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作为防弹玻璃夹层材料,PU的动态力学性能一直受到学者们的关注。为准确表征其动态力学性能,本文采用ABAQUS有限元软件对不同摩擦系数下的单轴压缩试验进行数值仿真,分析试样加载端面的摩擦效应和几何尺寸对单轴压缩试验结果的影响;结合高速摄影技术(HSP)与数字图像相关技术(DIC)观测到试样在拉伸试验中的动态变形场和应变场,探讨标距段的应力均衡性;同时对PU材料在不同应变率下的单轴压缩、拉伸力学性能进行测试。结果表明:压缩试样的端面摩擦效应限制横向变形,影响了试样内部的受力分布,使得测量得到的应力值偏大;试样长径比越小,端面摩擦效应的影响越大;在单轴动态拉伸试验中,板状拉伸试样的标距段选取应当考虑两端倒角尺寸。通过测试PU的拉、压力学性能,发现材料具有显著的应变率敏感性。
As a bullet-proof glass sandwich material, the dynamic mechanical properties of PU has always been the concern of scholars. In order to accurately characterize its dynamic mechanical properties, this paper uses ABAQUS finite element software to simulate the uniaxial compression tests under different friction coefficients, and analyzes the effect of the friction effect and the geometric size of the loaded end faces on the uniaxial compression test results. Combined with the high speed The dynamic deformation field and strain field of the specimen in the tensile test were observed by the technology of photographic technique (HSP) and Digital Image Correlation (DIC), and the stress balance of gauge length was discussed. At the same time, the single material of PU at different strain rates Axial compression, tensile mechanical properties of the test. The results show that the frictional effect of the end face of the compression specimen limits the transverse deformation and affects the stress distribution inside the specimen so that the stress value measured is larger. The smaller the aspect ratio of the specimen, the greater the effect of the friction effect of the face. In the uniaxial dynamic tensile test, the gauge length of the plate tensile specimen should be taken into consideration of the size of chamfer at both ends. By testing PU pull, pressure performance, found that the material has a significant strain rate sensitivity.