2012 ◽  
Vol 18 (7) ◽  
pp. 745-759 ◽  
Author(s):  
Stanisław Migórski ◽  
Anna Ochal ◽  
Mircea Sofonea

2012 ◽  
Vol 10 (6) ◽  
Author(s):  
Stanisław Migórski

AbstractWe survey recent results on the mathematical modeling of nonconvex and nonsmooth contact problems arising in mechanics and engineering. The approach to such problems is based on the notions of an operator subdifferential inclusion and a hemivariational inequality, and focuses on three aspects. First we report on results on the existence and uniqueness of solutions to subdifferential inclusions. Then we discuss two classes of quasi-static hemivariational ineqaulities, and finally, we present ideas leading to inequality problems with multivalued and nonmonotone boundary conditions encountered in mechanics.


2014 ◽  
Vol 06 (03) ◽  
pp. 1450028 ◽  
Author(s):  
MOHAMED A. ATTIA ◽  
AHMED G. EL-SHAFEI ◽  
FATIN F. MAHMOUD

This study presents a numerical finite element model to analyze the response of frictional thermo-viscoelastic contact systems, which experience material and geometrical nonlinearities. Thermo-rheologically complex behavior of the contacting bodies is assumed. The nonlinear viscoelastic constitutive model is expressed by an integral form of a creep function, whose elastic and time-dependent properties vary with stresses and temperatures. Adopting the assumption that the hydrostatic and deviatoric responses are uncoupled, the constitutive equation is expressed in an incremental form, with the hereditary integral updated at the end of each time increment by recursive computation. The Lagrange multiplier approach is applied to incorporate the inequality contact constraints, while friction effect along the contact interface is modeled using a local nonlinear friction law. The material and geometrical nonlinearities are modeled in the framework of the total Lagrangian formulation. The developed nonlinear viscoelastic model is verified using the available benchmarks. The applicability of the developed model is demonstrated by solving two thermo-viscoelastic frictional contact problems with different contact natures. Results show a distinct effect of the thermo-rheological behavior on viscoelastic contact status.


2015 ◽  
Vol 76 (10) ◽  
Author(s):  
A.K.X. Leong ◽  
W.W.F. Chong

Solid and elastic contact problems have been thoroughly investigated before. The most recent efforts incorporate the use of the Lennard-Jones (LJ) potential to describe the inter-surface forces that are present and substantial in micro-sized contact problems. But little work has been done on viscoelastic contact problems. Hence, there is a need to investigate the behaviour of a viscoelastic contact under the LJ interaction. This paper aims to investigate the deformation of an axisymmetric viscoelastic tip that is either pushed onto or pulled from a flat rigid surface. From existing elastic models, a mathematical model was developed to describe the contact problem in a viscoelastic context. This newly developed was solved via numerical means. The result is a model that readily accepts measureable physical properties and gives out the deformation of a viscoelastic tip.


2013 ◽  
Vol 37 (10-11) ◽  
pp. 6730-6745 ◽  
Author(s):  
F.F. Mahmoud ◽  
A.G. El-Shafei ◽  
A.A. Abdelrahman ◽  
M.A. Attia

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