Thermal Fatigue Reliability of High-Temperature-Resistant Joint for Power Devices

2009 ◽  
Author(s):  
Hiromi Sugihara ◽  
Masanori Yamagiwa ◽  
Masato Fujita ◽  
Toshikazu Oshidari ◽  
Qiang Yu
Keyword(s):  
High Temperature ◽  
Thermal Fatigue ◽  
Critical Issue ◽  
Nano Particles ◽  
Fatigue Reliability ◽  
Analysis Model ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Higher Temperature ◽  
Micro Structures

The power electronics equipments for Electric vehicles such as the inverter are strongly demanded on downsizing and weight reduction. For these requirements, Silicon Carbide (SiC) devices are receiving particular attention. SiC devices are characterized by lower-loss and higher temperature operation compared with Si devices. Using the devices under high temperature, the cooling equipments can be miniaturized. However, a function of stress relaxation that the existing solder has is difficult to be expected in a high-temperature-resistant joint layer for SiC devices, because the joint layer is generally hard. So, the authors have proposed a new mounting structure that a metal circuit on a substrate has the function instead of the joint layer. In this study, high-temperature-resistant mounting structures that the chip was bonded by low temperature sintering method using Ag nano-particles to substrate with Ag/Ni plating are prepared. Thermal Cycle Test (TCT) using these samples of harsh temperature range was conducted. As a result a new critical issue on the chip joint was identified. To clarify the thermal fatigue mechanism, the Finite-Element-Analysis (FEA) was carried out. The analysis model simulated a thin layer of Ag/Ni plating and the high-temperature-resistant joint layer. By the FEM results, the thermal fatigue, particularly occurring crack, was affected by the micro structures.

Modeling and experimental verification on directivity of an electret cell array loudspeaker

2012 ◽  
Vol 24 (3) ◽  
pp. 326-333 ◽  
Author(s):  
Yu-Chi Chen ◽  
Wen-Ching Ko ◽  
Han-Lung Chen ◽  
Hsu-Ching Liao ◽  
Wen-Jong Wu ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Digital Control System ◽  
Analysis Model ◽  
Cell Array ◽  
Element Analysis ◽  
Finite Element Analysis Model ◽  
The Finite Element Analysis ◽  
Directivity Characteristics

We propose a model to give us a method to investigate the characteristic three-dimensional directivity in an arbitrarily configured flexible electret-based loudspeaker. In recent years, novel electret loudspeakers have attracted much interest due to their being lightweight, paper thin, and possessing excellent mid- to high-frequency responses. Increasing or decreasing the directivity of an electret loudspeaker makes it excellent for adoption to many applications, especially for directing sound to a particular area or specific audio location. Herein, we detail a novel electret loudspeaker that possesses various directivities and is based on various structures of spacers instead of having to use multichannel amplifiers and a complicated digital control system. In order to study the directivity of an electret loudspeaker based on an array structure which can be adopted for various applications, the horizontal and vertical polar directivity characteristics as a function of frequency were simulated by a finite-element analysis model. To validate the finite-element analysis model, the beam pattern of the electret loudspeaker was measured in an anechoic room. Both the simulated and experimental results are detailed in this article to validate the various assertions related to the directivity of electret cell-based smart speakers.

The Mechanical Mechanism Analysis for Mortar Arch Framework Slope Protection Structure

2013 ◽  
Vol 859 ◽  
pp. 143-148
Author(s):  
Yang Xu ◽  
Ding Ling Li ◽  
Li Peng ◽  
Yan Xiao ◽  
Yi Hua Nie
Keyword(s):  
Finite Element Analysis ◽  
Mechanism Analysis ◽  
Analysis Model ◽  
Element Analysis ◽  
Finite Element Analysis Model ◽  
Vertical Loading ◽  
Total Displacement ◽  
The Finite Element Analysis ◽  
Calculation Results ◽  
Real Scale

The finite element analysis model was built as the real scale for mortar arch framework slope protection, and the displacement and strain at different points were collected by vertical loading pressure. So the mechanical mechanism can be studied, and the analysis was done between calculation results and testing results of solid miniature model. The studying results show that the point on the arch foot is the worst stress place for each arch, and the total displacement increase nonlinear as the distance from the slope top increases, and the bump phenomenon exists in the bottom of slope, the points are likely to be broken.

Image-Based Modeling for Assessing Thermal Conductivity of Thermal Spray Coatings at Ambient and High Temperature

2006 ◽  
Author(s):  
Y. Tan ◽  
A. Sharma ◽  
J. P. Longtin ◽  
S. Sampath ◽  
H. Wang
Keyword(s):  
Thermal Conductivity ◽  
High Temperature ◽  
Thermal Spray ◽  
Process Parameters ◽  
Thermal Spraying ◽  
Thermal Spray Coatings ◽  
Analysis Model ◽  
Element Analysis ◽  
Spray Coatings ◽  
Coating Microstructure

Thermal spray coatings are used extensively for protection of engineering components and structures in a variety of applications. Due to the nature of thermal spraying process, the coating thermal, mechanical, and electrical properties depend strongly on the coating microstructure, which consists of many individual splats, interfaces between the splats, defects and voids. The coating microstructure, in turn, is determined by the thermal spray process parameters. In order to relate coating process parameters to the final coating performance, then, it is desirable to relate coating microstructure to coating properties. In this work, thermal conductivity is used as the physical parameter of interest. Thermal conductivity of thermal spray coatings is studied by using an image analysis-based approach of typical coating cross sections. Three coating systems, yttria stabilized zirconia (YSZ), molybdenum, and Ni-5wt.%Al are explored in this work. For each material, thermal conductivity is simulated by using a microstructure image-based finite element analysis model. The model is then applied to high temperature conditions (up to 1200 °C) with a hot stage-equipped scanning electron microscope imaging technique to assess thermal conductivity at high temperatures. The coating thermal conductivity of metallic coatings is also experimentally measured by using a high-temperature laser flash technique.

The Study of 3-D Magnetic Field Finite Element Analysis for Giant Magnetostrictive Actuator

2012 ◽  
Vol 605-607 ◽  
pp. 1427-1430 ◽  
Author(s):  
Fan Zhang ◽  
Zhi Xin Ma ◽  
Shang Gao
Keyword(s):  
Magnetic Field ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Analysis Model ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Magnetic Field Model ◽  
Working Principle ◽  
Magnetostrictive Actuator ◽  
D Model

Based on the structure and working principle of our giant magnetostrictive actuator (GMA), the properties of the driving magnetic field were researched. A 3-D nonlinear magnetic field model of the GMA was established with the finite element analysis method, and the magnetic field distribution of the GMA was obtained with the software ANSYS. Then the 3-D model helped us to find the effects about the distribution of magnetic field of the GMA from the structure. The 3-D magnetic field finite element analysis model can give us a new tool of GMA design and analysis.

The Design Method of V-Tooth Coupling

2013 ◽  
Vol 871 ◽  
pp. 347-351
Author(s):  
Dun Cai Lei ◽  
Jin Yuan Tang
Keyword(s):  
Finite Element ◽  
Design Method ◽  
Operating Conditions ◽  
Bending Stress ◽  
Analysis Model ◽  
Element Analysis ◽  
Finite Element Analysis Model ◽  
Precision Design ◽  
The Finite Element Analysis ◽  
Paper Work

A lecture on the method to compute the the stress of V-tooth coupling under the actual operating conditions. the finite element analysis model of V-tooth coupling under the preload, axial load and torsion was established by used of the software ABAQUS,and the distribution of the bending stress at the root was obtained. The analytical method to compute the bending stress of V-tooth disk is deduced based on the basic principle of material mechanics, and the relative error within 10% compared with the results of finite element analysis.The paper work provide the reference for the precision design of V-tooth coupling.

Study of the Critical Load for Rigid Airport Pavement by the Finite Element Analysis

2012 ◽  
Vol 204-208 ◽  
pp. 1748-1753
Author(s):  
Jing Cai ◽  
Zong Bao Yue
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Critical Load ◽  
Vertical Displacement ◽  
Slab Model ◽  
Analysis Model ◽  
Element Analysis ◽  
Finite Element Analysis Model ◽  
Airport Pavement ◽  
The Finite Element Analysis

In the airport pavement design, the critical load position has the guiding significance for the airport pavement slab design. The finite element analysis model of rigid airport pavement is built, and 2-slab model and 9-slab model are analyzed. The corresponding load positions are obtained when the maximum stress and the maximum vertical displacement happen

Design and Optimization of Mechanically Resonant Torsional Spring Mechanism for Laser Light Dispersion Applications

2011 ◽  
Vol 133 (1) ◽  
Author(s):  
Loke Kean Koay ◽  
Horizon Gitano-Briggs
Keyword(s):  
Laser Light ◽  
Geometric Optimization ◽  
Geometrical Parameters ◽  
Analysis Model ◽  
Original Design ◽  
Element Analysis ◽  
Design And Optimization ◽  
Torsional Spring ◽  
The Finite Element Analysis ◽  
Spring Mechanism

A laser light scanning device consisting of an electronically driven mechanically resonant torsional spring-mirror system was developed for display applications. The original design suffers fatigue failure due to the repeated rotation of the torsional spring. The torsional spring design is investigated and analyzed to attain the lowest possible stress level while maintaining a constant resonant frequency. The finite element analysis model of the torsional spring was created and the stress was minimized by changing the geometrical parameters of the spring. Spring geometric optimization resulted in a maximum stress of 0.632 GPa, that is 12% reduction in stress from the original design, which should give an extended life span of 1 month for the intended application.

Estimation Local Strength of Bow Structure for High Tensile Steel Yacht Based on Optimum Design

2006 ◽  
Vol 326-328 ◽  
pp. 1463-1466
Author(s):  
Joo Shin Park ◽  
Yun Young Kim ◽  
Tetsuya Yao
Keyword(s):  
Optimum Design ◽  
Minimum Weight ◽  
Analysis Model ◽  
Element Analysis ◽  
Stress Criterion ◽  
Local Strength ◽  
The Finite Element Analysis ◽  
Small Craft ◽  
Weight Design

The optimum design for bow structure of high tensile steel yacht belongs to the nonlinear constrained optimization problem. The determination of scantlings for the bow structure is a very important matter out of whole structural design process of a yacht. The optimum design results are produced with the use of Real-coded Micro-Genetic Algorithm including evaluation LR small craft guideline, so that they can satisfy the allowable stress criterion. In this study, the minimum weight design of bow structure on the HTS yacht was carried out based on the finite element analysis. An analysis model is a bow structure of HTS yacht with structural scantling derived from the minimum weight optimization. The weight of bow structure and the main dimensions of structural members are chosen as an objective function and design variable, respectively. Optimization results were compared with a pre-existing design. From the FE analysis results, bow structure with high tensile steel (AH40) designed by using RμGA has a volume efficiency of 19% than the design of the actual mild yacht.

The Research of Subspan Oscillation and Configuration of Spacer for Transmission Line

2012 ◽  
Vol 614-615 ◽  
pp. 1855-1861
Author(s):  
Yu Xian Di ◽  
Kuan Jun Zhu ◽  
Cao Lan Liu
Keyword(s):  
Numerical Simulation ◽  
Transmission Lines ◽  
Simulation Method ◽  
Computational Method ◽  
Analysis Model ◽  
Element Analysis ◽  
Finite Element Analysis Model ◽  
The Finite Element Analysis ◽  
Computer Aided ◽  
Calculation Procedures

Based on the summarization of domestic and foreign experience, the computational method of spacer configuration was developed in order to depress sub-span oscillation principally. The requirements of the reverse recovery characteristics were considered. The computer-aided calculation procedures were programmed. The finite element analysis model of sub-span oscillation for cable-spacer system was established. The inherence modal and amplitude for sub-span oscillation of bundled transmission lines were calculated by using numerical simulation method. The dynamic configurations were analyzed by using the parameters of the cable and spacer obtained from vibration testing.

Crack Disappearance by High-Temperature Oxidation of Alumina Toughened by Ni Nano-Particles

2009 ◽  
Vol 68 ◽  
pp. 34-43 ◽  
Author(s):  
Ana L. Salas-Villaseñor ◽  
José Lemus-Ruiz ◽  
Makoto Nanko ◽  
Daisuke Maruoka
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Oxidation Reaction ◽  
High Temperature Oxidation ◽  
Annealing Temperature ◽  
Nano Particles ◽  
Ni Nanoparticles ◽  
Temperature Oxidation ◽  
Oxidation Period ◽  
Higher Temperature

Crack disappearance by high-temperature oxidation was studied in alumina (Al2O3) composites toughened by Ni nanoparticles. This process is performed in air at temperature ranging from 1000 to 1300°C for 1 to 48 h. The results showed that crack disappearance depends on both annealing temperature and time. Complete crack disappearance in this composite was confirmed at lower temperatures for long oxidation period, 1100oC for 48 h, and higher temperature for shorter time, 1300oC for 1 h in air. The crack disappearance mechanism was explained on the basis of the formation of NiAl2O4 spinel on sample surfaces produced by the oxidation reaction during the heat treatment.

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