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Shape Memory Materials, Simulation and Prosthetics

Shape memory alloys are composite materials which can 'remember' a given shape or form, and revert back to it when a charge is passed through them, or they are warmed past a critical point, or another condition is met. They deform then reform, essentially flowing like organic tissue without actually being organic.

Such materials are of obvious interest to both prosthetics and robotics, for these organic-like qualities. We are just starting to enter the level of technological maturity wherein they can actually be used for such, at least in a smattering of cases. There is a problem which is keeping their use out of the mainstream, for now. That is where simulation is stepping in.

The problem is the sheer complexity of crafting a metallic alloy with the right mix of different shape memory components in different areas, to produce the desired characteristics. That problem is mindbogglingly complex, and exceedingly delicate during the manufacturing stage. This leads to a great deal of trial and error, and predictably vastly inflated costs. Both need to be eliminated if such materials are ever to be used in the mainstream.

Fortunately, virtual prototyping has been becoming increasingly mainstream for a few years now. Virtual prototyping being the process of creating a fully functional, materials-accurate, physics based prototype of an object long before a physical version is made, allowing most of the bugs and blunders to be worked out prior to the expense of actually making a custom part.

It was not such a great leap to take virtual prototyping simulation software and adapt it, to the complex physics of shape memory metals. This for the first time allows the design and precise layering of shape memory components with an accurate understanding of what their properties will be, prior to even beginning to manufacture them. Combined with 3D printing of such metals, this would allow such devices to be constructed at a fraction of the current cost.

We don't have 3D printing for shape memory metal yet, but we do have the virtual prototyping section, up and running. Researchers at the Fraunhofer Institute for Mechanics of Materials are responsible for creating a first generation simulation which meets these requirements. The development has obviously triggered something of a stir across manufacturing segments.

The simulation's capabilities are not perfect of course, but they can take any shape, any combination of known shape metal alloys, and predict exactly how stress points will form under load, and as it bends and flexes due to temperature or electric current changes, with near perfect accuracy compared to actually machined products. This means the software, as-is, is already sufficiently powerful to eliminate the guesswork side of manufacturing, completely.


Design tool for materials with a memory

Computer Simulations Extend Abilities of Shape Memory Alloys

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