Material Stress Fringe Constant Measurement of Specimen under Pure Bending Load by Use of Photoelastic Phase Shifting Method

광탄성 위상이동법을 이용한 순수굽힘보 시편의 재료 응력 프린지 상수 측정

  • Received : 2014.06.24
  • Accepted : 2014.09.11
  • Published : 2014.12.01


In a photoelastic experiment, it is necessary to know the material stress fringe constant of the photoelastic specimen to determine the stresses from the measured isochromatic fringe orders. The material stress fringe constant can be obtained using a simple tension specimen and/or a circular disk under diametric compression. In these methods, there is generally a need to apply numerous loads to the specimen in response to the relationship of the fringe order. Then, the least squares method is used to obtain the material constant. In this paper, the fringe orders that appear on a four-point bending specimen are used to determine the fringe constant. This method requires four photoelastic fringes obtained from a circular polariscope by rotating the analyzer to 0, ${\pi}/4$, ${\pi}/2$, and $3{\pi}/4$ radians. Using the four-point bending specimen to determine the material stress fringe constant has an advantage because measurements can be made at different locations by applying a constant load. The stress fringe constant measured with this method is within the range suggested by the manufacturer of the photoelastic material.


Photoelasticity;Material Fringe Constant;Phase Shifting Method;Isochromatic Fringe;Pure Bending


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