Finite element analysis of a hybrid natural fibre sandwich wall panel loaded with in-plane shear

The world is rapidly growing and the need for sustainable materials is increasing. This project analysed a newly developed hybrid sandwich panel with in-plane shear loading in Strand7, finite element analysis software. The objective was to determine if adding natural fibre composites as intermediate layers between the core and skins would decrease the shear stresses within the core as well as reviewing the extension caused by the loading. his was completed by the creation and use of 2D and 3D models within Strand7. These models were validated by comparing the linear results against Dr. Fajrin's experimental testing results. The 2D models used the classic laminate theory and tested the diagonal extension as well as the overall shear stress within the panels. The 3D models used extruded plates and tested for the diagonal extension as well as shear stresses within each layer of the model. A convergence study was also done within Strand7 to determine the optimal mesh when considering accuracy, computational time and workability. It was found that an 80x80 mesh was suitable for the analysis and offered the best results based on the testing criteria. Four natural fibre composites were analysed and tested to see if they could aid in strengthening the sandwich wall panels mechanical properties. These fibres were jute, medium density fibres, hemp and sisal. The results were compared to the control panel which consisted of just an expanded polystyrene core and aluminium skins. Overall the results found that the jute and medium density fibres were viable whilst the hemp and sisal fibres increased the shear stress within the core making them redundant. Jute in both analysis' showed better results. The 3D results were able to provide a more detailed and in-depth analysis of likely real world results compared to the 2D laminated models. Non linear analysis was also trialed however due to time constraints could not be finalised. It was found that the models were not transitioning to a non linear state because the skins were absorbing more than 99% of the loading thus not putting enough strain on the core to allow for deformation. Further analysis of this section is recommended as future work