1986 Volume 34 Issue 391 Pages 436-446
The stress concentration around a hole in CFRP laminates is numerically studied by using the finite element method. The classical lamination theory is used for the plane stress problem, namely the effect of interlaminar stress is not included. The lamination constitutions studied are [0°, 90°, 45°, -45°; each 25%], [45°, -45°; each 50%], [0°; 75% and 90°; 25%], [0°, 90°; each 50%] and [0°; 25% and 90°; 75%]. Two types of load, i. e. uniform tension or bolt load, are applied. The eight points quadrilateral isoparametric elements are used. The mainpurpose of the present study is not to disclose the thickness-wise mean stress but the stresses in each layer and the principal strains and the maximum shearing strain. The stress concentration factor in each layer is much higher than that of the isotropic one, Furthermore the so-called initial failure stress is calculated by applying the maximum stress theory or Tsai-Wu theory for failure to the normal stresses in the fiber and transverse directions and the shearing stress in each layer. The influence of lamination constitution on the initial failure stress and the failure mode is disclosed.
