This paper describes the implementation of a parallel solver into the commercial finite element software SAM CEF The method implemented combines a direct solution on subdomains with an iterative solution of the dual prob lem on the global interface (finite element tearing and interconnecting [FETI] method). The presentation is lim ited here to its application in the context of linear statics and modal analysis of structures. The performance of the method is demonstrated through representative examples.

This paper presents a solution procedure made available at an industrial level to study delamination in composites. Two approaches are presented. The first one is based on an original VCE (Virtual Crack Extension) method used to provide a quick estimate of the propagation load and the critical inter-laminar cracks, in a linear finite element analysis. The second approach relies on cohesive elements, and implies a non linear analysis. More general than the fracture mechanics (VCE) approach, the cohesive elements technique allows to provide the value of the maximum load that can be sustained by the structure, and to predict the residual strength and stiffness over the fracture process. Those two methods are first compared in a DCB test case to show that the results agree well with those from the literature or with the analytical solutions. Finally, a multidelaminated industrial test case is solved with both approaches.

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This paper presents a solution procedure developed in the SAMCEF finite element code for the advanced optimal design of stiffened composite panels of an aircraft fuselage. The BOSS quattro, a task manager and optimization toolbox, is used for defining and running the optimization problem. The objective function to be minimized is the weight, and the restrictions depend on structural stability requirements, such as buckling and collapse. The design variables are the panel and stringer thicknesses of the conventional proportions (i.e. 0∘, 90∘ and ±45∘) in a homogenized laminate. Since a collapse analysis introduces geometric nonlinearities into the design process, the function evaluation can take a long time. In order to obtain a rapid optimal solution, a gradient-based method is used, and the first order derivatives need to be computed, in this case with an original semianalytical approach. The sensitivity analysis of buckling and collapse is reviewed. Numerical tests on an industrial case study demonstrate the possibility and the reliability of the approach. Solving such problems is clearly difficult and remains a challenge. Through the applications, this paper provides the opportunity to discuss convergence issues and the use of such advanced optimization techniques in the overall aircraft design process.