Numerical modelling of advanced materials subjected to high-energy particle beam impacts

Abstract

The High-Luminosity Large Hadron Collider (HL-LHC) upgrade for the LHC brings with it an increase in beam energy, necessitating improvements in all systems. The development of novel, high-performing materials is crucial in assuring targets are achieved. This is especially true in the context of collimators and other beam intercepting devices, which are required to cope with elevated intensities, while delivering a lower contribution to machine impedance. For this reason, experimental campaigns such as those conducted in the HiRadMat facility at the European Organisation for Nuclear Research (CERN) are essential for testing of materials under intense particle beam impact. Thermal and structural measurements allow for the validation of mathematical models describing the material behaviour, which are implemented in numerical models simulating the experimental scenario. Once validated, such models can be applied to simulate more complex, full-scale scenarios. In this Ph.D. study, a number of materials of interest in the field of particle accelerators and other thermomechanical applications are studied. Research on available literature highlights the need for accurate mathematical models describing the behaviour of materials under the extreme conditions imposed by quasi-instantaneous particle beam impacts. With this in mind, models for Silicon Carbide (SiC), Titanium Zirconium Molybdenum (TZM) alloy, and Copper Diamond (CuCD) metal-matrix composite are proposed and applied in finite element analyses modelling beam impacts from the HRMT36 experiment. The large amount of data collected in the experiment is used to benchmark computed numerical results. The material models put forward can be applied in analyses modelling impacts on collimator jaws and other absorbers and targets commissioned in CERN’s accelerator complex. The models are found to be able to successfully simulate various impact scenarios from the HRMT36 experiment, as well as phenomena of interest such as boundary condition effects and wave propagation in failure scenarios. Further study is conducted on the behaviour of CuCD on a mesoscopic level, for which a numerical model is built to simulate wave-particle interaction for particle-reinforced composites subjected to intense impacts. Additionally, a tabular equation of state for the material is formulated from constituent material data. The work presented also identifies a number of key areas of interest for future study of the materials considered, namely related to material testing at elevated temperatures and high strain-rates, which would allow for the full description of the material behaviour for the application in question.