Shape Optimization of Mechanical Logic Gates
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The need to compute in harsh environments has inspired the field of mechanical digital logic, i.e. logic gates that operate mechanically rather than using electricity. Mechanical logic gates mimic the behaviors of traditional logic gates through complex motion. For example, an “and” gate would have two input actuators and require they both be displaced to turn the gate “on”, i.e. displace an output feature. Similarly, an “or” gate would displace the output feature if either of the two inputs are actuated. An additional benefit to mechanical computing is the ability to store information for long periods of time without relying on external power sources. In fact, the information is stored through elastic deformation of materials rather than, e.g. batteries. Mechanical digital logic offers an exciting new application for design optimization. Indeed, the design of logic gates requires simulation of complex mechanics, e.g. nonlinearity, buckling, and bistability to design non-intuitive structures. This work builds on previous attempts at using topology optimization to design logic mechanisms and points out the pitfalls that were encountered. Shape optimization offers many benefits for these difficult simulations and proved to provide adequate design flexibility to obtain working logic gates. The 3D shape-optimized structures are demonstrated numerically via high-fidelity simulation and then compared with experimental data obtained by printing and testing the optimized logic gates.
