Papers by Author: Dieter Schramm

Abstract: This study aims to analyze the stress that occurred on the automotive coil spring made of SAE 5160 carbon steel due to various types of road surfaces. The 60-second strain signals measured on a coil spring of a car being driven on a flat, uphill, and downhill road surface were used as the loads in these dynamic analyses. The analysis results showed that the maximum stress occurred on the inside of the spring in the second coil from the top. The results of this dynamic analysis also showed that the three types of road surfaces provided almost the same stress. The downhill road surface gave the highest stress, which was 0.622 GPa, followed by flat road (0.621 GPa) and uphill road (0.62 GPa). The reasons for this are the shifting of the vehicle load to the front wheels together with the braking effect when driving downhill.

Abstract: This paper presents the ability of the wavelet transforms for compressing automobile strain data. The wavelet transforms identified and extracted higher amplitude segments and produced shorter edited signals. Based on the comparison of the edited signals resulted, it was found that the Morlet wavelet gave the shortest signals. It was able to summarize strain signals up to 77% and maintain more than 90% of the statistical parameters and the fatigue damage. Meanwhile the continuous and discrete Daubechies wavelet transforms summarized the signals below 60%. It proved that the Morlet wavelet was the best technique for fatigue data editing, especially for the automotive applications.

Abstract: The study presents the development of a wavelet-based segmentation algorithm for fatigue life assessment. Strain data was extracted using the Morlet family. The extraction process identified damaging segments, and it was able to shorten the original signal by 74.3%, with less than 10% difference with statistical parameters. The extraction algorithm was able to retain at least 97.9% of fatigue damage. The damaging segments drawn were clustered using the k-means method to provide three groups of segments, i.e., lower, moderate, and higher groups representing statistical values. The approach was suggested as an alternative method for evaluating and clustering fatigue strain signals.

Abstract: This paper considers the application of simulators or demonstrators in the development of mechatronic products. It is shown at what step of the mechatronic design process a simulator or demonstrator can be used to significantly improve a products quality and thus identify possible errors and provide potential workarounds. Cost reduction is achieved by the use of simulators or demonstrators in the early design stage and less real product tests have to be carried out which also could be hazardous for the test person.