【作者】 孔凡荣；

【导师】 游敏；

【作者基本信息】 三峡大学 ， 机械制造及其自动化， 2004， 硕士

【摘要】 本文在对国内外关于金属-胶层复合材料接头力学性能数值研究及发展现状进行综述的基础上,运用有限元法并结合实验手段主要研究了胶接接头承载后的力学行为,综合考虑了几何尺寸和物性参数对接头强度和应力分布的影响,并运用层次分析法对胶接质量进行综合评估,综合考虑接头形式,制造工艺,操作人员素质等因素的影响。运用弹塑性有限元法研究了搭接长度对单搭接胶接接头工作应力分布的影响,指出胶粘剂本身性能直接影响接头应力分布规律,增加搭接长度能够降低搭接端部应力集中,改善接头力学性能。三维弹性和弹塑性有限元分析结果表明劈裂载荷作用下的胶接接头应力场是复杂的三维分布,但对接头强度起主要决定作用的为正应力,剪切应力作用不明显;数值分析表明胶层内应力分布比较复杂,应力峰值产生在胶层左端;试样宽度方向上正应力呈中间高两边低分布态势,沿胶接长度正应力呈非线性下降趋势,并在加载过程中接头各点处应力呈三维传递趋势;实验结果与数值模拟相吻合。运用三维弹塑性有限元法分析胶层厚度,弹性模量和泊松比对劈裂接头应力分布的影响;结果表明胶层厚度增大,则胶层中各向正应力峰值降低,应力集中程度减弱,同时剪切应力却有所回升;在不引起较大胶层缺陷条件下采用较厚胶层对提高劈裂接头强度有利,实验结果与数值分析相吻合;胶粘剂弹模或泊松比越高,胶层内应力分布重心向左端移动,左端应力集中加强,峰值应力上升,但是泊松比对胶层最大主应力峰值的影响不如弹性模量的影响明显;同时考察了被粘物弹性模量和泊松比对劈裂接头应力分布的影响,总体上来说,被粘物弹模上升胶层应力集中趋于缓和,各向正应力峰值呈下降趋势,同时承载条件一定时,被粘物泊松比对劈裂接头应力分布的影响很小;还对被粘物与胶粘剂弹性模量之比,泊松比之比对劈裂接头界面应力分布的影响进行了有限元分析,结果表明两者弹模之比一定时,接头应力分布规律亦相同,即接头应力分布规律与两者弹模之比存在直接关系;与之相反,两者泊松比之比一定时,接头应力分布规律随着泊松比值变化而差异很大。更多还原

【Abstract】 In this dissertation, the mechanical behavior of the metal adhesively bonded composite joints under loading have been systematically investigated by numerical calculation methods and experiments, and effects of shape dimensions and physical parameters of joints on stress distribution and strength of adhesively bonded joints have been placed emphasis upon. Based on a review of its current states and developing tendency all over the world, the thesis presents some new achievements in the theoretical analysis in this field. Components qualities of bonding technology are influenced by many factors, which is complicated. This paper evaluates the quality of bonding technology based on analytical hierarchy process, which provides theory reference for quality controlling process, and proving it proper in contact with examples.The stress distribution of adhesively-bonded metal/metal single lap joints under tensile shear loading is analysed using elastic-plastic finite element method (FEM) .The influence of lap length on the strength of adhesively bonded metal joints which are bonded with phenolic resin and acrylic resin respectively is discussed in detail. It is shown that adhesive has great influence on the stress distribution of the lap region. With the increment of lap length, the stress concentration of adhesive layer decreases.The stress distribution of adhesively bonded metal/metal single lap joints under cleavage loading has been analyzed using three-dimensional elastic or elasto-plastic finite element method (FEM), stress state in adhesive layers and adherend is complex, and there exist mostly normal stress components. There exist greater stresses at left edge of bondline than those other region in adhesive layer. However, observations have been made in particular on normal and shear stress components at the interfaces and the middle of adhesive layer and in the upper adherend 3 mm parallel to the interface of ahesive- adherend, which provides useful insight into the 3D nature of the problem. For verification, experiments were performed on the joint strength. The analytical results were consistent with the experimental ones.And the effects of adhesive thickness, elastic modulus and Poisson’s ratio of adhesive or adherend, the ratio of elastic modulus of adherend to adhesive, the ratio of Poisson’s ratio on the stress distribution at the interface were clarified by numerical calculation. The analysis with elasto-plastic materials’behavior was performed in order to include a more general situation. It is shown that adhesive has great influence on the stress distribution of更多还原