Viscoelastic contact

The viscoelastic contact problem for a plate with the constitutive law (see Section 1.1.4)... 

Viscoelastic contact problems have drawn the attention of researchers for some time [2,3,104,105]. The mathematical peculiarity of these problems is their time-dependent boundaries. This has limited the ability to quantify the boundary value contact problems by the tools used in elasticity. The normal displacement (u) and pressure (p) fields in the contact region for non-adhesive contact of viscoelastic materials are obtained by a self-consistent solution to the governing singular integral equation given by [106] ... 

The quasi-static acquisition and interpretation of the force-distance curves is straightforward for elastic materials. The information is generally incomplete and less reproducible for polymers which demonstrate viscoelastic contact, plastic deformation, and ploughing type friction. Moreover, they exhibit a wide spectrum of relaxation times from 105 to 109 Hz [121]. 

Barquins, M. Courtel, R. "Rubber Friction and the Rheology of Viscoelastic Contact", Wear 32 (1975)... 

Hutcheson, S. A., and McKenna, G. B., Nanosphere embedding into polymer surfaces a viscoelastic contact mechanics analysis, Phys. Rev. Lett., 94, 076103-1 to 076103-4 (2005) Erratum, Phys. Rev. Lett., 94,189902-1 (2005). 

M. Sakai and S. Shimizu, Elastic, plastic, and viscoelastic contact problems in axisymmetric indenta tion. Ceramic Transactions (The American Ceramic Society), vol. 133, 105 114, (2002). 

Creep in Viscoelastic Contacts in the Absence of Adhesion. Viscoelastic effects are important whenever contact dimensions change in a time interval that is comparable to a characteristic relaxation time rof the viscoelastic material. Ting (5), following earlier work by Lee and Radok (26), Ting obtained a general solution to the Hertz contact problem for the case of a rigid axisymmetric probe and a substrate with linear viscoelastic response. He used the boundary conditions... 

Creep in Viscoelastic Contacts with Adhesion. The contact mechanics problem for a viscoelastic material including the effects of adhesion has not been solved. To do this, the elasticity problem must be solved for the viscoelastic continuity equation, equation 6, with the boundary conditions, equation 5, on z = 0 replaced by (27)... 

Sakai, M., Philosophical Magazine, Vol. 86, 5607-5624, Elastic and viscoelastic contact mechanics of coating/substrate composites in axi-symmetric indentation , (2006). 

The essence of the approach to viscoelastic contact is that it is reasonable to separate the effects of large-scale and small-scale viscoelasticity. Large-scale... 

I have benefited greatly from correspondence with several colleagues in the preparation of this chapter. These interactions have been particularly important with regard to the section on large-scale viscoelasticity. This section could not have been completed without the help of Dr. C.Y. Hui and Dr. Y.Y. Lin. Helpful comments regarding the entire manuscript from Dr. A.J. Crosby are also acknowledged, as are comments from Dr. W. Unertl, who also supplied preprints of his own unpublished work on viscoelastic contact mechanics. 

It should be possible to solve this problem with the help of recent techniques for analysing viscoelastic contact problems. At present however, neither experimental nor theoretical estimates are available. 

However, at higher velocities, and cases for which actual dummy head and the panel were us in the tests, the correlation was poor. This is due to the complications arised from modelling of the dummy head exterior (Butyl rubber) and also the plywood panel onto which a one-inch thick Nomax open all honeycomb with fiberglass laminate on both sides were fixed. From the experimental data, data fitting techniques were used to come-up with an alternative non-linear viscoelastic contact force model such that the contact force f is evaluated from the deformation (indentation) 6 and deformation rate 5 according to... 

Use of impact sled tests is the most common technique for determining the postcrash dynamic behavior of an aircraft occupant. The impact sled and target tracking facilities available at National Institute for Aviation Research (NIAR) were used to conduct a study on occupant responses in a crash environment. Parallel analysis capabilities, including a multibody dynamic model of the occupant and a finite element model of seat structures, have been developed. The analysis has been used to reasonably predict the Head Injury Criteria (HIC) as compart with the experimental impact sled tests for an occupant head impacting a panel. A nonlinear viscoelastic contact force model was shown to better predict the experimental data on the contact forces than the Hertzian models. Suitable values of the coefficients in the contact force model were obtained and the correlations between the coefficients, HIC, and maximum deformation of the front panel were determined. A non-sled test method of pendulum-type has been designed to determine the head injuries as well as the performance of each particular impact absorber. 

Golden, J.M. (1986a) Frictional viscoelastic contact problems. Q. J. Mech. Appl. Math. 39, 125-137 Golden, J.M. (1986b) Causality and viscoelastic boundary value problems. Int. J. Eng. Sci. 24, 1141-1149... 

Graham, G.A.C., Sabin, G.C.W. (1981) Steady state solutions for a cracked standard linear viscoelastic body. Mech. Res. Commun. 8, 361-368 Graham, G.A.C., Sneddon, I.N. (1981) The axisymmetric viscoelastic contact problem with rotational friction. J. Elasticity 11, 33-42... 

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