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T he design study of the vacuum system elements ( KOPIO experiment ). A. Ryabov, A. Soldatov, S.Chernichenko ( IHEP, Protvino ) V.Demitchev, A.Timofeev ( RDP Corp. KOMPOZIT, Korolev ). Geometry. General View. Pipe. Lid. Ribs. FE-Analysis Models. GA – connection. GB – connection.
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The design studyof the vacuum system elements(KOPIO experiment) A. Ryabov, A. Soldatov, S.Chernichenko (IHEP, Protvino) V.Demitchev, A.Timofeev (RDP Corp. KOMPOZIT, Korolev)
Geometry. General View Pipe Lid Ribs
FE-Analysis Models GA – connection GB – connection GC – connection • Three geometry models of the pipe-lid connection have been used in the Finite Element Structural Analysis (FE-Analysis): GA - the joint without any additional intermediate element; GB - the joint thru an intermediate conic surface; GC - the joint thru an intermediate “horn” surface. • Three sets of thickness for the lid, pipe and ribs have been considered. Values of these thickness (TS1, TS2 and TS3) are shown intable on next slide.
FE-Analysis (the stress distribution) Two versions of FE-Analysis have been done for each combination of the geometry model and thickness: first one for a free pipe end (V1), the second one for a fixed pipe end (V2). A typical example of a stress distribution with two critical zones Critical zone P1 Critical zone P2 V1: Von Mises Stress [MPa] SEQV_max = 330 MPa V2: Von Mises Stress [MPa] SEQV_max = 154 MPa
FE-Analysis (displacements) A typical example of a maximum displacement (GA, TS1) V1: USUM_max = 2.17 mm V2: USUM_max = 1.91 mm
FE-Analysis (the pipe displacements) V1 V2 Uz = -1.23 Uz = -0.05 Longitudinal displacements UZ [mm] V1 V2 Uy = ± 1.31 Uy = ±1.34 Vertical (Flexure) displacements UY [mm]
Summary Results of FE-Analysis TS1: t_cover = 1/2, t_pipe = 1/4, t_ribs = 3/8 inch TS2: t_cover = 1/4, t_pipe = 1/4, t_ribs = 3/8 inch TS3: t_cover = 1/3, t_pipe = 1/3, t_ribs = 1/3 inch
Conclusions • For all design variants of the lid-pipe system, the fixed end of a pipe allows to decrease the maximum displacements of pipe and to reduce also the stress of lid in critical zones (P1, P2) up to acceptable values. • The base variant of the lid-pipe design of the vacuum system (Beryllium alloy with thickness of 1/2”) can’t be made due to technological reasons - the today technology and the equipment allow to weld sheets of Beryllium alloy with the thickness up to 1/4”.
Conclusions • The variant of the lid-pipe design with Beryllium alloy of the thickness of 6 mm and with the conic joint of lid-pipe can be made on the modernized technological equipment. The estimated cost of this variant will be more than $2M, period of manufacturing will be 3 years. But, two comments have to be done for this version: - Even for this thickness of Beryllium alloy, ribs on the beam pipe will be soldered by silver, but not welded, because the existing technology allows to weld only an end-to-end shape, but not T-shape. - Opportunity of appearance of micro-cracks in the welded seams because of cyclic loading (vacuum - atmosphere). It will demand an additional polymeric covering on the product surfaces.
Conclusions • However, the today technology allows to produce the alternative variant of the lid-pipe design with a carbon-plastic composite of the thickness of 1/3” and with the conic joint of lid-pipe, which provides a safety factor almost 7 and the radiation thickness of 0.05X0. The estimated cost of this variant will be ~ $600K, period of manufacturing will be 2-3 years.
Schedule and the cost estimation for production of the composite version