Multi-Sensor Techniques to Assess Damage in Metallic Materials

ISfIM organized a distinguished lecture on Multi-Sensor Techniques to Assess Damage in Metallic Materials on 27 November 2023 at School of Mechanical Engineering, Nanyang Technological University, Singapore. The lecture was given by Professor Raghu Vasu Prakash from Department of Mechanical Engineering, Indian Institute of Technology Madras, India.

Lecture Abstract:

Any structure or component post-its commissioning experiences a combination of stresses (mechanical, thermal etc.) and environment (high temperature, corrosion etc.) which degrades its performance in terms of strength and stiffness – which is typically expressed as damage in a component or structure. The damage can result in progressive failure (due to fatigue, creep or stress corrosion cracking) or sudden failure (due to the exceed of stresses) and in several cases the damage can remain conspicuous. Non-destructive testing (NDT) is carried out on many industrial components to assess the presence of damage, primarily expressed in terms of cracks (or discontinuities) in a structure or a component. However, there are limitations due to the size resolution of NDT techniques.

This presentation will focus on the use of small specimen test techniques, some of which are in-situ and some are based on material property assessment from a small volume of material scooped from the component mid-life of its operation. Typically, ball indentation and small punch test techniques are discussed in this presentation. The material response to the presence of fatigue damage, creep damage will be discussed. Acoustic emission technique as well as infrared thermal imaging is used in-situ during fatigue testing to comprehend the damage progression in structural materials. The study further examines some cases of weldments in structural material to show how the mechanical behavior changes with material processing. In summary, the small specimen test techniques have the potential to assess the mechanical behavior of materials both in the pristine form, as well as in post-service operations.

Speaker Biography:

Prof Raghu Vasu Prakash is currently working as Senior Professor in Department of Mechanical Engineering, Indian Institute of Technology Madras (IIT Madras), Chennai, India. He specializes in the areas of fatigue, fracture of materials (metals, composites, hybrids), structural integrity assessment, remaining life prediction of critical components used in transportation, energy sectors, apart from new product design. He has more than twenty five years of professional experience in the field of fatigue and fracture and has more than 100 journal papers and book chapters (many in ASTM STPs) and 100 conference publications and has edited 7 book volumes. He headed sponsored research for Boeing, Aeronautical Development Agency while at National Aerospace Laboratories, Bangalore; he has developed test systems for use in academia, R&D and industry during his tenure as Technical Director at BiSS Research, Bangalore; at IIT Madras, he teaches courses relating to Fracture Mechanics, Design with Advanced Engineering Materials, Product Design and DFMA apart from being a researcher and consultant to several Industries. He is a voting rights member of ASTM International (Technical Committees, D-30, E-08 and E-28); Chair of the Materials Processing Technical Committee, Materials Division of ASME; Chair of Society for Failure Analysis (Chennai Chapter) and founding member, Senior Vice President and EC member of the Indian Structural Integrity Society (InSIS). He serves in the editorial boards of Journal of Structural Longevity, Frattura ed Integrità Strutturale (IGF Journal), Journal of Life Cycle Reliability and Safety Engineering.

Prof Prakash received his Bachelor’s degree in Mechanical Engineering from College of Engineering, Guindy, Madras (now Chennai); Master’s degree (by Research) and PhD from Department of Mechanical Engineering, Indian Institute of Science, Bangalore. He is a member of several technical societies (Indian Structural Integrity Society, Society for Failure Analysis, Indian Institute of Metals). He has won several prestigious awards (Binani Gold Medal, Indian Institute of Metals), scholarships and Erasmus-Mundus Fellowships. He is the recipient of Distinguished Fellow of the International Conference on Computational and Experimental Engineering and Sciences (ICCES) 2015. He has guided 13 students for their PhD and 18 students for their MS theses and about 60+ students for their Master’s dissertation at IIT Madras.