硬质聚氨酯泡沫在多轴压缩试验下的力学特性研究

doi:10.3901/JME.2017.20.089

摘要/Abstract

摘要： 硬质聚氨酯泡沫广泛应用于吸能装置。为研究硬质聚氨酯泡沫在多轴载荷下的力学响应，应用静水压试验和围压试验对其进行多轴压缩试验，分析其力学特性和吸能特性。结果表明：在静水压试验中，泡沫材料经历了弹性区域、平台区域和密实化区域三个阶段，相应的体积弹性模量、平台应力和单位体积吸能量均比单轴压缩试验的高；而在围压试验中，泡沫仅经历弹性阶段和峰值后阶段，无明显的平台区域和密实化区域。峰值偏应力随着围压增加而减少，但当围压超过一临界值时，偏应力-轴向应变曲线表现出一定的随机性，丧失了进一步承受轴向载荷的能力。基于试验数据和微分硬化屈服面模型，获得不同塑性应变下硬质聚氨酯泡沫的屈服面。

关键词: 多轴压缩试验, 力学响应, 泡孔形态, 屈服面, 硬质聚氨酯泡沫

Abstract: Rigid polyurethane foam is widely used as the energy absorption filling device. To research the mechanical response of the rigid polyurethane foam under multi-axial stress states, the triaxial compression experiments, including the multi-axial isobaric experiment and different confining pressure experiments, are performed. Experimental results show that the hydrostatic pressure versus volumetric strain curves go through the elastic stage, the plateau stage and the densification stage, and the corresponding bulk modulus of elasticity, plateau stress and energy absorption per unit volume are higher than that under the uniaxial compression. In addition, the axial deviation stress versus axial strain curves during the different confining pressure experiments experience the elastic stage and the peak back area stage, but no the apparent plateau stage and the densification stage. And the peak deviation stress decreases as the confining pressure increases generally. Moreover, the axial deviation stress of the rigid polyurethane foam shows evident randomness when the confining pressure exceeds a limit value, which can lead to losing the axial load carrying capacity. Based on the experimental data and the differential hardening model, the yield surface of the rigid polyurethane foam considering strain hardening are obtained.

Key words: cell morphology, mechanical response, multiaxial compression experiment, rigid polyurethane foam, yield surface

中图分类号:

U465

曲杰, 胡焱松, 岳凯, 张国杰. 硬质聚氨酯泡沫在多轴压缩试验下的力学特性研究[J]. 机械工程学报, 2017, 53(20): 89-97.

QU Jie, HU Yansong, YUE Kai, ZHANG Guojie. Research on the Mechanical Properties of Rigid Polyurethane Foam in the Multiaxial Compression Experiment[J]. Journal of Mechanical Engineering, 2017, 53(20): 89-97.

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