AN EFFICIENT METHOD FOR NONLINEAR DYNAMIC ANALYSIS OF 3D SPACE STRUCTURES
Basically two classes of algorithms can be identified;
The implicit methods are those which predict the response at the end of each time step in terms of the known variables at the beginning of the time step and the unknown variables at the end of the time step. Hence the implicit methods are trial and error producers involving either iterative schemes or the solution of simultaneous equations.
The explicit method predicts the response at the end of time step in terms of the responses at the previous time steps. They do not normally need the solution of a system of equations. In the evaluation of the structural property matrices the mass is assumed to be constant and it can usually be represented as an equivalent system of lumped masses. The damping forces are usually assumed to be viscous and the damping matrix often proportional to the mass and/or the stiffness of the structure. For the structural system with evenly distributed stiffness, a damping matrix evaluated from the knowledge of the damping ratios in the various modes can be used. The stiffness matrix of a nonlinear structure is assumed to consist of elastic and geometric term
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