胶层吸湿对单搭接接头影响的数值模拟

The numerical analysis of the moisture absorption on the adhesively bonded aluminium single lap joints

在建立胶粘剂吸湿本构模型的基础上,用弹塑性有限元法研究了聚丙烯酸酯胶层吸湿程度对单搭接接头上胶层中应力分布的影响。结果表明:随着胶层吸湿程度增加,单搭接接头上胶瘤处的峰值应力显著降低。对水分从搭接区两侧渗入胶层的总宽度变化时胶层中的应力分布作了研究,发现随渗入总宽度的增加,胶层中的等效应力Seqv峰值下降。因水分渗入后引起胶层溶胀,在胶瘤过渡到中间胶层的拐角处会产生严重变形,可能导致该处发生脱粘。

The numerical analysis was carried out to study the influence of the water absorption on the stress distribution in the polyacrylate adhesive layer of the single lap joint using the elasto-plastic finite element analysis(FEA) based on absorption constitutive model of the adhesive established by the authors.The results from the numerical simulation show that the peak stress at the corner of the fillet decreased evidently as the moisture absorption level increased.The stress distribution was also studied and it is found that the peak equivalent stress in the adhesive layer decreased greatly as the sum absorption width increased and the maximum equivalent plastic strain was gradually increased and maintained its location at the corner of the fillets when took the sum width of the adhesive as 2mm,4 mm,8 mm and 10 mm respectively.The swelling of the adhesive should be occurred after the moisture absorbed into the adhesive layer and the severe deformation of the adhesive taken place so that the de-bond of the adhesive layer at the interface may be occurred.