Peter W. Chung¹, Raju R. Namburu², Brian J. Henz³

CMES-Computer Modeling in Engineering & Sciences, Vol.5, No.1, pp. 45-62, 2004, DOI:10.3970/cmes.2004.005.045

Abstract A method is developed based on an additive modification to the first Lagrangian elasticity tensor to make the finite element method for hyperelasticity viable at the atomic length scale in the context of lattice statics. Through the definition of an overlap region, the close-ranged atomic interaction energies are consistently summed over the boundary of each finite element. These energies are subsequently used to additively modify the conventional material property tensor that comes from the second derivative of the stored energy function. The summation over element boundaries, as opposed to atom clusters, allows the mesh and nodes to be defined independently… More >

Ying Zhao¹, Mohammad Noori^1,2, Wael A. Altabey^1,3,*, Ramin Ghiasi⁴, Zhishen Wu¹

Structural Durability & Health Monitoring, Vol.13, No.1, pp. 85-103, 2019, DOI:10.32604/sdhm.2019.04695

Abstract This paper introduces a stiffness reduction based model developed by the authors to characterize accumulative fatigue damage in unidirectional plies and (0/θ/0) composite laminates in fiber reinforced polymer (FRP) composite laminates. The proposed damage detection model is developed based on a damage evolution mechanism, including crack initiation and crack damage progress in matrix, matrix-fiber interface and fibers. Research result demonstrates that the corresponding stiffness of unidirectional composite laminates is reduced as the number of loading cycles progresses. First, three common models in literatures are presented and compared. Tensile viscosity, Young’s modulus and ultimate tensile stress of composites are incorporated as… More >

Mingzhi Luo¹, Kai Ni¹, Peili Yu¹, Yang Jin², Lei Liu¹, Jingjing Li¹, Yan Pan¹, Linhong Deng^1,*

Molecular & Cellular Biomechanics, Vol.16, No.2, pp. 141-151, 2019, DOI:10.32604/mcb.2019.06756

Abstract Airway hyperresponsiveness (AHR) is the cardinal character of asthma, which involves the biomechanical properties such as cell stiffness and traction force of airway smooth muscle cells (ASMCs). Therefore, these biomechanical properties comprise logical targets of therapy. β2-adrenergic agonist is currently the mainstream drug to target ASMCs in clinical practice for treating asthma. However, this drug is known for side effects such as desensitization and non-responsiveness in some patients. Therefore, it is desirable to search for new drug agents to be alternative of β2-adrenergic agonist. In this context, sanguinarine, a natural product derived from plants such as bloodroots, that has been… More >

Shaoxiong Yang¹, Yingxin Qi², Zonglai Jiang², Xiaobo Gong^1,*

Molecular & Cellular Biomechanics, Vol.16, No.1, pp. 13-26, 2019, DOI:10.32604/mcb.2019.06096

Abstract Vascular diseases during aging process are closely correlated to the age-related changes of mechanical stimuli for resident cells. Characterizing the variations of mechanical environments in vessel walls with advancing age is crucial for a better understanding of vascular remodeling and pathological changes. In this study, the mechanical stress, strain, and wall stiffness of the femoropopliteal arteries (FPAs) were compared among four different age groups from adolescent to young, middle-aged, and aged subjects. The material parameters and geometries adopted in the FPA models were obtained from published experimental results. It is found that high mechanical stress appears at different layers in… More >

JA. Herzog^∗, TR. Leonard^†, A. Jinha^†, W. Herzog^†,‡

Molecular & Cellular Biomechanics, Vol.11, No.1, pp. 1-17, 2014, DOI:10.3970/mcb.2014.011.001

Abstract Titin is the third most abundant protein in sarcomeres and fulfills a number of mechanical and signaling functions. Specifically, titin is responsible for most of the passive forces in sarcomeres and the passive visco-elastic behaviour of myofibrils and muscles. It has been suggested, based on mechanical testing of isolated titin molecules, that titin is an essentially elastic spring if Ig domain un/refolding is prevented either by working at short titin lengths, prior to any unfolding of Ig domains, or at long sarcomere (and titin) lengths when Ig domain un/refolding is effectively prevented. However, these properties of titin, and by extension… More >

Match W L Ko^∗, Leo K K Leung^∗, David C C Lam^∗,†

Molecular & Cellular Biomechanics, Vol.9, No.4, pp. 251-268, 2012, DOI:10.3970/mcb.2012.009.251

Abstract Inter-individual differences in corneal properties are ignored in existing methods for measuring intraocular pressure IOP, a primary parameter used in screening and monitoring of glaucoma. The differences in the corneal stiffness between individuals can be more than double and this difference would lead to IOP measurement errors up to 10 mmHg. In this study, an instrumented partial-contact indentation measurement and analysis method that can account for inter-individual corneal difference in stiffness is developed. The method was tested on 12 porcine eyes ex vivo and 7 rabbit eyes in vivo, and the results were compared to the controlled IOPs to determine… More >

Judith Su^∗, Ricardo R. Brau^†, Xingyu Jiang^‡, George M. Whitesides^§, Matthew J. Lang^¶, Peter T. C. So^||

Molecular & Cellular Biomechanics, Vol.4, No.2, pp. 105-118, 2007, DOI:10.3970/mcb.2007.004.105

Abstract During migration, asymmetrically polarized cells achieve motion by coordinating the protrusion and retraction of their leading and trailing edges, respectively. Although it is well known that local changes in the dynamics of actin cytoskeleton remodeling drive these processes, neither the cytoskeletal rheological properties of these migrating cells are well quantified nor is it understand how these rheological properties are regulated by underlying molecular processes. In this report, we have used soft lithography to create morphologically polarized cells in order to examine rheological differences between the front and rear zone of an NIH 3T3 cell posed for migration. In addition, we… More >

Zejun Han¹, Hongyuan Fang^2,3,4,*, Juan Zhang⁵, Fuming Wang^2,3,4

CMC-Computers, Materials & Continua, Vol.59, No.3, pp. 853-871, 2019, DOI:10.32604/cmc.2019.03839

Abstract The pavement layered structures are composed of surface layer, road base and multi-layered soil foundation. They can be undermined over time by repeated vehicle loads. In this study, a hybrid numerical method which can evaluate the displacement responses of pavement structures under dynamic falling weight deflectometer (FWD) loads. The proposed method consists of two parts: (a) the dynamic stiffness matrices of the points at the surface in the frequency domain which is based on the domain-transformation and dual vector form equation, and (b) interpolates the dynamic stiffness matrices by a continues rational function of frequency. The mixed variables formulation (MVF)… More >

Libardo V. Vanegas-Useche¹, Magd M. Abdel-Wahab^2,3,4,*, Graham A. Parker⁵

CMC-Computers, Materials & Continua, Vol.56, No.1, pp. 169-184, 2018, DOI: 10.3970/cmc.2018.01827

Abstract In finite element modeling of impact, it is necessary to define appropriate values of the normal contact stiffness, K_n, and the Integration Time Step (ITS). Because impacts are usually of very short duration, very small ITSs are required. Moreover, the selection of a suitable value of K_n is a critical issue, as the impact behavior depends dramatically on this parameter. In this work, a number of experimental tests and finite element analyses have been performed in order to obtain an appropriate value of K_n for the interaction between a bristle of a gutter brush for road sweeping and a concrete… More >

Ying Zhou^1,*, Peng Chen¹

CMES-Computer Modeling in Engineering & Sciences, Vol.120, No.3, pp. 759-777, 2019, DOI:10.32604/cmes.2019.04383

Abstract This paper proposes a novel three-dimensional (3D) isolation system for facilities and presents the numerical simulation approach for the isolated system under earthquake excitations and impact effect using the OpenSees (Open System for Earthquake Engineering Simulation) software frame work. The 3D isolators combine the quasi-zero stiffness (QZS) system in the vertical direction and lead rubber bearing in the horizontal direction. Considering the large aspect ratio of the isolated facility, linear viscous dampers are designed in the vertical direction to diminish the overturning effect. The vertical QZS isolation system is characterized by a cubic force-displacement relation, thus, no elements or materials… More >