Abstract The static and time-dependent behaviours of adhesively bonded polyethylene Double-Strap (DS) joints were investigated to assess the viability of this joint configuration relative to the Single-Lap (SL) joints. Both experiments and finite element simulations are conducted. First, we individually characterise the tensile and creep behaviour of the adhesive and adherent materials; an epoxy-based adhesive and polyethylene, respectively. This information is used to develop suitable constitutive models that are then implemented in the commercial finite element package ABAQUS by means of user material subroutines, UMATs. The numerical models are used to design the creep tests on the adhesive joints. Afterwards, an extensive experimental campaign is conducted where we characterise the static and creep behaviour of two joint configurations, SL and DS joints, and three selected values of the overlap length. In regard to the static case, results reveal an increase in the failure load with increasing overlap length, of up to 10% for an overlap length of 39 mm. Also, slightly better performance is observed for the SL joint configuration. For the creep experiments, we show that the DS adhesive joint configuration leads to much shorter elongations, relative to the SL joints. These differences diminish with increasing overlap length but remain substantial in all cases. In both joint configurations, the elongation increases with decreasing overlap length. For instance, increasing the overlap length to 39 mm led to a 50% and a 30% reduction in elongation for SL and DS joints, respectively. Moreover, the numerical predictions show a good agreement with the experiments. The stress redistribution is investigated and it is found that the shear stress is highly sensitive to the testing time, with differences being more noticeable for the DS joint system. The findings bring insight into the creep behaviour of polyethylene-based adhesive joints, a configuration of notable industrial interest.

中文翻译：

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粘合聚乙烯接头的蠕变行为和拉伸响应：单搭接和双搭接

摘要 研究了粘合聚乙烯双带 (DS) 接头的静态和随时间变化的行为，以评估这种接头配置相对于单圈 (SL) 接头的可行性。进行了实验和有限元模拟。首先，我们分别表征粘合剂和粘附材料的拉伸和蠕变行为；分别是环氧基粘合剂和聚乙烯。该信息用于开发合适的本构模型，然后通过用户材料子程序 UMAT 在商业有限元包 ABAQUS 中实现。数值模型用于设计粘接接头的蠕变试验。之后，进行了广泛的实验活动，我们表征了两种接头配置的静态和蠕变行为，SL 和 DS 接头，以及重叠长度的三个选定值。对于静态情况，结果表明，随着重叠长度的增加，失效载荷也会增加，重叠长度为 39 毫米时，增加高达 10%。此外，观察到 SL 接头配置的性能略好。对于蠕变实验，我们表明，相对于 SL 接头，DS 粘合接头配置导致更短的伸长率。这些差异随着重叠长度的增加而减少，但在所有情况下仍然很大。在两种接头配置中，伸长率随着重叠长度的减少而增加。例如，将重叠长度增加到 39 毫米导致 SL 和 DS 接头的伸长率分别降低 50% 和 30%。此外，数值预测与实验显示出良好的一致性。对应力重新分布进行了研究，发现剪切应力对测试时间高度敏感，DS 接头系统的差异更为明显。这些发现深入了解了聚乙烯基粘合剂接头的蠕变行为，这是一种具有显着工业意义的配置。