Available at: https://digitalcommons.calpoly.edu/theses/63
Date of Award
MS in Aerospace Engineering
Dr. Faysal Kolkailah
This study presents the effect of the stacking sequence and fiber orientation on a composite sandwich panel subjected to static in-plane bolt loading. Six plates were constructed with laminates of unidirectional carbon fiber and cross ply weaves of fiberglass. The orientations that were examined included 0, +/- 45, and 90 degrees. Half of the plates had fiberglass lamina on the outside of the laminate while the other three plates had the carbon fiber on the outside. Experimental and analytical tests were performed to determine the best orientations and stacking sequence.
For the numerical analysis, plates with fibers oriented at +/- 45 degrees showed the highest strength. The experimental data also showed high strengths for the +/- 45 degree plates. However the experimental data also showed high strengths for the 90 degree laminate but with very high displacements. These high displacements would not allow the joint to maintain its relative position to the adjacent part. The discrepancy between the strength of the FEA models and the experimental data is attributed to inaccurate strength properties. The effect of in situ strength and compression strength was found to have a significant effect on the accuracy of the FEA solution. Good correlation was found between the FEA and experimental data in predicting the trend of the stiffness of the plates.