Piezoresistive UHMWPE WMCNT Sensors for Instrumented Total Knee Replacements

In this study, we have successfully developed and validate an instrumented total knee replacement using a novel piezoresistive polymeric sensor. The addition of multi-walled carbon nanotubes (MWCNT) as electrically conducting fillers to the ultra-high molecular weight polyethylene (UHMWPE) transforms the electrically insulating UHMWPE to a nano-composite whose resistance changes with the applied stress. A steel mold and a two-stage compression molding process were developed to instrument and hermetically seal the embedded sensors within the tibial insert. As the sensors were made from the same material as the UHMWPE tibial insert, the impact of the sensor instrumentation on the mechanical properties of the host insert was minimized, giving the fabricated sensors an advantage compared to existing metallic or ceramic strain gages. A finite element model was developed using ANSYS Workbench to study the effects of the embedded sensors on the mechanical behavior of the tibial insert and to determine the location within the bearing at which stress sensitivity is maximized. Experimental results from controlled cyclic compression loading of the instrumented bearing and its operation in a knee simulator confirmed that the combination of MWCNT-UHMWPE sensors and the developed instrumentation process is a viable technique to produce the instrumented total knee replacement. Areas for improvement of this prototype sensor design are also discussed.

Grantor dc:publisher

UNSW, Sydney

Year dc:date

2019

Author dc:creator

• Do, Quyen

• Instrumented total knee replacement
• Piezoresistive polymeric sensor

Statement dc:rights

• open access
• CC BY-NC-ND 3.0
• free_to_read

Licence

• https://purl.org/coar/access_right/c_abf2
• https://creativecommons.org/licenses/by-nc-nd/3.0/au/

Language dc:language

EN

Identifier

https://doi.org/10.26190/unsworks/21646

OAI identifier oai:identifier

oai:unsworks.library.unsw.edu.au:1959.4/64982