Defence Research and Development Laboratory

About: Defence Research and Development Laboratory is a facility organization based out in Hyderabad, India. It is known for research contribution in the topics: Mach number & Turbulence. The organization has 404 authors who have published 420 publications receiving 4183 citations. The organization is also known as: DRDL.

Adaptive Estimation of Line-of-sight Rate Measurement from a Radio Frequency Seeker

Abstract: The line-of-sight (LOS) rate output from a radio frequency (RF) seeker is widely used during the homing phase guidance of a tactical missile: The LOS rate is noisy and needs to be filtered. The application of an adaptive Kalman filter for the L.OS rate state estimation has been studied. This filter requires minimal a priori knowledge about technical parameters of the seeker. It is also capable of estimating the variable noise statistics.

Modal Analysis of Monolithic and Jointed Type Cantilever Beams with Non-Uniform Section

Abstract: Modal analysis of non-uniform bolted structures are of significance in modeling many complex mechanical structures. There are vast literatures available related with the analytical as well as numerical modeling of bolted joint. However, most of the analytical model discuss about the modeling of first mode of uniform structures with single bolted joint. In this paper, we present the modeling of single as well as bolted non-uniform beams using approximate mode shapes. To develop the model, we first carry out experiments to measures the modal frequencies and shapes of the test structures. Subsequently, we also do numerical modeling of non-uniform beams in ANSYS to verify the validity of the Euler-Bernoulli beam theory in developing the analytical models. Finally, using the Euler-Bernoulli beam theory, we obtain the analytical values of frequencies using the approximate the mode shapes. The analytical results are found to be closer to the experimental results with a maximum percentage error of about 15 %. The model presented in the paper can be extended to the mechanical structures with many non-uniform sections with or without bolted joints.

Mechanism of thermal decomposition of double base propellants

Abstract: Thermogravimetric studies were carried out with double-base propellants to find the rate-detg. stage and to understand the mechanism. The decompn. process can be divided into 3 stages as follows: diffusion of nitroglycerin [55-63-0] takes place at 120-160. Two processes occur at 170-205, namely the dissocn. of nitroglycerin and the cleavage of the C-O bond, the later being the rate-detg. step. The cleavage of the $C-O$ bond is followed by a considerable decompn. of nitrocellulose [9004-70-0].