折曲胶接接头应力分布的数值分析

运用有限元法研究了偏轴、同轴和折曲型等三种单搭接胶接接头的工作应力分布规律。结果表明：与其他两种接头相比,折曲型单搭接胶接接头可有效降低搭接区端部的剥离应力和剪切应力峰值;在数值分析所用参数及条件下,Ⅰ型折曲接头的剥离应力降幅超过了75％,其他峰值应力的降幅也超过了45％～50％,并且应力分布趋于均匀;Ⅰ型折曲接头使出现应力峰值的位置从搭接区的端部转移至中部,从而显著提高了接头的承载能力,是一种优于普通同轴接头的胶接接头形式;对于受剪切载荷作用的接头而言,采用Ⅱ型折曲接头更为合理,可进一步提高接头承受剪切载荷的能力。     

折曲单搭接胶接接头应力分布探讨

在同轴单搭接胶接接头的基础上,设计了一种新型折曲单搭接胶接接头。通过有限元方法研究了折曲胶接接头和同轴胶接接头的应力分布规律。研究结果表明:折曲单搭接胶接接头搭接区两端的应力峰值下降幅度均超过40%,并使搭接区出现应力峰值的位置从搭接区端部转移到中部,从而显著地提高接头的承载能力。当L1=7.5 mm时,胶层中应力分布较为理想,各应力呈对称分布,是一种优于普通同轴的胶接接头形式。     

胶粘剂弹性模量对折曲胶接接头应力分布的影响

通过ANSYS有限元软件建立了折曲胶接接头的弹塑性有限元模型,考察了胶粘剂的力学性能参数弹性模量对其应力分布的影响。研究结果表明:四种不同的胶粘剂,其弹性模量越大,胶层中各应力的峰值越大,搭接区被粘物剥离应力峰值逐渐呈现出上升的趋势;当胶粘剂弹性模量为50 MPa时,被粘物的各应力分量存在较大的应力尖角(应力集中现象)。     

同轴单搭接胶接接头应力分布的探讨

利用有限元方法研究了偏轴单搭接胶接接头和同轴单搭接胶接接头的力学性能.结果表明,同轴单搭接胶接接头可以使接头搭接末端的弯矩变为零,进而有效地降低剥离应力的峰值,减轻剪切应力的集中程度,是一种较为合理的胶接接头形式.     

斜削对折曲胶接接头的应力分布影响

采用弹塑性有限元法,研究了被粘物自由端外侧、内侧斜削角度对铝合金单搭接折曲接头中应力分布的影响。结果表明:被粘物自由端经外斜削处理后,胶层中间段的各应力分布无明显变化;外斜削角度越大,剥离应力峰值越高;被粘物自由端经内斜削处理后,内斜削角度越小,胶层端部的轴向应力峰值、剪切应力峰值越小,但剥离应力峰值越大。综合考虑胶层中部的应力分布情况,选择内斜削角度为5°时较适宜。     

胶接接头耐久性的综合研究

以AG—80/DDS、环氧—聚砜和环氧—丁腈结构胶为胶粘剂,45~#钢和LY_(12)—CZ铝合金为被粘材料,综合研究了胶接接头的耐久性。研究结果表明,除胶粘剂外,内外应力、温度、介质和被粘物的表面状态均是影响接头耐久性的重要因素。激光双折射法测定胶接接头内应力是较可行的新方法。     

单搭接胶接接头胶层的拓扑优化

利用有限元法,对单搭接胶接接头胶层进行拓扑优化,寻求胶粘剂最佳分配.结果表明,合理的胶粘剂分配能够在不影响接头整体力学性能的前提下,极大限度地减少胶粘剂的用量,且使胶粘剂中剪切应力分布更为均匀.     

同轴单搭接胶接接头力学性能的研究

利用有限元方法研究了偏轴单搭接胶接接头和同轴单搭接胶接接头的力学性能,结果表明：同轴单搭接胶接接头可以使接头趾部的弯矩为零,进而有效地降低剥离应力的峰值和减轻剪切应力的集中程度,是一种极为合理的胶接接头形式。     

胶接接头受劈裂载荷作用应力分布研究

对金属胶接接头劈裂试样承载后的应力分布情况进行了实测分析，结果表明胶层沿胶接面试样长度方向上受到分布较宽的拉伸力的作用，印证了作者所提出的胶接接头受劈裂载荷作用力学模型是符合实际的。     

基于ANSYS/PDS的铝合金折曲胶接接头可靠性分析

运用有限元法的概率设计系统(ANSYS/PDS),通过设定铝合金折曲胶接接头的几何尺寸、载荷、弹性模量等各参数为随机输入变量,采用蒙特卡罗有限元方法分析了各随机变量对接头胶层中最大剪应力的影响。研究结果表明:通过400次的拉丁超立方抽样法进行样本抽样,得出铝合金折曲胶接接头失效的概率;胶粘剂剪切强度、载荷对接头可靠性的影响最为显著,置信度为99.5%时,其可靠度为99.99%。     

胶粘剂特性和厚度对劈裂载荷作用下胶接接头应力分布的影响

运用三维弹塑性有限元法对劈裂栽荷作用下的胶接接头(即劈裂接头)承载后的应力分布特征进行了分析，重点研究了胶粘剂层厚度对劈裂接头应力分布的影响。结果表明，胶粘剂的性能对应力分布有较大影响，提高胶粘剂强度和减小胶层厚度，均导致胶层应力集中加剧，各向正应力峰值呈上升趋势，各向剪切应力则正好相反；并且劈裂接头中应力分布以三向主应力为主，剪切应力的存在亦不可忽略。故在不引起过大应力集中和较大胶层缺陷条件下采用高强度的胶粘荆和较厚胶层对提高劈裂接头强度有利，实验结果与有限元分析相吻合。     

A microcomputer program for stress analysis of adhesive-bonded joints

This paper presents the equations used in a stress analysis program for adhesive-bonded joints which is based on the finite element method and is written in BASIC for HP-9000 series computers. Thermal expansion of both the adherends and the adhesive layer is considered.     

Geometrically non-linear analysis of adhesively bonded corner joints

When adhesively bonded joints are subjected to large displacements, the small strain-small displacement (linear elasticity) theory may not predict the adhesive or adherend stresses and deformations accurately. In this study, a geometricaly non-linear analysis of three adhesively bonded corner joints was carried out using the incremental finite element method based on the small strain-large displacement (SSLD) theory. The first one, a corner joint with a single support, consisted of a vertical plate and a horizontal plate whose left end was bent at right angles and bonded to the vertical plate. The second corner joint, with a double support, had two plates whose ends were bent at right angles and bonded to each other. The final corner joint, with a single support plus angled reinforcement, was a modification of the first corner joint. The analysis method assumes that the joint members, such as the support, plates, and adhesive layers, have linear elastic properties. Since the adhesive accumulations (spew fillets) around the adhesive free ends have a considerable effect on the peak adhesive stresses, they were taken into account. The joints were analyzed for two different loading conditions: one loading normal to the horizontal plate plane P_y and the other horizontal loading at the horizontal plate free edge P_x. In addition, three corner joints were analyzed using the finite clement method based on the small strain-small displacement (SSSD) theory. In predicting the effect of the large displacements on the stress and deformation states of the joint members, the capabilities of both analyses were compared. Both analyses showed that the adhesive free ends and the outer fibres of the horizontal and vertical plates were subjected to stress concentrations. The peak stresses appeared at the slot corners inside the adhesive fillets and at the horizontal and vertical plate outer fibres corresponding to the locations where the horizontal and vertical adhesive fillets finished. The SSLD analysis predicted that the displacement components and the peak adhesive and plate stress components would show a non-linear variation for the loading condition P_x, whereas the SSSD analysis showed smaller stress variations proportional to the applied load. However, both the SSLD and the SSSD analyses predicted similar displacement and stress variations for the loading condition P_y. Therefore, the stress and deformation states of the joint members are dependent on the loading conditions, and in the case of large displacements, the SSSD analysis can be misleading in predicting the stresses and deformations. The SSLD analysis also showed that the vertical and horizontal support lengths and the angled reinforcement length played an important role in reducing the peak adhesive and plate stresses.     

含镶嵌块单搭接接头应力分布的数值分析

利用有限元方法研究了金属镶嵌对单搭接接头应力分布的影响。结果表明,采用镶嵌块组成混合连接接头,改变了接头的应力流线分布,镶嵌块承载,降低了搭接区中部胶层中的应力;同时使被粘物中部的应力增大,提高了接头搭接区中部的承载能力;在重要部件或承载较大等情况下使用胶接接头,建议采用金属镶嵌方式对接头增强,具有更强的承载能力和可靠性,有重要的实用价值。     

蜂窝夹层结构面板胶粘剂的研究

介绍了蜂窝夹层结构用面板胶SY -2 4B胶膜的力学性及工艺性能 ,并将其与双组分糊状胶SY -2 1作对比。实验结果表明 ,SY -2 4B胶膜具有更高的综合性能与耐疲劳性能 ,制成的蜂窝夹层结构具有更高的可靠性     

A method for predicting the curing residual stress for CFRP/Al adhesive single-lap joints

The purpose of this paper is to present a prediction model of the curing residual stress for carbon fiber reinforced plastic (CFRP) and aluminum (Al) adhesive single-lap joints. Based on the lamination theory and formation mechanism of the curing residual stress of composite structures, we have found that high curing temperature in joints will lead to a significant increase of the residual stress. In the CFRP/Al stacks, residual tensile stresses are found in the Al and glue layer, while compressive stresses in CFRP. Meanwhile, the residual stress in glue layer is smaller than that in the Al and CFRP. More comparisons are made among the prediction, finite element analysis (FEA) and experimental tests to prove the efficiently and validity of the predicting model.     

A two-dimensional stress analysis and strength evaluation of band adhesive butt joints subjected to tensile loads

The stresses in band adhesive butt joints, in which two adherends are bonded partially at the interfaces, are analyzed, using a two-dimensional theory of elasticity, in order to demonstrate the usefulness of the joints. In the analysis, similar adherends and adhesive bonds, which are bonded at two or three regions, are, respectively, replaced by finite strips. In the numerical calculations, the effects of the ratio of Young's moduli for adherends to that for adhesives, the adhesive thickness, the bonding area and position, and the load distribution are shown on the stress distributions at interfaces. It is seen that band adhesive joints are useful when the bonding area and positions are changed with external load distributions. Photoelastic experiments and the measurement of the adherend strains were carried out. The analytical results are in a fairly good agreement with the experimental results. In addition, a method for estimating the joint strength is proposed by using the interface stress distribution obtained by the analysis. Experiments concerning joint strength were performed and fairly good agreement is found between the estimated values and the experimental results.     

混合胶接劈裂接头胶层中应力分布的数值分析

采用ANSYS有限元分析软件,对由两种弹性模量相差悬殊的丙烯酸酯和环氧树脂胶粘剂连接的劈裂接头胶层中部的应力分布进行数值分析和讨论。结果表明:对于采用单一胶连接的劈裂接头来说,采用弹性模量较低的胶粘剂更为有利;混合胶劈裂接头因其存在应力集中程度较高,会导致接头的强度降低。     

台阶搭接铝合金接头应力分布的数值分析

用弹塑性有限元法研究了被粘物上台阶高度和长度对铝合金单搭接接头胶层中应力分布的影响。结果表明,被粘物自由端内侧的台阶使搭接区接头端部处的应力峰值显著下降,应力向搭接区中部转移;胶层中应力峰值大体上随着台阶高度的增大而降低,随台阶长度的增大而向中部转移;当台阶高度为0．5mm而台阶长度为4．5mm时,接头上胶层中应力分布较好。