FEM model of composite wing versus experimental measurement

Co-operation with the company Urban Air has enabled me to compare two approaches the real wing structure testing with the FEM modelling. The deflection and strains measured by the strain gauges installed on the real construction during manufacture were compared to the results of FEM analysis. The FEM model of the wing structure was prepared using the MSC Patran. Models of spars root and tip ribs and skin were generated. At the beginning, approximate properties taken from the literature were used. Response of the structure was determining by the MSC Nastran solving a linear static task. Since differences between the FEM results and measurement were bigger than expected, more accurate values of parameters were determined by experiments and with those new of material properties the task was solved again. The measured wing structure deflection and most of the strain values were very similar to the FEM results. Same strains showed the critical areas on the wing structure. The results and their comparison allow for using the FEM model as an adequate method for stress analysis of composite structures produced using a wet lay-up method.