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Geometric Stiffness Effects On Data Recovery Of An Idealized Mast/Blanket Model, Paul A. Bosela, D. R. Ludwiczak
Geometric Stiffness Effects On Data Recovery Of An Idealized Mast/Blanket Model, Paul A. Bosela, D. R. Ludwiczak
Civil and Environmental Engineering Faculty Publications
The photovoltaic arrays for the international space station consist of a pre-tensioned blanket of solar collectors and a deployable mast. NASA uses the MSC/NASTRAN finite element program for modeling the dynamic response of the structure due to various loading conditions, such as plume impingement during shuttle docking. This finite element program uses the updated stiffness matrix (elastic plus geometric, or initial stress stiffness matrix) in determining the natural frequencies and mode shapes, as well as the dynamic response, of a pre-loaded structure. However, during the data recovery phase, when the moment and shear at the supports, and internal stresses are …
A New Pre-Loaded Membrane Geometric Stiffness Matrix With Full Rigid Body Capabilities, Paul A. Bosela, D. R. Ludwiczak
A New Pre-Loaded Membrane Geometric Stiffness Matrix With Full Rigid Body Capabilities, Paul A. Bosela, D. R. Ludwiczak
Civil and Environmental Engineering Faculty Publications
Space structures, due to economic considerations, must be light-weight. Accurate prediction of the natural frequencies and mode shapes is critical for determining the structural adequacy of components, and designing a control system. The total stiffness of a member, in many cases, includes both the elastic stiffness of the material as well as additional geometric stiffness due to pre-load (initial stress stiffness). The pre-load causes serious reservations on the use of standard finite element techniques of solution. In particular, a phenomenon known as ''grounding'', or false stiffening, of the stiffness matrix occurs during rigid body rotation. The author has previously shown …