Insights into the micromechanical response of adhesive joint with stochastic surface micro-roughness
Insights into the micromechanical response of adhesive joint with stochastic surface micro-roughness
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DOI：
10.1016/j.engfracmech.2022.108954
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发表时间：
2022-11
影响因子：
5.4
通讯作者：
Xing-er Wang;Kai Pang;Xu-Hao Huang;Jian Yang-;Jianqiao Ye;X. Hou
中科院分区：
文献类型：
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作者：
Xing-er Wang;Kai Pang;Xu-Hao Huang;Jian Yang-;Jianqiao Ye;X. Hou
粘合表面的微观粗糙度对粘合接头的结构行为产生重大影响。对微观机械机制的研究极其有限。这项工作开发了一种新颖的基于粒子的接头模型，具有随机的粗糙度微观结构特征，可以捕获精细的多尺度响应，这是此类模型中的第一个。首先使用 3D 激光扫描显微镜对经过机械表面处理的铝被粘物进行扫描。确定了微观粗糙度轮廓的统计特征和重建方法。对由环氧树脂粘合剂 (Loctite EA 9497) 和经过处理的铝粘合体制成的接头进行单搭接剪切测试，以提供测试数据和失效模式观察结果。随后开发了精细的数值模型，以检查实际微观粗糙度对微观机械行为和失效机制的影响。研究了机械联锁、减缓由于不规则粗糙度导致的裂纹扩展。接下来介绍各种大小的重建粗糙度，并通过均方根粗糙度和相关长度等关键随机参数进一步对微机械响应进行数值检查。结果表明，机械互锁对增强接头强度的贡献大于微粗糙度增加粘合面积的贡献。水平或垂直方向上较粗糙的表面不会表现出接头强度的一致改善，这也取决于触发失效模式转变的粗糙度阈值和表面偏斜度。
Micro-roughness at adhesion surface yields significant influences on the structural behaviour of adhesive joints. Investigations into the micromechanical mechanism are extremely limited. This works developed a novel particle-based model of joints with stochastic microstructural features of roughness, which can capture refined multi-scale responses as first of this kind. Aluminium adherends with mechanical surface treatments were firstly scanned using 3D laser scanning microscope. The statistical features and reconstruction method of micro-roughness profiles were determined. Single lap shear tests on joints made of epoxy adhesive (Loctite EA 9497) and treated aluminium adherends were performed to provide testing data and observations on failure modes. The refined numerical models were subsequently developed to examine the influences of the actual micro-roughness on the micromechanical behaviors and failure mechanism. The mechanical interlocking, mitigation on crack propagation due to the irregular roughness were investigated. It is followed by introducing the reconstructed roughness of various magnitudes and further numerically examining the micromechanical responses by key stochastic parameters such as root mean square roughness and correlation length. The results indicate that the mechanical interlocking contribute more to enhancing the joint strength than the increase of adhesion area by micro-roughness. A rougher surface in either horizontal or vertical directions does not exhibit a consistent improvement of joint strength, which also depends on the threshold of roughness and the surface skewness triggering the transition of failure modes.