Computational studies of shape memory alloy behavior in biomedical applications.
BACKGROUND
Nowadays, shape memory alloys (SMAs) and in particular Ni-Ti alloys are commonly used in bioengineering applications as they join important qualities as resistance to corrosion, biocompatibility, fatigue resistance, MR compatibility, kink resistance with two unique thermo-mechanical behaviors: the shape memory effect and the pseudoelastic effect. They allow Ni-Ti devices to undergo large mechanically induced deformations and then to recover the original shape by thermal loading or simply by mechanical unloading.


METHODS
A numerical model is developed to catch the most significant SMA macroscopic thermo-mechanical properties and is implemented into a commercial finite element code to simulate the behavior of biomedical devices.


RESULTS
The comparison between experimental and numerical response of an intravascular coronary stent allows to verify the model suitability to describe pseudo-elasticity. The numerical study of a spinal vertebrae spacer where the effects of different geometries and material characteristic temperatures are investigated, allows to verify the model suitability to describe shape memory effect.


CONCLUSIONS
the results presented show the importance of computational studies in designing and optimizing new biomedical devices.
Petrini
Lorenza
L
Dipartimento di Meccanica Strutturale, Università di Pavia, Via Ferrata 1, 27100 Pavia, Italy. petrini@unipv.it
Migliavacca
Francesco
F
Massarotti
Paolo
P
Schievano
Silvia
S
Dubini
Gabriele
G
Auricchio
Ferdinando
F
D000497:Alloys / Q000737:chemistry*; D001672:Biocompatible Materials / Q000032:analysis / Q000737:chemistry*; D001698:Biomedical Engineering / Q000295:instrumentation / Q000379:methods*; D003198:Computer Simulation; D004548:Elasticity; D019544:Equipment Failure Analysis / Q000379:methods; D006244:Hardness; D008422:Materials Testing / Q000379:methods*; D008956:Models, Chemical; D009532:Nickel / Q000032:analysis / Q000737:chemistry*; D011474:Prosthesis Design / Q000379:methods*; D013314:Stress, Mechanical; D014025:Titanium / Q000032:analysis / Q000737:chemistry*
D000497:Alloys; D001672:Biocompatible Materials; C040654:titanium nickelide; D009532:Nickel; D014025:Titanium