Minneapolis / St. Paul Region

Local chapter of ASM International

The MN Chapter of ASM International invites you to our October Event:

Characterizing Mechanical Properties of NiTi used in Cardiovascular Devices

Presented by Dr. Shivram Sridhar, Medtronic

Wednesday, October 15^th

Biography

Dr. Shivram Kashyap Sridhar is a Principal Scientist in Global Technology & Innovation at Medtronic, based in Minneapolis, Minnesota. He earned his Bachelor of Technology in Metallurgy and Materials Engineering from IIT Madras, India and his Ph.D. in Materials Science and Engineering from Carnegie Mellon University. His work focuses on understanding how materials microstructure influences performance, employing mechanical testing, microscopy, and finite element analysis to solve challenges ranging from fundamental materials research to medical device failure analysis and next generation device design. He will share insights into the mechanical behavior of Nitinol (Nickel Titanium shape memory alloys) used in cardiovascular devices.

Abstract

This seminar examines the mechanical behavior of Nitinol (NiTi) in cardiovascular devices, with emphasis on the phase transformations that enable superelasticity and large recoverable strains. It considers the demands of catheter crimping, deployment, and repeated physiological loading, and the need for reliable methods to predict device stresses, strains, and fatigue performance.
The presentation explores experimental characterization methods, including mechanical testing, differential scanning calorimetry, and optical and scanning electron microscopy–based digital image correlation to measure local deformation. It discusses how these measurements support finite element model calibration and validation, capturing temperature-dependent behavior, tension–compression asymmetry, and strain localization, with applications to cyclic loading of stent structures. Finally, the seminar examines how thermomechanical processing shapes crystallographic texture and compares micromechanical modeling approaches to explain its influence on Nitinol’s stress–strain response.

5 PM – 6 PM: Dinner at Davanni’s Pizza, Plymouth, MN
6 PM – 7 PM: Characterizing mechanical properties of NiTi used in cardiovascular devices

Sustaining Members