Functionally Graded Adhesive Patch Repairs of Wood Beams in Civil Applications

Several investigations have been made concerning the fracture behavior of scaled specimens of wood beams repaired with adhesively bonded carbon fiber reinforced polymer (CFRP). However, one of the problems associated to these joints is the fact that the stress distribution (shear and peel) is concentrated at the ends of the overlap, leading to premature failure of the joint. The stress concentration can be reduced with use of a functionally graded adhesive, in which the mechanical properties vary along the bond length. This can be achieved with a graded cure, in which the temperature varies along the bond length. In this study, the repair of wood structures with CFRP was made using a homogeneous cure and a graded cure. The graded cure was performed by induction heating. This technique has already been successfully tested in single lap joints to increase the strength of the joint. Two common types of defects on beams under bending loads were analyzed (compression and cross grain tension damage). Scaled specimens of damaged wood beams were repaired and tested under four point bending. The results show that the cross grain tension beams repaired with a graded bondline were able to withstand higher loads than the beams repaired with a homogeneous bondline. This failure load of the graded repaired beam increases with an increase of the overlap length.


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  • Accession Number: 01531366
  • Record Type: Publication
  • Files: TRIS, ASCE
  • Created Date: Jul 2 2014 3:06PM