STP521

    Deformation and Failure of Boron-Epoxy Plate with Circular Hole

    Published: Jan 1973


      Format Pages Price  
    PDF Version (548K) 22 $25   ADD TO CART
    Complete Source PDF (6.9M) 22 $123   ADD TO CART


    Abstract

    The behavior under uniaxial tension of a boron-epoxy composite plate with a circular hole was studied by means of experimental stress analysis and finite-element methods. The specimens were 10 by 26 in. boron-epoxy panels of [0/±45/0/90¯]s layup. They were instrumented with strain gages, photoelastic coatings, and moiré grids. The latter were analyzed using moiré fringe multiplication techniques. Strain distributions as a function of applied nominal stress were obtained along the axes of symmetry and around the boundary of the hole. Young's modulus and Poisson's ratio were computed from the far-field strains. Tensile and compressive strain concentrations were computed for the linear range of strain response. Experimental results were compared with those obtained by homogeneous anisotropic elasticity and by finite-element analysis. The mode of failure was a combination of interlaminar shearing and tensile cracking starting at the hole boundary off the horizontal axis, at a point where the elastic shear stress and strain reach their maximum and where the tangential normal and shear strains increase rapidly and nonlinearly with load. The average applied stress at failure was 42 200 psi compared with a coupon strength of 94 000 psi. The average ultimate tensile strain at the hole boundary on the horizontal axis was 8 X 10-3 in./in. compared with a coupon ultimate strain of 6.8 X 10-3 in./in. At higher loads the peak of the tensile strain shifted, resulting in a higher ultimate strain away from the boundary.

    Keywords:

    composite materials, stress analysis, failure, plate with hole, strain gages, moiré methods, photoelastic analysis, shear properties, stress concentration, strength reduction, elastic properties, nonlinear response


    Author Information:

    Daniel, IM
    IIT Research Institute, Chicago, Ill.

    Rowlands, RE
    IIT Research Institute, Chicago, Ill.

    Whiteside, JB
    Grumman Aerospace Corp., Bethpage, N. Y.


    Paper ID: STP36483S

    Committee/Subcommittee: D30.04

    DOI: 10.1520/STP36483S


    CrossRef ASTM International is a member of CrossRef.