Modeling Method for Deformation Analysis in Thick Laminate Mechanical Joints

Accurately accessing both in-plane and out-of-plane deformations of the thick laminate multibolt single-lap joints is important to evaluate not only the stiffness of the aviation structures but also the prerequisite of efficiently and accurately predicting the strength in multibolt joints applying global local method. To decrease the computing time and resources, a two-dimensional finite-element method was presented, which takes into account the fastener's equivalent flexibility and the nonuniform contact relationships between fastener shank, fastener head, nut, and plates in detail. This two-dimensional finite-element method can be used to analyze the effect of friction conditions and fit conditions between fasteners and plates, the tightening torque of the fasteners, and the fastener head/nut thickness. The numerical results are validated through comparing with the experimental results on both in-plane and out-of-plane deformations. The effectiveness of the two-dimensional finite-element method in reducing the computation time is quite obvious, and this method is appropriate for the aircraft designer to optimize the structure configurations over lots of design variables in large-scale multifastener structures quickly.