Design And Characteristic Of Lightweight Composite Lattice Sandwich Panel Joints

Low cost, high efficiency and reliability are always the research subjects for structural designers in aerospace field. Composite lattice sandwich structures have attracted considerable interest not only because their excellent specific strength and stiffness but also their potential multi-functional application, owing to the open internal space. It is generally known that light-weight sandwich structures are not independent individuals in engineering application, which have to be joined or connected to other components. Therefore, effective design and strength research have to be adequately treated. In this dissertation, the connection design and mechanical characteristics of carbon fiber reinforced composite lattice sandwich panels are investigated, which provides the theoretical guidance and technical support for application. The main contents are as follows:Several groups of specimens are fabricated using pre-embedded square column inserts, which are designed for the condition of external connection to the surface of sandwich panels. A preliminary theoretical analysis and failure prediction are carried on under several loading conditions. In order to determine the failure mode and ultimate bearing capacity, the pull-out and shear propertiesof the structures are investigated by normal tensile and shear tests, respectively. Furthermore, the finite element method is employed to simulate the pull-out behavior, and the numerical results give a good agreement when compared with the experiments.For the corner joints of light-weight lattice sandwich panels, a disassembling L-model connection is designed through potting machining bowl-shaped bushings and blind nuts in the sandwich panels. Bending and shear properties are studied by experiments in order to investigate the failure mode and the ultimate bearing capacity. The finite element method is also utilized to simulate the shear behavior of the L-joints, and the numerical results give a reasonable explanation for the experiment phenomenon, which may be helpful to industry application of such lightweight lattice sandwich structures.