OCR Text |
Show 26 Sadee Hansen college of engineering Our group has manufactured micro electromechanical system (MEMS) charged pumped actuators (CPA) but has yet to simulate the movement of these devices which would greatly facilitate the design process. The charge pumping mechanism refers to our use of a scanning electron microscope (SEM) to inject elec-trons into a structure, and view the resulting response due to mutual repulsion of the charges as they ac-cumulate and re-distribute across the conductive, ungrounded surface. ANSYS Workbench was utilized to create simulations which predict the response of the MEMS CPA. The goal of these simulations is to predict the motion as well as the stress it causes to the system. The finite element analysis (FEA) for the CPA was divided into individual unit cells from the repeated pat-tern, comparing a sharp hourglass shape with a curved hourglass shape. The model was constrained in two corners and a uniform pressure was applied to all the inner walls of the part. This was necessary to simulate how the pieces of the CPA would respond to a repulsive force caused by an electric charge. The sharp-cornered hourglass shape demonstrated highly concentrated stresses at each corner. Under the same simulated pressure conditions, the curved shape produced a smaller stress that was distributed over a wider section of the element. There were many difficulties encountered while creating simulations for the complete model of the CPA. The complexity of the Solidworks model made it difficult to sufficiently simplify the meshing so that the ANSYS software could still run while producing a result. Due to the physics of the working CPA as neither a static system, nor as a two-electrode (e.g., with a ground plane) circuit, the ANSYS Workbench was not found to be a viable tool for simulating this problem. We concluded we must search for more appropriate FEA software or other means to simulate the problem. CREATING SIMULATIONS OF CHARGE PUMPED ACTUATORS Sadee Hansen (Ian Harvey) Department of Mechanical Engineering University of Utah UNDERGRADUATE RESEARCH ABSTRACTS Ian Harvey |