摘要
基于聚甲基丙烯酸甲酯(PMMA)/碳纳米管(CNT)微孔发泡复合吸能材料,建立了一种等密度差密度梯度泡沫模型,通过在非线性唯象本构模型拟合得到的准静态压缩下的本构方程,计算了泡沫模型在不同载荷下的吸能效率分布特性及相应优劣势。系统研究了泡沫模型层间密度差、上下限密度差、泡沫层厚度梯度规律3种因素对梯度泡沫吸能效能的影响规律。结果表明,层间密度差为25 kg/m3与50 kg/m3的泡沫吸能效能较好;上下限密度差越小,吸能效率的峰值越高,在较低载荷的吸能效能会越差;单层密度接近于平均表观密度的泡沫层越厚,吸能效率峰值会越高。基于实验结果优化设计了一种吸能效率峰值达到0.326且吸能效能在<15 MPa载荷范围内相对于均质泡沫更有优势的梯度泡沫。这些结果对于密度梯度吸能材料的设计思路具有重要指导意义。
Compared to homogeneous foams,the density-graded foams have significant advantages such as lighter weight and better energy-absorption efficiency.To investigate the influence factors of the energy-absorption characteristics of densi-ty-graded foams and optimize their design,this paper focused on a microcellular energy-absorption foam based on poly(me-thyl methacrylate)and carbon nanotubes.A graded foam model was established with an equal interlayer density difference.Through the nonlinear phenomenological constitutive model fitting of a constitutive equation under the quasi-static compre-ssion,the distribution features and corresponding advantages and disadvantages of energy absorption efficiency of the foam model were calculated under different loads.The influence rules of interlayer density difference,upper and lower density di-fferences and thickness graded rule of foam layer on the energy absorption efficiency of the foam model were studied.The re-sults indicated that the foams with interlayer density differences of 25 kg/m3 and 50 kg/m3 exhibited a better energy absorp-tion capability.With reducing the upper and lower density difference,the peak of energy absorption efficiency increased,but the energy absorption efficiency at lower loads decreased.The peak of energy absorption efficiency increased with an in-crease in the thickness of the foam layers,whose density was closer to the apparent density.based on the experimental re-sults,an optimal graded foam model was established,leading to a peak value of 0.326 for energy absorption efficiency as well as a better energy absorption capability than homogeneous foam within the loading range of 15 MPa.These results can provide an important guiding significance for the design of density gradient materials for energy absorption.
出处
《中国塑料》
CAS
CSCD
北大核心
2021年第5期32-39,共8页
CHINA PLASTICS
基金
国家自然科学基金(51932006)
湖北省技术创新专项重大项目(2019AFA176)。
关键词
梯度泡沫
碳纳米管
聚甲基丙烯酸甲酯
复合材料
微孔泡沫
准静态压缩
吸能性能
graded foam
carbon nanotube
poly(methyl methacrylate)
composite
microcellular foam
quasi-static compression
energy-absorption performance
