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Daeil Kwon,Azarian, Michael H.,Pecht, Michael IEEE 2015 IEEE transactions on components, packaging, and ma Vol.5 No.11
<P>Solder joints are among the most common failure sites in electronic assemblies. This paper presents a prognostic approach that allows for the remaining useful life prediction of solder joints using an RF impedance analysis and the Gaussian process (GP) regression. While the solder joints were exposed to a mechanical stress condition to generate fatigue failures, the RF impedance of the solder joint was continuously monitored. The RF impedance provided an early indication of the impending solder-joint failure in the form of a gradual increase prior to the end of life. A GP model was applied to the RF impedance obtained from the fatigue tests in order to estimate the remaining life of the solder joint in real time. It was demonstrated that the GP model successfully predicted the time to failure of the solder joint with high accuracy prior to failure. The prediction performance was also evaluated using prognostic metrics.</P>
A model-based prognostic approach to predict interconnect failure using impedance analysis
Daeil Kwon,Jeongah Yoon 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.10
The reliability of electronic assemblies is largely affected by the health of interconnects, such as solder joints, which provide mechanical, electrical and thermal connections between circuit components. During field lifecycle conditions, interconnects are often subjected to a DC open circuit, one of the most common interconnect failure modes, due to cracking. An interconnect damaged by cracking is sometimes extremely hard to detect when it is a part of a daisy-chain structure, neighboring with other healthy interconnects that have not yet cracked. This cracked interconnect may seem to provide a good electrical contact due to the compressive load applied by the neighboring healthy interconnects, but it can cause the occasional loss of electrical continuity under operational and environmental loading conditions in field applications. Thus, cracked interconnects can lead to the intermittent failure of electronic assemblies and eventually to permanent failure of the product or the system. This paper introduces a model-based prognostic approach to quantitatively detect and predict interconnect failure using impedance analysis and particle filtering. Impedance analysis was previously reported as a sensitive means of detecting incipient changes at the surface of interconnects, such as cracking, based on the continuous monitoring of RF impedance. To predict the time to failure, particle filtering was used as a prognostic approach using the Paris model to address the fatigue crack growth. To validate this approach, mechanical fatigue tests were conducted with continuous monitoring of RF impedance while degrading the solder joints under test due to fatigue cracking. The test results showed the RF impedance consistently increased as the solder joints were degraded due to the growth of cracks, and particle filtering predicted the time to failure of the interconnects similarly to their actual timesto-failure based on the early sensitivity of RF impedance.
Kwon Daeil,곽경민,Baek Kiook,Chi Youngchan,Na Sewhan,박종태 대한직업환경의학회 2021 대한직업환경의학회지 Vol.33 No.4
Background: Mental health problems are emerging issues in occupational safety and health, whereas the findings on the relationship between physical hazards and mental health are not consistent. The aim of our study was to investigate the association between physical hazard exposure and mental health outcomes including depression and anxiety. Methods: We included 48,476 participants from the fifth Korean Working Conditions Survey (KWCS) in this study. The χ2 test and logistic regression analyses were conducted to assess the association between physical hazard exposures and mental health. All statistical analyses were performed sex-specifically. Results: In logistic regression analysis, the odds ratios (ORs) of depression were significantly increased in male workers who were exposed to vibration (severe OR: 1.54, 95% confidence interval [CI]: 1.21–1.95) and noise (severe OR: 1.93, 95% CI: 1.49–2.48) whereas the ORs of depression were not significant in female workers from vibration (severe OR: 0.86, 95% CI: 0.50–1.38) or noise exposure (severe OR: 1.39, 95% CI: 0.84–2.17). The ORs of anxiety were significantly increased in male workers with vibration (severe OR: 1.76, 95% CI: 1.43–2.15) and noise exposure (severe OR: 2.12, 95% CI: 1.69–2.63) whereas the OR between vibration and anxiety (severe OR: 1.45, 95% CI: 0.91–2.21) was not significant in female workers. High or low temperature exposure had significant associations with depression and anxiety in both male and female subjects. Conclusions: Results of our study suggest that physical hazard exposures may be associated with increased risk of mental health problems including depression and anxiety. These associations are more prominent in male workers in comparison with female workers.
비선형모델링을 통한 온습도 바이어스 시험 중의 다층 세라믹축전기 수명 예측
Kwon, Daeil,Azarian, Michael H.,Pecht, Michael 한국마이크로전자및패키징학회 2013 마이크로전자 및 패키징학회지 Vol.20 No.3
This study presents an approach to predict insulation resistance failure of multilayer ceramic capacitors (MLCCs) using non-linear modeling. A capacitance aging model created by non-linear modeling allowed for the prediction of insulation resistance failure. The MLCC data tested under temperature-humidity-bias testing conditions showed that a change in capacitance, when measured against a capacitance aging model, was able to provide a prediction of insulation resistance failure.
임피던스 분석을 이용한 솔더 조인트의 실시간 수명 예측 방법 연구
권대일(Daeil Kwon) 대한기계학회 2014 대한기계학회 춘추학술대회 Vol.2014 No.11
This paper presents a PHM (Prognostics and health management) based method to predict solder joint remaining life in real time. During stress testing of solder joints, TDR (time domain reflectometry) coefficient, as a measure of RF impedance, exhibited early sensitivity to solder joint degradation in the form of non-linear increase prior to the end of life. The early sensitivity to degradation was trended as representative responses using support vector regression for remaining solder joint life prediction. During accelerated life testing, the TDR coefficients were continuously compared with the representative responses in order to detect anomalies and to predict the remaining life. This method successfully predicted solder joint failures prior to their actual failures. The results implied this approach using a data-driven prognostic algorithm can be an effective means to predict solder joint failures in real time without having a system model or complicated algorithms and assumptions.
Failure mechanism-based reliability assessment framework: a case study in an automotive component
강문식,Daeil Kwon 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.10
This paper presents a framework for failure mechanism-based reliability assessment, starting from collecting failed field samples. The framework includes failure analysis for identifying the failure mechanism and accelerated life tests (ALTs) for reproducing the failure mechanism. We consider that relevant information, such as warranty data and qualification test results, enables to be utilized in the framework. The proposed framework is validated by using it to identify the failure mechanism and estimate the lifetime of an automotive component under normal use conditions. The case study shows that the framework enables to quantitatively assess reliability based on the failure mechanism.