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Rings in Taylor Spatial Frame: Mechanical testing and finite element analysis
Ahmad Zamani1, Michalis Zenios2, S Olutunde Oyadiji3
1FECAD Ltd, Derby, UK.
Summary
Whole full rings offer superior stiffness compared to bolted rings in Taylor Spatial Frame (TSF) systems. Smaller TSF rings were found to be unexpectedly stronger than larger ones, highlighting a potential design concern for patient weight considerations.
Area of Science:
- Orthopedic biomechanics
- Biomedical engineering
- Materials science
Background:
- The Taylor Spatial Frame (TSF) is a critical hexapod external fixation device used in orthopedic surgery.
- Understanding the mechanical properties of TSF components is essential for ensuring patient safety and treatment efficacy.
- TSF rings are available in various configurations, including half, two-third, and whole full rings.
Purpose of the Study:
- To evaluate the compressive stiffness and ultimate load capacity of different Taylor Spatial Frame ring configurations.
- To compare the mechanical performance of whole full rings versus bolted full rings constructed from two half rings.
- To investigate the influence of loading direction and ring size on the structural integrity of TSF components.
Main Methods:
- Experimental compression testing of TSF half rings, two-third rings, whole full rings, and bolted full rings.
- Finite Element (FE) analysis using 3D solid elements to simulate mechanical tests.
- Validation of FE models against experimental load-deflection data.
- Analysis of load-deflection curves, stiffness, and ultimate loads for all tested configurations.
Main Results:
- Whole full rings demonstrated significantly higher stiffness and load capacity compared to bolted full rings.
- The stiffness of bolted rings varied depending on the loading diameter.
- Smaller TSF rings exhibited greater strength than larger ones, contrary to biomechanical expectations for patient weight.
- Two-third rings displayed the lowest stiffness when loaded parallel to the line connecting their open ends.
Conclusions:
- Whole full rings are mechanically superior to bolted configurations for Taylor Spatial Frame applications.
- A potential design flaw exists where smaller TSF rings are stronger than larger ones, posing risks under patient loading.
- The orientation of loading significantly impacts the stiffness of TSF components, particularly two-third rings.
Keywords:
Taylor Spatial Frame (TSF)external orthopaedic fixationfinite element (FE) methodhexapod external fixatorring fixatorring mechanicsMore Related Videos
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