Sheet Metal Forming of Niobium RF Crab Cavities at CERN
The installation of superconducting radio frequency (RF) Crab Cavities is one of the key upgrades in the framework of the High-Luminosity Large Hadron Collider (HL-LHC) at CERN. These devices - built out of niobium sheets- are shaped and joined into a complex geometry, entailing very tight tolerances, in order to comply with strict RF requirements. Numerical simulations via LS-DYNA® prove to be a useful tool for optimizing the fabrication of these RF cavities: different shaping approaches and tooling may be explored; furthermore, simulations are performed for optimizing the chosen shaping strategy and predicting the impact of such fabrication on the shaping process yield. Accurate simulations require a model of the behaviour of niobium sheets on top of proper loads, constraints and contacts definitions. An extensive dimensional control campaign is also performed on shaped pieces in order to validate the simulations in terms of final geometrical parameters. Data acquisition during the forming process allows a further validation of the simulations in terms of transferred load. The following contribution will detail the numerical models used and thoroughly compare simulation results with fabricated pieces.
13_Amorim Carvalho_Cern.txt
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The installation of superconducting radio frequency (RF) Crab Cavities is one of the key upgrades in the framework of the High-Luminosity Large Hadron Collider (HL-LHC) at CERN. These devices - built out of niobium sheets- are shaped and joined into a complex geometry, entailing very tight tolerances, in order to comply with strict RF requirements. Numerical simulations via LS-DYNA prove to be a useful tool for optimizing the fabrication of these RF cavities: different shaping approaches and tooling may be explored; furthermore, simulations are performed for optimizing the chosen shaping strategy and predicting the impact of such fabrication on the shaping process yield. Accurate simulations require a model of the behaviour of niobium sheets on top of proper loads, constraints and contacts definitions. An extensive dimensional control campaign is also performed on shaped pieces in order to validate the simulations in terms of final geometrical parameters. Data acquisition during the forming process allows a further validation of the simulations in terms of transferred load. The following contribution will detail the numerical models used and thoroughly compare simulation results with fabricated pieces.