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摘要: 针对泡沫杆撞击刚性壁的情形建立了2类动态压溃模型:一维冲击波模型和三维细观有限元模 型。以连续介质框架下的应力波理论为基础,并假定了刚性-非线性塑性硬化的加载和刚性卸载的本构关系, 建立了一维冲击波模型,给出了冲击波波后应变与冲击时间的隐式表达式。利用随机Voronoi技术构建了闭 孔泡沫金属结构的三维细观有限元模型,使用ABAQUS/Explicit有限元软件模拟了泡沫材料的动态压溃过 程,并基于最小二乘法计算局部变形梯度和局部应变得到了三维泡沫结构的应变场。通过理论解和数值解的 比较,发现该理论模型能够较好地预测泡沫金属杆撞击刚性壁的力学行为,得到了较为精确的结果。Abstract: Aone-dimensionalshockmodelandathree-dimensionalcell-basedfiniteelementmodelare developedforthedynamiccrushingofametallicfoamrodstrikingarigidwall.Theshockmodelis proposedbyusingthecontinuum-basedstresswavetheoryandassumingarate-independent,rigidnonlinearhardeningplasticconstitutiverelationofthefoam, thenanimplicitexpressionfordeterminingtherelationbetweenthelocalstrainbehindtheshockfrontandtheimpacttimeisobtained. The cell-basedfiniteelementmodelofaclosed-cellaluminumfoamisconstructedbythethree-dimensional Voronoitechnique,anditsdynamiccrushingprocessissimulatedbyusingtheABAQUS/Explicit code.Theleastsquaresmethodisusedtocalculatethedeformationgradientandlocalstrainfield. Comparingwiththesimulationresults,theshockmodelpresentsgoodpredictionsofthestressand strainbehindtheshockfront.
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Key words:
- solidmechanics /
- shockmodel /
- Voronoistructure /
- metallicfoam /
- localstrainfield
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