Finite element study of composite cuff connections for pultruded box sections

Detailed finite element models were developed to represent beam and column test frames comprising box sections connected together with innovative monolithic glass fiber reinforced plastic (GFRP) cuff connections. Model mechanical properties (both stiffness and strength) for the member and connection composite materials were determined from tests on the composite constituent materials and on composite lamina coupons. Damage was investigated in the models by employing the Tsai-Wu failure criterion. The models were validated with respect to stiffness and strength by comparing to the experimental test frame behavior. Frame stiffness and cuff damage patterns were well represented for the case of pultruded fiber reinforced plastic (PFRP) members connected by GFRP cuff connections of various thicknesses. The finite element models were also employed to proportion improved designs of GFRP cuff connections for the PFRP members used in the test frame configuration, so as to achieve appropriate levels of stiffness and damage strength while also keeping the materials used to a minimum.