非均质多孔泡沫弹性力学性能及导热性能的研究

发布时间：2018-03-07 18:14

本文选题：多孔泡沫材料　切入点：弹性模量　出处：《重庆大学》2015年硕士论文　论文类型：学位论文

【摘要】：多孔泡沫材料是一种由形成孔穴的棱边和壁面的固体杆或固体板所构成新型功能材料。相对于常规材料而言,多孔泡沫材料具有表观密度低、比表面积大、比强度高、耐高温等特点。航空航天、汽车工业、电子科技等行业的迅猛发展,对材料提出更多的要求,包括优良的热性能,良好的机械性能、减震、吸能等。多孔泡沫材料与常规材料相比,可以更好的满足这些要求,适应未来的发展,因此对其性能的研究尤为重要。与连续介质相比,多孔泡沫材料包含大量孔隙。孔隙的存在导致预测多孔泡沫材料性能变得复杂。目前大部分对泡沫材料性能的研究仅考虑孔隙率对于材料性能的影响。但实际的多孔材料大多是非均质的,孔隙结构的随机性、非周期性也会影响材料性能。本文用数值模拟的方法对非均质泡沫材料的线弹性压缩过程及导热过程进行模拟,研究孔隙结构对泡沫材料弹性力学性能及导热性能的影响。本文主要研究内容包括:建立多孔泡沫材料三维模型。基于面心立方体单元分别建立了D-R非均质模型和D-C-R非均质模型。分别定义了两种模型的孔隙均匀度,用孔隙均匀度来表征多孔泡沫材料的结构随机性。弹性力学性能方面,运用Auto CAD建立大量的D-R模型,采用有限元分析软件ANSYS进行线弹性压缩过程的模拟分析,计算材料的相对弹性模量。结果表明相对弹性模量同时受孔隙率和孔隙均匀度的影响。随着孔隙均匀度的减小,材料随机性增大,相对弹性模量减小。提出了非均质多孔泡沫材料相对弹性模量的预测式。导热性能方面,运用Auto CAD建立大量的D-C-R模型,导入有限元分析软件ANSYS进行导热过程的数值模拟,计算材料的相对有效导热系数。结果表明相对有效导热系数不仅与孔隙率有关,还受孔隙均匀度的影响。随着孔隙均匀度的减小,材料随机性增大,材料导热性能增强,相对有效导热系数增大。建立了非均质多孔泡沫材料相对有效导热系数预测式。本文做大量非均质泡沫导热过程和线弹性压缩过程的模拟,为非均质多孔泡沫的研究提供参考经验。
[Abstract]:Porous foam material is a new type of functional material consisting of solid rods or solid plates forming holes in edges and walls. Compared with conventional materials, porous foam materials have low apparent density, large specific surface area and high specific strength. The rapid development of aerospace, automobile, electronics and other industries, put forward more requirements for materials, including excellent thermal performance, good mechanical performance, shock absorption, Compared with conventional materials, porous foam materials can better meet these requirements and adapt to future development, so the study of their properties is particularly important. Porous foam materials contain a large number of pores. The existence of pores makes predicting the properties of porous foam materials more complicated. At present, most researches on the properties of foam materials only consider the effect of porosity on the properties of materials. Porous materials are mostly heterogeneous, The randomness and non-periodicity of pore structure also affect the properties of materials. In this paper, the linear elastic compression process and thermal conductivity process of heterogeneous foam materials are simulated by numerical simulation. The effect of pore structure on the elastic and thermal properties of foam materials is studied. The main contents of this paper are as follows: the three-dimensional model of porous foam material is established. The D-R heterogeneous model is established based on the surface cube element. And D-C-R heterogeneous model. The porosity uniformity of the two models is defined respectively. The porosity uniformity is used to characterize the structural randomness of porous foams. In terms of elastic mechanical properties, a large number of D-R models are established by Auto CAD, and the linear elastic compression process is simulated and analyzed by the finite element analysis software ANSYS. The results show that the relative modulus of elasticity is affected by both porosity and porosity uniformity. With the decrease of porosity, the randomness of the material increases. The relative elastic modulus is reduced. The prediction formula of relative elastic modulus of heterogeneous porous foams is proposed. In terms of thermal conductivity, a large number of D-C-R models are established by using Auto CAD, and the numerical simulation of the thermal conductivity process is carried out by introducing the finite element analysis software ANSYS. The results show that the relative effective thermal conductivity is not only related to porosity, but also affected by pore uniformity. With the decrease of porosity, the randomness of materials increases and the thermal conductivity of materials increases. The prediction formula of relative effective thermal conductivity of heterogeneous porous foams is established. In this paper, a large number of heat conduction processes and linear elastic compression processes of heterogeneous foams are simulated. It provides reference experience for the study of heterogeneous porous foam.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB34

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