In aerospace industries, adhesively bonded joints are used to join critical components, failure of which often leads to substantial monetary losses and loss of lives. Thus, it is of paramount importance to study the behaviour of these bonded joints till failure so that damage-tolerant structures can be designed. This study aims to model the crack propagation in finitely thick adhesive layers. Crack propagation in adhesive layers can be complex. Cracks can propagate along the interface or in the bulk of the adhesive. Experimentally [1], it has also been observed that a crack can periodically kink out of the adherend-adhesive interface, propagates in the bulk of the adhesive, and then kink back into the adherend-adhesive interface. Such interesting fracture patterns could not be captured if the thickness of the adhesive is only implicitly considered in a conventional traction-separation relationship. In this study, the finitely thick adhesive layer is explicitly modelled along with the adherends. A phase field-based damage model is used to simulate the bulk failure in the brittle adhesive, while a cohesive zone damage model is used to simulate the interfacial failure between the adhesive-adherend interfaces. Benchmark numerical simulations are first performed for Double Cantilever Beam (DCB) and Mixed Mode Bending (MMB) specimens [2] to highlight the model’s ability to capture interfacial failure. A scarf joint under uniaxial tension is then simulated to illustrate the crack kinking behaviour in the adhesive layer which was experimentally observed in Qian and Akisanya (1998) [1]. Good correlations between the model’s prediction and experimental crack patterns highlight the model’s robustness in capturing complicated crack patterns. REFERENCES [1] Qian, Z., & Akisanya, A. R. (1998). An experimental investigation of failure initiation in bonded joints. Acta Materialia, 46(14), 4895–4904. https://doi.org/10.1016/S1359-6454(98)00200-6 [2] Park, K., Paulino, G. H., & Roesler, J. R. (2009). A unified potential-based cohesive model of mixed-mode fracture. Journal of the Mechanics and Physics of Solids, 57(6), 891-908. http://doi.org/10.1016/J.JMPS.2008.10.003