Contact-free measurement and numerical and analytical evaluation of the strain distribution in a wood-FRP lap-joint
Wood specimens to each of which a laminate of carbon fibre reinforcement polymers (FRP) was glued (creating a lap joint in each case) were loaded to failure. A total of 15 specimens of three types differing in the glued length (anchorage length) of the FRP laminate (50, 150 and 250 mm respectively) were tested, their strength, stiffness and strain distribution being evaluated. Synchronized digital cameras (charge-coupled devices) used in testing enabled strain fields on surfaces they were directed at during the loading procedure to be measured. These results were also evaluated both analytically on the basis of generalized Volkersen theory and numerically by use of the finite element method. The lap joints showed a high level of stiffness as compared with mechanical joints. A high degree of accuracy in the evaluation of stiffness was achieved through the use of the contact-free evaluation system. The load-bearing capacity of joints of this type was found to be dependent upon the anchorage length in a non-linear fashion. The experimental, analytical and numerical results were shown to be in close agreement with respect to the strength and the strain distribution obtained.
KeywordsFRP Lap-joint Volkersen Wood
The authors want to express their sincere gratitude to Såg i Syd for the financial support to the studies.
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