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1 – 10 of over 93000
Article
Publication date: 1 March 1989

D.E. Riemer

This paper introduces thermal‐stress analysis methods which follow electrical engineering procedures. The spring constant or c‐value is found to be related to the…

Abstract

This paper introduces thermal‐stress analysis methods which follow electrical engineering procedures. The spring constant or c‐value is found to be related to the electrical impedance, combining dimensions and material characteristics in a performance parameter which simplifies calculations. Voltage is used to represent thermal deformation, and thermal forces are modelled as currents. Relationships equivalent to Ohm's Law are applied to calculate thermal stresses in leads or traces of surface‐mount assemblies. The thermal performance of laminates, e.g., thermal expansion coefficients of interconnect boards with a restraining core, and the thermal stresses in the bonded layers, are derived from the analysis of an electrical network which represents the composite structure. The method provides visual concepts which facilitate a first‐order solution of engineering problems related to thermal stress.

Details

Soldering & Surface Mount Technology, vol. 1 no. 3
Type: Research Article
ISSN: 0954-0911

Article
Publication date: 6 August 2018

Prashant Jaysing Patil, Maharudra Patil and Krishnakumar Joshi

The aim of this paper is to study the effect of pressure angle and helix angle on bending stress at the root of helical gear tooth under dynamic state. Gear design is a…

Abstract

Purpose

The aim of this paper is to study the effect of pressure angle and helix angle on bending stress at the root of helical gear tooth under dynamic state. Gear design is a highly complex process. The consistent demand to build low-cost, quieter and efficient machinery has resulted in a gradual change in gear design. Gear parameters such as pressure angle, helix angle, etc. affect the load-carrying capacity of gear teeth. Adequate load-carrying capacity of a gear is a prime requirement. The failure at the critical section because of bending stress is an unavoidable phenomenon. Besides this fact, the extent of these failures can be reduced by a proper gear design. The stresses produced under dynamic loading conditions in machine member differ considerably from those produced under static loading.

Design/methodology/approach

The present work is intended to study the effect of pressure angle and helix angle on the bending stress at the root of helical gear tooth under dynamic state. The photostress method has been used as experimental methods. Theoretical analysis was carried out by velocity factor method and Spott’s equation. LS DYNA has been used for finite element (FE) analysis.

Findings

The results show that experimental method gives a bending stress value that is closer to the true value, and bending stress varies with pressure angle and helix angle. The photostress technique gives clear knowledge of stress pattern at root of tooth.

Originality/value

The outcomes of this work help the designer use optimum weight-to-torque ratio of gear; this is ultimately going to reduce the total bulk of the gear box.

Details

World Journal of Engineering, vol. 15 no. 4
Type: Research Article
ISSN: 1708-5284

Keywords

Article
Publication date: 8 May 2018

Sen-Yung Lee, Li-Kuo Chou and Chao Kuang Chen

The purpose of this paper is to propose the Laplace Adomian Decomposition Method (LADM) for studying the nonlinear temperature and thermal stress analysis of annular fins…

Abstract

Purpose

The purpose of this paper is to propose the Laplace Adomian Decomposition Method (LADM) for studying the nonlinear temperature and thermal stress analysis of annular fins with time-dependent boundary condition.

Design/methodology/approach

The nonlinear behavior of temperature and thermal stress distribution in an annular fin with rectangular profile subjected to time-dependent periodic temperature variations at the root is studied by the LADM. The radiation effect is considered. The convective heat transfer coefficient is considered as a temperature function.

Findings

The proposed solution method is helpful in overcoming the computational bottleneck commonly encountered in industry and in academia. The results show that the circumferential stress at the root of the fin will be important in the fatigue analysis.

Originality/value

This study presents an effective solution method to analyze the nonlinear behavior of temperature and thermal stress distribution in an annular fin with rectangular profile subjected to time-dependent periodic temperature variations at the root by using LADM.

Details

Engineering Computations, vol. 35 no. 3
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 24 April 2007

Aleksandar Marinković, Božidar Rosić and Georgios Petropoulos

This paper aims to develop a simulating model of a journal porous metal bearing under elastohydrodynamic conditions and combined (radial, friction and thermal) load…

Abstract

Purpose

This paper aims to develop a simulating model of a journal porous metal bearing under elastohydrodynamic conditions and combined (radial, friction and thermal) load distribution and to carry out structural optimization.

Design/methodology/approach

The structure analysis is carried out for each kind of load separately and for the combined load distribution of the bearing, where a dynamically loaded porous metal bearing is simulated. This simulating model is developed by finite elements method using the structure analysis module of the CATIA V5 software. Further, a parameter optimization of a porous metal bearing is presented considering the elastic deformations of the bearing shell.

Findings

It is revealed that the bearing, even at points with maximum displacements, could not reach the mounting clearance value during its operational life. Relatively small bearing dimensions produce very high values of eigenfrequency response (over 150 kHz) and common dynamic loads met in all sorts of sliding bearing are not dangerous for bearing damage compared with static loads. In the stage of structural optimization based on the correlation between stress and geometric bearing parameters like wall thickness and outer diameter, the influence of finite element dimension on calculated results can be also analyzed and a proper choice of the latter is achieved.

Research limitations/implications

The present porous bearing optimization model with the aid of CATIA V5 module for optimum design uses only single objective optimization. For a complete optimum design a multi‐objective optimization has to be carried out.

Practical implications

The analysis under dynamic load conditions proved that relatively small dimensions of bearing commonly used in micro technique and precision mechanics result in extended safe and reliable operation.

Originality/value

This paper provides a methodology for bearing stress and deformation analysis in the elastic range and on the basis of this analysis it is possible to develop an optimization model for porous bearings offering help to designers for the selection of optimal bearing dimensions considering the bearing load caused by dynamic radial force, friction and temperature variation.

Details

Engineering Computations, vol. 24 no. 3
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 1 January 1990

Clive Loughlin

Sensor Review provides an update on photoelastic and thermoelastic stress analysis.

Abstract

Sensor Review provides an update on photoelastic and thermoelastic stress analysis.

Details

Sensor Review, vol. 10 no. 1
Type: Research Article
ISSN: 0260-2288

Article
Publication date: 1 January 1950

H. Roberts

THE stress analysis of perfect frameworks, in either two or three dimensions, is possible by a large number of standard methods. The case of structures which under a…

Abstract

THE stress analysis of perfect frameworks, in either two or three dimensions, is possible by a large number of standard methods. The case of structures which under a prescribed loading system have some of the members unloaded deserves a little consideration, since it is often possible to use the principle of superposition to break down a given external loading into loads each of which give only a limited number of stressed members. When this is possible, the technique of stress analysis can be radically simplified by consideration of the principle of uniqueness as stated below.

Details

Aircraft Engineering and Aerospace Technology, vol. 22 no. 1
Type: Research Article
ISSN: 0002-2667

Article
Publication date: 31 May 2006

Aizzat Mohd. Nasurdin, T. Ramayah and Yeoh Chee Beng

The aim of this study is to determine the effects of organizational structure (formalization and centralization) and organizational climate on job stress in a non‐Western…

2729

Abstract

The aim of this study is to determine the effects of organizational structure (formalization and centralization) and organizational climate on job stress in a non‐Western context. Data were collected from a sample of 151 salespersons working in the stock broking industry of Malaysia. Regression results demonstrated that both structural variables (formalization and centralization) have a positive influence on job stress. Organizational climate dimension, however, has no effect on stress. Implications for managerial practice and future research are provided.

Details

International Journal of Commerce and Management, vol. 16 no. 2
Type: Research Article
ISSN: 1056-9219

Keywords

Article
Publication date: 21 March 2016

Zhijie Tang, Qian Luo, Xinnan Leng, Pinglong Liu and Jun Luo

The purpose of this study is to design a spherical sensor which can detect the surge from various directions to lay the foundation of the research of surge.

Abstract

Purpose

The purpose of this study is to design a spherical sensor which can detect the surge from various directions to lay the foundation of the research of surge.

Design/methodology/approach

This paper designed a spherical sensor to detect the impact force generated by the surge. To realize the depth and stability control of the shallow underwater vehicles, it is necessary to do research and analysis on the surge in shallow waters. The spherical sensor with novel structure was skillfully composed of 24 cantilever beam pressure-type strain sensors. It is powerful to detect the surge from various directions simultaneously.

Findings

It is proved that the spherical sensor can accurately collect the surge data from multiple directions through experiments, which laid the foundation of the anti-surge study.

Research limitations/implications

Surge is not a new topic. But there is no effective tool to detect surge. The research of this paper is an attempt to provide an available tool to analyze surge. The research limitation is that the pool where the spherical sensor is installed is a little small. In the future, a bigger pool can be used.

Practical implications

A deep and comprehensive analysis of surge can be conducted according to the surge data detected by the spherical sensor to achieve the essential features of surge. This lays the foundation for the accurate control of Autonomous Underwater Vehicles (AUVs), especially fixed depth and stability control.

Social implications

As the control accuracy of AUVs increases, the AUVs can perform much more difficult tasks such as port monitoring, underwater salvaging, underwater pipeline maintenance and so on. These can be applied in commercial applications or in the national defense of many countries.

Originality/value

A novel spherical sensor using 24 cantilever beam pressure-type strain sensors to detect the surge was designed. The spherical sensor was installed in the physical surge simulator to collect surge data and conduct an analysis of the collected data.

Details

Sensor Review, vol. 36 no. 2
Type: Research Article
ISSN: 0260-2288

Keywords

Content available
Article
Publication date: 1 June 2005

96

Abstract

Details

Aircraft Engineering and Aerospace Technology, vol. 77 no. 3
Type: Research Article
ISSN: 0002-2667

Keywords

Article
Publication date: 28 June 2011

Jue Li, Hongbo Xu, Jussi Hokka, Toni T. Mattila, Hongtao Chen and Mervi Paulasto‐Kröckel

The purpose of this paper is to study the reliability of SnAgCu solder interconnections under different thermal shock (TS) loading conditions.

Abstract

Purpose

The purpose of this paper is to study the reliability of SnAgCu solder interconnections under different thermal shock (TS) loading conditions.

Design/methodology/approach

The finite element method was employed to study the thermomechanical responses of solder interconnections in TS tests. The stress‐strain analysis was carried out to study the differences between different loading conditions. Crack growth correlations and lifetime predictions were performed.

Findings

New crack growth data and correlation constants for the lifetime prediction model are given. The predicted lifetimes are consistent with the experimental results. The simulation and experimental results indicate that among all the loading conditions studied the TS test with a 14‐min cycle time leads to the earliest failure of the ball‐grid array (BGA) components.

Originality/value

The paper presents new crack growth correlation data and the constants of the lifetime prediction models for SnAgCu solder interconnections, as well as for the BGA components. The paper adds insight into the thermomechanical reliability evaluation of SnAgCu solder interconnections.

Details

Soldering & Surface Mount Technology, vol. 23 no. 3
Type: Research Article
ISSN: 0954-0911

Keywords

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