Residual Stresses in Surgical Growing Rods.

Autor:	Croonenborghs M; Institute of Mechanics, Materials and Civil Engineering, Université catholique de Louvain, Place Sainte Barbe 2 L5.02.02, Louvain-la-Neuve 1348, Belgium., Ismail K; Institute of Mechanics, Materials and Civil Engineering, Université catholique de Louvain, Place Sainte Barbe 2 L5.02.02, Louvain-la-Neuve 1348, Belgium., Mousny M; Centre Plurisanté, 11 avenue de l'Andalousie, Bruxelles 1140, Belgium., Delannay L; Institute of Mechanics, Materials and Civil Engineering, Université catholique de Louvain, Place Sainte Barbe 2 L5.02.02, Louvain-la-Neuve 1348, Belgium., Everaerts J; Department of Materials Engineering, KU Leuven, Kasteelpark Arenberg 44 box 2450, Leuven 3001, Belgium., Korsunsky AM; Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, UK., Jacques PJ; Institute of Mechanics, Materials and Civil Engineering, Université catholique de Louvain, Place Sainte Barbe 2 L5.02.02, Louvain-la-Neuve 1348, Belgium., Pardoen T; Institute of Mechanics, Materials and Civil Engineering, Université catholique de Louvain, Place Sainte Barbe 2 L5.02.02, Louvain-la-Neuve 1348, Belgium; Wel Research Institute, Avenue Pasteur, 6, Wavre 1300, Belgique.
Jazyk:	angličtina
Zdroj:	Journal of biomechanical engineering [J Biomech Eng] 2024 Jan 01; Vol. 146 (1).
DOI:	10.1115/1.4063745
Abstrakt:	The treatment of early onset scoliosis using surgical growing rods suffers from high failure rate. Fatigue resistance can be improved by inducing compressive residual stresses within the near surface region. An in-depth investigation of the residual stresses profile evolution is performed through the sequence of material processing steps followed by surgeons handling operations, in connection to material properties. The final goal is to guide further improvements of growing rod lifetime. Residual stress evaluation was carried out on Ti-6Al-4V rods using digital image correlation applied to microbeam ring-core milling by focused ion beam. This provided experimental stress profiles in shot-peened rods before and after bending and demonstrated that compressive residual stresses are maintained at both concave and convex rod sides. A finite element model using different core and skin conditions was validated by comparison to experiments. The combination of an initial shot peening profile associated with a significant level of backstress was found to primarily control the generation of compressive stresses at the rod surface after bending. Guidelines to promote larger compressive stresses at the surface were formulated based on a parametric analysis. The analysis revealed the first order impact of the initial yield strength, kinematic hardening parameters and intensity of the shot peening operation, while the bending angle and the depth of shot peening stresses were found to be of minor importance. Materials exhibiting large kinematic hardening and low yield strength should be selected in order to induce compressive residual stresses at key fatigue initiation site. (Copyright © 2024 by ASME.)
Databáze:	MEDLINE
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