The recent years, 3D printing has become a hot topic, however, it’s hard to design parts without a deep understanding of the material properties. The aim of this study is to estimate the modal parameters and the damping properties via experimental dynamic analysis of a part made from PLA. We will study the effects of the different directions of printing. With the results we can provide data for FEM software input.
Ján Kortiš, Ľuboš Daniel, Milan Škarupa and Maroš Ďuratný
The experimental modal analysis is often used to validate the accuracy of dynamic numerical models. It is also a good tool to obtain valuable information about current condition of the structures that could help to determine residual lifetime. The quality of modal testing results is highly dependent on the proper estimation of the natural frequencies from the frequency response function. This article presents the experimental modal test of the laboratory steel structure in which the natural frequencies and mode shapes are determined.
Puja Basu Chaudhuri, Anirban Mitra and Sarmila Sahoo
This article deals with finite element method for the analysis of antisymmetric angle-ply laminated composite hypar shells (hyperbolic paraboloid bounded by straight edges) that applies an eight-noded isoparametric shell element and a three-noded beam element to study the mode-frequency analysis of stiffened shell with cutout. Two-, 4-, and 10-layered antisymmetric angle-ply laminations with different lamination angles are considered. Among these, 10-layer antisymmetric angle-ply shells are considered for elaborate study. The shells have different boundary conditions along its four edges. The formulation is based on the first-order shear deformation theory. The reduced method of eigen value solution is chosen for the undamped free vibration analysis. The first five modes of natural frequency are presented. The numerical studies are conducted to determine the effects of width-to-thickness ratio (b/h), degree of orthotropy (E11/E22), and fiber orientation angle (θ) on the nondimensional natural frequency. The results reveal that free vibration behavior mainly depends on the number of boundary constraints rather than other parametric variations such as change in fiber orientation angle and increase in degree of orthotropy and width-to-thickness ratio.