| The contribution of this thesis is an extended high-order sandwich panel theory (EHSAPT) for sandwich beams/wide panels, in which the axial stresses are taken into account as well as the shear and transverse normal stresses in the core, and its validation. The general nonlinear formulation of EHSAPT is given in Chapter 2. Validation of the present theory is made by comparison with elasticity solutions and experimental data. The accuracy of EHSAPT is assessed for the standard class of structural analysis problems which include: static loading, static instability (global buckling and wrinkling), free vibrations, and dynamic loading. In Chapter 3 the static response to a half-sine distributed load applied to the top face sheet of a simply supported sandwich beam/wide panel is solved. Validation is made with elasticity, and Euler-Bernoulli beam, first order shear deformation theory, and HSAPT were also included for comparison. In Chapter 4 the static global buckling critical load is determined for a simply supported sandwich beam/wide panel under edgewise loading. Validation is made with elasticity, and Allen's formula and HSAPT are included for comparison. In Chapter 5 the static wrinkling critical load of a simply supported sandwich beam/wide panel is investigated. Validation includes comparison with elasticity, experimental results reported in literature, and recently acquired experimental results. Results using Hoff-Mautner's wrinkling formula and HSAPT are also shown. In Chapter 6 the free vibrations of a simply supported sandwich beam/wide panel are explored, and the predicted antisymmetric and symmetric natural frequencies are compared to experimental results found in the literature and with elasticity. The last validation of EHSAPT is made for the dynamic response to a half-sine distributed load with an exponential time decay applied to the top face sheet of a simply supported sandwich beam. Results are compared with elasticity. The response from using HSAPT is also shown. Chapter 8 presents results from an impact experiment upon a sandwich panel and comparison with EHSAPT. Finally, Chapter 9 gives overall comments on the future work that can be done with EHSAPT. |
