A study on the development of photoelastic experimental hybrid method for colour isochromatics (II)

Abstract

Using the photoelastic experimental hybrid method, we can obtain stress intensity factors and separate the stress components near the crack tip of any material under various loading conditions from only isochromatics. However, monochromatic light has, until now been used in the photoelastic experimental hybrid method to produce black and white isochromatics. The existing photoelastic experimental hybrid method using black and white isochromatics requires high order fringes to obtain sufficient experimental data for photoelastic hybrid techniques. If a photoelastic experimental hybrid method for colour isochromatics is developed, isochromatics with a maximum fringe order of 2 will be adequate for gathering the necessary experimental data for stress analyses using photoelastic hybrid techniques. Therefore, in this work, photoelastic experimental hybrid method for colour isochromatics of a crack problem was developed, and its superiority demonstrated by comparing its results with the results from black and white isochromatics. The use of few fringe orders in photoelastic experimental hybrid method for colour isochromatics is an important feature of this method. Because of this feature, this method, specifically the reflection type photoelastic method where low fringe orders are produced compared to the transmission type photoelastic method, can be widely used in stress analysis of real components.

Synergistic determination of mode I stress intensity factors using photoelastic experimental hybrid method

“…Similarity of isochromatics also denotes the point of convergence when minimum errors in iteration process occur. Hooke's and Jeeves’ numerical method was used in this research, with a convergence criterion of 10 −5 [38]. This means the functions of the complex variable ϕ and $${{\rm \Psi }}$$ in Muskhelishvili's Equation (2) were determined when the errors approach the limiting value of 10 −5 . $$$\vcenter{\openup.5em\halign{$\displaystyle{#}$\cr {\rm \sigma} {_{{\rm x}}}={\rm Re}\ [2\Phi \ ({\rm z})-\bar z\Phi {^\prime}({\rm z})-\Psi ({\rm z})]\hfill\cr {\rm \sigma} {_{{\rm y}}}={\rm Re}\ [2\Phi ({\rm z})+\bar z\Phi {^\prime}(z)+\Psi ({\rm z})]\hfill\cr {\rm \tau} {_{{\rm xy}}}={\rm Im}\ [\bar z\Phi {^\prime}(z)+\Psi ({\rm z})]\hfill\cr}}$$$ …”

“…The resin has capacity to alleviate formation of residual processing stress that usually blurs load induced isochromatic fringe patterns. The resin consisted of a mixture of araldite and hardener (Aradur HT 903-1) in the ratio of 100 : 30 by weight and was prepared according to procedure summarized in the pictorial description, Figure 1 [38].…”

“…Similarity of isochromatics also denotes the point of convergence when minimum errors in iteration process occur. Hooke's and Jeeves' numerical method was used in this research, with a convergence criterion of 10 À 5 [38]. This means the functions of the complex variable � and Y in Muskhelishvili's Equation (2) were determined when the errors approach the limiting value of 10 À 5 .…”

“…With the exception of studies on reflective photoelasticity and on color photoelasticity, little attention has been given to the use of hybrid photoelasticity for the crack problem [37,38]. This study therefore, seeks to use photoelastic experimental hybrid method to determine mode I stress intensity factors.…”

Effect of environmental atmosphere and stress-loading storage on the intrinsic stress and its distribution in polycarbonate screw cap

“…Both mechanisms have important effect on material's usage. Stress in different transparency materials can be determined by photo-elastic method [9][10][11][12][13][14].…”