Tamura Atsutaka, Matsumoto Koki
Department of Mechanical and Aerospace Engineering, Graduate School of Engineering, Tottori University, 4-101 Koyama-minami Tottori, Tottori, 680-8552, Japan.
Department of Mechanical Engineering, Graduate School of Sustainability Science, Tottori University, 4-101 Koyama-minami Tottori, Tottori, 680-8552, Japan.
Cardiovasc Eng Technol. 2025 Feb;16(1):91-107. doi: 10.1007/s13239-024-00759-6. Epub 2024 Nov 25.
It is known that elastic laminae (ELs) in the aortic wall, especially the inner layers, are structurally buckled due to residual stresses under unpressurized conditions. Herein, we aimed to develop a realistic computational model, replicating the mechanical behavior of an aortic ring from no-load to physiological conditions by considering inherent residual stresses, which has not been widely included in conventional modeling studies.
We determined specific conditions to reproduce EL buckling with a "preferable" residual stress distribution under no-load conditions by combining the design of experiments and multiobjective optimization. Subsequently, we applied these conditions to two ring models with distinct wall structures comprised ELs and smooth muscle layers (SMLs), and compared their mechanical responses to assess the effect of implemented residual stresses by tracking changes in stress distribution in the aortic wall and corresponding EL waviness under no-load and pressurized conditions.
We successfully reproduced EL buckling with a steady upward residual stress distribution that was considered "preferable" under no-load conditions. Furthermore, we replicated radially cut ring models that spontaneously opened in vitro, and confirmed that an SML circumferential stress distribution approached a uniform state under pressurized conditions, effectively mediating stress concentrations induced at the inner layers.
We established a ready-to-use scheme to implement intrinsic residual stresses in the aortic wall. Our computational model of the aortic ring, reproducing realistic mechanical responses and behavior, represents a valuable tool that offers essential insights for hypertension prevention and potential new clinical applications.
已知主动脉壁中的弹性层（ELs），尤其是内层，在未加压条件下由于残余应力而在结构上发生屈曲。在此，我们旨在开发一个逼真的计算模型，通过考虑固有残余应力来复制主动脉环从空载到生理条件下的力学行为，而固有残余应力在传统建模研究中并未被广泛纳入。
我们通过结合实验设计和多目标优化，确定了在空载条件下以“优选”的残余应力分布来重现EL屈曲的特定条件。随后，我们将这些条件应用于两个具有不同壁结构（包括ELs和平滑肌层（SMLs））的环模型，并通过跟踪空载和加压条件下主动脉壁应力分布的变化以及相应的EL波纹度，比较它们的力学响应，以评估所施加残余应力的效果。
我们成功地以稳定的向上残余应力分布重现了EL屈曲，该分布在空载条件下被认为是“优选”的。此外，我们复制了在体外自发张开的径向切割环模型，并证实了在加压条件下SML周向应力分布接近均匀状态，有效地介导了在内层诱导的应力集中。
我们建立了一种在主动脉壁中施加固有残余应力的现成方案。我们的主动脉环计算模型再现了逼真的力学响应和行为，是一个有价值的工具，为高血压预防和潜在的新临床应用提供了重要见解。
