Implementing Immersive Virtual Reality in an Aviation/Aerospace Teaching and Learning Paradigm

The ubiquity of computing technology has revolutionized the workplace and has also had a significant impact on education. The use of interactive simulations based on virtual reality (VR), augmented reality (AR), and mixed reality (MR) has gained wide acceptance and become a prominent mechanism for learning to occur. Interactive simulations may afford unique learning advantages revealed as effective knowledge retention and skill transfer when information is presented using multi-modal sensory approach. The goal of VR is to create an environment that mimics real world complexities; one that offers comparable stimuli in the virtual environment (VE) to elicit cognitive and psychomotor behavior in the learner, similar to those elicited when performing the same function in the live-task environment. To be effective, practitioners must understand the fundamental elements of cognition and knowledge construction. VE designs must be grounded in theoretical learning constructs to accentuate the cognitive learning process. As part of a cooperative research project within the College of Aviation at Embry-Riddle Aeronautical University, Daytona Beach, Florida, we present our research in developing a highly-immersive, state-of-the-art VR laboratory to train students on complex flight aviation and maintenance related tasks. Development for VR applications is underway as a proof of concept test bed. The lab also supports an F/A-18 Hornet VR part-task trainer that simulates the aerial refueling process; a Head Mounted Display (HMD) enhances fidelity and training realism. Spaceflight Operations students regularly utilize a VR experience of the International Space Station (ISS), Mission ISS, to explore spaceflight concepts often reserved for astronauts

An Investigation into the Effect of the Shell on SALM Processed Parts

Shell Assisted Layer Manufacturing (SALM) is a novel process for rapid prototyping/ tooling/ manufacture (RP/RT/RM) which is presently undergoing feasibility studies. SALM is based on layered manufacturing technology (LMT). Initially it develops the shell (boundaries) of a selected layer using a technique similar to fused deposition modelling (FDM). The developed shell is filled with a UV curable resin and is exposed to UV radiation for curing. This procedure is repeated until the complete part is built. This paper compares and contrasts properties of parts made using two options available with the SALM technique: building the part using a soluble shell (FDM support structure material, finally dissolved to recover the part); or using a polymer material such as ABS that is bonded with the resin whilst making the part.Mechanical Engineerin

Hybrid-aligned nematic liquid-crystal modulators fabricated on VLSI circuits

A new method for fabricating analog light modulators on VLSI devices is described. The process is fully compatible with devices fabricated by commercial VLSI foundries, and the assembly of the modulator structures requires a small number of simple processing steps. The modulators are capable of analog amplitude or phase modulation and can operate at video rates and at low voltages (2.2 V). The modulation mechanism and the process yielding the modulator structures are described. Experimental data are presented

A Review of Structural Health Monitoring Techniques as Applied to Composite Structures.

Structural Health Monitoring (SHM) is the process of collecting, interpreting, and analysing data from structures in order to determine its health status and the remaining life span. Composite materials have been extensively use in recent years in several industries with the aim at reducing the total weight of structures while improving their mechanical properties. However, composite materials are prone to develop damage when subjected to low to medium impacts (ie 1 – 10 m/s and 11 – 30 m/s respectively). Hence, the need to use SHM techniques to detect damage at the incipient initiation in composite materials is of high importance. Despite the availability of several SHM methods for the damage identification in composite structures, no single technique has proven suitable for all circumstances. Therefore, this paper offers some updated guidelines for the users of composites on some of the recent advances in SHM applied to composite structures; also, most of the studies reported in the literature seem to have concentrated on the flat composite plates and reinforced with synthetic fibre. There are relatively fewer stories on other structural configurations such as single or double curve structures and hybridised composites reinforced with natural and synthetic fibres as regards SHM

Damage detection in CFRP Composite Plates based on evolving Modal Parameters

Despite the good mechanical properties of composite structures, it is still prone to low impact damages resulting in defects such as delamination and the effect is usually not detected by visual inspection. Although the use of modal parameters for identification of damage in Carbon Fibre Reinforced Polymer (CFRP) composite laminates is not new, it is still a subject of discussion within the research community. In this study composite of different stacking configuration manufactured by hand lay-up and autoclave curing were used to conduct the free-free experimental modal analysis within the frequency range of 0 -- 400 Hz. The experiments were performed for both healthy and damage induced samples of same configuration. The effect of the modal parameters such as damping factors, natural frequencies, etc were assessed and the results presented here-in

On reducing uncertainty on the Elliptical Plane modal identification method

The Elliptical Plane has been recently introduced as a modal identification method that uses an alternative plot of the receptance. The method uses the dissipated energy per cycle of vibration as a starting point. For lightly damped systems with conveniently spaced modes, it produces quite accurate results, especially when compared to the well-known method of the inverse. When represented in the Elliptical Plane, the shape of the receptance is elliptical near resonant frequencies. The modal damping factor can be determined from the angle of the ellipse’s major axis with the horizontal axis, whereas the real and imaginary parts of the modal constants can be determined from numerical curve-fitting (as in the method of the circle - Nyquist plot). However, the lack of points that can be used near the resonance (due to limitations in the frequency resolution, and effects from other modes near each resonance) and the fact that measurements are polluted by noise, bring uncertainty to the numerical curve-fitting. This paper aims at providing the first steps on the improvement of the quality of the modal identification of the receptance in the Elliptical Plane. The method and results are discussed with a multiple degree-of-freedom numerical example

Chord line force versus displacement for thin shallow arc pre-curved bimetallic strip

This is the accepted version of the following article: G D Angel, G Haritos, A Chrysanthou & V Voloshin, “Chord line force versus displacement for thin shallow arc pre-curved bimetallic strip”, Journal of Mechanical Engineering Science, Vol. 229(1): 116-124, first published online April 29, 2014, published by SAGE Publishing. All rights reserved. The version of record is available online at doi: http://dx.doi.org/10.1177/0954406214530873A pre-curved bimetallic strip that is applied with a force in an axial orientation, i.e. along its chord line, exhibits nonlinear force-displacement characteristics. For thin bimetallic strips, whereby the radius of curvature is large compared to the thickness of the strip, the non-linearity tends to be tangent related. The new theoretical formula introduced here was correlated to the results of a set of force-displacement tests, and a good overall fit of the theory to the test data was achieved. The formula put forward in this work enables the evaluation of large chord line displacements but is limited to the permissible stress limits of the material. This work can also be directly applied to thin shallow arc beams of a single material. The application of this work is in the field of bimetallic force-displacement actuators.Peer reviewe

Elliptical Method for Damage Identification in Carbon Fibre Reinforced Polymer Laminates

Oftentimes, researchers in the area of vibration-based Structural Health Monitoring (SHM) and Damage Detection focused their attention on the global properties of structures, which are the modal frequencies and modal damping factors. However, the effects on the local properties for SHM, that is modal constants, has not been so extremely explored. In this paper, the Elliptical Plane modal identification method is proposed to be used as a Damage identification method itself. It is observed that, when the receptance is plotted in the Elliptical plane, the area of the ellipse formed close to the resonant frequencies (which depends on the modal constants) can be used to detect damage, namely in composite Carbon Fibre Reinforced Polymer (CFRP) rectangular plates. Although a mathematical correlation has not been established yet, results show that the method is sensitive to the presence of damage in the test plates, as the area of the ellipse changes with damage

Experimental investigation on transient characteristics of a dual compensation chamber loop heat pipe subjected to acceleration forces

In this article, an experimental study has been conducted to provide better understanding of the transient characteristics of a dual compensation chamber loop heat pipe (DCCLHP) subjected to the acceleration force. A new acceleration test rig was set up to provide the acceleration up to 11 g with three different directions. The heat load on the evaporator ranging from 25 W to 300 W was applied with the acceleration force simultaneously. Experimental results indicated that the DCCLHP could start up at a small heat load of 25 W and the startup behavior was different under acceleration direction conditions because of the vapor-liquid distribution change in the evaporator and compensation chambers (CCs). Under the current operating conditions, the effect of acceleration force was significant to the operating performance at small heat loads whereas was weak at large heat loads. Experimental results also clearly showed that both acceleration magnitude and direction can alter the operating mode. What’s more, it was found that temperature oscillation, reverse flow and evaporation in the evaporator core phenomena occurred under acceleration conditions