TY - JOUR A1 - Starke, Peter ED - Böllinghaus, Thomas T1 - StressLifetc – NDT-related assessment of the fatigue life of metallic materials JF - MP Materials Testing N2 - Weight-optimized component design as well as a reliable estimation of the lifetime of metallic materials and components requires a comprehensive understanding of fatigue processes and a systematic investigation of the underlying fatigue behavior. Therefore, nondestructive testing methods, digitalization of measurement techniques as well as signal processing can be combined with a short-term procedure in order to acquire potentially more information about fatigue processes, while experimental effort and costs are reduced significantly. This leads not only to considerable advantages over conventional methods for determining S-N curves, but also over established short-term procedures, due to the possibility of applying this information from just a few specimens to attain fatigue life calculations. The StressLifetc approach is a new short-term calculation method which considers the nonlinear relation between the elastic, elastic-plastic and plastic portion of the material response in the deformation process. Within the scope of the present work, the change in temperature of SAE 1045 (C45E) specimens was measured during fatigue tests via an infrared camera in order to feed the thermal response back into the new StressLifetc approach for a reliable fatigue life calculation. KW - Thermography KW - Magnetics KW - Non-Destructive Testing KW - Fatigue Life Evaluation KW - Metallic Materials Y1 - 2019 U6 - https://doi.org/10.48537/opus4-48 SP - 297 EP - 303 ER - TY - JOUR A1 - Urschel, Sven A1 - Bold, Sebastian T1 - A Knowledge Discovery Process Extended to Experimental Data for the Identification of Motor Misalignment Patterns N2 - The diagnosis of misalignment plays a crucial role in the area of maintenance and repair since misalignment can lead to expensive downtime. To address this issue, several solutions have been developed, and both offline and online approaches are available. However, online strategies using a small number of sensors show a higher false positive rate than other approaches. The problem is a lack of knowledge regarding the interrelations of a fault, disturbances during the diagnosis process, and capable features and feature vectors. Knowledge discovery in database is a framework that allows extracting the missing knowledge. For technical systems, optimal results were achieved by aligning (partially) automated experiments with a data mining strategy, in this case classification. The results yield a greater understanding of the interrelations regarding parallel misalignment, i.e., feature vectors that show good results also with varying load and realistic fault levels. Moreover, the test data confirm a specificity (range 0 to 1) for classification between 0.87 and 1 with the found feature vectors. For angular misalignment, potential vectors were identified, but these need further validation with a modified experiment in future work. For the study, two induction motors with 1.1 kW and 7.5 kW were considered. Furthermore, the findings were compared with additional motors of the same rated power. The findings of this work can help to improve the implementation of sensorless diagnostics on machines and advance the research in this field. KW - Condition monitoring KW - Data mining KW - Induction motor KW - Knowledge discovery from data KW - Misalignment Y1 - 2023 U6 - https://doi.org/10.3390/machines11080827 VL - 2023 PB - MDPI CY - Basel ER - TY - JOUR A1 - Becker, Vincent A1 - Schwamm, Thilo A1 - Urschel, Sven T1 - Fault Investigation of Circulation Pumps to Detect Impeller Clogging N2 - Pumps have a wide range of applicat ions. Methods for fault detection of motors are increasingly being used for pumps. In the context of this paper, a test bench is built to investigate circulation pumps for faults. As a use case, the fault of impeller clogging was first measured and then examined with the help of motor current signature analysis. It can be seen that there are four frequencies at which there is an increase in amplitude in case of a fault. The sidebands around the supply frequency are in particular f ocus. The clogging of three and four of a total of seven channels leads to the highest amplitudes at the fault frequencies. The efficiency is reduced by 9 to 15% in case of faulty opera tion. These results indicate that the implementation of fault detection algorithms on the pump electronics represents added value for the pump operator. Furthermore, the results can be transferred to other applications. KW - Impeller faults KW - Impeller clogging KW - Permanent magnet motor KW - Fourier transformation KW - Condition monitoring KW - Circulation pump KW - Pump test bench KW - Motor current signature analysis Y1 - 2020 U6 - https://doi.org/10.3390/app10217550 VL - 10 SP - 1 EP - 13 ER -