三维冲击荷载弹塑性弯曲裂纹张开位移
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摘要
主要研究冲击载荷作用下的三维弹塑性弯曲裂纹尖端的张开位移问题.综合考虑了冲击作用应力,三维塑性区域边界上正应力与剪应力,利用二阶摄动方法计算了三维弹塑性弯曲裂纹尖端的张开位移.用数值解法计算出三维弹塑性弯曲裂纹尖端张开位移,作图分析了三维弹塑性弯曲裂纹尖端张开位移与三维裂纹体几何尺寸之间的变化关系.三维弹塑性弯曲裂纹尖端张开位移随着三维裂纹体厚度的增大而减小,随着三维裂纹体厚度的均匀增大,三维弹塑性弯曲裂纹尖端张开位移尺寸不断减小,减小的幅度越来越小,最终趋于平面应变状态下的弹塑性弯曲裂纹尖端张开位移尺寸.当三维裂纹体几何尺寸相同时,三维弯曲裂纹尖端动态张开位移随外部冲击载荷的不断增大而逐渐增大,三维弯曲裂纹尖端动态张开位移随动荷系数的增大而迅速增大,建立了一个计算三维弹塑性弯曲裂纹尖端动态张开位移的崭新理论模型.
In this article, three-dimensional elastic-plastic curved crack tip opening displacement under impact load has been mainly studied, and three-dimensional curved crack tip opening displacement has been calculated using a second order perturbation method, where the effects of applied impact stresses as well as normal and shear impact stresses on the boundaries of plasticity area are taken into account. Three dimensional curved elastic-plastic crack tip opening displacement has been calculated by numerical methods. Diagrams have been constructed to analyze the transformation relationship between the curved crack tip opening displacement and the geometrical parameters of three-dimensional crack body. Curved crack tip opening displacement will decrease when three-dimensional crack body thickness increases. When crack body thickness increases uniformly, three-dimensional curved crack tip opening displacement will continuously decrease. Furthermore, the decrease will gradually slow down, and tend to plane strain state ultimately. Curved crack tip dynamic opening displacement will increase when the external impact load increases with the same crack body thickness. Curved crack tip dynamic opening displacement will increase abruptly when dynamic load coefficient increases with the same crack body thickness. A new theoretical model has been established to calculate the curved crack tip dynamic opening displacement for three-dimensional crack body.
In this article, three-dimensional elastic-plastic curved crack tip opening displacement under impact load has been mainly studied, and three-dimensional curved crack tip opening displacement has been calculated using a second order perturbation method, where the effects of applied impact stresses as well as normal and shear impact stresses on the boundaries of plasticity area are taken into account. Three dimensional curved elastic-plastic crack tip opening displacement has been calculated by numerical methods. Diagrams have been constructed to analyze the transformation relationship between the curved crack tip opening displacement and the geometrical parameters of three-dimensional crack body. Curved crack tip opening displacement will decrease when three-dimensional crack body thickness increases. When crack body thickness increases uniformly, three-dimensional curved crack tip opening displacement will continuously decrease. Furthermore, the decrease will gradually slow down, and tend to plane strain state ultimately. Curved crack tip dynamic opening displacement will increase when the external impact load increases with the same crack body thickness. Curved crack tip dynamic opening displacement will increase abruptly when dynamic load coefficient increases with the same crack body thickness. A new theoretical model has been established to calculate the curved crack tip dynamic opening displacement for three-dimensional crack body.
引文
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[3]程站起,尹航.功能梯度材料斜裂纹动态扩展的近场动力学模拟[J].力学季刊,2017,38(4):641-647.
[4]陈特,杨凤鹏,兰天.恒扭对汽车薄板Ⅰ型疲劳裂纹扩展的影响[J].力学季刊,2017,38(4):772-779.
[5]朱志鹏,杨凤鹏,林峤岳.位移模式下PMI泡沫夹层结构疲劳损伤试验研究[J].力学季刊,2017,38(1):94-101.
[6]AFOLAGBOYE L O,HE J M,WANG S J.Experimental study on cracking behaviour of moulded gypsum containing two non-parallel overlapping flaws under uniaxial compression[J].Acta Mechanica Sinica,2017,33(2):1-12.
[7]SONG Y J,HU H S,RUDNICKI J W.Normal compression wave scattering by a permeable crack in a fluid-saturated poroelastic solid[J].Acta Mechanica Sinica,2017,33(2):356-367.
[8]丁遂栋,孙利民.断裂力学[M].北京:机械工业出版社,1997,148-169.
[9]杨卫.宏微观断裂力学[M].北京:国防工业出版社,1995,65-70.
[10]杨大鹏,赵耀,白玲.准静载荷作用下的弹塑性微弯延伸裂纹塑性区[J].应用力学学报,2010,27(2):401-405.
[11]郭万林,于培师.构件三维断裂与疲劳力学及其在航空工程中的应用[J].固体力学学报,2010,31(5):553-571.
[12]张斌.材料结构宏观三维断裂和微观破坏行为研究[D].南京:南京航空航天大学,2005,20-25.
[13]杨大鹏.微弯延伸裂纹断裂特性的研究[D].武汉:华中科技大学,2006,20-28,82-86.
[14]余同希,华云龙.结构塑性动力学引论[M].合肥:中国科学技术大学出版社,1994,89-100.