Dr. Akshaya Gomathi K has won the “ASTRA 2023 Title, Asia’s Young Researcher Award for her specialization in, Civil (Structural) Engineering”. She has done her Bachelor of Engineering, B.E., in Civil Engineering, from Thiagarajar College of Engineering, Madurai, India, 2018. She has obtained both Master of Technology (M.Tech.) and Ph.D. degrees in Structural Engineering Specialization from Indian Institute of Technology (IIT) Hyderabad and was the topper of the class with a 9.19 CGPA in 2023. She has also received Defense Research and Development Organization (DRDO) funded project support for the M.Tech program and MHRD Scholarship for Ph.D. program. She completed her dual degree (M.Tech. and Ph.D.) within 4 years, so was awarded the Institute post-doc fellowship for 6 months as a reward for completing within the stipulated time. This shows her enthusiasm to work on the research topic and her problem-solving ability. She has worked passionately on her research topic and has 7 journals, 3 book chapters and has presented at 5 other conferences during her PhD duration. Her research work has been published in the International Journal of Impact Engineering, the International Journal of Structural Stability and Dynamics and Theoretical and Applied Fracture Mechanics which are considered top journals in the Civil and Mechanics department domain. She has a total citation of 63 as of April 2023.
Her research areas are the Strain rate-dependent damage model, Plasticity-based damage model, Dynamic behaviour of concrete, Blast and impact mechanics, High strain rate analysis, Split Hopkinson Pressure Bar and Shock tube.
The strain rate-dependent model for concrete under dynamic loading has been developed for a century now. But the understanding of the physics of the concrete under multi-axial dynamic loading conditions is far from complete. The objective of her study is to develop the pressure and strain rate-dependent plasticity-based damage model for concrete. The behaviour of concrete under quasi-static and dynamic conditions is different. The developed rate-sensitive damage model incorporates the key experimental evidence related to strain rate and damage rate. With increasing strain rates, the model is able to predict a decrease in the rate of damage evolution due to artificial stiffening effects together with a final higher level of damage. The major contribution of the work is to include the effect of damage rate, and strain rate and also to consider all the physical mechanisms of damage. This is achieved by using a power law model to relate the rate of damage to the equivalent plastic strain rate. The damage parameter considers hydrostatic, tension and compression damage. Such a damage definition helps in the prediction of pulverized damage due to a loss in cohesive strength at increased hydrostatic stress, shear-induced compressive damage and tensile microcracking. A strain rate-dependent failure surface is considered and with increasing strain rate there is an increase in the size of the failure surface which is
capped at an upper limiting value. The incremental effective stress-strain relationship is defined in terms of rate of damage, accumulated damage and viscosity parameters reflecting the inherent inertial, thermal and viscous mechanisms respectively. The stress-strain relationship in the model also accounts for stress reversals that occur due to interference of an incident and reflected wave, by including a Heaviside function. The developed model is implemented in LS-DYNA using vectorized User Material (UMAT). Verification, validation and parameterization of the developed model have been made through several numerical analyses. The application of the model is to understand the blast, impact and combined impact and blast analysis of concrete structure.