A simple differential equation is developed to include the effect of dry friction in the oscillatory behavior of a material. It is assumed, following Alptekin and Zorowski, that the viscoelastic behavior is described adequately by a linear Voigt model. The contribution of dry friction to the stress is represented by a step function of the strain rate. The nonlinear equation obtained is solved by means of the perturbation theory. The amplitude of the oscillatory displacement is calcu lated, and it is found that the strain in the testpiece shows a number of discontinuities, the number depending on the length of the testpiece.
Alptekin, A. T., On the Dynamic Mechanical Properties of Fiber Assemblies, Thesis , N. C. State University, Raleigh, N. C., 1968.
2.
Alptekin, A. T., Private discussions.
3.
Zorowski, C.F. , Murayama, T., and Alptekin, A.T., Strain Wave in Twisted Filament Assemblies, Proc. Fifth Intern. Congress Rheology, Japan, 1969; Vol. III, University Park , Press, Baltimore, Md., 1970 .
