PSI - Issue 43

Raghu V. Prakash / Procedia Structural Integrity 43 (2023) 190–196 Author name / Structural Integrity Procedia 00 (2022) 000 – 000

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reinforced composite as well as hybrid composite material system. Further, we have coupled the thermographic measurements during testing to understand the temperature profile of specimen and correlate it with stiffness drop. Our earlier studies considered use of ultrasonic C-scan measurements at periodic intervals to quantify damage in CFRP laminate [Moghe et. al, 2015]. Many details pertaining to the results reported have been elaborated elsewhere [Prakash et. al, 2017; Mathew and Prakash, 2018, Prakash and Maharana, 2018]. Currently work is in progress to correlate the acoustic emission (AE) signatures during post-impact fatigue damage with stiffness measurements as well as measurements from other sensors such as infrared thermography, CT scan imaging. It is hoped that when multiple sensors are used in tandem, the understanding of the physics of damage progression would improve significantly. Coupled with input on residual strength and correlation with prior damage in materials would be useful for remaining life assessment. 3. Summary and Conclusions This paper presented a bird ’s eye view of two non-destructive techniques – infrared thermography and X-ray Computed Tomography used to study the fatigue damage progression in metals and polymer reinforced composite material. Recognizing that fatigue damage is gradual and follows the three stages of primary, secondary and tertiary damage, it is the desire to assess damage in dynamically loaded components in a non-destructive manner and quantify the damage. The observation of increasing temperature slope with prior fatigue cycles and presence of steady state of temperature evolution suggests technical feasibility of existing damage assessment and expected life prediction. By the same argument, characterization of damage volume or stiffness drop helps in quantification of damage in polymer composites. It is hoped that other on-line measurement techniques such as acoustic emission would add value to the knowledge base established over here. Acknowledgements The author wishes to place on record the support received from several colleagues including Prof. Michele Carboni (Politecnico di Milano, Italy), Prof. Krishnan Balasubramanian (IIT Madras) and a host of research scholars (Dr. Mathew John, Dr. Kathirvel Thiyagarajan, Mr. Pravin Patil in particular) who participated in this research initiative in a painstaking manner over several years. References Lemaitre, J. and Desmorat, R., “Engineering Damage Mechanics”, Springer Berlin, Heidelberg, 2005, https://doi.org/10.1007/b138882 Mathew John, Raghu V. Prakash, 2018, “ Quantification of fatigue damage in carbon fiber composite laminates through image processing ” , Materials Today: Proceedings, Volume 5, Issue 9, Part 1, Pages 16995-17005, ISSN 2214-7853, https://doi.org/10.1016/j.matpr.2018.04.104. Moghe, RP, Prakash, RV, Sudevan, D, and Katta Shambhayya, H. 2015, "Characterization of Resin-Injection Repair of Impact Damage in Polymer Matrix Composite.", in Proceedings of the ASME 2015 International Mechanical Engineering Congress and Exposition. Volume 1: Advances in Aerospace Technology. Houston, Texas, USA. November 13 – 19, 2015. V001T01A022. ASME. https://doi.org/10.1115/IMECE2015-50400 Pandey K N and Chand S, 2003, “ Deformation based temperature rise: a review ”, International Journal of Pressure Vessels and Piping, 80, 673. Prakash, R. V. and Sudevan, D. 2016, "Post-Impact Thermo-Mechanical Response of Woven Mat Composites Subjected to Tensile Loading” , in Proceedings of the ASME 2016 International Mechanical Engineering Congress and Exposition. Volume 14: Emerging Technologies; Materials: Genetics to Structures; Safety Engineering and Risk Analysis. Phoenix, Arizona, USA. November 11 – 17, 2016. V014T11A003. ASME. https://doi.org/10.1115/IMECE2016-66343 Prakash, Raghu; John, Mathew; Sudevan, Deepika; Gianneo, Andrea and Carboni, Michele, “ Fatigue Studies on Impacted and Unimpacted CFRP Laminates ”, in Fatigue and Fracture Test Planning, Test Data Acquisitions and Analysis, ASTM STP 1598, Zhigang Wei, Kamran Nikbin, Peter C. McKeighan, and D. Gary Harlow (Eds.), ASTM International, West Conshohocken, PA, 2017, 94-118, DOI: 10.1520/STP159820160094 Prakash, RV, and Maharana, M. 2017, "Thermo-Mechanical Response of Hybrid Polymer Composites during Tensile Loading." In Proceedings of the ASME 2017 International Mechanical Engineering Congress and Exposition. Volume 14: Emerging Technologies; Materials: Genetics to Structures; Safety Engineering and Risk Analysis. Tampa, Florida, USA. November 3 – 9, 2017. V014T11A005. ASME. https://doi.org/10.1115/IMECE2017-71335 Venkatraman B, Mukhophadyay CK, Raj B (2004) Prediction of tensile failure of 316 stainless steel using infrared thermography, Exp Tech, 28:35 – 38