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Hyderabad, India

Sarkar A.K.,DRDL | Padhi R.,Indian Institute of Science
Proceedings of the IEEE International Conference on Control Applications | Year: 2013

Three-dimensional impact angle constrained air-to-air missile guidance problem with third order autopilot in loop is investigated using model predictive static programming (MPSP). MPSP is inspired from the model predictive control and approximate dynamic programming philosophies. It inherently minimizes control (lateral acceleration) demand throughout the trajectory in addition to meeting the terminal hard constraint. Two different formulations are explored in this study. In one case MPSP is kept blind about existence of autopilot, where as in other case autopilot dynamics is incorporated explicitly in MPSP problem formulation. Terminal impact angle constraint along with required miss distance are posed as hard terminal constraint in the problem definition itself. It is observed from the extensive simulation studies that the proposed scheme performs better as compared to the classical proportional navigation guidance for intercepting moving and maneuvering targets in the air. © 2013 IEEE. Source

Chakrabarti A.K.,DRDL
2010 2nd International Conference on Reliability, Safety and Hazard, ICRESH-2010: Risk-Based Technology and Physics-of-Failure Methods | Year: 2010

To produce an item defect-free has been a challenge in engineering industry. Well-established statistical methods are available to estimate the reliability of the product, but such methods are mostly applicable when a large data base is available. Attempts have been made through various logical means to design and produce a component with high reliability. Identifying the critical parameters and essentially their inter-connectivity are major issues to ensure reliability. A concept christened as Bird's Nest is evolved to bring out all issues of design, manufacturing, marketing etc. in a single frame. Availability of such information in the beginning of a development process helps in a big way to achieve defect free and safe system. © 2010 IEEE. Source

Sanjay Anandrao K.,Advanced Systems Laboratory | Gupta R.K.,Advanced Systems Laboratory | Ramchandran P.,DRDL
Structural Engineering and Mechanics | Year: 2012

Large amplitude free vibration and thermal post-buckling of shear flexible Functionally Graded Material (FGM) beams is studied using finite element formulation based on first order Timoshenko beam theory. Classical boundary conditions are considered. The ends are assumed to be axially immovable. The von-Karman type strain-displacement relations are used to account for geometric non-linearity. For all the boundary conditions considered, hardening type of non-linearity is observed. For large amplitude vibration of FGM beams, a comprehensive study has been carried out with various lengths to height ratios, maximum lateral amplitude to radius of gyration ratios, volume fraction exponents and boundary conditions. It is observed that, for FGM beams, the non-linear frequencies are dependent on the sign of the vibration amplitudes. For thermal post-buckling of FGM beams, the effect of shear flexibility on the structural response is discussed in detail for different volume fraction exponents, length to height ratios and boundary conditions. The effect of shear flexibility is observed to be predominant for clamped beam as compared to simply supported beam. Source

Jain P.C.,DRDL | Mukherjee A.,Thapar University | Krishna Y.,DRDL
Aerospace Science and Technology | Year: 2011

In this study, response of a flight vehicle component to rocket noise is considered. Tuned mass dampers, hitherto used in low frequency excitation, have been utilized to attenuate high frequency, broad band excitations. Modally tuned dampers have been investigated for a variety of input excitations. Modal dampers exhibit significant attenuation of all input signals. © 2010 Elsevier Masson SAS. Source

Sudhirsastry Y.B.,Institute of Aeronautical Engineering | Krishna Y.,DRDL | Budarapu P.R.,Bauhaus University Weimar
Computational Materials Science | Year: 2015

The lateral buckling analysis of cold-formed thin walled beams subjected to pure bending moments has been performed. The critical buckling loads are estimated based an optimization criteria. The estimated critical buckling stresses are compared with the published results, they show excellent agreement. The effect of the beam length, radius and thickness of the flanges and the length of the extended open flanges, on the critical buckling stresses have been studied for several combinations of the geometric parameters of the beam. Among the three beams, the critical buckling moments for the beam with the extended open flanges are found to be the maximum. However, considering the material and manufacturing costs, beams with rounded cross section are efficient in resisting the buckling loads. © 2014 Elsevier B.V. Source

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