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Design Approach for FPGA based High Bandwidth Fibre Channel Analyser for Aerospace Application
No full textFibre Channel (FC) data transmission protocols are widely used as an interconnecting protocol to cater for the requirement of high-speed data transmission. FC has unique features like high bandwidth, strong anti-interference, flexible topology, distance insensitiveness and low latency. The highspeed, high reliability and low latency of FC communication protocol offers a promising solution for communication protocol in avionics environment. The video / data transmission system performance being critical in aerospace applications, verifying the data flow in the network is vital in order to prevent Hazardous Misleading Information being displayed to the pilot and endangering safety of flight. This paper puts forth a design approach for a receiver module of a Field Programmable Gate Array (FPGA) based high bandwidth Fiber Channel Analyser (FCA). The proposed design is to be implemented using Xilinx Spartan-6 FPGA SP605 evaluation board. The receiver module design addresses the requirements of transmission of soft real time video with resolution (VGA) and link speed with the incorporation of ethernet interface. The concept of developing a high bandwidth FCA for enhanced speed and quality of data, audio and video transmission in avionics system is critical and need of the hour. The outcome of such an effort can be utilized for multiple aerospace applications
Optically controlled polarization, photovoltaic and switchable diode behavior in multifunctional KBiFe2O5 composite film
No full textThis paper presents a light-induced diode effect in connection with the polarization direction and enhanced remanent polarization in polymer composite of the well-known multiferroic KBiFe2O5 film. Composite films of KBiFe2O5 with different PVA ratios were prepared by spin coating of ceramic slurry and the best composition with PVA was selected on the basis of its suitability for visible light absorption. KBiFe2O5-PVA composite film showed enhanced photovoltaic response under visible-light exposure with open circuit voltage of 2.11 V, photocurrent density of −8.3 × 10−5 A/cm2 and efficiency of 0.076%. The observed diode-like behavior in the composite film switched its direction with the flipping of electric polarization by an external voltage. The enhanced ferroelectric properties in the film were due to the reduction in leakage owing to the presence of non-conductive polymer in it. The composite film exhibited a piezoelectric coefficient of 1.98 nm/V and 2.2 nm/V corresponding to 15 V and −15 V respectively
Results and discussion
No full textIt is noted from the literature that though the servo valve system nonlinear is often and satisfactorily modelled as a linear system
Matrix cracking in polymer matrix composites under bi-axial loading
No full textA model to predict the matrix crack evolution in a continuous fiber polymer composite laminate under in-plane bi-axial static loading has been presented in the current work. Oblique co-ordinate based shear lag analysis was used to estimate the stress distribution inside the cracked [0/90] s cross-ply T300/934 carbon fiber reinforced plastic (CFRP) laminate. Weibull probability distribution has been used to account for the variation in ply transverse strength. Size-dependent strength due to variation in ply thickness has been accounted for by appropriate volume scaling based
Weibull scale factor. The Weibull parameters have been estimated using a ‘master laminate’ crack evolution data.
By applying incremental stress to the laminate, using the probabilistic variation of transverse strength and the stress at a material point, the new crack location has been identified using the Hashin matrix cracking criterion. The
reciprocal of the normal distance between two cracks has been termed as crack density. The crack density evolution
for cross-ply laminates with an increase in applied loading has been estimated for various bi-axial ratios and
compared with the data available from the literature. A good correlation is found to exist between the literature
evolution data and current simulation predictions.
Keywords: Matrix cracking; Bi-axial loading; Weibull strength
* Corresponding author. Tel.: +91-80-25086316; fax: +91-80-25086301
E-mail address: [email protected]
2 Jagannathan et al./ Structural Integrity Procedia 00 (2018) 000–000
1. Introduction
The use of polymer matrix composites (PMCs) in structural airframes as compared to conventional aluminum
alloys has been increasing steadily; today 50% by weight of the new Boeing 787 airframe is made from PMCs. The
first indigenous Indian light combat aircraft (LCA) uses PMCs for more than 40% of its weight. Aircraft structures
undergo time-varying structural loads during their operation and are subject to environmental degradation and
external damage threats like impact, runway debris, hailstorm, etc. These events can cause initiation as early as the
first cycle and evolution of multi-scale structural degradation steadily with loading due to their inherent
inhomogeneous and distinctly anisotropic nature. The commonly observed damages are matrix cracking, interfacial
fiber-matrix de-bonding, fiber breaks, delamination, fiber micro-buckling, etc., under static and fatigue loading,
Berthelot (2003), Harris (2003). Matrix cracking happens to be the most dominant mode of damage to first appear in
a laminate. Matrix cracking generally leads to loss of stiffness, local stress redistribution and most importantly, a
path for moisture or other fluid ingression leading to further reduction in composite strength or loss of its integrity,
Talreja and Singh (2012). Experimental investigation of matrix cracking and its effects on composite materials have
been extensively reported and reviews on such findings are available in the literature, Berthelot (2003), Talreja and
Singh (2012). Following matrix crack saturation, also referred to as ‘characteristic damage state’, delamination is
observed to initiate at the matrix crack tips, growing slowly and steadily. Fiber breaking is also observed at all the
above stages. At the final stages of life, linking up delamination, the complex interaction of matrix cracks and fiber
breaking is observed leading to the final failure of the laminate. The damages are randomly distributed across
various length scales and locations; oriented in different directions, Highsmith and Reifsnider (1982), Reifsnider and
Jamison (1982).
Energy based models have been successfully used to predict the matrix crack initiation and evolution, Singh
(2008). Energy-based models utilize the critical energy released during new matrix crack formation as a parameter to
predict the matrix cracking, Nairn (2000). Various stress analysis methods have been developed to estimate the
stresses or energy in the cracked laminate, Talreja and Singh (2012). In strength-based models, as the local stresses
reach the strength at a point, a new matrix crack is assumed to initiate. Strength-based models fail to predict the
crack initiation when deterministic single strength obtained from the uni-directional (UD) laminate experiments are
used. However, successful prediction of matrix cracking behavior has been reported if statistical strength distribution
is considered Jagannathan et al. (2016); studies have shown that the matrix cracks initiate at locations of largest
voids created during the manufacturing process and the matrix crack evolution rate can be correlated to the statistical
variation of flaws, Nairn (2000), Berthelot (2003), Talreja and Singh (2012). Cross-ply laminates matrix cracking
has been extensively studied and reported in the literature, Berthelot (2003). Various models have been used to
predict the stiffness of the cracked laminate as a function of crack density estimated using the above approaches. In
the simplest model termed ply-discount method, the stiffness of cracked ply is assumed zero and discounted while
estimating the stiffness of the laminate. An extensive review of different models can be found in the literature by
Talreja and Singh (2012).
In most practical applications, a multi-axial loading scenario exists. Most of the models developed in the literature
are limited to uni-axial loading condition and have not addressed matrix cracking under bi-axial loading. It has been
reported that when a cross-ply laminate is subjected to in-plane bi-axial loading, splitting in 0o ply occurs in addition
to matrix cracking in the 90o ply by Montesano and Singh (2015). In particular, such bi-axial loading conditions are
expected to occur under thermal loading of composite cylindrical shells. There have been limited studies to account
for cross-ply laminates under bi-axial loading conditions by Spain (1971), Adams et al. (1986), Maddocks (1995),
Montesano and Singh (2015). All the models developed have used some form of energy parameter to predict the
matrix cracking in the cross-ply laminate. In this work, an attempt has been made to predict the matrix cracking in
cross-ply laminates using statistical strength-based approach under bi-axial loading condition
Study of Different Modelling Techniques of SMA Actuator and Their Validation Through Simulation
No full textWith the increased emphasis on both reliability and functionality, shape memory alloys (SMAs) are fast becoming an enabling technology capturing the attention of engineers and scientists worldwide. The thermal-electrical-mechanical dynamics of SMA are nonlinear and hysteretic in nature, possessing a problem for the researchers to model the actuator. The increased range of applications and better realisation of SMA actuators have led to the research on modelling of SMA’s thermo-mechanical response. The paper discusses various SMA actuator modelling approaches such as Preisach model, Fermi–Dirac statistics, Duhem hysteresis model and Brinson model and attempts to elucidate their advantages and limitations through Simulink-based models and simulation results
Development and Integration of Graphical User Interface (GUI) with JUNGO Device Drivers for PCI Express Interface
No full textHigh-bandwidth Video Bus is a video interface protocol defined for high bandwidth, low latency, and uncompressed digital video transmission in avionics systems. This protocol is used for interfacing aircraft system(s) into the cockpit display. Current day technology realizes the systems or Line Replaceable Units (LRU) using Field-Programmable Gate Array (FPGA) based Intellectual Property (IP) Cores for communication between two systems. However, these communication protocols are realized using FPGA and as part of development, the Peripheral Component Interconnect (PCI) express based FPGA embedded modules are used for realization. These embedded modules will be interfaced to the host computers to transmit the data as similar to the communication on aircraft for real LRU. Hence host computers need to be integrated with required GUI application which shall communicate with PCI express bus connecting the FPGA based embedded module. This paper describes the development of the GUI application program for PCI express data simulator using device drivers generated by JUNGO (WinDriver) tool for memory read/write transaction(s). The paper also presents the integration, testing and data transfer for discrete and continuous data over PCI express from the host machine to the embedded FPGA-based modul
Grey literature archiving pattern in open access (OA) repositories with special emphasis on Indian OA repositories
No full textPurpose: This paper aims to examine the grey literature archiving pattern at open-access repositories with special reference to Indian open-access repositories.
Design/methodology/approach: The Bielefeld Academic Search Engine (BASE) was used to collect data from different document types archived by open-access repositories across the world. Data were collected by advanced search and browse features available at the BASE on document types, the number of repositories by country wise and Indian academic and research repositories. Data were tabulated using MS Excel for further analysis. Findings: Findings indicated that open-access repositories across the world are primarily archiving reviewed literature. Grey literature is archived more at European and North American repositories compared to rest of the world. Reports, theses, dissertations and data sets are the major grey document types archived. In India, a significant contributor to the BASE index with 146 open-access sources, reviewed literature is the largest archived document types, and grey literature is above world average due to the presence of theses and dissertations at repositories of academic institutions. Originality/value: Grey literature is considered as valuable sources of information for research and development. The study enables to get insights about the amount of grey content archived at open-access repositories. These findings can further be used to investigate the reasons/technology limitations for the lesser volume of grey content in repositories. Furthermore, this study helps to better understand the grey literature archiving pattern and need for corrective measures based on the success stories of repositories of Europe and North America
Limitations of Flight Path Reconstruction techniques
No full textThe Flight Path Reconstruction (FPR) techniques are performed to verify the data compatibility check and post-flight. This is often achieved by calibrating the onboard sensors such as inertial and airdata sensors. In this paper, the limitations of FPR techniques in terms of
Maximum Likelihood Estimation (MLE) and Extended Kalman Filter (EKF) and Unscented Kalman Filter (UKF) have been reported. To demonstrate the FPR and sensor calibration, kinematic trajectory simulations with wind box type maneuvers have been performed. It is also shown as how a kinematic simulation is valid for the studies carried out in this work
Performance Evaluation of Interleaved Concept for Non-Isolated Converter Topology
No full textDC-DC converter are the electronics devices that
converts the available voltage level into required voltage level.
There are different DC-DC converter topologies. The suitable
converter topology is selected based on the accuracy, efficiency
and ripple content. In this paper, a novel interleaved BuckBoost KY (K.I.HWU, Y.T.YAU) topology has been proposed.
In order to evaluate the proposed converter performance,
converters such as Buck converter, Boost converter, BuckBoost converter, Buck-Boost KY converter and the ripple
reduction using interleaved techniques are designed. The
design and analysis of all these converts are carried out using
MATLAB/Simulink Platform. The performance analysis of all
these converters have been carried out and results are
compared. The proposed converter having above 95% of
efficiency is comparable with other converters. The output
current ripple in the proposed converter is less than 10mA for
Buck mode and less than 5mA for Boost mode. The output
voltage ripple is less than 60mV for Buck Mode and 80mV for
Boost mode which are very less compared to other converter
Nanolayered multilayer Ti/TiN coatings: Role of bi-layer thickness and annealing on solid particle erosion behavior at elevated temperature
No full textSolid particle erosion is a very serious and inevitable issue faced by key components of modern machinery in various applications such as compressor blades and vanes of turbine engines, and turbine blades of advanced aircraft engines. In this direction third generation Ti/TiN nanolayered multilayered erosion resistant coatings were developed using sputtering technique. Films of around 7–10 μm total thickness with bi-layer thicknesses from 7.5–115 nm were deposited. Structural and mechanical properties such as hardness, toughness and stress of the films were studied, and correlated with the bi-layer thickness and deposition conditions. Erosion test was carried out according to ASTM G76-13 standard parameters at 30, 45, 60, and 90° impinging angles. Since the compressor blades of the gas turbine engines usually operate at 100 to 550 °C, the erosion tests were conducted at 400 °C. Films with lower bi-layer thickness showed better erosion resistance in comparison with higher bi-layer thickness films. Further, effect of bi-layer thickness, annealing and internal stress of the films on erosion resistance performance is studied. Detailed studies revealed that the optimized coating exhibited an improvement in the erosion performance by a factor of 15 compared to Ti6Al4V substrate