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Experimental Mechanics

, Volume 34, Issue 3, pp 224–229 | Cite as

Stress concentrations associated with circular holes in cylinders and bone in torsion

  • M. Mahinfalah
  • M. Harms
Article

Abstract

Experimental studies were undertaken to determine the torsional stress concentration factors (Kt) associated with circular holes in bone. Reflective photoelasticity was used to determine the stress field around a circular hole through one wall of the bone. A single adult sheep femur was used as the torsional model, in which six circular holes were concentrically machined through the posterior cortex. These holes ranged from 10.4 percent to 66.4 percent of the mediolateral bone diameter. From the photoelastic data, a stress concentration curve was developed for bone. The maximum stress location on the boundary of the hole was found to shift from the previously expected 45-deg location.

Studies on tubes made of steel and plastic, both coated with photoelastic coating, were also performed. Three different pieces of steel tubing with similar inner to outer diameters were coated with different thicknesses of photoelastic coating. The variation in coating thickness did not appear to influence the stress-concentration factors in steel. TheKt in steel for 10 percent and 20 percent defects agreed with theKt associated with similar defects in bone. A single piece of plastic tubing was used in which six holes from 10 percent to 60 percent of the tube's outer diameter were concentrically machined through one wall. The location of the maximum stress around the boundary of the hole was found to shift, and this agreed with the maximum stress shift found in the bone.

Keywords

Stress Concentration Outer Diameter Maximum Stress Circular Hole Stress Concentration Factor 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Society for Experimental Mechanics, Inc. 1994

Authors and Affiliations

  • M. Mahinfalah
    • 1
  • M. Harms
    • 2
  1. 1.Mechanical Engineering DepartmentNorth Dakota State UniversityFargo
  2. 2.BM CorporationSt. Paul

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