Journal of Elasticity 15 (1985) 109-114. © 1985 Martinus Nijhoff Publishers, Dordrecht. Printed in The Netherlands. Interface slip between two half-planes caused by a steadily moving force R.D. LOW * and MARIA COMNINOU Mechanical Engineering and Applied Mechanics, University of Michigan, Ann Arbor, MI 48109, USA (Received August 18, 1983) Abstract A computationally simple problem is devised to study the behavior of steadily moving slip zones. Results are presented graphically. Introduction Frictional interface slip due to moving loads has been the subject of renewed interest [1,2] following the earlier work of Anscombe and Johnson [3]. One of the interesting differences between moving and stationary loads is the absence of slope discontinuity or "hook" in the shear tractions at the trailing edge of the moving slip zone. The problem considered in [1,2] involved forces moving steadily over the surface of a layer which was pressed against a half plane of identical elastic constants. Because this problem is computationally complex, a simpler problem is considered here to bring out the salient features of moving slip zones. The layer is replaced by another half plane and the surface force by an internal force. Then the solution can be obtained in closed form but is of great algebraic complexity. Only the case of a force parallel to the interface is examined. In addition to applied pressure, the solids are also sheared at infinity. Formulation and solution Two half planes with similar elastic constants are pressed and sheared at infinity with applied tractions pO~, qO~ respectively. A force P moves parallel to the interface at distance h with velocity ¢ to the right as shown in Fig. 1. We assume that the motion is quasistatic and neglect inertia effects. The fixed coordinates are denoted by 2, ~ and the coordinates moving with P by x, y so that x=Sc-ct, (1) * Deceased. 109