Compressive Damage in Nitinol
Nitinol is a superelastic nickel-titanium material used in stents, guidewires, and other medical devices. Exponent engineers have extensive experience with failure analysis, finite element analysis, fatigue testing, corrosion testing, metallurgy, and design validation of nitinol devices. During an investigation of a device that occasionally exhibited very low strength, Exponent engineers found that shear cracks formed on the compressive-side of tight bends. These cracks then resulted in significantly reduced tensile behavior. Exponent engineers have since helped many clients with nitinol compressive damage problems, and have published and presented papers on this interesting phenomenon.