IPAC2018 - List of Authors (Lacny, L.L.)

Paper	Title	Page
WEPMF079	Experimental Modal Analysis of Lightweight Structures used in Particle Detectors: Optical non-contact Method	2565
	M. Guinchard, M. Angeletti, F.B. Boyer, A. Catinaccio, C.G. Gargiulo, L.L. Lacny, E.L. Laudi, L.S. Scislo CERN, Geneva, Switzerland
	CERN's specialized structures such as particle detectors are built to have high rigidity and low weight, which comes at a cost of their high fragility. Shock and vibration issues are a key element for their successful transport, handling operations around the CERN infra-structure, as well as for their operation underground. The experimental modal analysis measurement technique is performed to validate the Finite Element Analysis in the case of complex structures (with cables and substructure coupling). In the case of lightweight structures, standard contact measurements based on accelerometers are not possible due to the high mass ratio between the accelerometers and the structure itself. In such a case, the vibration of the structure can be calculated based on the Doppler shift of the laser beam reflected off the vibrating surface. This paper details the functioning and application of an advanced laser-scanning vibrometry system, which utilizes the fore-mentioned non-contact method. The results of the Experimental Modal Analysis of selected lightweight structure using this instrument is also presented and discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMF079
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WEPMF080	Investigation and Estimation of the LHC Magnet Vibrations Induced by HL-LHC Civil Engineering Activities	2568
	M. Guinchard, M. Cabon, C. Charrondière, K. Develle, P. Fessia, L.L. Lacny, J.A. Osborne, L.S. Scislo, J. Wenninger CERN, Geneva, Switzerland
	HL-LHC requires the excavation of large underground infrastructures in order to host new equipment. The tunnel shall be ready for installation for LS3 (2022) and therefore its construction shall take in place in parallel with the LHC exploitation. Effect of vibrations induced by civil engineering activities need to be evaluated in order to take required corrective actions. For this purpose, several diverse measurements and experiments have been performed in order to estimate the vibration sources and determine the vibration transfer path through the floor and the structure. The transfer functions from amplitude and phase point of view were determined through molasses rock, for both horizontal and vertical vibrations, with dedicated tools and Experimental Modal Analysis was carried out on mechanical structure. The campaign of measurements have been used to confirm the effect of the surface induced vibration on the circulating beam orbit at the resonance frequencies of the structure. This paper reviews the advanced technique of measurements, results and the conclusion about the impact of operating civil engineering machines (road header, hydraulic hammer) during beam exploitation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMF080
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Experimental Modal Analysis of Lightweight Structures used in Particle Detectors: Optical non-contact Method

2565

M. Guinchard, M. Angeletti, F.B. Boyer, A. Catinaccio, C.G. Gargiulo, L.L. Lacny, E.L. Laudi, L.S. Scislo
CERN, Geneva, Switzerland

CERN's specialized structures such as particle detectors are built to have high rigidity and low weight, which comes at a cost of their high fragility. Shock and vibration issues are a key element for their successful transport, handling operations around the CERN infra-structure, as well as for their operation underground. The experimental modal analysis measurement technique is performed to validate the Finite Element Analysis in the case of complex structures (with cables and substructure coupling). In the case of lightweight structures, standard contact measurements based on accelerometers are not possible due to the high mass ratio between the accelerometers and the structure itself. In such a case, the vibration of the structure can be calculated based on the Doppler shift of the laser beam reflected off the vibrating surface. This paper details the functioning and application of an advanced laser-scanning vibrometry system, which utilizes the fore-mentioned non-contact method. The results of the Experimental Modal Analysis of selected lightweight structure using this instrument is also presented and discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMF079

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMF080

Investigation and Estimation of the LHC Magnet Vibrations Induced by HL-LHC Civil Engineering Activities

2568

M. Guinchard, M. Cabon, C. Charrondière, K. Develle, P. Fessia, L.L. Lacny, J.A. Osborne, L.S. Scislo, J. Wenninger
CERN, Geneva, Switzerland

HL-LHC requires the excavation of large underground infrastructures in order to host new equipment. The tunnel shall be ready for installation for LS3 (2022) and therefore its construction shall take in place in parallel with the LHC exploitation. Effect of vibrations induced by civil engineering activities need to be evaluated in order to take required corrective actions. For this purpose, several diverse measurements and experiments have been performed in order to estimate the vibration sources and determine the vibration transfer path through the floor and the structure. The transfer functions from amplitude and phase point of view were determined through molasses rock, for both horizontal and vertical vibrations, with dedicated tools and Experimental Modal Analysis was carried out on mechanical structure. The campaign of measurements have been used to confirm the effect of the surface induced vibration on the circulating beam orbit at the resonance frequencies of the structure. This paper reviews the advanced technique of measurements, results and the conclusion about the impact of operating civil engineering machines (road header, hydraulic hammer) during beam exploitation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMF080

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)