Nonlinear analysis of adhesively bonded lap joints considering viscoplasticity in adhesives
This paper presents nonlinear finite element analysis of adhesively bonded joints considering the elasto-viscoplastic constitutive model of the adhesive material and the finite rotation of the joint. Though the adherends have been assumed to be linearly elastic, the yielding of the adhesive is represented by a pressure sensitive modified von Mises yield function. The stressstrain relation of the adhesive is represented by the RambergOsgood relation. Geometric nonlinearity due to finite rotation in the joint is accounted for using the GreenLagrange strain tensor and the second PiolaKirchhoff stress tensor in a total Lagrangian formulation. Critical time steps have been calculated based on the eigenvalues of the transition matrices of the viscoplastic model of the adhesive. Stability of the viscoplastic solution and time dependent behaviour of the joints are examined. A parametric study has been carried out with particular reference to peel and shear stress along the interface. Critical zones for failure of joints have been identified. The study is of significance in the design of lap joints as well as on the characterization of adhesive strength.
adhesive nonlinear finite element analysis bonded joints elasto-viscoplasticity finite rotation adherends critical time shear stress peel stress