二维建模的水分和热量扩散在胶着地保税关节
描述
在本文的研究中,提出了一个新颖的二维模型adhesively-bonded单搭接接头(SLJ)结合机械载荷和水分/热扩散。管理本构扩散模型的偏微分方程的配方和数值求解。为个人和各种场景结合水分和热量的扩散是通过联合基质和直接到胶粘剂层进行了分析。生成的依赖所在材料模型送入控制偏微分方程中。在胶粘剂层剪切和剥离应力。结果,重点是改进了该模型预测能力的扩散模式的影响,垂直于轴向tensile-shear负载。水分扩散在发现接缝宽度有显著影响的剪切应力分布结构环氧胶粘剂弹性模量高。与线性有限元素数值对比分析。商用的材料属性是来源于实验测试双组分环氧和聚氨酯粘合剂。本文的组织结构如下:第一章“介绍和文献综述”包括的描述分析、数值计算和实验工作,作为本文的基础。先前的一维分析模型修正,动机推动这项研究工作。 Chapter Two "Modeling of Heat and Moisture Diffusion" lays the groundwork for the analysis of diffusive patterns in the joint substrates and in the adhesive layer. Multiple scenarios of moisture and heat diffusion are explored, and their effect on the elastic properties of the adhesive is investigated. Governing partial differential equations are derived, and solution strategies are discussed. Chapter Three "Elastic Model" includes the formulation of coupled stress-diffusion partial differential equations for the shear and peel stresses in the adhesive layer, resulting from the application of an external tensile-shear load on the two adherends. Equilibrium considerations, stress-strain, and strain-displacement relationships are used to generate the constitutive equations, with adequate assumptions and simplifications. Chapter Four "Elastic Modulus of Structural Adhesives: Relationship to Bulk Material Temperature" contains the experimental procedure and results for the bulk adhesive tests. The elastic moduli of two-component epoxy and polyurethane adhesives are measured using a DMA Q800, and a linear law relating temperature to material properties is inferred. Chapters Five, Six, and Seven present the results of the shear and peel stress models for adhesive joints subjected to two-dimensional moisture-only, heat-only, and combined moisture/heat diffusion, respectively. A convergence study is performed on the two-dimensional solution to the heat equation governing moisture and heat diffusion in the adhesive layer. Stress gradients along the length and width of the bondline are analyzed, and the results are compared to the previous one-dimensional coupled stress-diffusion model. The results of the two-dimensional model are compared with a Finite Elements Analysis in Chapter Eight "FEA Comparison". Chapter Nine "Conclusions and Future Work" summarizes the major findings of this dissertation research, and outlines the potential for future work.
日期
2021-11-15
主题
机械工程
粘合剂
建模
单搭接接头
应力分布
粘合剂
建模
单搭接接头
应力分布