Experimental Mechanics

, Volume 22, Issue 9, pp 348–353 | Cite as

On the analysis of neutral holes

Neutral-hole theory is extended to account for bending stresses in the reinforcement. Effectiveness of neutral reinforced openings in panels subject to uniaxial tension is investigated by photoelastic analysis
  • D. R. Budney
  • D. G. Bellow
Article

Abstract

When an opening must be located in a tension panel the inevitable stress concentration that results can be reduced if the edge of the opening is reinforced. While there is a variety of solutions for providing reinforcements which reduce stress concentrations in the panel, none of these consider the state of stress that exists in the reinforcement.

This paper extends the theory of neutral holes to consider bending of the reinforcement as well as to allow for the use of a different material in the reinforcement. Photoelastic experiments demonstrate the effectiveness of neutral holes for uniform uniaxial tension panels for which the opening consists of parabolic sections.

Keywords

Mechanical Engineer Fluid Dynamics Stress Concentration Uniaxial Tension Reduce Stress Concentration 

List of Symbols

ϕ

Airy stress function

\(\left. \begin{gathered} \sigma _x = \frac{{\partial ^2 \phi }}{{\partial y^2 }} \hfill \\ \sigma _y = \frac{{\partial ^2 \phi }}{{\partial x^2 }} \hfill \\ \sigma _{xy} = - \frac{{\partial ^2 \phi }}{{\partial x\partial y}} \hfill \\ \end{gathered} \right\}\)

plane stress components

ψ

inclination of boundary tox-axis

P

axial force in reinforcement boundary

t

panel thickness

σ0

uniaxial-tensile stress iny-direction

PV,PH

vertical and horizontal components of force in reinforcement

Ar

area of reinforcement cross section

Er

reinforcement modulus

Ep

panel modulus

νp

Poisson's ratio for panel

εψ

strain parallel to boundary of reinforcement

r

arbitrary parameter for size of reinforcement

At

area of cross section of vertical reinforcement

σt

stress in vertical reinforcement member

Ac

area of cross section of compressive reinforcing member

σc

stress in compressive reinforcing member

M

bending moment in reinforcement

σr

mean tensile stress in reinforcement

f

stress-optical coefficient

n

fringe order

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References

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  2. 2.
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  3. 3.
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  8. 8.
    Budney, D. and Bellow, D.G., “Photoelastic Analysis of Neutral Holes,” Proc. 4th Symp. Engrg. Appl. of Solid Mech., 1, Ontario Research Foundation, 106–126 (1978).Google Scholar

Copyright information

© Society for Experimental Mechanics, Inc. 1982

Authors and Affiliations

  • D. R. Budney
    • 1
  • D. G. Bellow
    • 1
  1. 1.Department of Mechanical EngineeringThe University of AlbertaEdmontonCanada

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