【作者】 于英华；

【导师】 梁冰；

【作者基本信息】 辽宁工程技术大学 ， 工程力学， 2007， 博士

【摘要】 泡沫铝是近年来发展起来的一种新型材料,由于其独特的结构特点,使其具有许多良好的功能特性,在诸多应用领域显示出良好的应用前景,成为力学和材料科学等领域的研究热点。目前国内外对泡沫铝的研究取得了一定的成果,但仍有许多有待进一步研究的问题。如泡沫铝结构中的大量孔洞,使其力学性能必然有所损失,为此,如何在保持其原有功能特性的基础上进一步提高其力学性能成为该领域国内外研究学者共同关注的课题。本文采用浸渗法制备了泡沫铝/环氧树脂类复合材料,对该材料的力学行为和应用进行了研究。主要研究的内容和得出的结论如下:通过常压水浴加热向泡沫铝孔洞中渗入环氧树脂和环氧树脂纳米蒙脱土,制备出了泡沫铝/环氧树脂类复合材料。综合运用实验、有限元模拟和理论分析研究等方法对泡沫铝/环氧树脂复合材料的压缩行为进行了研究。结果表明:泡沫铝/环氧树脂复合材料压缩行为取决于泡沫铝的结构参数和填充材料的性能参数及载荷应变率。与泡沫铝相比泡沫铝/环氧树脂复合材料强度和刚度均有一定的提高,其中以渗入环氧树脂纳米蒙脱土的复合材料为最佳。泡沫铝/环氧树脂类复合材料在压缩载荷的作用下,其微观变形机制与泡沫铝相比略有改变,在准静态压缩的情况下,应力-应变曲线仍大致满足多孔材料的三阶段特征,但压缩开始时的弹性阶段,该材料的应力-应变曲线的斜率(即有效弹性模量)及平台阶段的坪应力均有一定提高,提高的程度依填充材料的性能的不同而不同;而在动态压缩的情况下,只表现出线弹性阶段和屈服平台2阶段,而没有致密化阶段,且塑性平台区比泡沫铝的高且长,尤其是泡沫铝/环氧树脂纳米蒙脱土复合材料。泡沫铝几何参数对其环氧树脂类复合材料压缩力学行为的影响规律类似于对泡沫铝的:相对密度越大,有效弹性模量和屈服平台阶段的坪应力越大;孔径对应力—应变曲线的影响受应变率的制约,对静态压缩,几乎无影响,对动态压缩有影响。在相同的应变率下,泡沫铝复合材料的压缩坪应力随孔径的增大而升高。应变率越高,升高得越多。有限元模拟方法是研究泡沫铝及其环氧树脂复合材料力学行为的一种省时、省力、低成本且较为可靠的研究方法。根据网络交织复合材料细观力学胞元方法,对泡沫铝及其环氧树脂复合材料的压缩行为进行了理论分析,建立了该材料的有效弹性模量预测模型和弹塑性本构关系框架。采用复合材料的“混合率”和“协同效应”建立了泡沫铝/环氧树脂复合材料的压缩坪应力的数学模型。通过所建立的模型与实验结果和有限元模拟结果的比较,证明所建模型的正确性。综合运用实验研究、理论分析研究方法对泡沫铝及其环氧树脂复合材料的阻尼的机理、影响因素进行了研究,并尝试建立了泡沫铝/环氧树脂复合材料阻尼的半定量化数学模型,该模型可对材料的阻尼变化规律做出合理地解释。研究表明,在泡沫铝孔隙中渗入环氧树脂特别是环氧树脂纳米蒙脱土,可进一步提高材料的阻尼性能。以泡沫铝及其环氧树脂复合材料在齿轮阻尼环中的应用为例,较系统地研究该材料在减振降噪方面应用的优越性。通过理论分析和数值模拟研究,对泡沫铝及其环氧树脂复合材料填充金属园管压缩力学行为进行了系统地研究,建立了考虑管与填充物相互作用的泡沫铝填充圆管的压缩吸能特性理论模型。在此基础上对泡沫铝/环氧树脂复合材料填充金属园管压缩吸能性进行了预见。研究结果表明:泡沫铝/环氧树脂复合材料填充圆管的吸能性优于泡沫铝填充圆管的吸能性,更优于金属空心圆管的吸能性。系统研究了泡沫铝及其环氧树脂复合材料在汽车保险杠中的应用,结果表明泡沫铝填充圆管特别是泡沫铝高分子复合材料填充圆管制造的汽车保险杠可设计性强,有利于汽车向轻质量、小体积、低能耗、安全和环保等方向发展,泡沫铝/环氧树脂复合材料在吸能缓冲应用领域具有更大的潜能。更多还原

【Abstract】 Foamed aluminum (FA) is a new-type material developing in recent years. Because of its unique structure characteristics, it has a lot of good functional properties, shows a good applying prospect in many fields and becomes the researching focus in the fields of mechanics and science of material. But because of lots of holes in the foamed aluminum, it,s mechanical properties has lost somewhat. So it becomes a significant to increase its mechanical properties on the basis of keeping its functional properties. This paper processes the foamed aluminum/ epoxy resin compound material (FA/ERCM) by the infiltration method and studies on the mechanical behavior and application of the FA/ERCM. The main contents and conclusions are as following:The FA/ERCM is perpetrated by infiltration ER and ER with nanomotmorillonite into the holes of foamed aluminum.The compressive behavior of the FA/ERCM is studied on by using the method of experiment analysis, FE simulation analysis and theoretical analysis synergistically. It is shown that the properties of FA/ERCM depend on the structure parameters and property parameters of FA and filled material and loading strain rate of force. Compared with FA, the strength and stiffness of the FA/ERCM is increased considerable, especially the ER with nanomotmorillonite. As compressed, FA/ERCM,s micro deformation was a little different from FA. The curve of stress-strain is still fit the three stage as multi-holes material, but at the beginning. Its effective elastic modulus and the plateau stress of the flat stage were increased, the degree of increase varied as the change of property of the filling material.Theσ?εcurves of FA/ERCM have tow stages (elastic stage dynamic compression and yielding stage) only, but haven’t the densification stage. Its plateau area was higher and longer than FA,s, especially that of FA/ERCM with nanomotmorillonite. The influence of FA parameters on the compressing mechanical behavior of FA/ERCM is similar to that of FA. The bigger the relative density, the bigger the effective elastic modulus and the plateau stress. The influences of diameter on theσ?εcurve depends on strain rate. It has no influence on static compression but had influence on dynamic compression. As same strain, the compressing plateau stress of FA /ERCM increase with diameter. The higher the strain rate, the more increasing. FE simulation method is a time-saving, energy-saving, low-cost and reliable method to study the mechanical behavior of foamed compound materials.By IPC micromechanics unit cell, the compressing behavior of FA /ERCM is analyzed and established model for the elastic modulus and the frame of elastic-plastic construction. The compressive plateau stresses mathematical model of FA /ERCM are established by the“Mixture Law”and“Synergistic Effect Law”of FA /ERCM. The model established was proved to be correct by experiment result and FE simulation result.We studies the mechanism and influencing factor of the damping of the FA /ERCM and establish the semi-quantitative mathematic model of FA /ERCM, which can explain the damping changing of FA /ERCM rationally. It indicated that embedding with ER especially nanomotmorillonite into FA hole can increase the damping property.By studying on the application of FA /ERCM in the gear-damping ring, we study the priority of the material in the application of noise reduction systematically.we study on the compressing mechanical behavior of the circular tube filled with FA and establish the model of energy-absorption considering the interaction of the cube and filling material. It is shown that the energy-absorption property of the circular tube filled with FA /ERCM is better filled with FA which was better than circular cube .We study the application of FA and FA /ERCM in the automobile bumper. It is shown that the automobile bumper made of circular tube filled with FA especially FA /ERCM is better design,. It is benefit automobile developing into the direction of light weight, small volume, low energy consumption, safety and environment protection. FA /ERCM have greater latent capacity in the field of application of energy-absorption and buffering.更多还原