FINITE-ELEMENT ANALYSIS OF LAMINATED COMPOSITES WITH CONTACT CONSTRAINT BY EXTENDED INTERIOR PENALTY METHODS

In this paper the extended interior penalty methods are applied to solve the bolted joint problems of the laminated composite plates. The conventional interior penalty methods have the weak point such that the searches for optimized solution in the neighbourhood of the constraint surfaces are difficult since the values of penalty term in the infeasible domain are infinity. To improve the weak point, the extended interior penalty formulation is proposed. In this work mathematical analysis on the characteristics of the solutions is attempted and the convergence of the penalized solutions is estimated. As a numerical example, first, the case of single bolted joint is solved for a variety of lamination angles of the composite plates. The computed results are compared with the previous works and are proved to agree well. Next the problem of the two bolt holes in series and in parallel are treated in a similar manner. It is concluded that the formulations for the class of the problems by the extended interior penalty methods are mathematically sound and numerically efficient.