This paper presents numerical and experimental investigations on a typical thermal break composite façade profile under four-point bending. The purpose of this study is to gain the knowledge of the interfacial behaviour between aluminum extrusion and polyamide insert beyond elastic range. Understanding the behaviour of this energy efficient façade profile within plastic range is important for the design under extreme loading, such as earthquakes, strong wind conditions and even blast loads. The experimental investigation was carried out on four types of beam specimens. The specimens were grouped by their span lengths with three specimens for each span length. As the specimens’ geometry and composite action are complicated, seven strain gauges were used per specimen including small strain gauges to fit in the limited space of the thermal break section. A three stage failure process was observed during the experiments. A numerical investigation was carried out by using Finite Element modelling to simulate behaviour of the thermal break composite façade profile under similar loading condition in order to compare with the testing results as well as to capture the corresponding failure mechanisms. Numerical simulations were setup by applying a proposed partitioned multi-phase failure model to simulate three stage failure process discovered by experiments. The results from FE models were compared and discussed with experimental counterparts. In summary, FE models showed consistent results to the experimental counterparts and it also provided the insight and more details of failure mechanism and stress distribution including interfacial condition details. Behaviour of the thermal break façade profile in the plastic range displayed excellent ductility and high strength capacity of this type of thermal break section in the plastic range after slip.

本文介绍了在四点弯曲下典型的热断裂复合立面轮廓的数值和实验研究。这项研究的目的是获得有关铝挤压件和聚酰胺嵌件之间超出弹性范围的界面行为的知识。对于在极端载荷（例如地震，强风条件甚至爆炸载荷）下的设计，了解塑料范围内这种节能立面轮廓的行为非常重要。对四种类型的梁样本进行了实验研究。将样本按其跨度长度分组，每个跨度长度各三个样本。由于标本的几何形状和复合作用很复杂，每个样本使用七个应变仪，包括小型应变仪，以适合热断面的有限空间。在实验过程中观察到了三个阶段的失败过程。使用有限元模型进行了数值研究，以模拟在相似载荷条件下的热破坏复合立面轮廓的行为，以便与测试结果进行比较并捕获相应的破坏机理。通过应用提议的分区多相故障模型来建立数值模拟，以模拟实验发现的三阶段故障过程。有限元模型的结果进行了比较，并与实验对象进行了讨论。综上所述，有限元模型对实验对象显示出一致的结果，它还提供了洞察力以及破坏机理和应力分布的更多细节，包括界面条件细节。在塑料范围内，热断裂立面轮廓的行为表现出出色的延展性和滑移后在塑料范围内这种类型的热断裂截面的高强度能力。