Colonoscope flexural rigidity measurement |
| |
Authors: | Dr J A Wehrmeyer J A Barthel J P Roth T Saifuddin |
| |
Institution: | (1) University of Missouri-Columbia, 65211 Columbia, Missouri, USA |
| |
Abstract: | A testing device is developed that determines the stiffness, or flexural rigidity, of an endoscope at specific locations down
its length by subjecting it to a compressive axial force, a situation similar to the actual forces applied to the endoscope
during a clinical procedure. The endoscope is made to deform in a similar fashion to a slender buckled column and the force
causing this deformation is related to the flexural rigidity using column buckling theory. A direct relationship between the
critical load needed to cause buckling and the square of column length L is demonstrated experimentally and is expected theoretically,
giving confidence in the application of column buckling theory to endoscope testing. Additional confidence in the validity
of the columnbuckling test results is obtained by their similarity to data obtained by subjecting the endoscope to a transverse
load, determining deflection, and modelling the endoscope as a bent elastic beam. Several makes and models of endoscopes were
tested, with flexural rigidity values typically ranging between 160 to 240 Ncm2. The effect of a metal stiffener inserted in an endoscope's accessory channel is quantified, as is the change in flexural
rigidity down the insertion shaft of a graded-stiffness endoscope. Significant differences in flexural rigidity were obtained
between identical endoscopes, each sharing similar usage histories, indicating the need for flexural rigidity measurements
for each individual endoscope of a particular model line, though a more extensive study is required to reliably determine
scope-to-scope stiffness variations for a particular model line. |
| |
Keywords: | Colonoscopes Column buckling Endoscopes Flexural rigidity |
本文献已被 PubMed SpringerLink 等数据库收录! |
|