Shape morphing solar shadings: a review

This paper provides an overview of available innovative shape morphing building skins and their design principles. In particular, the proposed review deals with comfort-related issues associated with dynamic solar shading devices, building integration of smart materials, and morphological analyses related to the most recent shape morphing solar skins. In the first part of the paper, an introduction to the typologies of movement in architecture, its concept and application are presented. An explanation of biomimetic principles together with an overview of user's response to dynamic shading devices is also provided. This is followed by the description of the design principles for shape morphing solar shadings with particular focus on energy and comfort aspects, smart materials and biomimetic principles for efficient movements. A review of most recent developments on the topics of comfort, users' response and control of dynamic shading devices, is presented and summarized in a comparison table. The main technical and mechanical properties of the most diffused smart materials (Shape Memory Alloys, Shape Memory Polymers and Shape Memory Hybrids) that can be used for innovative shape morphing solar skins are illustrated in detail and compared. Biomimetic principles for efficient movements complete this part of the work. The principles illustrated in the previous part of this paper are then used to critically analyse the most recent examples of building integrated shape morphing shadings

Transforming composite design by use of structural health monitoring

Commercial composite aerospace structure is required to be designed and managed under the damage tolerant principle. Airworthiness is maintained through a process of regulated inspections and if required maintenance. Currently inspections use visual and assisted visual (non-destructive inspection - NDI) techniques. Damage tolerant operation is therefore reliant on inspectability. Unlike metal structure composite and adhesively bonded structure may show few if any recognisable indicators prior to rapid failure, either visually or using NDI. Although stringent manufacturing processes are demanded to best ensure components are fit for service strategies such as reducing stresses by oversizing components or in the case of bonded features additional mechanical fasteners may be included to allow operation with this potential structural uncertainty. Structural Heath Monitoring (SHM) uses data from in-situ sensors to assess the condition of the structure. If via SHM any uncertainty associated with difficult to inspect components could be eliminated less reliance would be required of additional structure or features allowing lighter and more efficient structure to be viable with no impact on current airworthiness demands. Despite much previous research no SHM system is in use with in-service composite or bonded aerospace components. When operating a structure under Damage-tolerance operational requirements damage must be positively identified to allow repairs to be made whist ensuring appropriate airworthiness demands are maintained. Such demands must also be met by structure inspected using SHM. Unlike previous studies this research combines the process of structural design and in-situ monitoring to address the issues identified. Termed SHM enabled design this approach allows the implementation of monitoring technology and the potential for benefits including the reduced reliance on inefficient additional structure to be viably included in actual structure ... [cont.]

Impact detection techniques using fibre-optic sensors for aerospace & defence

Impact detection techniques are developed for application in the aerospace and defence industries. Optical fibre sensors hold great promise for structural health monitoring systems and methods of interrogating fibre Bragg gratings (FBG) are investigated given the need for dynamic strain capture and multiplexed sensors. An arrayed waveguide grating based interrogator is developed. The relationships between key performance indicators, such as strain range and linearity of response, and parameters such as the FBG length and spectral width are determined. It was found that the inclusion of a semiconductor optical amplifier could increase the signal-to-noise ratio by ~300% as the system moves to its least sensitive. An alternative interrogator is investigated utilising two wave mixing in erbium-doped fibre in order to create an adaptive system insensitive to quasistatic strain and temperature drifts. Dynamic strain sensing was demonstrated at 200 Hz which remained functional while undergoing a temperature shift of 8.5 °C. In addition, software techniques are investigated for locating impact events on a curved composite structure using both time-of-flight triangulation and neural networks. A feature characteristic of composite damage creation is identified in dynamic signals captured during impact. An algorithm is developed which successfully distinguishes between signals characteristic of a non-damaging impact with those from a damaging impact with a classification accuracy of 93 – 96%. Finally, a demonstrator system is produced to exhibit some of the techniques developed in this thesis

NASA Tech Briefs, March 2011

Topics covered include: Optimal Tuner Selection for Kalman-Filter-Based Aircraft Engine Performance Estimation; Airborne Radar Interferometric Repeat-Pass Processing; Plug-and-Play Environmental Monitoring Spacecraft Subsystem; Power-Combined GaN Amplifier with 2.28-W Output Power at 87 GHz; Wallops Ship Surveillance System; Source Lines Counter (SLiC) Version 4.0; Guidance, Navigation, and Control Program; Single-Frame Terrain Mapping Software for Robotic Vehicles; Auto Draw from Excel Input Files; Observation Scheduling System; CFDP for Interplanetary Overlay Network; X-Windows Widget for Image Display; Binary-Signal Recovery; Volumetric 3D Display System with Static Screen; MMIC Replacement for Gunn Diode Oscillators; Feature Acquisition with Imbalanced Training Data; Mount Protects Thin-Walled Glass or Ceramic Tubes from Large Thermal and Vibration Loads; Carbon Nanotube-Based Structural Health Monitoring Sensors; Wireless Inductive Power Device Suppresses Blade Vibrations; Safe, Advanced, Adaptable Isolation System Eliminates the Need for Critical Lifts; Anti-Rotation Device Releasable by Insertion of a Tool; A Magnetically Coupled Cryogenic Pump; Single Piezo-Actuator Rotary-Hammering Drill; Fire-Retardant Polymeric Additives; Catalytic Generation of Lift Gases for Balloons; Ionic Liquids to Replace Hydrazine; Variable Emittance Electrochromics Using Ionic Electrolytes and Low Solar Absorptance Coatings; Spacecraft Radiator Freeze Protection Using a Regenerative Heat Exchanger; Multi-Mission Power Analysis Tool; Correction for Self-Heating When Using Thermometers as Heaters in Precision Control Applications; Gravitational Wave Detection with Single-Laser Atom Interferometers; Titanium Alloy Strong Back for IXO Mirror Segments; Improved Ambient Pressure Pyroelectric Ion Source; Multi-Modal Image Registration and Matching for Localization of a Balloon on Titan; Entanglement in Quantum-Classical Hybrid; Algorithm for Autonomous Landing; Quantum-Classical Hybrid for Information Processing; Small-Scale Dissipation in Binary-Species Transitional Mixing Layers; Superpixel-Augmented Endmember Detection for Hyperspectral Images; Coding for Parallel Links to Maximize the Expected Value of Decodable Messages; and Microwave Tissue Soldering for Immediate Wound Closure

Advanced Manned Launch System (AMLS) study

To assure national leadership in space operations and exploration in the future, NASA must be able to provide cost effective and operationally efficient space transportation. Several NASA studies and the joint NASA/DoD Space Transportation Architecture Studies (STAS) have shown the need for a multi-vehicle space transportation system with designs driven by enhanced operations and low costs. NASA is currently studying an advanced manned launch system (AMLS) approach to transport crew and cargo to the Space Station Freedom. Several single and multiple stage systems from air-breathing to all-rocket concepts are being examined in a series of studies potential replacements for the Space Shuttle launch system in the 2000-2010 time frame. Rockwell International Corporation, under contract to the NASA Langley Research Center, has analyzed a two-stage all-rocket concept to determine whether this class of vehicles is appropriate for the AMLS function. The results of the pre-phase A study are discussed

12th EASN International Conference on "Innovation in Aviation & Space for opening New Horizons"

Epoxy resins show a combination of thermal stability, good mechanical performance, and durability, which make these materials suitable for many applications in the Aerospace industry. Different types of curing agents can be utilized for curing epoxy systems. The use of aliphatic amines as curing agent is preferable over the toxic aromatic ones, though their incorporation increases the flammability of the resin. Recently, we have developed different hybrid strategies, where the sol-gel technique has been exploited in combination with two DOPO-based flame retardants and other synergists or the use of humic acid and ammonium polyphosphate to achieve non-dripping V-0 classification in UL 94 vertical flame spread tests, with low phosphorous loadings (e.g., 1-2 wt%). These strategies improved the flame retardancy of the epoxy matrix, without any detrimental impact on the mechanical and thermal properties of the composites. Finally, the formation of a hybrid silica-epoxy network accounted for the establishment of tailored interphases, due to a better dispersion of more polar additives in the hydrophobic resin