In order to numerically simulate the contact pressure distribution and area during sliding when w... more In order to numerically simulate the contact pressure distribution and area during sliding when wear occurs, the combined finite element method and boundary element method (FEM–BEM) developed by the authors is extended based on a linear wear law merged with the space- and time-resolved cumulative dissipated frictional energy. In each computed time step, the dissipated frictional energy and the wear rate are determined. Simultaneously, the topography of surfaces in contact are updated after every sliding cycle, providing for each sliding cycle a new input for BEM which is consequently used to redetermine the contact pressure distribution. The numerical results obtained with the proposed FEM–BEM algorithm are found to match qualitatively well with the amount of wear observed in high-frequency reci-procating rig experiments. This demonstrates the suitability of the FEM–BEM contact scheme for wear applications.
Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, 2011
ABSTRACT An extremely small roughness of constant height magnitude is considered on the femoral h... more ABSTRACT An extremely small roughness of constant height magnitude is considered on the femoral head of an artificial hip joint in order to determine the consequences of various regular shapes and clearances on the mechanical performance of this hip prosthesis via a properly coupled finite and boundary element method. In addition, different material combinations typical for widely used hard-on-hard and hard-on-soft hip joint replacements are also taken into account. By analysing the calculated pressure distribution and contact area between the femoral head and the acetabular cup in frictionless dry contact irrespective of material pairings in hip joints, it is shown that both the wavelength of roughness and the clearance significantly affect these mechanical quantities and accordingly too loose or too tight hip implants have to be avoided. Finally, in terms of all numerical findings a suitable optimal design of hip implants is also discussed.
Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, 2009
ABSTRACT A novel formulation of elastic multi-asperity contacts based on the boundary element met... more ABSTRACT A novel formulation of elastic multi-asperity contacts based on the boundary element method (BEM) is presented for the first time, in which the influence coefficients are numerically calculated using a finite element method (FEM). The main advantage of computing the influence coefficients in this manner is that it makes it also possible to consider an arbitrary load direction and multilayer systems of different mechanical properties in each layer. Furthermore, any form of anisotropy can be modelled too, where Green's functions either become very complicated or are not available at all.
Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, 2013
ABSTRACT In order to numerically simulate the contact pressure distribution and area during slidi... more ABSTRACT In order to numerically simulate the contact pressure distribution and area during sliding when wear occurs, the combined finite element method and boundary element method (FEM–BEM) developed by the authors is extended based on a linear wear law merged with the space- and time-resolved cumulative dissipated frictional energy. In each computed time step, the dissipated frictional energy and the wear rate are determined. Simultaneously, the topography of surfaces in contact are updated after every sliding cycle, providing for each sliding cycle a new input for BEM which is consequently used to redetermine the contact pressure distribution. The numerical results obtained with the proposed FEM–BEM algorithm are found to match qualitatively well with the amount of wear observed in high-frequency reciprocating rig experiments. This demonstrates the suitability of the FEM–BEM contact scheme for wear applications.
In order to numerically simulate the contact pressure distribution and area during sliding when w... more In order to numerically simulate the contact pressure distribution and area during sliding when wear occurs, the combined finite element method and boundary element method (FEM–BEM) developed by the authors is extended based on a linear wear law merged with the space- and time-resolved cumulative dissipated frictional energy. In each computed time step, the dissipated frictional energy and the wear rate are determined. Simultaneously, the topography of surfaces in contact are updated after every sliding cycle, providing for each sliding cycle a new input for BEM which is consequently used to redetermine the contact pressure distribution. The numerical results obtained with the proposed FEM–BEM algorithm are found to match qualitatively well with the amount of wear observed in high-frequency reci-procating rig experiments. This demonstrates the suitability of the FEM–BEM contact scheme for wear applications.
Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, 2011
ABSTRACT An extremely small roughness of constant height magnitude is considered on the femoral h... more ABSTRACT An extremely small roughness of constant height magnitude is considered on the femoral head of an artificial hip joint in order to determine the consequences of various regular shapes and clearances on the mechanical performance of this hip prosthesis via a properly coupled finite and boundary element method. In addition, different material combinations typical for widely used hard-on-hard and hard-on-soft hip joint replacements are also taken into account. By analysing the calculated pressure distribution and contact area between the femoral head and the acetabular cup in frictionless dry contact irrespective of material pairings in hip joints, it is shown that both the wavelength of roughness and the clearance significantly affect these mechanical quantities and accordingly too loose or too tight hip implants have to be avoided. Finally, in terms of all numerical findings a suitable optimal design of hip implants is also discussed.
Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, 2009
ABSTRACT A novel formulation of elastic multi-asperity contacts based on the boundary element met... more ABSTRACT A novel formulation of elastic multi-asperity contacts based on the boundary element method (BEM) is presented for the first time, in which the influence coefficients are numerically calculated using a finite element method (FEM). The main advantage of computing the influence coefficients in this manner is that it makes it also possible to consider an arbitrary load direction and multilayer systems of different mechanical properties in each layer. Furthermore, any form of anisotropy can be modelled too, where Green's functions either become very complicated or are not available at all.
Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, 2013
ABSTRACT In order to numerically simulate the contact pressure distribution and area during slidi... more ABSTRACT In order to numerically simulate the contact pressure distribution and area during sliding when wear occurs, the combined finite element method and boundary element method (FEM–BEM) developed by the authors is extended based on a linear wear law merged with the space- and time-resolved cumulative dissipated frictional energy. In each computed time step, the dissipated frictional energy and the wear rate are determined. Simultaneously, the topography of surfaces in contact are updated after every sliding cycle, providing for each sliding cycle a new input for BEM which is consequently used to redetermine the contact pressure distribution. The numerical results obtained with the proposed FEM–BEM algorithm are found to match qualitatively well with the amount of wear observed in high-frequency reciprocating rig experiments. This demonstrates the suitability of the FEM–BEM contact scheme for wear applications.
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