IITM Releases State of the Art Software for Photoelastic analysis and Simulation

The recent years in science and engineering has seen a resurgence in the use of photoelasticity in diverse fields ranging from agricultural applications to locomotion of organisms to mitigating stresses or identifying defects in 3D electronics. Novel applications in biomedical and even conventional stress analysis involving complex loading and boundary conditions in aerospace, civil, mechanical, and manufacturing engineering fields have also been the focus. Three-dimensional models with porosity and varied aggregates of arbitrary shapes that were not possible hitherto have now become possible with the use of rapid prototyping technologies, which is promising to develop more realistic models for studying material behaviour. Comparisons with numerical models to validate as well as to improve numerical frameworks in terms of boundary conditions using innovative methods of comparisons based on plotting the isochromatic/isoclinic fringe fields rather than stress separation has made photoelastic stress analysis even more attractive.

Prof. K. Ramesh, K Mahesh Chair Professor, Department of Applied Mechanics has made available the processing software (DigiTFP®, PSIF and DigiPhoto) for photoelastic analysis based on digital photoelastic techniques developed over the last three decades for other researchers to use. A simulation module called P_Scope® has also been made available, which is expected to bring about a renaissance in solid mechanics education in conjunction with his video lectures on Strength of Materials. Many nuances of concepts of solid mechanics can be brought out easily with the P-Scope® software and it can also be integrated with laboratory courses and even amenable for online teaching.

Prof. K. Ramesh, a Fellow of the Indian National academy of Engineering, is the first Indian in the last sixty years to receive the M. M. Frocht award of the Society for Experimental Mechanics, USA for his outstanding contributions as an educator in the field of Experimental Mechanics. He has also been the first researcher from India to have received the Zandman Award from the same society in 2012 for outstanding contributions in the application of photoelastic coatings.

IIT has entered with a Licensing and Monetization agreement with Online Solutions (Imaging) Pvt Ltd., Chennai for licensing these softwares on behalf of IIT Madras in the country. The agreement has been signed and exchanged today in the presence of the Dean, ICSR Prof. Manu Santhanam.

Brief Outline of Software

P_Scope^® is an innovative software that simulates conventional/generic polariscopes using Jones calculus for eight different problems for which theory of elasticity solution exists. It can also plot isochromatic and isoclinic phasemaps to understand the nuances of Digital Photoelasticity. The parameters governing the problems can be changed to customize the simulation. A variety of light sources and model materials can be selected. Other features include plotting of isopachics, all isoclinics, influence of carrier fringes, zoom in/out etc.

DigiTFP^® is capable of exploiting the colour information to extract both isochromatic (difference in principal stresses) and isoclinic (orientation of principal stress direction) parameters over the model domain using the latest developments in the field. It can provide isochromatic results from a single dark field colour image. In case, one requires the isoclinic data also, the software would require four plane polariscope images recorded in colour having 0°, 22.5°, 45° and 67.5° isoclinics. It also has an advanced feature to extract isochromatic data from these isoclinic images. It accepts images in TIFF and BMP formats and also individual image planes.

PSIF uses the multiparameter solution to evaluate the SIF values from the data points collected around the crack tip. Data can be collected from thinned fringes or directly from phase shifting or twelve fringe photoelasticity results of fringe data. The software has modules for crack-tip refining as well as evaluation of the uncertainty in SIF evaluation. The software has a facility to reconstruct the fringe patterns with data points echoed thereby verifying the solution obtained.

DigiPhoto employs the ten-step phase-shifting method to extract both isoclinic (orientation of principal stress direction) and isochromatic (difference in principal stresses) parameters over the complete model domain. DigiPhoto can also do digital fringe thinning and digital fringe multiplication.

for more details:  Please visit https://home.iitm.ac.in/kramesh/p_scope.html

https://home.iitm.ac.in/kramesh/dtfp.html

https://home.iitm.ac.in/kramesh/dphoto.html

https://home.iitm.ac.in/kramesh/psif.html