| || Auto-video Tracking System: Performance Evaluati
Author : Chauhan, B.S.;Singh, Manvendra;Sharma, V.K.;Pandey, P.C.
Source : Defence Science Journal ; Vol:58(4) ; 2008 ; pp 565-572
Subject : 621.38 Electronics
Keywords : Automatic target tracking;Auto-video tracking system;Tracker system evaluation;Target-tracking algorithms
Abstract : Automatic target tracking systems are employed in a wide variety of missions and tracking environment such as fire control, guidance, navigation, passive range estimation, and automatic target discrimination. The tracker performance depends upon target size, contrast, speed, and signal-to-noise ratio. The evaluation of a tracker system involves lengthy field trials and measurements. In the present article, a method for quick evaluation of tracker system and working out selection criteria for different tracking algorithm for various target and background combinations have been suggested. Performance measures such as aiming point error, duration of successful tracking, number of tracking losses, indication of confidence, and system reaction time have been used to evaluate the performance of a tracking system.
| || Adhesively-bonded Patch Repair with Composites
Author : Pandey, P.C.;Kumar, S.
Source : Defence Science Journal ; Vol:60(3) ; 2010 ; pp 320-329
Subject : 62 Engineering;Defence Science Journal
Keywords : Three-dimensional finite elements;adhesively-bonded composite-patch repair;structure life extension;geometric and material nonlinearity
Abstract : Adhesively-bonded composite patch repairs over cracked or corrosion-damaged metallic aircraft structures have shown great promise for extending life of ageing structures. This study presents the numerical investigation into the interface behaviour of adhesively-bonded cracked aluminum alloy substrate patched with fibre-reinforced composite material. The adhesive is modelled as an elasto-plastic bilinear material to characterise the debond behaviour, while the defective substrate is regarded as linear elastic continuum. Two typical patch shapes were selected based on information available in the literature. Geometric and material nonlinear analyses for square and octagonal patches were performed to capture peel and shear stresses developed between the substrate and the patch to examine the possibility of interface delamination/debonding. Parametric studies on adhesive thickness and patch thickness were carried out to predict their infuence on damage tolerance of repaired structures.