopic long crack，the results are in good agreement with the Paris model，which proves the accuracy and applicability of the model to predict both the two stages of the structural life．When add a two level loading，the Chaboche—Pari