|
A hybrid stress multilayer element model together with the
contact mechanics analysis procedure are developed to study the
three dimensional frictionless contact problem between a
general composite laminate and a rigid sphere. The multilayer
element model is formulated based on a modefied complementary
energy priciple. To relax the equilibrium of interelement
tractions, in addition to the stress field in the interior of
the element, the Lagrangian multipliers which are physically
the interelement boundary displacements are introduced and the
interelement traction reciprocity and mechanical boundary
conditions are satisfied. Besides, in the multilayer elements
model, the undetermined stress parameters and total degrees of
freedom are independent of the number of layers and the
kinematic conditions are satisfied on the ntact surfaces.
Hence, the application of the present techique has no limiation
of the geometry, stacking arrangement , boundary conditions and
number of layers. The contact problem of a general graphite/
epoxy laminate and a rigid sphere is solved. Excellent
agreements between the present result andference solutions show
the high accuracy and validity of the technique developed. The
effects of sphere diamenter, stacking arrangement, span and
boundary conditions on the indentation law are also disscussed
in details.
|