IMPACT OF LAMINATE PROPERTIES ON INTERFACE STRESSES AND STRESS INTENSITY FACTOR IN CRACKED STEEL PLATES REPAIRED WITH CARBON FIBER REINFORCED POLYMERS

摘要

Impact of laminate properties on laminate stresses and stress intensity factor (SIF) was studied numerically for edge cracked steel plates, repaired with bonded carbon fiber reinforced polymers (CFRP). The study included repairs with identical axial stiffness under applied far-field stress of 100 MPa. Parameters of the study were thickness and tensile modulus of adhesive and CFRP. It was found that maximum adhesive shear stress at crack location and the SIF were varied with the variation in adhesive G/t ratio (shear modulus per unit thickness) but these were less affected by the variation in CFRP properties. Peel stress at patch end was much sensitive to the adhesive modulus (E_A) and CFRP properties than the adhesive thickness (t_A). An increase in adhesive G/t of 8 times (by reducing its t_A) resulted in 200% increase in the maximum adhesive shear stress, 26% decrease in the SIF and a negligible impact on the peel stress. Similarly, increase in adhesive G/t of 16 times (by increasing its E_A) resulted in 360% increase in the maximum adhesive shear stress, 50% decrease in the SIF and 300% increase in the peel stress. Variation in CFRP properties had negligible impact on adhesive shear stress and the SIF but it affected the peel stress at the patch end. An increase in the CFRP thickness of 400% (with a corresponding decrease in E_A by 400%) increased the peel stress by 42% with negligible impact on the maximum adhesive shear and the SIF.