National Aerospace Laboratories

About: National Aerospace Laboratories is a facility organization based out in Bengaluru, India. It is known for research contribution in the topics: Coating & Corrosion. The organization has 1838 authors who have published 2349 publications receiving 36888 citations.

Repair Effectiveness Studies on Impact Damaged Sandwich Composite Constructions

Abstract: Experimental studies were carried out using sandwich composite panel specimens, consisting of both polyurethane foam core (PUF) and aramid honeycomb core (Nomex) type constructions. These specimens were subjected to impact damage at energy levels ranging between 7.56 and 15.6J. A ply-drop-patching technique was employed to repair the impact damaged sandwich specimens. The undamaged (virgin), impact damaged, and repaired specimens were then subjected to flexural (four point bending) and edgewise compression tests and strength recoveries were measured to determine the efficiency of the repair technique employed. In flexure, strength recoveries of upto 97% in PUF core and 90% in honeycomb core sandwich specimens were realized after repair, whereeas in compression, the corresponding values were upto 9O% in PUF core and 88% in honeycomb core sandwich specimens. A repair effectiveness factor(Ref)has been conceived and introduced to quantify the efficiency of the repair technique. Further, the repair quality was assessed using a simple NDT method prior to subjecting the sandwich specimens for destructive tests.

Reactive hot pressing of ZrB2–ZrCx ultra-high temperature ceramic composites with the addition of SiC particulate

Abstract: Starting with non-stoichiometric Zr-B 4 C powder mixture ZrB 2 -ZrC matrix composites with SiC particulate addition have been made It was found that variable amounts (5-25 vol%) of SiC could be incorporated and reactively hot pressed (RHPed) to relative densities of 97-99% at 1400-1500 °C This technique has the potential to fabricate ZrB 2 -based matrices at low temperatures with a variety of reinforcements whose composition and volume fraction are not limited by stoichiometric considerations The hardness of the composites is in the range of 17-22 GPa

Detection of Runway and Obstacles using Electro-optical and Infrared Sensors before Landing

Abstract: For safe aircraft operations, detection of runway incursions especially during landing and takeoff is essential And it is important that such detection technique is capable of detecting the distant objects so that pilot has enough response time to take corrective action This paper presents techniques to detect runway and runway incursions using electro-optical color camera and medium wave infrared sensor on-board the aircraft during approach for landing The detection process consists of horizon detection to reduce runway search space in sensor image and then detect runway and obstacles The information is then presented to the pilot to improve pilot situational awareness The performance of the proposed techniques are evaluated in flight simulators with simulated images of electro-optical and infrared sensors on-board the aircraft during approach for landing at a distance of 3 nautical miles from runway threshold during day/night and in low visibility CAT II foggy conditions Effectiveness of the techniques with statistics of runway detection, miss detection and false alarm for different case studies have been provided and discussed