Shailendra Kumar – författare

Cementitious materials, rocks and fibre-reinforced composites commonly termed as quasibrittle, need a different fracture mechanics approach to model the crack propagation study because of the presence of significant size of fracture process zone ahead of the crack-tip. Recent studies show that concrete structures manifest three important stages in fracture process: crack initiation, stable crack propagation and unstable fracture or failure. Fracture Mechanics concept can better explain the above various stages including the concepts of ductility, size-effect, strain softening and post-cracking behavior of concrete and concrete structures. 

The book presents a basic introduction on the various nonlinear concrete fracture models considering the respective fracture parameters. To this end, a thorough state-of-the-art review on various aspects of the material behavior and development of different concrete fracture models is presented. The development of cohesive crack model for standard test geometries using commonly used softening functions is shown and extensive studies on the behavior of cohesive crack fracture parameters are also carried out. The subsequent chapter contains the extensive study on the double-K and double-G fracture parameters in which some recent developments on the related fracture parameters are illustrated including introduction of weight function method to Double-K Fracture Model and formulization of size-effect behavior of the double-K fracture parameters. The application of weight function approach for determining of theKR-curve associated with cohesive stress distribution in the fracture process zone is also presented. Available test data are used to validate the new approach. Further, effect of specimen geometry, loading condition, size-effect and softening function on various fracture parameters is investigated. Towards the end, a comparative study between different fracture parameters obtained from various models is presented.

This book contains select proceedings of EPREC-2021 with a focus on power electronics and drives. The book includes original research and case studies that present recent developments in power electronics focusing on power inverters and converters. The book also consists of research work on electrical drives, regulated power supplies, operation of FACTS & HVDC, etc. The book will be a valuable reference guide for beginners, researchers, and professionals interested in the advancements of power electronics and drives.

This book presents select proceedings of the Electric Power and Renewable Energy Conference 2022 (EPREC-2022). It provides rigorous discussions, case studies, and recent developments in the emerging areas of power electronics, especially power inverters and converter, electrical drives, regulated power supplies, operation of FACTS and HVDC, etc. The readers would be benefited from enhancing their knowledge and skills in these domain areas. The book is a valuable reference for beginners, researchers, and professionals interested in advancements in power electronics and drives.

This book presents novel idea and concepts developed by the researchers/academia and practicing engineers working in the domain of the power sector infrastructures where power electronics infrastructures are used for improving the system reliability and efficiency in on-grid and off-grid systems. The infrastructures of distributed power generation based on wind, solar, hydro and many other renewable energy sources have increased manifold since last decade due to availability of efficient power converters and small rating generators. The application of power electronics switching devices has made job much easier to make such system infrastructures more reliable and controllable. The power quality (PQ) issues in infrastructures of distributed power generation system are a major concern for customers. The custom power devices such as voltage source converter are used to mitigate the PQ and other issues such as voltage and frequency control under different loading conditions on the supply system. The operation of these custom power devices or other power converters is dependent on the duty cycles generated by control algorithm. The scope of control algorithm may be varying from model predictive control techniques, machine learning techniques to other artificial intelligence-based techniques. In addition to it, some classical control algorithm and adaptive-type control algorithm may also be used for power converter operation. This book creates awareness among teachers, research students and industry persons about better utilization of infrastructures of distributed power generation system by making it more efficient with the use of power electronics and its control.

The book presents the select proceedings of National Conference on Recent Advances in Structural Engineering (NCRASE 2020). Various topics covered in this book include advanced structural materials, computational methods of structures, earthquake resistant analysis and design, analysis and design of structures against wind loads, pre-stressed concrete structures, bridge engineering, experimental methods and techniques of structures, offshore structures, composite structures, smart materials and structures, port and harbor structures, structural dynamics, high rise structures, sustainable materials in the construction technology, advanced structural analysis, extreme loads on structures, innovative structures, and special structures. The book will be useful for researchers and professional working in the field of structural engineering.