Chen, Tzikang | Search NASA

NASA NTRS2005

Modeling of Triangular Lattice Space Structures with Curved Battens

Techniques for simulating an assembly process of lattice structures with curved battens were developed. The shape of the curved battens, the tension in the diagonals, and the compression in the battens were predicted for the assembled model. To be able to perform the assembly simulation, a cable-pulley element was implemented, and geometrically nonlinear finite element analyses were performed. Three types of finite element models were created from assembled lattice structures for studying the effects of design and modeling variations on the load carrying capability. Discrepancies in the predictions from these models were discussed. The effects of diagonal constraint failure were also studied.

Chen, Tzikang↗

NASA NTRS2004

Simulating Nonlinear Deformations of Solar Sail Membranes Using Explicit Time Integration

In this study, the explicit time integration method is employed to predict deformation of highly flexible solar sail structural components. The nonlinear static analysis of a highly flexible ribbon structure is presented to demonstrate the need for having the explicit time integration method in the analysis toolbox for solar sail. Static analyses of the ribbon structure produce ambiquous results whereas the explicit time integration method determines the correct results. Extensive benchmarking examples are also presented to build confidence in the use of the explicit method. Previously determined nonlinear wrinkling deformations of solar sail membranes are found by the explicit method. As the explicit method is known to often require more computational time than nonlinear static methods, a study on mass scaling was also conducted. The computational times are reported for the nonlinear static and explicit time integration solutions to calibrate the advantage of using mass scaling for these problems.

Wang, John T.↗