Figure 5. C) Dependence of the average filopodial extension velocity on the adhesion strength γ and surface roughness. α here represents the shrinking factor with α = 1 corresponding to the initial MCD topography. Error bar here indicates the standard deviation of simulation results from eight different MCD topographies. For comparison, the measured speeds of growing filopodia on MCD and NCD substrates are also given by the purple and blue cross markers (assuming γ = 9 × 10 −5 J m −2 ), respectively.The above error does not affect the scientific conclusions drawn from the work. The authors apologize for any inconvenience or misunderstanding that this error may have caused. correction

An increasing number of studies have demonstrated the positive role nanotopographies can have toward promoting various cell functions. However, the relevant mechanism(s) behind this improvement in biological interactions at the cell-material interface is not well understood. For this reason, here, osteoblast (bone forming cell) functions (including adhesion, proliferation, and differentiation) on two carefully-fabricated diamond films with dramatically-different topographies were tested and modeled. The results over all the time periods tested revealed greater cell responses on nanocrystalline diamond (NCD, grain sizes <100 nm) compared to submicron crystalline diamond (SMCD, grain sizes 200-1000 nm). To understand this positive impact of cell responses per stiff nanotopographies, cell filopodia extension and cell spreading were studied through computational simulations and the results suggested that increasing the lateral dimensions or height of nanometer surface features could inhibit cell filopodia extension and, ultimately, decrease cell spreading. The computational simulation results were further verified by live cell imaging (LCI) experiments. This study, thus, describes a possible new approach to investigate (through experiments and computational simulation) the mechanisms behind nanotopography-enhanced cell functions.

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Computational modelling of damage and rupture of non-connective and connective soft tissues due to pathological and supra-physiological mechanisms is vital in the fundamental understanding of failures. Recent advancements in soft tissue damage models play an essential role in developing artificial tissues, medical devices/implants, and surgical intervention practices. The current article reviews the recently developed damage models and rupture models that considered the microstructure of the tissues. Earlier review works presented damage and rupture separately, wherein this work reviews both damage and rupture in soft tissues. Wherein the present article provides a detailed review of various models on the damage evolution and tear in soft tissues focusing on key conceptual ideas, advantages, limitations, and challenges. Some key challenges of damage and rupture models are outlined in the article, which helps extend the present damage and rupture models to various soft tissues.

Composite structures such as hull of a ship and wings of aircraft are subjected to compressive loading. The behavior and strength of carbon fiber-reinforced polymer (CFRP) panels subjected to tensile loading has been studied rigorously by various researchers, whereas compressive behavior is not well addressed. In this study, behavior of CFRP panel with multiple interacting holes of various configurations (1H, 2HL, 2HT, and 2HD) under compressive loading is studied. A three-dimensional finite element-based progressive failure analysis (PFA) is used to model the damage progression in CFRP laminates. Damage detection is carried out using both Hashin’s failure and Ye’s-delamination criterions. Using these failure criterions, failure and post failure behavior of CFRP laminate with cutouts are predicted. The material is assumed to behave as linear elastic until final failure. Sudden degradation rule of material property is employed and subsequently PFA is carried out successively. Using digital image correlation (DIC) technique, whole field surface strain is obtained experimentally and is used for validating finite element analysis (FEA) model. Load–deflection behavior as well as path of damage progression is predicted by both PFA simulation and experiment. They are found to be in good agreement thereby confirming the accuracy of PFA implementation. Among all the configurations, one with two holes along the longitudinal direction (2HL) is recommended for design application as it exhibits low stress concentration factor and sustains higher initiation and final failure load.

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Abstract:The effect of varying wall flexibility on the deformation of an artery during steady and pulsatile flow of blood is investigated. The artery geometry is recreated from patient-derived data for a stenosed left coronary artery. Blood flow in the artery is modeled using power-law fluid. The fluid-structure interaction of blood flow on artery wall is simulated using ANSYS 16.2, and the resulting wall deformation is documented. A comparison of wall deformation using flexibility models like Rigid, Linear Elastic, Neo-hookean, Mooney-Rivlin and Holzapfel are obtained for steady flow in the artery. The maximum wall deformation in coronary flow conditions predicted by the Holzapfel model is only around 50% that predicted by the Neo-Hookean model. The flow-induced deformations reported here for patient-derived stenosed coronary artery with physiologically accurate model are the first of its kind. These results help immensely in the planning of angioplasty.