Adhesive bonding is a commonly used technology for joining dissimilar materials. However, production-related effects on the performance of the bondline have to be considered for an accurate joint design. In case of an adhesive joint in an automotive multi-material body in white, these effects arise from the so-called mismatch in thermal expansion coefficients, which leads to distortions of the adhesive in an uncured state or even damage in the cured one. The distortion of the uncured adhesive in the normal direction is called the ‘viscous fingering effect’, which reduces the adhesively bonded cross section by changing the adhesive bondline's shape to thin ‘fingers’ and therefore influences the materials properties. To investigate the effect of viscous fingering on the modulus, strength and energy release rate, linear butt bonded specimens and Tapered Double Cantilever Beams (TDCB) with different elongations of the adhesive bondline in the viscous state are investigated. The results are used to parameterize a cohesive zone model (CZM) and perform numerical analysis of the TDCB specimen for validation and to build up a model of a dissimilar joint consisting of a steel hatprofile and an adhesively bonded aluminum panel subjected to thermal distortions.

中文翻译：

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生产相关对连接异种材料的结构胶粘剂胶层性能的影响

粘合剂粘合是连接异种材料的常用技术。然而，为了准确的接头设计，必须考虑与生产相关的对胶层性能的影响。对于白色汽车多材料车身中的粘合接头，这些影响是由所谓的热膨胀系数不匹配引起的，这会导致未固化状态下的粘合剂变形，甚至固化状态下的损坏。未固化粘合剂在法线方向上的变形称为“粘性指状效应”，它通过将粘合剂粘合线的形状改变为细“指状”来减小粘合横截面，从而影响材料性能。为了研究粘性指进对模量、强度和能量释放率的影响，对粘性状态下具有不同胶粘线伸长率的线性对接试样和锥形双悬臂梁（TDCB）进行了研究。结果用于参数化粘性区​​模型 (CZM)，并对 TDCB 样本进行数值分析以进行验证，并建立由钢帽型材和经受热变形的粘合铝板组成的异种接头模型。