Free Vibration Analysis of Curvilinear-Stiffened Plates and Experimental Validation

In this research, the vibration analysis of plates with curvilinear stiffeners is carried out. The Ritz method is applied while stiffeners are considered as discrete elements. The first-order shear deformation theory is used to represent the plate and stiffener. Chebyshev polynomial functions are used as the basic functions in the Ritz method. The major part of this work is concerned with modeling the curvilinear stiffeners and comparing the results with experimental data. By considering the curvilinear stiffeners, the curvature, the continuous variation in orientation, can be used in controlling different mode shapes in addition to the associated frequencies. It can provide a mechanism to passively control the dynamic response under certain excitations. In the present method, the geometric properties of curvilinear stiffeners can be modified without changing the plate geometric properties. In the developed formulations, both eccentric and concentric stiffeners were studied. Natural frequencies for plates with straight stiffeners were compared with the results available in the literature. A good agreement was seen. A 24 by 28 in. curvilinear-stiffened panel was machined from 2219-T851 aluminum for experimental validation of the Ritz and meshfree method of vibration mode shape predictions. Results were obtained for this panel mounted vertically to a steel clamping bracket using acoustic excitation and a laser vibrometer. Experimental results appear to correlate well with theoretical predictions. [PUBLICATION ABSTRACT]