Phase field models have been extensively studied in the analysis of ductile fracture. However, few have been explored to simulate additively manufactured materials and validated by experimental data to date. This study aims to develop a phase field framework for modelling complex mechanical behaviours of laser powder bed fusion printed metallic materials. To consider the laser powder bed fusion induced microstructural orientation, transversely isotropic Hill48 and modified Mohr-Coulomb constitutive models are incorporated here to depict the plastic and fracture behaviours, respectively. Five types of material specimens representing a wide spectrum of stress states are designed to identify the material parameters of plasticity and fracture. Three groups of crack propagation specimens are also tested to demonstrate the capacity of the developed model. The numerical results divulge that, by considering the stress state-dependent crack initiation, the proposed phase field model is able to better reproduce force-displacement responses of all specimens. Remarkably, the complex cracking sequences, including crack initiation, propagation and final rupture, can be properly captured by the proposed phase field model. More importantly, it is necessary to apply a transversely isotropic fracture model to characterise the orientation-dependent fracture behaviour; otherwise, the crack path would be predicted incorrectly, resulting in unacceptable global force-displacement responses. This study offers an effective phase field modelling framework for the sophisticated constitutive characterisation of laser powder bed fusion fabricated metallic materials.

相场模型已在韧性断裂分析中得到广泛研究。然而，迄今为止，很少有人探索模拟增材制造材料并通过实验数据进行验证。本研究旨在开发一个相场框架，用于模拟激光粉末床熔融打印金属材料的复杂机械行为。为了考虑激光粉末床熔化引起的微观结构取向，横向各向同性 Hill48 和修改后的 Mohr-Coulomb 本构模型被结合在这里分别描述塑性和断裂行为。代表广泛应力状态的五种类型的材料样本被设计用来识别塑性和断裂的材料参数。还测试了三组裂纹扩展样本，以证明所开发模型的能力。数值结果表明，通过考虑应力状态相关的裂纹萌生，所提出的相场模型能够更好地再现所有样本的力-位移响应。值得注意的是，所提出的相场模型可以正确捕获复杂的开裂序列，包括裂纹萌生、扩展和最终破裂。更重要的是，有必要应用横向各向同性断裂模型来表征与方向相关的断裂行为；否则，将错误地预测裂纹路径，导致不可接受的全局力-位移响应。