Optimization and Comparison of Electromagnetic Vibration Energy Harvesters Under Constant Volume Conditions

Author(s):  
Hanmin Lee ◽  
Young-Cheol Kim ◽  
Jaewon Lim ◽  
Seong-Whan Park

Previous studies on optimization of electromagnetic vibration energy harvesters assumed the radius and the height of a cylindrical construction volume to be fixed. We present optimization and comparison of three different types of electromagnetic vibration energy harvesters under constant volume conditions where the radius or the height can also be a design variable. The voltage and the power output are calculated for each architecture using finite element analysis. We found that different types of electromagnetic coupling architectures can be optimized with different shapes of the construction volumes.

2013 ◽  
Vol 405-408 ◽  
pp. 3222-3228
Author(s):  
Rong Gang Yin ◽  
Zhi Guo Li ◽  
Hong Xiang She ◽  
Jian Hai Zhang

In order to improve the modeling efficiency for finite element analysis pre-processing, a parametric modeling method of underground powerhouse for finite element analysis is proposed. By inputting the basic geometric parameters, different types of underground powerhouse models are built by using this method. The basic ideas, basic principle and the process of this parametric modeling are presented. And the parametric modeling procedure is coded by using VC++, interactive interface and display window are designed by using MFC and OpenGL. Finite element model of Houziyan underground powerhouse which is built by using the procedure proves that this method greatly improves the efficiency and precision of modeling.


1990 ◽  
Vol 112 (2) ◽  
pp. 157-168 ◽  
Author(s):  
Y. Ueda ◽  
S. M. H. Rashed ◽  
K. Nakacho

In tubular frames with simple joints, joints may show considerable flexibility in the elastic as well as the elastic-plastic ranges. Such flexibility may have large effects on the behavior of the structure as a whole. In a previous paper, an effective simple model of tubular joints is developed. The model takes account of joint flexibility in the elastic as well as the elastic-plastic ranges based on elastic-fully plastic load-displacement relatioships. In this paper an improved joint model is presented to provide better accuracy while maintaining simplicity. The accuracy of the model is confirmed through comparisons with results of finite element analysis. Equations to evaluate the initial stiffness of tubular T and Y-joints when braces are subjected to axial compression or in-plane bending moment are also presented. Such equations for different types of joints in different loading conditions are needed in order to avoid expensive calculations to evaluate the initial stiffness of joints.


2020 ◽  
Vol 9 (2) ◽  
pp. 1033-1043

This research mainly concentrates on ultimate strength and buckling behaviour of cold formed steel (CFS) laterally un-braced longitudinally stiffened box sections under flexure. A total of five various stiffener combinations for box sections has been studied by modifying the shape of a simple end stiffened section by the provision of intermediate stiffeners along web, flange or both along web and flange. The influence of different types of stiffeners with respect to various aspect radio’s (H/T, B/T, C/T and H/B) have been studied using Finite Element Method (FEM), and recommendations have been proposed on provisions of different stiffener’s combinations. This study mainly details with ultimate strength and buckling behaviour of CFS laterally unbraced stiffened box sections made by C sections connected face to face.


Author(s):  
Pramod Chaphalkar ◽  
Mike Maletta

Many universities have started introducing Finite Element Analysis (FEA) at an earlier point in the curriculum. However, there is a wide diversity of university backgrounds, course content and sequence, pedagogical objectives and approaches, etc. This paper describes the development of FEA lab modules in the second course of solid mechanics in our specific context. Students in this course were introduced to FEA earlier in the first course of statics and solid mechanics. They had learned the basic steps in FEA for axially loaded and planar truss structures. In the second course, the FEA was extended to the planar cases. One of the objectives was to make the students aware of the descretization and numerical errors of the FEA. Hence there was a particular focus on element displacement fields and how they influence element behavior in comparison with an actual structure behavior. The lab modules were designed to be complementary to the class room learning. Approximate nature of the FEA was taught via the lab modules on descretization errors and numerical errors. The descretization error was demonstrated in the first part of the lab wherein different types of elements for planar problems were compared. One cantilever beam problem was solved with different types of elements and the results were compared with the theoretical value. Numerical error was studied in the second part of the lab wherein the effect of the element shape quality on the results was studied. A systematic study of the effect of mesh distortion was undertaken. ANSYS Parametric Design Language (APDL) macros were developed to change the mesh distortion quickly in a controlled fashion. A study of convergence of the results followed in the third part of the lab. A reasonable convergence was obtained for a plate with a central hole for which the theoretical results are known. Once the students grasped the need of convergence, a real life problem was attempted in the fourth part of the lab. The actual results are not known in the real life and a reasonable convergence needs to be established for acceptable results and for subsequent analysis and design. Design of a seat belt buckle was undertaken. A Pro/E CAD model was imported into ANSYS. The students used the subset of the CAD model to build their FE model considering only the relevant part, the symmetry and the mid plane. At the end of the semester, the students used the FEA tools for a real life design problem with a firm grasp of the approximate nature of the method.


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