Three-Dimensional Stress Analysis of Single Lap Adhesive Joints with and without a Hole

Stress analysis;Adhesive bonding;Lap joints;3D stresses;Joint deformation;Magnesium substrate;Joint strength;Light weight materials;Automotive Engineering;Automotive Systems Engineering, College of Engineering & Computer Science

Bansal, RajatJayaraman, Tanjore V. ;

University of Michigan

关键词: Stress analysis;    Adhesive bonding;    Lap joints;    3D stresses;    Joint deformation;    Magnesium substrate;    Joint strength;    Light weight materials;    Automotive Engineering;    Automotive Systems Engineering, College of Engineering & Computer Science;   

Others  :  https://deepblue.lib.umich.edu/bitstream/handle/2027.42/142371/Thesis%20Report_Rajat%20Bansal_02022018.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Conventional joining techniques, such as resistance spot welding and gas metal arc welding are commonly used for sheet metal steel parts in automotive applications. While there is a rising need for utilizing light weight metals, such as aluminum alloys, magnesium alloys and fiber reinforced composites in body in white (BIW) applications,finding joining technologies compatible with properties of these new materials without compromising on the joint strength is very challenging. Unlike steels, welding techniquesare not suitable for most lightweight materials; so there is a major need to explore other joining techniques such as adhesive bonding, that can provide for high joint strength and long term structural integrity. This study focuses on determining stresses in an adhesive bonded lap joint between two magnesium substrates with and without a hole. The prime motivation for this work is to investigate if the stresses in the adhesive layer can be reduced by either applying lateral pressure in the overlap area or by combining the adhesive joint with a mechanical fastener. Since mechanical fastening using a bolted connection requires drilling a hole through the substrates and the adhesive layer, the effect of a hole on the stresses in the adhesive layer is also of interest in this study. Alinear elastic three-dimensional finite element stress analysis was performed to determine stresses in a single lap adhesive joint of two magnesium substrates under a tensile force. Stress distributions in the length, thickness and width directions of the adhesive layer were determined and the effect of substrate thickness difference on the maximum stresses were examined. In an adhesive joint without a hole, high tensile peel stress andhigh in-plane shear stress are present at the lap ends, both of which are known to contribute to joint failure. Thedifference in substrate thicknesses increases both peel and shear stresses. The lateral pressure in the overlap area creates compressive stressesthat can be beneficial in preventing failure due to high peel and shear stresses at the lap ends. With a hole at the center of the overlap, high tensile stresses are created at the hole boundary. If a clamping pressure is applied around the hole, these stresses are reducedsubstantially and can even become compressive in nature, which is also beneficial for improved joint strength.