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A multifrontal solver that combines multifrontal schemes with mesh-mapping schemes and graph partitioners has been developed. The solver, which retained the good attributes of traditional frontal methods, including core memory requirement reduction, efficiency, robustness and finite element procedure fitness, has been demonstrated to be a superior product. The multifrontal solver was able to provide the required solutions in a number of large-scale structural analysis problems.

A study of laminated composite plates under low-velocity impact shows that the modified Hertz contact law, generally used for isotropic materials, has limitations when considering lamination patterns and the thickness effect. The effects of curvature on impact behaviours of composite laminates are discussed.

A penalized weighted residual formulation for the second-order initial value problems caters to the need for network parallel computing in the whole time domain. The initial velocity is imposed to the weighted residual equation as a penalized form in such a way that the approximated initial velocity fulfills the initial condition. This is necessary for the proper imposition of both the initial displacement and velocity. This technique helps utilize the conventional-displacement-based finite element technique without any other artificial routine.

Finite element methods with a penalty parameter are used to calculate the boundary-value problem for laminated composites. Analysis of the elastoviscoplastic nature of the orthotropic composites laminates is based on an unmixing-mixing scheme. A computer code is used to solve the bolted joint problem of laminated composite materials with complex geometry and boundary conditions. Numerical solutions explain the propagations of inelastic deformation, stress distributions in the plies and different viscoplastic effects.

Analysis of the transverse shear deformations and structural damping effects on composite rotor blade aeroelastic behavior during hover reveals the usefulness of the beam model. Transverse shear is capable of stabilizing or destabilizing rotor motion. An alteration in the ply orientation angle enhances the damping properties of composite laminates.

The viscoplastic behavior of thermoplastic composites at high temperatures are studied using a constitutive matrix model. The model relies on a modified Bodner and Partom flow rule to analyze the composites' elastic properties, such as volume, fiber and matrix, which are expressed in terms of the rule of mixture equation. The new flow rule equations are then solved by means of the direction iteration method and other related techniques. Results indicate that it is possible to predict the composites' viscoplastic behavior using only the viscoplastic properties of the matrix.