摘要
高速列车结构与材料在长期服役过程中因受复杂边界条件的影响将逐渐趋于劣化,存在潜在的安全风险。本文以高速列车常用铝合金6005A-T6为对象,首先将材料细观微结构解耦为基体相与空洞相,推导符合微结构连续度Weibull分布特征的损伤演化方程;继而提出一种考虑应变率的试验−数值方法,识别材料颈缩后损伤的加速演化行为,进而推导得到覆盖空洞相萌生、生长、聚合全过程的损伤演化方程,并得出基体相的无损本构;最后结合细观物理机制提出损伤顺序交互作用模型,以实现仅测量材料表观弹性模量即可获取含先前服役损伤材料在后续延性变形中的损伤演化方程,准确预测含服役损伤材料的率相关剩余强度。研究结果表明:预测值与试验值的平均相对误差不超过1%。损伤随延性发展由应变率正敏感性转变为负敏感性;对于疲劳−延性机制,空洞在先前疲劳损伤发展的空洞基础上继续生长。
The structure and materials of high-speed trains will gradually deteriorate under the influence of complex boundary conditions during long-term service,posing potential safety risks.The commonly used aluminum alloy 6005A-T6 for high-speed trains was focused in this study.Firstly,the mesostructure of the material was decoupled into matrix phase and void phase,and a damage evolution equation that conforms to the Weibull distribution characteristics of mesostructure continuity was derived.Secondly,an experimental−numerical method considering strain rate was proposed to identify the accelerated damage evolution behavior after material necking.The damage evolution equation covering the entire process of void nucleation,growth,and aggregation was deduced.The undamaged constitutive of the matrix phase was obtained.Finally,a damage sequence interaction model was proposed based on the mesoscopic physical mechanism,which achieved the damage evolution equation of materials containing previous service damage in subsequent ductile deformation by measuring only the apparent elastic modulus.The rate−dependent residual strength of materials containing service damage was accurately predicted.The results show that the average relative error between the predicted and the experimental values is less than 1%.The damage changes from positive sensitivity to negative sensitivity in strain rate as the damage develops.For the fatigue−ductility mechanism,voids continue to grow based on the voids developed from the previous fatigue damage.
作者
王小瑞
朱涛
张敬科
丁浩谞
肖守讷
鲁连涛
杨冰
阳光武
WANG Xiaorui;ZHU Tao;ZHANG Jingke;DING Haoxu;XIAO Shoune;LU Liantao;YANG Bing;YANG Guangwu(State Key Laboratory of Rail Transit Vehicle System,Southwest Jiaotong University,Chengdu 610031,China)
出处
《中南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2024年第5期2000-2010,共11页
Journal of Central South University:Science and Technology
基金
国家自然科学基金资助项目(52175123)
四川省杰出青年基金资助项目(2022JDJQ0025)
四川省国际科技创新合作项目(2022YFH0075)。
关键词
高速列车
率相关
本构模型
损伤演化
剩余强度
high-speed train
rate-dependent
constitutive model
damage evolution
residual strength
