DYNAMIC INSTABILITY OF TIRES UNDER ASYMMETRIC LOADS

This paper presents an analytical procedure for predicting instability loads of composite tires using a simplified tire model. The tire is m odeled as a closed composite torus with geometric nonlinearities. The equations of motion of the torus are derived using differential geomet ry, and the Galerkin procedure is used to discretize the spatial domai n. The resulting equations are nonlinear ordinary differential equatio ns with constant coefficients. However, the special form of these equa tions allows their reduction to linear ordinary differential equations with periodic coefficients. The Floquet theory is then used to determ ine the stability characteristics of these equations under various loa ds and an impact velocity loading. The torus is studied in two reinfor cement configurations and various fiber volume fractions, Both configu rations show a threshold value for the applied load at which the stabi lity of the periodic solution is lost in a catastrophic manner. Both r einforcement schemes shows the same optimum value for fiber volume fra ction at which the instability load is maximum.