Nonlinear dynamics of slender structures: a new object-oriented framework

With this work, we present a new object-oriented framework to study the nonlinear dynamics of slender structures made of composite multilayer and hyperelastic materials, which combines finite element method and multibody system formalism with a robust integration scheme. Each mechanical system under consideration is represented as a collection of infinitely stiff components, such as rigid bodies, and flexible components like geometrically exact beams and solid-degenerate shells, which are spatially discretized into finite elements. The semi-discrete equations are temporally discretized for a fixed time increment with a momentum-preserving, energy-preserving/dissipative method, which allows the systematic annihilation of unresolved high-frequency content. As usual in multibody system dynamics, kinematic constraints are employed to render supports, joints and structural connections. The presented ideas are implemented following the object-oriented programming philosophy. The approach, which is perfectly suitable for wind energy or aeronautic applications, is finally tested and its potential is illustrated by means of numerical examples.