PMMA/CNT微孔泡沫复合材料的本构方程与吸能特性研究

Investigation on the Constitutive Equation and Energy Absorption Properties of PMMA/CNTs Microcellular Composite Foam

采用超临界二氧化碳发泡方法制备不同密度的聚甲基丙烯酸甲酯(PMMA)/碳纳米管(CNT)微孔发泡复合材料,并详细研究了该材料的压缩性能、本构方程与吸能特性。基于非线性唯象本构模型拟合得到了PMMA/CNT微孔发泡复合材料在准静态压缩下的本构方程,并基于此获得该材料的吸能特性。从吸能特性的分析结果可知,PMMA/CNT微孔发泡复合材料的吸收能量、吸能效率与理想吸能效率均与密度相关。当应变相同时,密度越大,吸收能量越大。不同密度的发泡样品的吸能效率峰值和应力大小有关,当材料密度为325kg/m^3,应力为16.94MPa时,微发泡复合材料吸能效率达到极大值,为0.38。当材料密度为300kg/m^3且应变为0.35时,吸能效率达到极大值0.79,此时最接近理想吸能材料。

In this paper,polymethyl methacrylate(PMMA )/carbon nanotubes(CNTs)microcellular foamed composites with different densities were prepared by supercritical carbon dioxide foaming method.The compressive properties,constitutive equation and energy absorption properties of the composites were studied.Based on the nonlinear phenomenological constitutive model,the constitutive equation of PMMA/CNTs microcellular foamed composites under quasi-static compression were simulated and the energy absorption characteristics of the composites were studied.Results show that the energy absorption,energy absorption efficiency and ideal energy absorption efficiency of PMMA/CNTs microcellular foamed composites are related to the density.At the same strain,the absorbed energy increases with the increase of density.The maximum energy absorption efficiency of different densities of foamed composites is related to the stress.When the density is 325 kg/cm 3 and the stress is 16.9 MPa,the energy absorption efficiency of the foam could reach 0.38.When the material density is 300 kg/m 3 and the strain is 0.35,the ideal energy absorption efficiency could achieve the maximum value of 0.79,which is closest to the ideal energy absorption material.