BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Talks.cam//talks.cam.ac.uk// X-WR-CALNAME:Talks.cam BEGIN:VEVENT SUMMARY:Acoustic Emission Data Analysis in Concrete Fatigue and Fracture: An Entropic Perspective - Nitin Burud\, University of Surrey DTSTART:20240315T150000Z DTEND:20240315T160000Z UID:TALK212443@talks.cam.ac.uk CONTACT:Sam Cocking DESCRIPTION:ABSTRACT:\n\nConcrete may appear as a boring material on a mac roscopic level. However\, the concrete fracture process exhibits an intere sting complex behaviour dominated by disorder\, long-range interactions\, and long memory in the intensified stress field ahead of the crack tip kno wn as the fracture process zone. The fracture process resulting from such complexity usually generates long-tailed distributions leading to self-org anization signifying the emergence of order from the disorder. The existen ce of self-organization also hints at a universal pattern dominated by sim ple governing rules\, regardless of system configuration. Consequently\, e ntropy can be used as a measure of disorder to quantify the randomness of the probability distributions arising from the system variable. In this st udy\, we propose cumulative distribution functions for acoustic emission f eatures derived from Tsallis' non-extensive entropy formulation. The Tsall is entropy is well-suited for modeling long-tailed distributions due to it s sensitivity to the tail behaviour. Furthermore\, the non-linearly intera cting multi-scale cracks in the fracture process zone of concrete are inse parable and the whole system cannot be divided into simple sub-systems wit hout tampering with the systemic properties\, resulting in non-additivity and non-extensivity. \n\nAn experimental investigation was conducted to ac quire acoustic emission data from the concrete fracture process. The testi ng involves three different sizes of notched plain concrete beams under th ree-point bending subjected to monotonic and fatigue loading. Two features of the AE stress wave\, amplitude (magnitude) and inter-event time appear to be correlated with crack size and crack occurrence rate respectively. Distribution functions derived using the Tsallis entropy formulation are t hen fitted to the experimental data and compared across the beam sizes and loading conditions. The pattern in the collective behavior of entropic in dices evaluated from the AE distribution is illustrated to highlight the p ossibility of self-organization. Monotonic loading controlled by crack mou th opening displacement allows stable crack growth resulting in critical A E distribution parameters that are used as a reference to track the damage evolution under sub-critical fatigue loading.\n\nKEYWORDS: Concrete\, Fra cture\, Fatigue\, Acoustic emission\, Tsallis Entropy\n\nSPEAKER BIO:\n\nD r. Nitin Burud is currently working at the University of Surrey as a post- doctoral researcher. He received a doctorate from the Indian Institute of Science\, Bangalore\, India. His research work focuses on fracture and fat igue in materials\, specializing in structural health monitoring applicati ons using statistical data analysis. He worked extensively on acoustic emi ssion techniques for understanding the fracture process in concrete-like c ementitious materials. Consequently\, his doctoral dissertation is a thema tic exploration of acoustic emission data for mechanistic as well as stati stical description\, diagnosis\, and prediction of damage evolution in con crete. Bringing a complexity perspective to understand the fracture proces s in concrete\, and the use of Tsallis entropy as a measure of the complex ity\, is a central idea of his recent research. Before joining the Univers ity of Surrey\, he shortly worked as an assistant professor at a deemed un iversity in India. At the University of Surrey\, he is investigating the f atigue behavior of a 130-year-old railway bridge through large-scale testi ng and numerical modeling. LOCATION:CivEng Seminar Room (1-33) (Civil Engineering Building) END:VEVENT END:VCALENDAR