Experimental flexural behaviors of CFRP strengthened aluminum beams

• Hybrid bond method was applied to strengthen aluminum beam by CFRP strip.
• Hybrid bond method improves flexural rigidity at a ratio of 32.8%.
• Hybrid bond method improves load carrying capacity at a ratio of 31.13%.
• A beam model is suggested to predict the nonlinear behavior of the strengthened beam.
• A design procedure is proposed for CFRP strengthened aluminum beam.

To improve the flexural rigidity and load carrying capacity, aluminum beams were strengthened by carbon fiber reinforced plastic (CFRP) sheets. A hybrid bond technique with mechanical fastening was suggested to improve the reinforcement efficiency. Four-point-bending experiments were carried out to reveal the flexural behaviors and failure styles of the strengthened beams. Flexural rigidity can be increased at a ratio of 32.8%. The hybrid bond technique changes the failure style from normal debonding to tangential slippery and improves the load carrying capacity at a ratio of 31.13%. It is found that CFRP hybrid bond method is more efficient for aluminum members than steel ones. A simplified analytical method based on full interaction between the beam and the reinforcement was suggested to predict the nonlinear behaviors, flexural rigidity and load carrying of the strengthened beam. Based on the experiments and analyses, a design procedure was put forward for CFRP sheets to strengthen aluminum structural members using hybrid bond technique.