InSIS Webinar Series (28)The effect of stiffener size and position on fracture parameter and remaining life & residual strength of stiffened panels under fatigue loading

Abstract:

Abstract:

In most of the industrial structures, the strength of structural components is generally improved by providing stiffening members such as stiffeners or stringers. The main function of a stiffener is to improve the strength and stability of the structure and to slow down or arrest the growth of cracks in the panel. Remaining life prediction of the cracked structural components in these structures is necessary for their in-service inspection, planning, repair, retrofitting, rehabilitation, requalification and health monitoring. In view of these, it is essential to use the damage tolerant design concepts for designing structural components. Practically for all the high strength materials employed in the construction of above structures/components, damage tolerant analysis can be performed using linear elastic fracture mechanics (LEFM) principles, in which case, stress intensity factor (SIF) is the influencing design parameter. In general, it is difficult to quantify SIF for most of the practical applications.

Fracture analysis and remaining life& residual strength prediction has been carried out for aluminium alloy and steel plate panels with concentric stiffener by varying sizes and positions under fatigue loading. Tension coupon tests and compact tension tests on 2014A have been carried out to evaluate mechanical properties and crack growth constants. Domain integral technique has been used to compute the Stress intensity factor (SIF) for various cases. Generalized empirical expressions for SIF have been derived for various positions of stiffener and size. From the study, it can be concluded that the remaining life and residual strength may vary significantly depending on position, type and size of the stiffener.

Bio-data of the speaker:

Dr. Ramachandra Murthy, currently serving as Chief Scientist and Head of the Fatigue and Fracture Laboratory of CSIR-Structural Engineering Research Centre (CSIR-SERC) , Chennai obtained his PhD in Structural Engineering from the Indian Institute of Science, Bangalore. He has 26 years of experience as a Scientist apart from a few years of teaching experience prior to his Scientist Career. He is also serving as a Professor in the Academy of Scientific and Industrial Research (AcSIR) of CSIR, an Institute of National importance. He is an active researcher in the domain and has received several awards and accolades. His research interests are: Fatigue and Fracture of concrete and metals, Repair and retrofitting of concrete members, Computational Mechanics, Advanced statistical models.

Organized by:

InSIS and Center for Structural Integrity of Safety Critical Systems, IIT Madras