General Electric composite ring-disk flywheel: Recent and potential developments

Recent developments of the General Electric hybrid rotor design are described. The relation of the hybrid rotor design to flywheel designs that are especially suitable for spacecraft applications is discussed. Potential performance gains that can be achieved in such rotor designs by applying latest developments in materials, processing, and design methodology are projected. Indications are that substantial improvements can be obtained

Flywheel containment and safety considerations

Flywheel safety and containment design technology are discussed. The effects of axial loading resulting from composite rotor burst tests are considered. Analysis of the radial burst problem is also included

Containment of composite fan blades

The development of containment concepts for use with large composite fan blades, taking into account the frangible nature of composite blades is considered. Aspects of the development program include; (1) an analysis to predict the interaction between a failed fan blade and the blade containment structure; (2) scaling factors to allow impact testing using subscale containment rings and simulated blades; (3) the design and fabrication of containment systems for further evaluation in a rotating rig test facility; (4) evaluate the test data against the analytically predicted results; and (5) determine overall systems weights and design characteristics of a composite fan stage installation and compare to the requirements of an equivalent titanium fan blade system. Progress in the blade impact penetration tests and the design and fabrication of blade containment systems is reported

Development of a special multi-wavelength pyrometer for temperature distribution measurements in rocket engines

Previously a fast multi-wavelength pyrometer was developed in a collaboration between the Harbin Institute of Technology of China and Rome University of Italy. The main features of the instrument include the use of a dispersing prism and a photodiode array to cover the entire spectral band. Following this experience, a new type of six-target eight-wavelength pyrometer for solid propellant rocket engine plume temperature distribution measurements has been developed. The instrument can record the radiation fluxes of eight wavelengths for six different uniformly distributed points on the target surface, which are well defined by holes on a field stop. The fast pyrometer with a specially designed synchronous data acquisition system can assure that the recorded thermal radiation fluxes of different spectral regions are at the same time and the same true temperature, even with dramatically changed targets

COMPARING DATA ACQUISITION METHODOLOGIES FOR DTM PRODUCTION

In this paper we present the results related to several field campaigns conducted in the last three years in a small (4.4 km2) wilderness basin in Carnia, a tectonically active alpine region in northeast Italy. The study area is a typical alpine debris-flow dominated catchment where several landslides, including a significantly large one, were observed and mapped. The field survey carried out in 2007, 2008, 2009 and 2010 were focused on the large landslide of the basins and they consisted in the following steps: 1 – development of an accurate GPS network, 2 – make use of a long range Terrestrial Laser Scanner (TLS) for a detailed and local analysis of landslide movements, 3 – merge the data with an airborne LiDAR for a large scale analysis of the processes. Preliminary analysis consist in the comparison of different high resolution Digital Terrain Models (DTMs) in order to estimate the debris volume that has been triggered during the last movements of the landslides. Achieved results show that the integration between ALS and TSL data allows to produce DTMs of limited extent, with higher quality and level of detail. Such DTMs improve the capabilities for landslides analysis and modelling with respect to the use of LiDAR data only, even in areas providing limited or difficult access for the survey activity

Temperature increase during composites polymerisation using two LED curing lights

The aim of curing light technology has been the development of lights that would result in faster curing of resin composites and less heat generation (Aravamudhan et al., Dent Mater 2006). The purpose of this in vitro study was to evaluate thermal changes on the tooth structures during the exposure of two different light emitting diode curing units (LED)

Experimental Investigation on Thermal Diffusivity of PM Steels

The scanty literature data on thermal diffusivity of P/M steels seems contradictory, if the cooling speed on quenching is the evaluation parameter. Due to the basic importance of diffusivity on the response of P/M steels to heat-treating, an experimental survey has been carried out, to collect data on various P/M steels, based on prealloyed, or diffusion-bonded, or admixed powders. The study has also covered the influence of processing parameters, such as compaction pressure and sintering temperature. The flash method has been used to measure the thermal diffusivity of P/M steels. This method directly measures the thermal diffusivity of a sample in slab shape. A plane-parallel sample is inserted in the test apparatus and then a short light pulse, produced by a laser or a flash lamp, heats the front surface of the sample. The heat diffuses through the sample, leading to a temperature rise on the sample rear surface. An infrared detector measures this temperature rise, versus time, and thermal diffusivity is derived from the least square regression on the whole temperature trend, using the analytical solution of heat conduction. The results show that thermal diffusivity increases as density increases. This achievement can be justified by a simple theoretical analysis of the thermal conductivity on thermal diffusivity. The collected data also enable us to ascertain the influence of sintered material composition and carbon content on thermal diffusivity. The results should contribute to clarify some uncertainties and perplexities on the behavior of properly elaborated P/M steels, to be hardened by heat treatment, conventional – such as oil quenching – or innovative, such as sinter -hardening