两级变幅应变疲劳本征损伤耗散寿命预测模型研究
STUDY ON THE PREDICTION MODEL OF THE INTRINSIC DAMAGE DISSIPATION LIFE OF TWO-STAGE VARIABLE AMPLITUDE STRAIN FATIGUE
李文奇 1向忠 1李浩然 1任忠凯 2王嘉栋1
作者信息
- 1. 浙江理工大学机械工程学院,杭州 310018
- 2. 太原理工大学机械与运载工程学院,太原 030024
- 折叠
摘要
在变幅低周疲劳载荷条件下,材料的疲劳损伤累积过程中呈现出了显著的载荷顺序效应.这种现象复杂化了变幅疲劳寿命的预测,因此,如何更精确地预测变幅低周载荷下的疲劳寿命,已经成为了一个亟待解决的问题.针对变幅低周疲劳载荷下损伤累积表现的载荷顺序效应,考虑到本征损伤耗散与疲劳损伤构成一一映射,且刻画低周疲劳破坏的热力学本质,基于连续介质损伤力学及其不可逆热力学框架,推导本征损伤耗散功演化模型D型描述并以等同本征损伤耗散功作为损伤转换条件,建立了一种考虑载荷顺序效应的变幅低周疲劳寿命预测模型.为了验证新模型的有效性和先进性,进行了P355NL1 结构钢和Ti-6Al-4V钛合金在两级变幅载荷下的单轴低周疲劳实验验证,并与Manson模型、Kwofie模型和Peng模型进行了比较分析.研究结果表明,新建模型的预测效果都在 1.5 倍的误差范围内,与实验结果相当吻合,且优于现有的预测模型.运用本征损伤耗散理论开展变幅疲劳寿命预测,为金属材料变幅疲劳寿命预测提供了新思路.
Abstract
Under conditions of varying amplitude low-cycle fatigue loading,materials have shown a pronounced load sequence effect during the fatigue damage accumulation process.This observed phenomenon introduces complexities in predicting the fatigue life under such varying amplitude conditions,making it a pressing challenge in the field of material science.Taking into account the concept of intrinsic damage dissipation—which establishes a one-to-one correspondence with fatigue damage and encapsulates the thermodynamic essence of low-cycle fatigue failures—we have meticulously derived an evolution model for intrinsic damage dissipation,termed as the type D model.This derivation is grounded in the principles of continuum damage mechanics coupled with the framework of irreversible thermodynamics.By adopting the equivalent intrinsic damage dissipation as a pivotal criterion for damage conversion,we have innovatively constructed a fatigue life prediction model for varying amplitude low-cycle loads,which inherently considers the load sequence effect.To ascertain the robustness,effectiveness,and advanced capabilities of our proposed model,we embarked on rigorous uniaxial low-cycle fatigue testing.This involved materials such as P355NL1 structural steel and the Ti-6Al-4V titanium alloy,subjected to two distinct stages of varying amplitude loads.Our empirical findings were then juxtaposed with established models in the domain,namely the Manson model,Kwofie model,and Peng model.The outcomes of our research unequivocally indicate that the predictions rendered by our novel model consistently fall within a margin of 1.5 times the error range.This level of accuracy is not only in close alignment with our experimental results but also demonstrably superior to the predictions offered by existing models.The application of the intrinsic damage dissipation theory,as showcased in our research,heralds a pioneering direction for predicting the fatigue life of metallic materials under varying amplitude conditions.
关键词
低周疲劳/载荷顺序效应/损伤力学/本征损伤耗散/寿命预测Key words
low cycle fatigue/load sequence effect/damage mechanics/intrinsic damage dissipation/life prediction引用本文复制引用
基金项目
国家重点研发计划(2021YFB3401002)
浙江省教育厅一般项目(21020078-F)
浙江理工大学科研启动金项目(20022302-Y)
出版年
2024
NETL
NSTL
维普
万方数据