Effect of Boundary Conditions on Seismic Response of Electrical Equipment subjected to High-Frequency Ground Motions. (April 2022)

• Record Type: Journal Article
• Authors: Singh, Sugandha; Gupta, Abhinav
• Is Part Of: Annals of nuclear energy. Volume 168(2022)
• Publication Date: 2022-04
• Subjects: Seismic response of electrical systems -- High frequency earthquakes -- Nonlinear mounting of cabinets -- Incabinet response spectra -- ICRS; Nuclear energy -- Periodicals; Nuclear engineering -- Periodicals; 621.4805
• DOI: 10.1016/j.anucene.2021.108878
• Languages: English
• ISSNs: 0306-4549

Abstract

Highlights: Seismic response of electrical cabinets and control panels in nuclear plants. Effect of high frequency ground motions on seismic response of electrical cabinets. Effect of nonlinear mounting arrangements in cabinets. Effect of localized impacts in cabinet mounting arrangement. Abstract: The updated ground motion hazard in Central and Eastern United States contains high frequency motions. Such motions do not cause structural damage. However, safety-related electrical equipment are sensitive to high-frequency accelerations. Seismic qualification of electrical equipment requires an in-cabinet response spectrum (ICRS) which depends on the dynamic response of electrical cabinets and buildings. A linear analysis to generate ICRS can give excessively high spectral accelerations. Cabinet models with geometric nonlinearities such as a gap in the connection with building floor show that high-frequency accelerations may not propagate to the electrical equipment. Unlike linear analysis, results from nonlinear analysis of a building-cabinet model with a gap show a periodic pattern of secondary peaks and valleys at higher frequencies. In this research, the unique observation of secondary peaks is explained through fundamental principles by considering the sliding response of a cabinet representation with gap subjected to harmonic excitation. It is observed that a periodic pattern of peaks and valleys exist due to a significantly large contribution from transient response, due to localized impacts at the gap in cabinet base, and its interaction with the steady-state response.