APPLYING PHOTOELASTICITY WITH OPTICAL MAGNIFICATION METHOD TO INCREASE PRECISION OF DETERMINING FRINGE ORDER UNDER MONOCHROMATIC LIGHT

Author(s): 

M.B.H Sitorus1*, Melvin Emil Simanjuntak1, Agus Sigit Pramono2, Henry Lumbantoruan3, Udur January Hutabarat1, B. Ginting1, Piktor Tarigan1, Teng Sutrisno4

Affiliation(s): 

1Department of Mechanical Engineering, Politeknik Negeri Medan, Jl. Almamater No.1, Kampus USU, Medan 20155

2Department of Mechanical Engineering, FTI ITS, Jl. A. R. Hakim, Sukolilo – Surabaya 60111

3Department of Electronics Engineeri ng, Politeknik Negeri Medan, Jl. Almamater No.1, Kampus USU, Medan 20155

4Mechanical Engineering Department, Petra Christian University, Jl. Siwalankerto No.121-131, Siwalankerto, Wonocolo, Surabaya, Jawa Timur 60236

*Corresponding Author Email: bsm4rk@gmail.com

 This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Photoelasticity method was used to measure strain and stress fields to address the precision problem of determining fringe order of loading and cracking and notch areas. In this study, microscope was used as an additional tool in a photoelastic device for magnification of isochromatic fringe size. An experimental method was used by utilizing optical system and reflective polariscope. A simple compression tool was designed to provide a compression load on the solid disk-shaped specimens. Isochromatic fringe field was observed in the loading zone for different loading and captured image based on the following conditions: 9x, 15x and 20x without magnification and with magnification using SLR type Nikon camera Serie D3000. The image was processed using OpenCV software while C + + was used to produce clearer isochromatic fringe pattern formed on the surface of the specimen in the determination of the maximum fringe order observed. The average of additional fringe could be obtained as the optical magnification result. Data was analyzed using Finite Element Analysis Software. The result showed an increasing trend in fringe order with increasing levels of optical magnification. Its maximum value was obtained on20x optical zoom, which was 2-order fringe.