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… More >

Gaoyang Li¹, Xiaorui Song², Aike Qiao³, Makoto Ohta^4,5,*

CMES-Computer Modeling in Engineering & Sciences, Vol.117, No.2, pp. 143-155, 2018, DOI:10.31614/cmes.2018.04100

Abstract For patients with type 2 diabetes, the evaluation of pulse waveform characteristics is helpful to understand changes in arterial stiffness. However, there is a lack of comprehensive analysis of pulse waveform parameters. Here, we aimed to investigate the changes in pulse waveform characteristics in patients with type 2 diabetes due to increased arterial stiffness. In this study, 25 patients with type 2 diabetes and 50 healthy subjects were selected based on their clinical history. Age, height, weight, blood pressure, and pulse pressure were collected as the subjects’ basic characteristics. The brachial-ankle pulse wave velocity (baPWV)… More >

Zhengzheng Cao¹, Feng Du^2,3,4, Zhenhua Li², Qinting Wang¹, Ping Xu¹, Haixiao Lin¹

CMES-Computer Modeling in Engineering & Sciences, Vol.113, No.3, pp. 275-293, 2017, DOI:10.3970/cmes.2017.113.287

Abstract The stability of ore pillar in mine is essential for the safe and efficient mining. Based on the energy evolvement rule in ore pillar and roadway roof system, the roadway roof and ore pillar are treated as energy release body and energy dissipation body, respectively. Therefore, the double-block mechanical model is established with energy dissipation body and energy release body, and the energy mechanism of ore pillar instability is obtained, based on the fold catastrophe mathematical theory. The research result indicates that the dynamic instability of ore pillar is a physical instability problem caused by… More >

X. Wang¹, W.T. Ang^1,2, H. Fan¹

CMES-Computer Modeling in Engineering & Sciences, Vol.107, No.2, pp. 81-101, 2015, DOI:10.3970/cmes.2015.107.081

Abstract A micromechanical model is proposed here for estimating the effective stiffness of a pair of parallel microscopically damaged interfaces in a trimaterial under inplane elastostatic deformations. The trimaterial is made of an orthotropic thin layer sandwiched between two orthotropic half-spaces. The microscopically damaged interfaces are modeled using periodically distributed interfacial micro-cracks. The micromechanical model is formulated and numerically solved in terms of hypersingular boundary integro-differential equations. The effects of the width of the thin layer, the micro-crack densities of the two interfaces and the material constants of the thin layer and the two half-spaces on 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… More >

T.A. Elgohary¹, L. Dong², J.L. Junkins³, S.N. Atluri⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.98, No.6, pp. 543-563, 2014, DOI:10.3970/cmes.2014.098.543

Abstract In this study, the Scalar Homotopy Methods are applied to the solution of post-buckling and limit load problems of solids and structures, as exemplified by simple plane elastic frames, considering only geometrical nonlinearities. Explicitly derived tangent stiffness matrices and nodal forces of large-deformation planar beam elements, with two translational and one rotational degrees of freedom at each node, are adopted following the work of [Kondoh and Atluri (1986)]. By using the Scalar Homotopy Methods, the displacements of the equilibrium state are iteratively solved for, without inverting the Jacobian (tangent stiffness) matrix. It is well-known that,… More >

W. Kaewjuea¹, T. Senjuntichai², R.K.N.D. Rajapakse³

CMES-Computer Modeling in Engineering & Sciences, Vol.101, No.3, pp. 207-228, 2014, DOI:10.3970/cmes.2014.101.207

Abstract Dynamic response of an infinite cylindrical borehole in a poroelastic medium with an excavation disturbed zone is investigated in this paper. The borehole is subjected to axisymmetric time-harmonic loads and fluid sources applied to its surface, which is either fully permeable or impermeable. The governing equations based on Biot’s poroelastodynamics theory are solved by using two scalar potentials and two vector potentials. The general solutions are then derived through the application of Fourier integral transform with respect to the vertical coordinate. An exact stiffness matrix scheme is established from the derived general solutions to include More >

Q.W. Yang^1,2, S.G. Du¹, C.F. Liang¹, L.J. Yang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.100, No.3, pp. 223-248, 2014, DOI:10.3970/cmes.2014.100.223

Abstract Although the model-independent damage localization algorithms have been extensively developed in recent years, the theoretical relationship between these damage indicators and the definition of damage is not clear. Moreover the existing damage localization methods are usually dependent on the boundary conditions and the type of structure. In view of this, the paper presents a universal model-independent algorithm for structural damage localization. To this end, the explicit relationship between the damage and damage-induced displacement variation is firstly clarified by using the well-known Sherman-Morrison and Woodbury formulas. A theorem is then presented for structural damage localization. According More >

J.R. Lin¹, L.M. Chu², T.L. Chou³, L.J. Liang³, P.Y. Wang³

FDMP-Fluid Dynamics & Materials Processing, Vol.10, No.2, pp. 163-177, 2014, DOI:10.3970/fdmp.2014.010.163

Abstract We investigate the influence of non-Newtonian micropolar fluids on the dynamic characteristics of wide tapered-land slider bearings. The study is carried out on the basis of the micro-continuum theory originally developed by Eringen (1966). Analytical expressions for the linear dynamic coefficients are provided and compared with earlier results in the literature. In particular, direct comparison with the Newtonian fluid-lubricated tapered-land bearings by Lin et al. (2006) indicates that the use of non-Newtonian micropolar fluids can lead to a significant increase in the values of stiffness and damping coefficients. Such improvements are found to be even More >

Chandra Veer Singh^1,*

CMC-Computers, Materials & Continua, Vol.34, No.3, pp. 227-249, 2013, DOI:10.3970/cmc.2013.034.227

Abstract A non-linear damage model is developed for the prediction of stiffness degradation in composite laminates due to transverse matrix cracking. The model follows the framework of a recently developed synergistic damage mechanics (SDM) approach which combines the strengths of micro-damage mechanics and continuum damage mechanics (CDM) through the so-called constraint parameters. A common limitation of the current CDM and SDM models has been the tendency to over-predict stiffness changes at high crack densities due to linearity inherent in their stiffness-damage relationships. The present paper extends this SDM approach by including higher order damage terms in More >