Dipartimento di Ingegneria, Università degli Studi di Napoli "Parthenope", Isola C4, Centro Direzionale di Napoli, 80143, Naples, Italy.
Zienkiewicz Centre for Computational Engineering, College of Engineering, Swansea University, Swansea, SA2 8PP, UK.
Biomech Model Mechanobiol. 2019 Oct;18(5):1429-1442. doi: 10.1007/s10237-019-01156-y. Epub 2019 May 11.
Objective of the work is to investigate stress and deformation that conrneal tissue and donor graft undergo during endothelial keratoplasty. In order to attach the donor graft to the cornea, different air bubble pressure profiles acting on the graft are considered. This study is carried out by employing a three-dimensional nonlinear finite element methodology, combined with a contact algorithm. The ocular tissues are treated as isotropic, hyper-elastic and nearly-incompressible materials. The contact algorithm, based on the penalty-based node-to-surface approach, is used to model the donor graft-corneal interface region. First, the proposed computational methodology is tested against benchmark data for bending of the plates over a cylinder. Then, the influence of geometrical and material parameters of the graft on the corneal contact-structural response is investigated. The results are presented in terms of Von Mises stress intensity, displacement and mean contact force. Results clearly indicate that the air bubble pressure plays a key role in the corneal stress and strain, as well as graft stiffness and thickness.
本工作的目的是研究内皮角膜移植术中相关组织和供体移植物所承受的应力和变形。为了将供体移植物固定在角膜上，考虑了作用于移植物的不同气泡压力分布。本研究采用三维非线性有限元方法，并结合接触算法来进行。将眼部组织视为各向同性、超弹性和近乎不可压缩的材料。基于罚节点-面接触算法的接触算法用于模拟供体移植物-角膜界面区域。首先，将所提出的计算方法与平板在圆柱上弯曲的基准数据进行了对比验证。然后，研究了移植物的几何和材料参数对角膜接触-结构响应的影响。结果以冯·米塞斯（Von Mises）应力强度、位移和平均接触力的形式呈现。结果清楚地表明，气泡压力在角膜的应力和应变以及移植物的刚度和厚度方面起着关键作用。
