This paper presents a strain-based damage model to predict the stress-strain relationship and investigate the damage onset and evolution of the fibre and matrix of a fully bio-resorbable phosphate glass fibre reinforced composite under three-point bending. The flexural properties of the composite are crucial, particularly when it is employed as implant for long bone fracture. In the model, the 3D case of the strain and stress was used and the response of the undamaged material was assumed to be linearly elastic. The onset of damage was indicated by two damage variables for the fibre and matrix, respectively. The damage evolution law was based on the damage variable and the facture energy of the fibre and matrix, individually. A finite element (FE) model was created to implement the constitutive model and conduct numerical tests. An auto-adaptive algorithm is integrated in the FE model to improve the convergence. The FE model was capable of predicting the flexural modulus with around 3% relative error, and the flexural strength within 2% relative error in comparison with the experimental data. The numerical indices showed that the top surface of the sample was the most vulnerable under three-point bending. It was also found that the damage initiated in the fibre, was the primary driver for composite failure under three-point bending.

本文提出了一种基于应变的损伤模型，以预测应力-应变关系，并研究完全生物可吸收的磷酸盐玻璃纤维增​​强复合材料在三点弯曲下纤维和基质的损伤发生和演化。复合材料的弯曲性能至关重要，特别是当其用作长骨骨折的植入物时。在该模型中，使用了应变和应力的3D情况，并且假定未损坏材料的响应是线性弹性的。损伤的发生分别由纤维和基质的两个损伤变量指示。损伤演化定律分别基于损伤变量和纤维和基质的断裂能。创建了一个有限元（FE）模型来实现本构模型并进行数值测试。在FE模型中集成了自适应算法，以提高收敛性。与实验数据相比，FE模型能够以3％左右的相对误差预测弯曲模量，并以2％相对误差以内的挠曲强度进行预测。数值指数表明，样品的顶表面在三点弯曲下最易损坏。还发现，纤维引起的损坏是三点弯曲下复合材料破坏的主要驱动力。数值指数表明，样品的顶表面在三点弯曲下最易损坏。还发现，纤维引起的损坏是三点弯曲下复合材料破坏的主要驱动力。数值指数表明，样品的顶表面在三点弯曲下最易损坏。还发现，纤维引起的损坏是三点弯曲下复合材料破坏的主要驱动力。