State Key Lab of Structural Analysis for Industrial Equipment, Department of Engineering Mechanics, Dalian University of Technology, Dalian, 116024, People's Republic of China.
Mechanik - Materialtheorie, Ruhr-Universität Bochum, Bochum, Germany.
Biomech Model Mechanobiol. 2019 Oct;18(5):1443-1460. doi: 10.1007/s10237-019-01155-z. Epub 2019 Apr 29.
Healing of soft biological tissue is the process of self-recovering or self-repairing the injured or damaged extracellular matrix (ECM). Healing is assumed to be stress-driven, with the objective of returning to a homeostatic stress metrics in the tissue after replacing the damaged ECM with new undamaged one. However, based on the existence of intrinsic length scales in soft tissues, it is thought that computational models of healing should be non-local. In the present study, we introduce for the first time two gradient-enhanced constitutive healing models for soft tissues including non-local variables. The first model combines a continuum damage model with a temporally homogenized growth model, where the growth direction is determined according to local principal stress directions. The second one is based on a gradient-enhanced healing model with continuously recoverable damage variable. Both models are implemented in the finite-element package Abaqus by means of a user subroutine UEL. Three two-dimensional situations simulating the healing process of soft tissues are modeled numerically with both models, and their application for simulation of balloon angioplasty is provided by illustrating the change of damage field and geometry in the media layer throughout the healing process.
软生物组织的愈合是指自我恢复或修复受损或损坏的细胞外基质（ECM）的过程。愈合被认为是应激驱动的，其目的是在用新的未损坏的 ECM 替换受损的 ECM 后，使组织内的稳态应激指标恢复正常。然而，基于软组织中存在固有长度尺度这一事实，人们认为愈合的计算模型应该是非局部的。在本研究中，我们首次引入了两种包括非局部变量的软组织梯度增强本构愈合模型。第一个模型将连续损伤模型与时间均匀化生长模型相结合，其中生长方向根据局部主应力方向确定。第二个模型基于具有连续可恢复损伤变量的梯度增强愈合模型。这两个模型都通过用户子程序 UEL 在有限元包 Abaqus 中实现。使用这两种模型对三个二维情况进行了数值模拟，模拟了软组织的愈合过程，并通过说明在愈合过程中介质层中损伤场和几何形状的变化，提供了它们在模拟球囊血管成形术方面的应用。
