Contact/collision Dynamics Of Space Membrane Structures Described By Absolute Nodal Coordinate Formulation

Membrane structures, such as inflatable membrane structures and spinning deployment solar sail structures, are widely used in large deployable space structures because of their light weight and great deployed-area/mass ratio. With the movement of deployable space structures, membrane structures not only undergo overall rigid motions and large elastic deformations, but also suffer from the contact/collision problem. Therefore, it is urgent to present an accurate and efficient methodology to deal with the contact problem between the membrane structures in the framework of the flexible multibody dynamics.Previous studies have indicated that the Absolute Nodal Coordinate Formulation(ANCF) can accurately describe the coupled dynamics of the flexible structures with large rotations and large deformations. In this dissertation, the flexible components are described by the ANCF element and the constraints between these components are introduced in the system equation of the motion by the Lagrange multipliers. Besides, the implicit numerical integration algorithm is employed to solve the equation of motion established by the Lagrange equations of the first kind. However, how to deal with the contact problem between the membrane structures is still an open problem. The major contributions of the dissertation can summarized as follows.1. In the framework of the nonlinear finite element, the general description of contact/collision problem and finite element discrete method are revisited firstly. The penalty method is employed to enforce the constraints in the contact problems, as these constraints can be removed explicitly from the equation of motion. Based on the ANCF, an energy-restoring and momentum-conserving scheme is proposed and some formulations to evaluating the contact forces and elastic forces are also derived. Furthermore, a simple mathematical proof is given to validate the effectiveness and correctness of the proposed scheme. And, several numerical examples are also presented.2. According to the dynamic characteristics of membrane structures subjected to large rotations and large deformations, a collision detection algorithm including the global detection and the local detection is proposed. In the global detection, hierarchal bounding volumes are constructed by the topology of membrane elements in order to reduce the computational cost of contact searching. In the local detection, the Newton Raphson iteration is exploited to obtain the accuracy contact information in the closest elements, in which the initial iteration values are estimated by the global detection. 3. Based on the proposed method above, several contact/collision dynamic problems including membrane strap, spiral membrane tube and circular membrane solar wing are investigated via using Intel Visual Fortran. The numerical results verify the feasibility and correctness of the proposed method.