FRICTIONLESS CONTACT OF LAYERED METAL-MATRIX AND POLYMER-MATRIX COMPOSITE HALF-PLANES

This paper examines the differences and similarities in the response o f metal-matrix and polymer-matrix composite half planes indented by a rigid, parabolic punch. The quantities of interest are the load versus contact length and the normal stress distribution in the contact regi on. In particular, the effect of material properties and off-axis ply orientation on these quantities is investigated for homogeneous and la yered configurations. Layered configurations include [0-degrees/+/-45] layer sequences bonded to 90-degrees half planes, as well as to a hal f plane with significantly lower elastic stiffness moduli. The analysi s is conducted using a recently developed solution method for friction less contact problems of arbitrarily layered half planes consisting of isotropic, orthotropic, or monoclinic layers. The results indicate th at homogeneous metal-matrix composite half planes exhibit a substantia lly stiffer load versus contact length response than homogeneous polym eric matrix half planes owing to their higher transverse material para meters, in particular the transverse Young's modulus, E33. In situatio ns where local bending is present, which occurs in sandwich-type confi gurations with a substantially softer substrate, the ratio of the long itudinal to transverse Young's moduli plays a significant role for the considered laminate configurations. In this case, the normalized cont act stress profiles of certain metal-matrix and polymer-matrix composi tes exhibit substantial departures from elliptical that appear similar in shape despite differences in the actual magnitudes of the material parameters.