scholarly journals A Study on the Effects of Local Added Masses on the Natural and the Sound Radiation Characteristics of Thin Plate Structures

2016 ◽  
Vol 40 (4) ◽  
pp. 25-39
Author(s):  
Pingping Zhang ◽  
Huaiyu Wu ◽  
Lin Ji ◽  
Marko Jokić
Keyword(s):  
Thin Plate ◽  
Sound Radiation ◽  
Radiation Characteristics ◽  
Plate Structures ◽  
Added Masses

Analysis of Sound Radiation Characteristics of Rail by BEM.

1999 ◽  
Vol 65 (638) ◽  
pp. 3986-3991
Author(s):  
Mitsuru ENDO ◽  
Tsutomu NISHIGAKI ◽  
Ko MIZUNO
Keyword(s):  
Sound Radiation ◽  
Radiation Characteristics

Contouring Medial Surface of Thin-Plate Structures Using Local Marching Cubes

2005 ◽  
Vol 5 (2) ◽  
pp. 111-115 ◽  
Author(s):  
Tomoyuki Fujimori ◽  
Hiromasa Suzuki ◽  
Yohei Kobayashi ◽  
Kiwamu Kase
Keyword(s):  
Thin Plate ◽  
Computer Aided Design ◽  
Prototype System ◽  
Marching Cubes ◽  
Plate Structures ◽  
Medial Surface ◽  
Surface Models ◽  
Marching Cubes Algorithm ◽  
Computer Aided ◽  
Ct Data

This paper describes a new algorithm for contouring a medial surface from CT (computed tomography) data of a thin-plate structure. Thin-plate structures are common in mechanical structures, such as car body shells. When designing thin-plate structures in CAD (computer-aided design) and CAE (computer-aided engineering) systems, their shapes are usually represented as surface models associated with their thickness values. In this research, we are aiming at extracting medial surface models of thin-plate structures from their CT data for use in CAD and CAE systems. Commonly used isosurfacing methods, such as marching cubes, are not applicable to contour the medial surface. Therefore, we first extract medial cells (cubes comprising eight neighboring voxels) from the CT data using a skeletonization method to apply the marching cubes algorithm for extracting the medial surface. It is not, however, guaranteed that the marching cubes algorithm can contour those medial cells (in short, not “marching cubeable”). In this study, therefore we developed cell operations that correct topological connectivity to guarantee such marching cubeability. We then use this method to assign virtual signs to the voxels to apply the marching cubes algorithm to generate triangular meshes of a medial surface and map the thicknesses of thin-plate structures to the triangle meshes as textures. A prototype system was developed to verify some experimental results.

Minimization of the Vibration Energy of Thin-Plate Structures

1992 ◽  
Author(s):  
Katsumi Inoue ◽  
Dennis P. Townsend ◽  
John J. Coy
Keyword(s):  
Finite Element ◽  
Modal Analysis ◽  
Thin Plate ◽  
Optimization Method ◽  
Optimum Shape ◽  
Vibration Energy ◽  
Plate Structures ◽  
Constant Weight ◽  
Exciting Frequency ◽  
The Given

Abstract An optimization method is proposed to reduce the vibration of thin-plate structures. The method is based on a finite-element shell analysis, a modal analysis, and a structural optimization method. In the finite-element analysis, a triangular shell element with 18 degrees of freedom is used. In the optimization, the overall vibration energy of the structure is adopted as the objective function, and it is minimized at the given exciting frequency by varying the thickness of the elements. The technique of modal analysis is used to derive the sensitivity of the vibration energy with respect to the design variables. The sensitivity is represented by the sensitivities of both eigenvalues and eigenvectors. The optimum value is computed by the gradient projection method and a unidimensional search procedure under the constraint condition of constant weight. A computer code, based on the proposed method, is developed and is applied to design problems using a beam and a plate as test cases. It is confirmed that the vibration energy is reduced at the given exciting frequency. For the beam excited by a frequency slightly less than the fundamental natural frequency, the optimized shape is close to the beam of uniform strength. For the plate, the optimum shape is obtained such that the changes in thickness have the effect of adding a stiffener or a mass.

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