Accession Number : ADA301736

Title :   Impact on MultiLayered Composite Plates.

Descriptive Note : Final rept. Sep 75-Dec 76,

Corporate Author : CORNELL UNIV ITHACA NY DEPT OF THEORETICAL AND APPLIED MECHANICS

Personal Author(s) : Kim, B. S. ; Moon, F. C.

PDF Url : ADA301736

Report Date : APR 1977

Pagination or Media Count : 121

Abstract : Stress wave propagation in a multilayer composite plate due to impact has been examined by means of the anisotropic elasticity theory. The plate is modelled as a number of identical anisotropic layers and the approximate plate theory of Mindlin is then applied each layer to obtain a set of difference differential equations of motion. Dispersion relations for harmonic waves and correction factors are found. The governing equations are reduced to difference equations via integral transforms. With given impact boundary conditions these equations are solved for an arbitrary number of layers in the plate and the transient propagation of waves is calculated by means of a Fast Fourier Transform algorithm. The multilayered plate problem is extended to examine the effect of damping layers present between two elastic layers. A reduction of the interlaminar normal stress is significant when the thickness of the damping layer is increased but it seems that the effect is mostly due to the softness of the damping layer. Finally the problem of a composite plate with a crack on the interlaminar boundary has been formulated.

Descriptors :   *LAMINATES, *CRACKING(FRACTURING), *IMPACT SHOCK, STRESSES, ALGORITHMS, TRANSIENTS, THICKNESS, EQUATIONS OF MOTION, LAYERS, HARMONICS, ELASTIC PROPERTIES, DAMPING, DIFFERENCE EQUATIONS, COMPOSITE STRUCTURES, REDUCTION, WAVE PROPAGATION, PLATES, ANISOTROPY, DIFFERENTIAL EQUATIONS, FAST FOURIER TRANSFORMS, INTEGRAL TRANSFORMS, STRESS WAVES, DISPERSION RELATIONS.

Subject Categories : Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE