{"title":"Shaker Testing with Simultaneous Control of PSD and FDS","authors":"A. Steinwolf","doi":"10.17764/1557-2196-63.1.21","DOIUrl":null,"url":null,"abstract":"\n The fatigue damage spectrum (FDS) model characterizes how the damage potential is distributed over the excitation frequency range, similarly to how the power spectral density (PSD) characterizes the distribution of the excitation level. However, reproducing the operational PSD during in-house shaker testing does not necessarily mean that the FDS would be also reproduced because some unusually distinctive peaks, higher than those in a signal generated from the PSD, occur in vibrations of automobiles and railway vehicles. Presence of these peaks in real operational vibrations and their absence in the PSD-based random testing is the reason why the shaker testing FDS obtained by the ordinary PSD control is different in shape and usually lies below the operational FDS. It is shown in this paper that the FDS shape as a function of frequency can be controlled by manipulating some of the IFFT phases instead of making all of them random. Since the phase manipulation does not affect the excitation PSD, the FDS and the PSD can be controlled simultaneously, which is demonstrated for an example of operational vibrations of an automobile. This new concept of shaker testing with the PSD+FDS control can also be used for accelerated testing when the FDS target needs to be artificially increased. It can be done without scaling up the PSD, thereby avoiding concerns about the test exaggeration factor being too high.","PeriodicalId":35935,"journal":{"name":"Journal of the IEST","volume":"63 1","pages":"21-34"},"PeriodicalIF":0.0000,"publicationDate":"2020-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of the IEST","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.17764/1557-2196-63.1.21","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"Engineering","Score":null,"Total":0}
引用次数: 0
Abstract
The fatigue damage spectrum (FDS) model characterizes how the damage potential is distributed over the excitation frequency range, similarly to how the power spectral density (PSD) characterizes the distribution of the excitation level. However, reproducing the operational PSD during in-house shaker testing does not necessarily mean that the FDS would be also reproduced because some unusually distinctive peaks, higher than those in a signal generated from the PSD, occur in vibrations of automobiles and railway vehicles. Presence of these peaks in real operational vibrations and their absence in the PSD-based random testing is the reason why the shaker testing FDS obtained by the ordinary PSD control is different in shape and usually lies below the operational FDS. It is shown in this paper that the FDS shape as a function of frequency can be controlled by manipulating some of the IFFT phases instead of making all of them random. Since the phase manipulation does not affect the excitation PSD, the FDS and the PSD can be controlled simultaneously, which is demonstrated for an example of operational vibrations of an automobile. This new concept of shaker testing with the PSD+FDS control can also be used for accelerated testing when the FDS target needs to be artificially increased. It can be done without scaling up the PSD, thereby avoiding concerns about the test exaggeration factor being too high.
期刊介绍:
The Journal of the IEST is an official publication of the Institute of Environmental Sciences and Technology and is of archival quality and noncommercial in nature. It was established to advance knowledge through technical articles selected by peer review, and has been published for over 50 years as a benefit to IEST members and the technical community at large as as a permanent record of progress in the science and technology of the environmental sciences