Accession Number : ADA305097

Title :   Off-Axis Impact of Unidirectional Composites with Cracks: Dynamic Stress Intensification.

Descriptive Note : Interim rept. 13 Feb 78-12 Feb 79,

Corporate Author : LEHIGH UNIV BETHLEHEM PA INST OF FRACTURE AND SOLID MECHANICS

Personal Author(s) : Sih, G. C. ; Chen, E. P.

PDF Url : ADA305097

Report Date : JAN 1979

Pagination or Media Count : 75

Abstract : The dynamic response of unidirectional composites under off-axis (angle loading) impact is analyzed by assuming that the composite contains an initial flaw in the matrix material. The analytical method utilizes Fourier transform for the space variable and Laplace transform for the time variable. The off-axis impact is separated into two parts; one being symmetric and the other skew-symmetric with reference to the crack plane. Transient boundary conditions of normal and shear tractions are applied to a crack embedded in the matrix of the unidirectional composite. The two boundard conditions are solved independently and the results superimposed. Mathematically, these conditions reduce the problem to a system of dual integral equations which are solved in the Laplace transform plane for the transform of the dynamic stress intensity factor. The time inversion is carried out numerically for various combinations of the material properties of the composite and the results are displayed graphically. (AN)

Descriptors :   *STRESS ANALYSIS, *CRACKS, *MATRIX MATERIALS, STRESS STRAIN RELATIONS, MATHEMATICAL MODELS, FOURIER TRANSFORMATION, LOAD DISTRIBUTION, TIME DEPENDENCE, DEFORMATION, DYNAMIC RESPONSE, FIBER REINFORCED COMPOSITES, MODULUS OF ELASTICITY, FRACTURE(MECHANICS), IMPACT STRENGTH, DEFECTS(MATERIALS), SHEAR STRESSES, PARTIAL DIFFERENTIAL EQUATIONS, DYNAMIC LOADS, INTEGRAL EQUATIONS, UNIDIRECTIONAL, LAPLACE TRANSFORMATION, STRESS CONCENTRATION.

Subject Categories : Laminates and Composite Materials
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE