@misc{13433, abstract = {{The use of lubricants on electrical connector contacts is essential for certain applications in order to reduce mating forces, minimize wear, and mitigate fretting corrosion. However, increasing performance requirements (e.g., operation at elevated temperatures) and regulatory restrictions are prompting a reassessment of lubricant selection. In this study, the influence of three lubricants (one oil and two greases), operating temperature (room temperature and 130°C), and applied volume (low, medium and high volume) on electrical contact resistance (ECR) and coefficient of friction (CoF) is investigated by means of fretting wear tests on silver-plated contacts. The results show that unlubricated silver contacts exhibit a longer stable phase at 130 °C than at room temperature. For lubricated contacts, service life is influenced by both temperature and lubricant volume. Certain lubricants demonstrate earlier fail at room temperature than at elevated temperatures. The findings highlight the importance of careful selection and optimization of lubricants for electrical connectors under varying environmental conditions.}}, author = {{Blauth, Michael and Tülling, Sören and Song, Jian}}, booktitle = {{Proceedings of the 70th IEEE Holm Conference on Electrical Contacts (HLM)}}, isbn = {{979-8-3315-5997-7}}, issn = {{2158-9992}}, keywords = {{Connectors, Resistance, Silver, Lubricants, Contacts, Oils, Friction, Corrosion, Optimization}}, location = {{San Antonio, TX, USA }}, publisher = {{IEEE}}, title = {{{Effect of Operating Temperature and Application Quantity of Lubricants on the Fretting Behavior of Silver Plated Electrical Contacts}}}, doi = {{10.1109/hlm51652.2025.11278329}}, year = {{2025}}, } @misc{12761, abstract = {{For modern machines, factories and electric and autonomous vehicles, the importance of vreliable electrical connectors cannot be overstated. With an increasing number of connectors being used in machines, factories and vehicles, ensuring their reliability is crucial for comfort and safety alike. One of the key indicators of reliability is the lifetime of connectors. To evaluate the lifetime of electrical connectors, a testing method and a model for calculating their lifetime based on the test data were developed. The results from these tests were compared to failure analysis data from long-term field operations. The findings indicate that the laboratory tests can accurately reproduce the main failures observed in the field. However, such lifetime tests can be time- and labor-intensive. To address this challenge, a data-driven method is proposed that predicts the lifetime of electrical connectors using statistical analysis of electrical contact resistance data collected from short-term tests. The predictions from this method were compared to actual results obtained from long-term tests. A strong correlation was observed between the contact resistance development in short-term tests and the number of failures in later stages of testing. Thus, apart from predicting the lifetime of connectors, this method can also be applied for failure prognosis in real-time operations.}}, author = {{Song, Jian and Shukla, Abhay Rammurti and Probst, Roman}}, booktitle = {{Machines}}, issn = {{2075-1702 }}, keywords = {{electrical connectors, accelerated life testing, statistical model, lifetime prognosis, reliability, state of health}}, number = {{12}}, pages = {{474}}, publisher = {{MDPI}}, title = {{{The State of Health of Electrical Connectors}}}, doi = {{https://doi.org/10.3390/machines12070474}}, volume = {{7}}, year = {{2024}}, } @misc{9206, abstract = {{Failure in time (FIT) is an important measure for the reliability of electrical connectors. Due to the very long lifetime of connectors, the tests for the determination of FIT rate are time and labour intensive. In this paper a data driven method using a statistical process to estimate the FIT rate of electrical connectors with data of electrical contact resistance development in short term tests is proposed. The results of prediction are then compared with the results from long term tests. The study shows a strong correlation between contact resistance development in short term tests and the development of the number of failures in later stages of tests. In order to predict the development of degradation precisely, the distribution of resistance data in many different tests with different connectors is investigated. The Generalized Extreme Value Distribution, which reveals an ideal fitting, has been implemented for the prediction of the failure rates of connectors, thereby enabling a remarkable time-lapse of lifetime tests. This method can also be employed in the prognosis and management of system health through the forecast of health of connectors in different systems in operation.}}, author = {{Song, Jian and Shukla, Abhay Rammurti and Probst, Roman}}, booktitle = {{Microelectronics reliability : an internat. journal & world abstracting service}}, issn = {{0026-2714}}, keywords = {{Electrical connectors, Prediction of lifetime, FIT, Correlation between data in short and long term tests, Time-lapse of lifetime tests}}, number = {{November 2022}}, publisher = {{Elsevier}}, title = {{{Prediction of failure in time (FIT) of electrical connectors with short term tests}}}, doi = {{10.1016/j.microrel.2022.114684}}, volume = {{138}}, year = {{2022}}, } @misc{9207, abstract = {{A new acceleration model for the reliability prediction of electrical connectors has recently been published. This model enables the evaluation of failure rates gained in highly accelerated life tests (HALT) and considers thermal and vibrational loading. However, since the initial study only covered a small set of test parameters, further study of the model is required. Previous studies have sufficiently investigated the influence of the vibration test mode on the failure rate of electrical connectors. Therefore, this study now focuses on the influence of the thermal cycling test. A commonly used automotive connector is chosen and subjected to stresses in HALT covering various upper temperatures, test durations and thermal cycling frequencies. Additionally, the principles of determining the coefficient of temperature difference and the coefficient of the thermal cycling frequency are presented, since these coefficients are connector specific and required for the acceleration model. Based on the numbers of failures in test, the influence of the various thermal cycling tests is discussed, and the coefficients are calculated for the chosen connector. In conclusion a guideline to select an appropriate upper temperature and test duration in order to compare the reliability of different electrical connectors is provided.}}, author = {{Krüger, Kevin and Song, Jian}}, booktitle = {{Microelectronics reliability : an internat. journal & world abstracting service}}, issn = {{0026-2714}}, keywords = {{Electrical connectors, Life test, Thermal cycling, Upper temperature Duration, Temperature difference, Cycling frequency}}, number = {{November 2022}}, publisher = {{Elsevier}}, title = {{{The influence of thermal cycling test parameters on the failure rate of electrical connectors}}}, doi = {{https://doi.org/10.1016/j.microrel.2022.114633}}, volume = {{138}}, year = {{2022}}, } @misc{9211, abstract = {{Lifetime tests of connectors are time consuming and labor intensive. Our study reveals a strong correlation between the statistical characteristics of contact resistance development in the early stages of lifetime tests and the final results of the tests. This correlation enables a further time lapse of lifetime tests and the prediction of the state of the health of connectors which can be utilized in the development of diagnostic strategy in sophisticated networks with very high number of connectors as well as in a quick classification of connectors with respect to their design features. Methods of statistical evaluation are introduced and the sensitivity analyses of different characteristics for the state of health of connectors are conducted.}}, author = {{Song, Jian and Shukla, Abhay Rammurti and Probst, Roman}}, booktitle = {{Electrical contacts - 2022 : proceedings of the Sixty-Seventh IEEE Holm Conference on Electrical Contacts}}, isbn = {{978-1-6654-5966-2}}, issn = {{2158-9992}}, keywords = {{Connectors, Correlation, Sensitivity analysis, Contact resistance, Lifetime estimation, Reliability, Electrical resistance measurement}}, location = {{Tampa, FL, USA}}, pages = {{272 -- 278}}, publisher = {{IEEE}}, title = {{{State of Health of Connectors – Early Indicators}}}, doi = {{10.1109/HLM54538.2022.9969839}}, year = {{2022}}, } @misc{9213, abstract = {{The function and reliability of electrical connectors in automotive applications is crucial for vehicle safety, especially with regard to E-mobility and autonomous driving. For this reason, electrical connectors are being developed for long-term use applications. However, a small amount of function failures are still being observed in long-term use field vehicles. In this study all electrical connectors of five long-term driven vehicles from various car manufacturers are disassembled and analyzed. The same analysis procedure is followed for every vehicle and the electrical resistance of the connectors is measured to determine electrical failures. The contacts of failed connectors are further analyzed using optical microscopy, XRF spectroscopy, EDS and detailed contact resistance mapping. By comparing the connectors with electrical failures to the same types of connectors with a proper electrical resistance, failure mechanisms can be detected and analyzed. The frequency of various failure mechanisms is statistically evaluated. The results of the analysis provide valuable indications with respect to improvement of the reliability of connectors.}}, author = {{Hilmert, Dirk and Yuan, Haomiao and Song, Jian}}, booktitle = {{Electrical contacts - 2022 : proceedings of the Sixty-Seventh IEEE Holm Conference on Electrical Contacts}}, isbn = {{978-1-6654-5966-2}}, issn = {{2158-9992}}, keywords = {{Connectors, Resistance, Spectroscopy, Optical microscopy, Microscopy, Vehicle safety, Failure analysis}}, location = {{Tampa, FL, USA}}, pages = {{9 -- 16}}, publisher = {{IEEE}}, title = {{{The Analysis of Failure Mechanisms of Electrical Connectors in Long-term Use Field Vehicles}}}, doi = {{10.1109/HLM54538.2022.9969820}}, year = {{2022}}, } @inproceedings{6317, abstract = {{The electrical-thermal behavior of an electrical connector is determined by heat generation due to Joule heating and heat absorption by conduction, convection and radiation. Heat flow from the connector to the wire is an important heat absorption mechanism for most electrical connectors. The temperature difference between the connector and the wire at infinity is proportional to the axial heat flow induced into the wire. The purpose of this study is to dimension the electrical resistance of a connector for power distribution by the heat flow into the wire. The heat flow is used as a design factor in order to define the maximum power loss for wires with different cross-section areas. With this approach the maximum acceptable electrical resistance for connectors with different sizes can be estimated in the early stages of the design process.}}, author = {{Blauth, Michael and Berger, Frank and Song, Jian}}, booktitle = {{60th IEEE Holm Conference on Electrical Contacts}}, isbn = {{978-1-4799-6069-9 }}, keywords = {{Wires, Connectors, Temperature measurement, Resistance, Heat transfer, Resistance heating}}, location = {{New Orleans, LA, USA }}, pages = {{192 -- 199}}, publisher = {{IEEE}}, title = {{{Influence of the Electrical Resistance and Wire Size on the Current Carrying Capacity of Connectors}}}, doi = {{10.1109/HOLM.2014.7031043}}, year = {{2014}}, }