Exponent Publication Named Editor's Choice by Shape Memory and Superelasticity

Man holds heart stent

June 6, 2023

Exponent research addresses knowledge gap in Nitinol stent fatigue

A paper published by five Exponent engineers in collaboration with Fort Wayne Metals was recently named a 2022 Editor's Choice article by the editor-in-chief of research journal Shape Memory and Superelasticity.

The paper, "Fatigue, Fracture, and Crack Arrest from Bending Induced Pre-strain in Superelastic Nitinol," helps increase our understanding of the effects of high crimping-induced pre-strains on fatigue and fracture in superelastic Nitinol in endovascular and cardiovascular medical device applications.

The paper was published in partnership between Exponent engineers and longtime client Fort Wayne Metals. Exponent's Louis Malito, Paul Briant, Matthew Bowers, Sarah Easley, and Brad James collaborated with Fort Wayne Metals research and development director Jeremy Schaffer on the paper's research and experimental design.   

"We are pleased to be recognized by Shape Memory and Superelasticity and to be able to contribute to the collective knowledge of medical device materials performance alongside Fort Wayne Metals," said Paul Briant, Exponent principal engineer and mechanical engineering practice director. "This is what combining the work of materials and mechanical engineers is all about."

As a critical material for medical device applications, superelastic Nitinol devices are self-expanding and hold their shape in blood vessels across a service lifetime of hundreds of millions of fatigue cycles in the vascular environment. In stents and other medical devices, Nitinol undergoes the highest bending stress/strain during crimping onto the catheter for device delivery.  

This study sought to better understand the effects of bending induced crimp/pre-strain on Nitinol fatigue behavior in a scenario that can occur in vascular devices.

To learn more about the article, click here