[Finite element analysis of shape memory alloy intrasegmental fixator for lumbar spondylolysis].
OBJECTIVE
To study the tensile strength of shape memory alloy intrasegmental fixator and tensile stress distribution in the device during force loading with finite element method (FEM).


METHODS
The designed parameters, scanning image, and mechanical properties of shape memory alloy intrasegmental fixator were input into computer for the construction of the FEM model of the device in inherent coordinate of ANSYS. The model was extended with restriction in different parts, and the tensile strength and the distribution of tensile stress in the model was calculated.


RESULTS
When the device was loaded with pulling force to induce a relative displacement of 2 mm between the 2 hooks along the two midpoints, the pull was about 281 N, and the tensile stress concentrated more on the middle of device than on the two sides.


CONCLUSIONS
The shape memory alloy intrasegmental fixator is strong enough against tensile stress, which concentrates in the middle portion of the device where fatigue breakage is liable to occur when excessive force is loaded.
Zhang
Hui
H
Department of Orthopaedics, Zhujiang Hospital, First Military Medical University, Guangzhou 510282, China.
Jin
An-Min
AM
Zhang
Mei-Chao
MC
D000497:Alloys; D001696:Biomechanical Phenomena; D020342:Finite Element Analysis; D006801:Humans; D016268:Internal Fixators; D008159:Lumbar Vertebrae / Q000503:physiopathology; D013169:Spondylolysis / Q000628:therapy*; D013718:Tensile Strength
D000497:Alloys