Major Software Upgrades Aid Thermal, Mechanical SimulationsJune 10, 2020
Our CIO, Ivy Karamitsos, carried out a major IT upgrade thanks to the Wefunder crowdfunding investments that we gained this March. The upgrade cost just under $40K, but it was a long overdue investment into our infrastructure as we needed improved in-house capabilities for our engineering drawing software and simulation productions. We also purchased SolidWorks PDM, a project data management system, with this SolidWorks upgrade. This can help us to keep track of design versioning by various team members while ensuring the full compatibility of multi-layer components within each project. The upgrade includes a custom-made workstation for the simulation module, designed by Systems Administrator Jose Varela, and a network license server which will help our ongoing collaboration with many of our consultants, allowing them to work with us remotely.
With the new system in place, LPPFusion is expanding its use of a number of simulations in preparation for a new set of experiments in the fall. LPPFusion Mechanical Engineer Rudy Fritsch is working on a thermal and mechanical dynamic simulation of new anode designs. He is using a recently upgraded version of the commercial SolidWorks simulation suite combined with our new and faster hardware. The simulation will model the range of stresses that the anode will be subject to with the higher current expected from the new switches, showing how the part will react.
During the few microseconds that each shot lasts, the millions of amps of current moving through the anode will compress it through the pinch force—the same basic phenomena that compresses the plasma to produce fusion. At the same time, the resistance of the beryllium to the current will be heating it up, with the current and heat concentrated by the current filaments. That causes expansion. A third big effect is the ten-nanosecond-long pulse of heat from the plasmoid, mostly from X-rays. While most of the X-rays will harmlessly pass through the beryllium, the lowest-energy ones will be absorbed in the outer few microns of the metal.
The inertia of the solid beryllium will prevent it from moving significantly during the shot. But the unbalanced forces, and deposited heat will act as “instantaneous” impulses that will start the anode vibrating after the pulse passes. The simulation will model these vibrations, showing us the maximum stresses.
For each design of the anode—different shapes and sizes of holes for example—we’ll do a number of simulation runs with different combinations of currents and plasmoid radiation, to sample the range of conditions we expect. We anticipate that the simulations will be a major help in selecting an optimum design.