Author N. Wang
,
B.S. Zhou
,
Z.D. Wang and D.D. Wu College of Mechanical Engineering
,
East China University of Science and Technology
,
Shanghai 200237
,
ChinaManuscript received 18 October 1998
金属学报(英文版)
Based on the fundamental definition of damage and inelastic strain energy hypothesis, this paper presents an inelastic strain energy damage model under creepfatigue interaction condition, with the damage constitutional equations and life prediction formulae respectively described by strain and stress. Creepfatigue tests with notchedbar specimens were carried out at 550. The actual creepfatigue lives are in good agreement to the predicted lives according to inelastic strain energy damage model.
关键词:
damage mechanics
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null
,
null
,
null
ZO U Hongcheng DAI Shujuan QIAN Zhixiong LI Guangxia Huazhong University of Science and Technology
,
Wuhan
,
China [Originally published in ACTA METALL SIN(CHINESE EDN)25(3)1989 pp A207—A212
,
Associate Professor
,
Division of Materials
,
Huazhong University of Science and Technology
,
Wuhan
,
China
金属学报(英文版)
The change of microstructure of fatigue specimens before and after laser radiation was studied by transmission electron microscopy.The results show that the diameter of dislocation cell λ tends to a constant at fatigue failure.Based on the principles of continuous damage mechanics,expressions of the fatigue damage criterion and processes of fatigue damage evolu- tion for L Y12CZ have been derived.
关键词:
laser radiation
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null
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null
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null
黄来
,
李毅超
,
车红卫
,
周挺
,
龚政雄
,
杨湘衡
,
吕江林
玻璃钢/复合材料
采用实验方法研究了编织碳纤维/环氧树脂复合材料层合板在干燥环境下受到不同强度等级模拟雷电冲击后的电击破坏特性,并进行了系统分析与机理解释.研究显示,雷电冲击对复合材料造成了三种典型破坏形式,并随着电击强度的增加及铺层角度的改变呈现出不同形态的变化.微观扫描分析发现,电击会对树脂与纤维界面造成严重破坏.
关键词:
编织复合材料
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雷电冲击
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破坏机理
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超声扫描
孙志礼
,
柴小冬
,
柳溪溪
,
王健
材料导报
doi:10.11896/j.issn.1005-023X.2017.08.026
针对金属构件疲劳裂纹的萌生、扩展寿命及其规律等问题,应用损伤力学理论与有限元相结合的方法,建立了计算疲劳裂纹全寿命的统一模型.引入附加载荷法,通过MATLAB编程计算,实现了对刚度矩阵的连续计算,并给出了编程的流程.通过对单个单元的损伤计算,得到了单元从无损到破坏过程中等效应力的变化;通过计算各个构件损伤单元寿命,进而给出了金属构件总体疲劳寿命.分析得到了微裂纹萌生及扩展寿命占总体疲劳寿命的80%以上,并应用有限元软件ANSYS模拟给出了缺口件裂纹萌生及扩展过程.理论计算的结果与试验数据对比基本一致,验证了本工作方法的准确性.
关键词:
疲劳裂纹
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损伤力学
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疲劳寿命
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扩展规律
杨武林
,
杨晓华
,
李晓延
材料热处理学报
对TC4钛合金薄板母材及其激光焊缝进行了低周疲劳损伤规律的理论分析和试验研究。在对应力疲劳不同周次后试样的拉伸性能进行测定及分析表明,残余伸长率对该材料的疲劳损伤较为敏感,可以作为表征其低周疲劳损伤的有效物理参量。结果表明,对TC4钛合金薄板母材,以残余伸长率定义的损伤变量初始值D0为0.037,损伤变量D随着循环周次的增加缓慢增加,当循环周次达寿命的90%后才进入快速增加阶段。连续损伤力学理论分析结果可以很好的解释TC4薄板的低周疲劳损伤规律,理论模型与实验结果吻合很好。而激光焊接接头试样中由于存在组织不均匀性及焊接缺陷,使得焊缝的低周疲劳损伤规律偏离了理论模型,由于焊缝中有气孔等缺陷的存在使得焊缝试样循环到寿命的1%时,初始损伤变量值即达到0.4,而且由于焊缝中心晶粒粗大使得循环周次达寿命的50%时损伤变量即开始快速增加。
关键词:
钛合金
,
低周疲劳
,
损伤力学
