The influence of notching and mixed-adhesives at the bonding area on the strength and stress distribution of dissimilar single-lap joints
The influence of notching and mixed-adhesives at the bonding area on the strength and stress distribution of dissimilar single-lap joints
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DOI：
10.1016/j.compstruct.2020.112136
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发表时间：
2020-06-01
影响因子：
6.3
通讯作者：
Ye, Jianqiao
中科院分区：
文献类型：
--
作者：
Kanani, Armin Yousefi;Hou, Xiaonan;Ye, Jianqiao
随着新型工程材料的快速发展，多材料结构被广泛采用来代替传统的结构以达到预期的性能。在过去的几十年里，在航空航天、海事、民用和运输结构中越来越多地使用不同的粘结物，如复合材料和金属，这使得寻找方法来改善这类接头的性能变得至关重要，因为这种类型的接头有可能成为轻量化产品。这项研究的第一个目的是通过在粘合区引入缺口来最大限度地减少峰值应力集中，以提高使用环氧胶的单搭接接头的性能。这是通过利用ABAQUS(R)软件中的有限元方法(FEA)对具有各种缺口设计的一系列单搭接接头(SLJ)进行建模以找到最佳方案来实现的。对设计进行了试验验证，并利用优化设计对不同粘结物的单层搭接接头和混合粘接接头进行了建模，优化了不同粘接材料的单搭接接头。这种新的几何修改显著降低了粘结物不同的接头处的峰值应力，从而导致沿粘结线的不对称应力分布较小。试验结果表明，异种接头强度有明显提高。与使用单一材料作为胶粘剂相比，同时使用环氧树脂和聚氨酯作为胶粘剂可以提供更高的破坏载荷。这可以解释为，通过将应力集中转移到重叠长度的内部，聚氨酯胶粘剂提供了更均匀的应力分布。
With the rapid development of new engineering materials, multi-material structures are now widely used to achieve desired performances instead of conventional ones. The increased use of dissimilar adherends such as composites and metals for joining structural parts in aerospace, maritime and civil and transport structures in the past decades make it essential to find methods to improve the performance of this type of joints due to the potential for lightweight products. The first aim of this research is to minimise peak stress concentration by introducing notches in the bonding area to increase the performance of single-lap joints with epoxy adhesive. This is done by utilising the finite element method (FEA) in Abaqus (R) software to model a series of single lap joints (SLJ) with various notch designs to find the optimum. Experimental tests are carried out to verify the designs.The optimal design is used then to model various SLJs with mono-adhesive and mixed-adhesives to optimise single-lap joints with dissimilar adherends. The novel geometrical modification reduces peak stresses significantly in the joints with dissimilar adherends, which leads to smaller asymmetric stress distribution along bond-line. The experimental results show significant improvement in the dissimilar joint strength. Compared with using a single material as the adhesive, it is found that using both epoxy and polyurethane as adhesive offers a higher failure load. This can be explained as the polyurethane adhesive provides more uniform stress distribution by transferring stress concentration to the interior part of the overlap length.