Hybrid-Trefftz formulation for analysis of thick orthotropic plates

To analyze thick orthotropic plates, two triangular and rectangular elements with high accuracy are suggested. The proposed formulations utilize the Hybrid-Trefftz function. In this method, two displacement fields are considered for inner and boundaries of the element. After establishing the governing differential equation of orthotropic thick plates, its analytical solution is obtained. This response presents the inner displacement field. By using interpolation functions, the boundary field is related to the elemental nodal degrees of freedom. In this study, the interpolation functions of the orthotropic Timoshenko beam are used for the boundary fields. Based on the mentioned functions, the triangular and rectangular elements are suggested. The degrees of freedom for the new elements are nine and twelve, respectively. To demonstrate the efficiency and accuracy of the suggested formulations, some thick orthotropic plates are solved. These tests show the high accuracy and potential of the authors' elements.