VISCOPLASTIC ANALYSIS OF ADHESIVELY BONDED JOINTS IN COMPOSITE-MATERIALS

Adhesively bonded joints are being preferred to mechanical fasteners i n structural members because of distinct advantages they offer, such a s uniform stress distribution, stiff connection, excellent fatigue pro perties and light weight. In addition, these joints are found to be mo re suitable with composite materials, particularly in the case of fibr e reinforced plastics. At moderately large loads the polymeric adhesiv e material behaviour tends to elasto-plastic and elasto-visco-plastic. In the present work, a finite element code is developed and visco-pla stic analyses of adhesively bonded joints are carried out. Single lap, stepped lap, and double lap joints are considered for the analyses. I nfluences of various parameters, such as (i) stacking sequence in comp osite adherends, (ii) critical strain energy release rate of the adhes ive, (iii) overlap length and (iv) thickness of the adhesive on the st rength of the adhesively bonded double lap joints, are also investigat ed.