Effect of fiber content and curvature on probabilistic free vibration analysis of cylindrical shallow shells reinforced by short natural fibers

Abstract

In the present paper, the effect of the fiber contents and the curvature on the probabilistic analysis of free vibration of Short Alpha Fibers (SAF) reinforced Cylindrical Shallow Shells has been presented. Firstly, an experimental study is carried out to manufacture the cylindrical shallow shells with different fiber contents from Alfa (Wf = 5%, 10% and 15%) impregnated with Medapoxy STR resin. Using a hammer, free vibration testing is made to predict damping coefficients, frequencies and mode shapes versus Wf and cylinder curvature (k). A numerical model was developed by ANSYS software to compute the natural frequencies and the corresponding shapes and compare them with the experimental results. Finally, a Monte Carlo simulation (MCS) is developed to study the probabilistic free vibration of cylindrical shallow shells modeled by finite element (FE). Material and physical properties are considered uncertain parameters and are represented by different Coefficients of Variation (CoV). The results show that reinforcing the epoxy matrix with SAF makes the cylindrical shallow shells more flexible and deformable due to high strain values and low stiffness. In fact, it can also reduce the effect of high resonance by considering the damping phenomenon. The reliable design of cylindrical shallow shells can only be ensured by intensive control of Young's modulus CoV (Ec).