T.E. Wong, C.Y. Lau and H.S. Fenger
A simple analysis method was developed to determine the fatigue life of a ceramic ball grid array (CBGA) solder joint when exposed to thermal environments. The solder joint…
Abstract
A simple analysis method was developed to determine the fatigue life of a ceramic ball grid array (CBGA) solder joint when exposed to thermal environments. The solder joint consists of a 90Pb/10Sn solder ball with eutectic SnPb solder on both top and bottom of the ball. A closed‐form solution, based on the calculation of the equilibrium of the displacements within the electronic package assembly, was first derived in order to calculate the solder joint strains during temperature cycling. In the calculation, an iteration technique was used to obtain a convergent solution for the solder strains, and the elastic material properties were used for all the electronic package assembly components except for the solder materials. A fatigue life prediction model was established.
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Supriyono, Tzu-Chia Chen, Lis M. Yapanto, Zagir Azgarovich Latipov, Angelina Olegovna Zekiy, Lyubov A. Melnikova, Lakshmi Thangavelu, A. Surendar, Nikolay I. Repnikov and Zeinab Arzehgar
In this paper, a lifetime estimation model for the solder joint is proposed which is capable of considering both severe and running mechanical shocks which is the real case in…
Abstract
Purpose
In this paper, a lifetime estimation model for the solder joint is proposed which is capable of considering both severe and running mechanical shocks which is the real case in electric converters in the automotive and aerospace applications. This paper aims to asses the reliability of the solder joint under mixed exposure of mechanical loads.
Design/methodology/approach
Mechanical failure process may put at risk the perfect performance of any kinds of electronic systems regardless of the applications they are prepared for. Observation of solder joint health in an electronic assembly under simultaneous exposure of severe and running shocks is an open problem. Three commonly used soldering compositions are considered while the electronic assembly is exposed to three well-known driving cycles.
Findings
The results show that the best performance is achieved using SAC405 soldering alloy in comparison with Sn63Pb37 and SAC387 solder alloy. Consideration of mixed exposure to the mechanical loads leads to much more accurate lifetime estimation of the solder joint in the electronic assemblies.
Originality/value
The originality of the paper is confirmed.
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Ping Yang, Xiusheng Tang, Yu Liu, Shuting Wang and Jianming Yang
The purpose of this paper is to perform experimental tests on fatigue characteristics of chip scale package (CSP) assembly under vibration. Some suggestions for design to prolong…
Abstract
Purpose
The purpose of this paper is to perform experimental tests on fatigue characteristics of chip scale package (CSP) assembly under vibration. Some suggestions for design to prolong fatigue life of CSP assembly are provided.
Design/methodology/approach
The CSP assembly which contains different package structure modes and chip positions was manufactured. The fatigue characteristics of CSP assembly under vibration were tested. The fatigue load spectrum of CSP assembly was developed under different excitation. The fatigue life of chips can be estimated by using the high-cycle fatigue life formula based on different stress conditions. The signal–noise curve shows the relationship between fatigue life and key factors. The design strategy for improving the fatigue life of CSP assembly was discussed.
Findings
The CSP chip has longer fatigue life than the ball grid array chip under high cyclic strain. The closer to fixed point the CSP chip, the longer fatigue life chips will have. The chip at the edge of the printed circuit board (PCB) has longer fatigue life than the one in the middle of the PCB. The greater the excitation imposed on the assembly, the shorter the fatigue life of chip.
Research limitations/implications
It is very difficult to set up a numerical approach to illustrate the validity of the testing approach because of the complex loading modes and the complex structure of CSP assembly. The research on an accurate mathematical model of the CSP assembly prototype is a future work.
Practical implications
It builds a basis for high reliability design of high-density CSP assembly for engineering application. In addition, vibration fatigue life prediction method of chip-corner solder balls is deduced based on three-band technology and cumulative damage theory under random vibration so as to verify the accuracy of experimental data.
Originality/value
This paper fulfils useful information about the dynamic reliability of CSP assembly with different structural characteristics and material parameters.
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Feng Wang, Fangfang Zhang, Qixiang Huang and Mohammad Salmani
The purpose of this paper is to propose a method with capability of short-time implementation.
Abstract
Purpose
The purpose of this paper is to propose a method with capability of short-time implementation.
Design/methodology/approach
This paper was directed using both experimental tests and simulations to propose a comprehensive method for lifetime estimation of the solder joints.
Findings
A new method with good agreement with experimental tests has been proposed.
Originality/value
It is confirmed that paper is original.
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Tanja Istenič, Jože Sambt and Daša Farčnik
European Union (EU) member states are dedicated to a set of sustainable development goals, among them to: (1) promote well-being for all at all the ages and (2) achieve gender…
Abstract
European Union (EU) member states are dedicated to a set of sustainable development goals, among them to: (1) promote well-being for all at all the ages and (2) achieve gender equality. This chapter uses the National Transfer Accounts (NTA) methodology that enables comprehensive measurement of intergenerational transfers, both public and private, and differences in the gender equality promotion among the countries. Our analysis is based on the fully comparable NTA results for 25 EU countries from 2010. The authors perform cluster analysis based on five indicators, measuring the importance of different types of age reallocations and the differences in gender equality promotion among the EU countries. Since the economic life cycle (showing the level of dependency) and its financing strongly depend on country-specific institutional and cultural settings, the authors link their results with the typical welfare regimes’ typology. The authors end up with three different groups of countries showing a clear north–south division of countries.
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Timothy P. Munyon, James K. Summers, Robyn L. Brouer and Darren C. Treadway
Coalitions are informal and interdependent groups of actors operating within organizations, yet their effects in organizations are not widely understood. In this paper, we develop…
Abstract
Coalitions are informal and interdependent groups of actors operating within organizations, yet their effects in organizations are not widely understood. In this paper, we develop a model of coalition formation and functioning inside organizations. By extrapolating the behavioral intentions (i.e., altruistic or antagonistic) and compositional differences (i.e., supplementary or complementary) among these informal group structures, we classify coalitions into four forms (i.e., lobby, cartel, circle, and alliance), theorizing how each coalition form affects work role innovation, resource allocations, and work performance. Our conceptualization helps clarify previous theoretical inconsistencies and establish an agenda for the study of coalitions at work. Furthermore, this paper provides insights into the ways that coalitions support or impede the organization’s objectives.
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Babs Broekema, Menno Fenger and Jeroen van der Waal
This article aims to explore whether and how economic, political and demographic municipal conditions shape citizens' attitudes regarding decentralised social policies.
Abstract
Purpose
This article aims to explore whether and how economic, political and demographic municipal conditions shape citizens' attitudes regarding decentralised social policies.
Design/methodology/approach
The authors analysed the 2018 wave of the Dutch Local Election Studies, which includes a novel survey item asking respondents whether they prefer local social policies to be primarily: (1) protection-based, (2) cohesion-building or (3) activation-based. The authors appended context indicators to that survey and performed multilevel logistic regression analyses (1,913 respondents nested in 336 municipalities).
Findings
At the individual level, these preferences are affected by gender, age, income, education and political inclination, as expected. However, preferences towards local social policies are not shaped by local economic, demographic or political conditions. The authors discuss the implications of these findings for future research.
Originality/value
By using unique data, including a newly developed survey item, this study is the first to explore whether and how municipal conditions shape preferences regarding local welfare. Understanding those preferences is increasingly important as many Western European countries have decentralised swathes of social policies from the national to the local level in recent decades.
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Saddam Bensaoucha, Sid Ahmed Bessedik, Aissa Ameur and Ali Teta
The purpose of this study aims to focus on the detection and identification of the broken rotor bars (BRBs) of a squirrel cage induction motor (SCIM). The presented diagnosis…
Abstract
Purpose
The purpose of this study aims to focus on the detection and identification of the broken rotor bars (BRBs) of a squirrel cage induction motor (SCIM). The presented diagnosis technique is based on artificial neural networks (NNs) that use as inputs the results of the spectral analysis using the fast Fourier transform (FFT) of the reduced Park’s vector modulus (RPVM), along with the load values in which the motor operates.
Design/methodology/approach
First, this paper presents a comparative study between FFT applied on Hilbert modulus, Park’s vector modulus and RPVM to extract feature frequencies of BRB faults. Moreover, the extracted features of FFT applied to RPVM and the load values were selected as NNs’ inputs for the detection of the number of BRBs.
Findings
The obtained simulation results using MATLAB (Matrix Laboratory) environment show the effectiveness and accuracy of the proposed NNs based approach.
Originality/value
The current paper presents a novel diagnostic method for BRBs’ fault detection in SCIM, based on the combination between the signal processing analysis (FFT of RPVM) and artificial intelligence (NNs).
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Maria A. Davia and Nuria Legazpe
Adults raised in poor households tend to be more prone to live in poverty than the rest, ceteris paribus. This holds true even in the presence of observed income transmission…
Abstract
Adults raised in poor households tend to be more prone to live in poverty than the rest, ceteris paribus. This holds true even in the presence of observed income transmission channels such as education attainment. We identify this differential poverty risk as intergenerational transmission of economic disadvantage (ITED). This chapter contributes to the literature on cross-country differences in the intensity of ITED in the EU by explicitly testing how macro-economic/institutional features shape the phenomenon. Working on a sample of 30- to 39-year-old interviewees from the EU-SILC 2011 module on Intergenerational transmission of disadvantages, the authors find that, first, past income inequality is positively correlated with current ITED intensity; second, past efforts on inequality reduction via social protection for families with children and unemployment benefits are negatively correlated with later ITED levels; finally, educational expansion correlates with lower ITED, pointing to the relevance of public investments in education as a way to fight inequality of opportunity.