A. Shintani, Takuma Yoshida, C. Nakagawa, Tomohiro Ito
This paper deals with the motion of coupled cabinets containing electronics subjected to seismic input. In power plants, chemical plants, etc., several rectangular cabinets containing important electronics are always lined up in the control center. These electronics are necessary for the control of the entire plant; thus, when they are damaged, the entire plant cannot be controlled, and a serious accident may occur. These cabinets are frequently put directly on the floor. Thus, it is perceived that in the worst case, cabinets may turn over by rocking motion during earthquakes and electronics may break. Moreover, even when the cabinets do not overturn, there is a concern about a large acceleration applied to the internal electronics due to the seismic waves. Hence, the need to develop methods that can reduce rocking motion and prevent electronics damage simultaneously. First, we consider the single cabinet with electronics. The cabinet is modeled as a rotating rigid body around its corner. The internal electronics are modeled as a rigid body moving in the translational direction in the cabinet. This system is referred to as single system. We input a seismic wave to the single system and investigate the rocking angle of the cabinet and the acceleration of the electronics in the cabinet. Consequently, we consider the adjacent cabinets connected by an elasto-plastic damper containing electronics. The cabinets are modeled as rotating rigid bodies. The internal electronics are modeled as rigid bodies moving in the translational direction in the cabinets. The whole system is known as a connected system. The elasto-plastic damper has bilinear hysteretic characteristics and can absorb the energy of earthquake inputs. We input the same seismic wave to the connected system to obtain the rocking angle of cabinets and the acceleration of electronics in the connected system. In these simulations, it is assumed that cabinets do not collide with each other. Then, we investigate the effect of the parameters of the elasto-plastic damper suppressing the rocking angle of the cabinets and the acceleration of electronics. Finally, we compare the maximum rocking angle and the maximum acceleration of the single system with that of the connected system and consider an ideal method to reduce the rocking angle and the acceleration simultaneously.
{"title":"Study on Vibration Mitigation of Connected Cabinets Storing Electronics Subjected to Seismic Input Using Elasto-Plastic Damper","authors":"A. Shintani, Takuma Yoshida, C. Nakagawa, Tomohiro Ito","doi":"10.1115/pvp2020-21395","DOIUrl":"https://doi.org/10.1115/pvp2020-21395","url":null,"abstract":"\u0000 This paper deals with the motion of coupled cabinets containing electronics subjected to seismic input. In power plants, chemical plants, etc., several rectangular cabinets containing important electronics are always lined up in the control center. These electronics are necessary for the control of the entire plant; thus, when they are damaged, the entire plant cannot be controlled, and a serious accident may occur. These cabinets are frequently put directly on the floor. Thus, it is perceived that in the worst case, cabinets may turn over by rocking motion during earthquakes and electronics may break. Moreover, even when the cabinets do not overturn, there is a concern about a large acceleration applied to the internal electronics due to the seismic waves. Hence, the need to develop methods that can reduce rocking motion and prevent electronics damage simultaneously.\u0000 First, we consider the single cabinet with electronics. The cabinet is modeled as a rotating rigid body around its corner. The internal electronics are modeled as a rigid body moving in the translational direction in the cabinet. This system is referred to as single system. We input a seismic wave to the single system and investigate the rocking angle of the cabinet and the acceleration of the electronics in the cabinet.\u0000 Consequently, we consider the adjacent cabinets connected by an elasto-plastic damper containing electronics. The cabinets are modeled as rotating rigid bodies. The internal electronics are modeled as rigid bodies moving in the translational direction in the cabinets. The whole system is known as a connected system. The elasto-plastic damper has bilinear hysteretic characteristics and can absorb the energy of earthquake inputs. We input the same seismic wave to the connected system to obtain the rocking angle of cabinets and the acceleration of electronics in the connected system. In these simulations, it is assumed that cabinets do not collide with each other. Then, we investigate the effect of the parameters of the elasto-plastic damper suppressing the rocking angle of the cabinets and the acceleration of electronics.\u0000 Finally, we compare the maximum rocking angle and the maximum acceleration of the single system with that of the connected system and consider an ideal method to reduce the rocking angle and the acceleration simultaneously.","PeriodicalId":273060,"journal":{"name":"Volume 9: Seismic Engineering","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115191899","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hideaki Itabashi, Y. Tsutsumi, K. Nishino, S. Kumagai
The functional requirements of Main Steam Isolation Valves (MSIVs) provided in the Boiling Water Reactor (BWR) nuclear power plants in Japan have been previously evaluated via seismic tests and so forth. However, since the response acceleration has increased in line with a recent reassessment of standard earthquake ground motions, it is necessary to evaluate seismic operability with respect to high acceleration. In addition, from the viewpoint of equipment fragility in seismic PRA, it is necessary to determine practical seismic operability limits. We used a resonant shaking table in the Central Research Institute of the Electric Power Industry (CRIEPI), which is capable of seismic tests at acceleration levels previously unachievable, and in seismic tests carried out on an MSIV, we obtained results confirming that validated seismic operability was possible even at response accelerations as high as 15 × 9.8 m/s2. The seismic operability results obtained for this MSIV will be applied to a fragility analysis of seismic PRA.
{"title":"Seismic Test Results of the Main Steam Isolation Valve for Japanese Boiling Water Reactor Nuclear Power Plants","authors":"Hideaki Itabashi, Y. Tsutsumi, K. Nishino, S. Kumagai","doi":"10.1115/pvp2020-21362","DOIUrl":"https://doi.org/10.1115/pvp2020-21362","url":null,"abstract":"\u0000 The functional requirements of Main Steam Isolation Valves (MSIVs) provided in the Boiling Water Reactor (BWR) nuclear power plants in Japan have been previously evaluated via seismic tests and so forth. However, since the response acceleration has increased in line with a recent reassessment of standard earthquake ground motions, it is necessary to evaluate seismic operability with respect to high acceleration. In addition, from the viewpoint of equipment fragility in seismic PRA, it is necessary to determine practical seismic operability limits.\u0000 We used a resonant shaking table in the Central Research Institute of the Electric Power Industry (CRIEPI), which is capable of seismic tests at acceleration levels previously unachievable, and in seismic tests carried out on an MSIV, we obtained results confirming that validated seismic operability was possible even at response accelerations as high as 15 × 9.8 m/s2.\u0000 The seismic operability results obtained for this MSIV will be applied to a fragility analysis of seismic PRA.","PeriodicalId":273060,"journal":{"name":"Volume 9: Seismic Engineering","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132511217","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ryuya Shimazu, I. Tamura, S. Matsuura, M. Sakai, Yohei Ono
Loads applied to structures by means of vibration can be classified into load-controlled and displacement-controlled loads. The realistic elastic-plastic behavior of structures subjected to seismic loads is not fully understood, and the classification of the load applied to structures by means of earthquakes is unclear. The failure mode differs depending on the load classification, and thus clarifying the classification of the load applied to the structure is useful for designing the structure. This study clarified the realistic load classification of structures under an elastic-plastic response. Vibration tests were conducted using sinusoidal waves as inputs, and the elastic-plastic behavior of the piping supports undergoing buckling or fatigue failure was obtained. The maximum restoring force and the maximum deformation relationship were obtained from the envelope of the time history data of the test results. In addition, it was shown that the classification of the load could be determined from the maximum force-deformation diagram, even in cases involving buckling and fatigue. In the maximum force-deformation diagram, when the change in the ratio of dynamic restoring force to static restoring force is small, a load-controlled load is applied to the structure because the restoring force of the structure follows the change in the input wave. By contrast, when the change in the ratio of dynamic response displacement to static displacement is small, a displacement-controlled load is applied to the structure because the response displacement of the structure follows the change in the input wave.
{"title":"Characteristics of Dynamic Loading Obtained From Braced Piping Support Under Sinusoidal Shaking Condition","authors":"Ryuya Shimazu, I. Tamura, S. Matsuura, M. Sakai, Yohei Ono","doi":"10.1115/pvp2020-21816","DOIUrl":"https://doi.org/10.1115/pvp2020-21816","url":null,"abstract":"\u0000 Loads applied to structures by means of vibration can be classified into load-controlled and displacement-controlled loads. The realistic elastic-plastic behavior of structures subjected to seismic loads is not fully understood, and the classification of the load applied to structures by means of earthquakes is unclear. The failure mode differs depending on the load classification, and thus clarifying the classification of the load applied to the structure is useful for designing the structure. This study clarified the realistic load classification of structures under an elastic-plastic response. Vibration tests were conducted using sinusoidal waves as inputs, and the elastic-plastic behavior of the piping supports undergoing buckling or fatigue failure was obtained. The maximum restoring force and the maximum deformation relationship were obtained from the envelope of the time history data of the test results. In addition, it was shown that the classification of the load could be determined from the maximum force-deformation diagram, even in cases involving buckling and fatigue. In the maximum force-deformation diagram, when the change in the ratio of dynamic restoring force to static restoring force is small, a load-controlled load is applied to the structure because the restoring force of the structure follows the change in the input wave. By contrast, when the change in the ratio of dynamic response displacement to static displacement is small, a displacement-controlled load is applied to the structure because the response displacement of the structure follows the change in the input wave.","PeriodicalId":273060,"journal":{"name":"Volume 9: Seismic Engineering","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129092953","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-08-03DOI: 10.1299/transjsme.20-00129
Y. Takayama, Ayaka Yoshida, Nobuyoshi Iriki, Eiichi Maeda
The independent support motion response spectrum method (ISM) is currently used for seismic analysis to calculate the response of multiply supported piping with independent inputs of support excitations. This approach may derive considerable overestimation in the combination of group responses under the absolute sum rule of NUREG-1061 [1]. Then authors have developed an advanced method of the ISM approach named SATH (Spectrum Method Assisted by Time History Analysis). In the SATH method, both of floor response spectra and time histories of floor acceleration are used as independent inputs of support excitations. The group responses are summed with correlation coefficients which are calculated by considering each time history of modal response by independent inputs of support excitations. In this paper, the necessity of taking the effects of correlation coefficients for the group responses into account in the ISM approach is examined. The SATH method has advantage to derive a more realistic sum rule of the group responses and applicability for the actual design.
{"title":"Floor Response Spectrum Method of Multiply Supported Piping System Assisted by Time History Analysis","authors":"Y. Takayama, Ayaka Yoshida, Nobuyoshi Iriki, Eiichi Maeda","doi":"10.1299/transjsme.20-00129","DOIUrl":"https://doi.org/10.1299/transjsme.20-00129","url":null,"abstract":"\u0000 The independent support motion response spectrum method (ISM) is currently used for seismic analysis to calculate the response of multiply supported piping with independent inputs of support excitations. This approach may derive considerable overestimation in the combination of group responses under the absolute sum rule of NUREG-1061 [1]. Then authors have developed an advanced method of the ISM approach named SATH (Spectrum Method Assisted by Time History Analysis). In the SATH method, both of floor response spectra and time histories of floor acceleration are used as independent inputs of support excitations. The group responses are summed with correlation coefficients which are calculated by considering each time history of modal response by independent inputs of support excitations. In this paper, the necessity of taking the effects of correlation coefficients for the group responses into account in the ISM approach is examined. The SATH method has advantage to derive a more realistic sum rule of the group responses and applicability for the actual design.","PeriodicalId":273060,"journal":{"name":"Volume 9: Seismic Engineering","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132863618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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