Amrita School of Engineering, Coimbatore Campus organized a workshop on Topics in Engineering Failure Analysis in association with Society for Failure Analysis (SFA), Hyderabad. The key resource persons were from the Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam and Gas Turbine Research Establishment (GTRE), Bangalore. The high profile seminar gave an insight into the modes of failure manifest as cracking, corrosion, creep, fatigue, incipient melting, wear, deformation as well as the non-destructive testing methods available now to detect impending failure.
"Devastating catastrophes such as Chernobyl disaster and Bhopal gas tragedy were nothing but engineering failures the likes of which could be avoided today, to a certain extent, with the technology capability that we have in the study, Advance Detection and Prevention of Failures" according to eminent scientists of the Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam.
Quoting Henry Petrosky Dr. K. V. Kasiviswanathan, IGCAR, stated, “The concept of failure is central to understanding engineering, for engineering design has its first and foremost objective - the obviation of failure. To understand what engineering is and what engineers do is to understand how failures can happen and how they can contribute more than success to advance technology.”
Failure prevention is a continuous process. Projects of failure analysis could identify problems in many core industries and lead to solutions. The cause of failure in Reboiler Heat Exchanger of a fertilizer plant, for instance, was crevice corrosion between a tube and tube sheet leading to the Heat Exchanger. The study recommended tubes inside the tube sheet to be expanded to the designed length. In an Aero-Engine Turbine Blade, similarly, the cause of failure was found to be over temperature exposure due to faulty temperature indicator. The recommendation was improved protective coating. He presented many other case studies in the core sector. In failure analysis, along with tribology, deformation of solids, fracture science, corrosion science, mechanics, stress, design criteria, NDE, mechanical testing, metallography, phase transformation and alloy theory experience and intuition also counted.
Dr. S. Jalaldeen, IGCAR, spoke on Design Methodologies against Failures. Citing an example of PFBR (Prototype Fast Breeder Reactor) Reactor Assemblies, he said that deformation, plastic instability, creep, fatigue, ratcheting and buckling, vibration and fretting could happen in low temperature and elevated temperature areas.
Prevention and Control Measures against Corrosion in different situations were presented in detail by Dr. M. G. Pujar, IGCAR. "Corrosion is the deterioration of materials/ components due to interaction with the environment. Corrosion occurs in various forms in different materials depending upon conditions of environment – rusting of iron, pitting and cracking in stainless steel, patina over copper and brass surfaces, degradation of wood and plastic wall thinning in metallic pipes etc."
Dr. B. P. C. Rao, Head, Non-Destructive Evaluation (NDE) division, Metallurgy and Materials group, IGCAR, presented on Non-Destructive Evaluation (NDE) and Early Detection of Failures. “Benefits of NDE are safe and uninterrupted operation, prevention of accidents, avoidance of unplanned shutdowns and taking decision on repair, upgradation, modernization and replacement of components for overall life extension,” Dr. Rao explained. "More than 50 NDE techniques based on physical principles and every form of energy – like magnetic particle, flux leakage, liquid penetrant, visual, optical and laser analysis, infrared thermography, radiography, eddy current and ultrasound testing, acoustic emission testing etc- are available today. NDE enables detection and location of flaws such as fatigue cracks, brittle cracks due to stress corrosion cracking or environmental stress cracking etc. it averts catastrophic failures of components ensuring safety, plant availability and profit.”
Dr. P. Parameswaran, Programme Leader, Structure-Property Correlations, MSSCD, Physical Metallurgy Group, IGCAR, spoke on Mettallography and Micro Mechanisms. “Understanding the micro-structural degradation has become essential and systematic structure-property correlations are carried out on chosen materials for engineering applications,” he shared. He explained in detail the possible hazards from changes in micro-mechanisms and the preventive steps that can be taken in power plants. He said that failures of microstructure of materials, as they change due to their components – atoms, ions and molecules built-in well defined, structural arrangements in space, had to be studied. Early failure of components occurs due to unexpected service load, defect from processing, local changes in the composition during high temperature service, varied microstructure changes in properties, welded joints, elevated temperatures, stress and corrosive media. This often results in catastrophic and unsafe incidents.
Dr. V. S. Srinivasan, Mechanical Metallurgy Division, IGCAR spoke on High Temperature Failure Modes with specific reference to Prototype Fast Breeder Reactor (PFBR) and factors like Creep and Life Prediction, Fatigue, Creep-Fatigue Interaction, High Temperature Fracture Mechanics, and Atomistic Simulations of Mechanical Behavior.
Dr. Swati Biswas, Gas Turbine Research Establishment (GTRE), Bangalore, spoke on Failures in Aeroengine components.
The seminar was attended by experts, chief academicians and research scholars from engineering colleges, scientists and engineers from R & D organizations and industries.