L. Rodríguez-Tembleque¹, M.H. Aliabadi²

CMES-Computer Modeling in Engineering & Sciences, Vol.102, No.3, pp. 183-210, 2014, DOI:10.3970/cmes.2014.102.183

Abstract This work presents new contact constitutive laws for friction and wear modelling in fiber-reinforced plastics (FRP). These laws are incorporated to a numerical methodology which allows us to solve the contact problem taking into account the anisotropic tribological properties on the interfaces. This formulation uses the Boundary Element Method for computing the elastic influence coefficients. Furthermore, the formulation considers micromechanical models for FRP that also makes it possible to take into account the fiber orientation relative to the sliding direction, the fiber volume fraction, the aspect ratio of fibers, or the fiber arrangement. The proposed More >

F. Marín¹, F. Alhama¹, J.A. Moreno¹

CMC-Computers, Materials & Continua, Vol.43, No.1, pp. 1-20, 2014, DOI:10.3970/cmc.2014.043.001

Abstract The field of nanotribology in the last decades was established through the introduction of Atomic Force/Friction Force Microscopes. However, our theoretical understanding of the individual processes involved in friction force microscopy is limited. This work designs a reliable and efficient model for the stickslip phenomenon, following the rules of network simulation. The model is able to manage different types of potential between the tip and the sample surface, allowing different kinds of sample material and microscope tip properties to be simulated with only minor changes in the code. The most analysed tribological materials in technical More >

L. Rodríguez-Tembleque¹, A. Sáez¹, F.C. Buroni¹

CMES-Computer Modeling in Engineering & Sciences, Vol.96, No.2, pp. 131-158, 2013, DOI:10.3970/cmes.2013.096.131

Abstract A boundary element based formulation is applied to study numerically the tribological behavior of fiber-reinforced plastics (FRP) under different frictional contact conditions, taking into account the micromechanics of FRP. Micromechanical models presented consider continuous and short fiber reinforced plastics configurations. The Boundary Element Method (BEM) with an explicit approach for fundamental solutions evaluation is considered for computing the elastic influence coefficients. Signorini’s contact conditions and an orthotropic law of friction on the potential contact zone are enforced by contact operators over the augmented Lagrangian. The proposed methodology is applied to study carbon FRP under frictional More >

Dan Dumitriu¹, Ligia Munteanu¹, Cornel Brişan², Veturia Chiroiu¹, Rǎzvan-Vlad Vasiu², Octavian Melinte¹, Victor Vlǎdǎreanu¹

CMES-Computer Modeling in Engineering & Sciences, Vol.94, No.2, pp. 159-173, 2013, DOI:10.3970/cmes.2013.094.159

Abstract The continuum modeling of tire/road vibro-contact dynamics is developed in this paper by assuming continuum relationship between the contact force and the deformation. An important aspect of this model is that the damping depends on the indentation. In the continuum approach, no difference is made between impact and contact, and the friction law can be other than the Coulomb’s law. Since the road is rocky, a bristle model was chosen to take into account the effect of the road irregularities. The identification of the contact domain is performed by checking the minimum distance between bodies. More >

D. Cherrared¹, E. G. Filali¹

FDMP-Fluid Dynamics & Materials Processing, Vol.9, No.2, pp. 127-151, 2013, DOI:10.3970/fdmp.2013.009.127

Abstract Our study deals with the characterization of the flow and related heat transfer in a smooth, circular minichannel. A duct with a sudden (sharp-edged) contraction is also considered. Prediction of the pressure loss coefficient in this case is obtained via the commercial code CFX 5.7.1. This code is based on the finite volume method for the solution of the Navier-Stokes and offers several turbulences models (in this study we use the shear stress turbulence model - SST). The numerical results are compared with experimental results obtained for a configuration similar to those considered in the More >

L. N. McCartney¹

CMC-Computers, Materials & Continua, Vol.35, No.3, pp. 183-227, 2013, DOI:10.3970/cmc.2013.035.183

Abstract Analytical stress transfer models are described that enable estimates to be made of the stress and displacement fields that are associated with fibre fractures or matrix cracks in unidirectional fibre reinforced composites. The models represent a clear improvement on popular shear-lag based methodologies. The model takes account of thermal residual stresses, and is based on simplifying assumptions that the axial stress in the fibre is independent of the radial coordinate, and similarly for the matrix. A representation for both the stress and displacement fields is derived that satisfies exactly the equilibrium equations, the required interface… More >

Arafat A. Bhuiyan^a,1, A. K. M. Sadrul Islam^a, M. Ruhul Amin^b

Frontiers in Heat and Mass Transfer, Vol.3, No.3, pp. 1-9, 2012, DOI:10.5098/hmt.v3.3.3006

Abstract This numerical analysis presents the airside performance of a wavy fin-and-tube heat exchanger having 4 row configurations considering steady, incompressible and 3D flow using Commercial CFD Code ANSYS CFX 12.0. Results are presented in the form of friction factor (f), Colburn factor (j) and efficiency index (j/f). The numerical procedure has been validated by comparison with published numerical and experimental results and good agreement has been observed. A series of numerical calculations have been carried out in order to analyze the influence of various geometric characteristics on different fields as well as on the heat More >

Deli Gao^1,2, Lianzhong Sun^1,3, Hongshu Wei⁴, Shunwen Wang⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.89, No.2, pp. 143-162, 2012, DOI:10.3970/cmes.2012.089.143

Abstract Due to the complexity of forces acting on the down-hole tubular strings in extended reach drilling (ERD), the factors which influence the process should be taken into account as much as possible, in order to predict the down-hole drag & torque more accurately. This can help us to identify and prevent the problems related to downhole drag & torque in ERD. The effects of such factors, as the tubular buckling, the buoyancy, the mechanical resistance and the friction reducer, on down-hole drag & torque, are taken into account in this paper, in order to improve… More >

L. Rodríguez-Tembleque¹, R. Abascal¹, M.H. Aliabadi²

CMES-Computer Modeling in Engineering & Sciences, Vol.87, No.2, pp. 127-156, 2012, DOI:10.3970/cmes.2012.087.127

Abstract A boundary element based formulation is proposed to simulate 3D fretting wear under gross-sliding and partial slip conditions, assuming anisotropic friction and wear laws. Contact problem is based on an Augmented Lagrangian formulation, and restrictions fulfilment is established by a set of projection functions. The boundary element method reveals to be a very suitable numerical method for this kind of problems, where the degrees of freedom involved are those on the solids surfaces, and a very good approximation on contact tractions is obtained with a low number of elements. The present boundary element anisotropic fretting More >

Li Liping, Pan Yishan, Zhang Mengtao

The International Conference on Computational & Experimental Engineering and Sciences, Vol.16, No.4, pp. 103-104, 2011, DOI:10.3970/icces.2011.016.103

Abstract The block model of effect of anomalous low friction in rock mass was established based on plasticity kinetics and theoretical analysis. And the normal stress formulas of contact interface between rock stratum and roof on elastic stage and elastic-plasticity stage were presented. The theoretical analysis indicates that under dynamic loading, the normal stress of contact interface between rock stratum and roof on elastic stage and elastic-plasticity stage of simple beam both reduce, and the reduction amplitude are both great. The friction force of the contact interface reduces sharply, therefore the existence of effect of anomalous More >