The development of tissue-engineered cardiovascular implants can improve the lives of large segments of our society who suffer from cardiovascular diseases. Regenerative tissues are fabricated using a process called tissue maturation. Furthermore, it is highly challenging to produce cardiovascular regenerative implants with sufficient mechanical strength to withstand the loading conditions within the human body. Therefore, biohybrid implants for which the regenerative tissue is reinforced by standard reinforcement material (e.g. textile or 3d printed scaffold) can be an interesting solution. In silico models can significantly contribute to characterizing, designing, and optimizing biohybrid implants. The first step towards this goal is to develop a computational model for the maturation process of tissue-engineered implants. This paper focuses on the mechanical modeling of textile-reinforced tissue-engineered cardiovascular implants. First, we propose an energy-based approach to compute the collagen evolution during the maturation process. Then, we apply the concept of structural tensors to model the anisotropic behavior of the extracellular matrix and the textile scaffold. Next, the newly developed material model is embedded into a special solid-shell finite element formulation with reduced integration. Finally, we use our framework to compute two structural problems: a pressurized shell construct and a tubular-shaped heart valve. The results show the ability of the model to predict collagen growth in response to the boundary conditions applied during the maturation process. Consequently, we can predict the implant's mechanical response, such as the deformation and stresses of the implant.

翻译：心血管组织工程植入体的开发有望改善罹患心血管疾病人群的生活质量。再生组织的制造需经历称为组织成熟的过程。然而，制造具有足够力学强度以承受人体内负荷条件的心血管再生植入体极具挑战性。因此，采用标准增强材料（如织物或3D打印支架）强化再生组织的生物混合植入体是一种颇具前景的解决方案。计算模型可显著促进生物混合植入体的表征、设计与优化。实现这一目标的首要步骤是开发组织工程植入体成熟过程的计算模型。本文聚焦于织物增强型组织工程心血管植入体的力学建模。首先，我们提出一种基于能量的方法来计算成熟过程中胶原蛋白的演变。随后，应用结构张量概念对细胞外基质和织物支架的各向异性行为进行建模。接着，将新开发的材料模型嵌入具有减缩积分的特殊实体-壳有限元公式中。最后，利用该框架计算两个结构问题：加压壳结构体与管状心脏瓣膜。结果表明，该模型能够预测成熟过程中施加边界条件引发的胶原蛋白生长。因此，我们可以预测植入体的力学响应，例如变形与应力分布。