Performance of truss panels with kagome cores and design of a high authority shape morphing structure

This dissertation includes two parts: First, the performance of a light weight truss panels with Kagome cores; Second, design of a high authority morphing structure for hinging and twisting. The performance characteristics of a truss core sandwich panel design based on the 3D Kagome are measured and compared with earlier numerical simulations and the consistency is demonstrated. Panels are fabricated by investment casting and tested in compression, shear and 3-point bending. The isotropic nature of this core design is confirmed. The superior performance relative to truss designs based on the tetrahedron is demonstrated and attributed to the greater resistance to plastic buckling at the equivalent core density. The failed samples are examined in the scanning electron microscope and imperfections are identified to have caused the premature failures. A concept for a high authority shape morphing plate is described. The design incorporates an active Kagome back-plane capable of changing the shape of a solid face by transmitting loads through a tetrahedral core. The two shape deformations to be achieved and demonstrated consist of hinging and twisting. The design is performed by a combination of analytic estimation and numerical simulation, guided by previous assessments of the Kagome configuration. The objective is to ascertain designs that provide the maximum edge displacement subjected to specified passive load. An optimization is used to ascertain the largest displacement achievable within the force capacity of the actuators. These displacements have been demonstrated and shown to correspond with values predicted by numerical simulation. Non-linear effects, such as face wrinkling, are probed by using a finite element method and the fidelity of the results assessed through comparison with measurements. The numerical results are used to validate a dimensional analysis of trends in the actuation resistance of the structure with geometry, as well as the passive load capacity. The forces determined by such analysis are combined with the failure mechanisms for all sub-systems to establish the constraints. The important domains are visualized using mechanism maps. An optimization is used to generate load capacity maps that guide geometric design and provide actuator capacity requirements.