Room Temperature Chemoresistive Gas Sensor Based on Organic-Functionalized Graphene Oxide

In the wide palette of chemoresistive sensing materials, hybrid nanocomposites have quickly gained [...

Sheep Updates 2005 - Part 6

This session covers seven papers from different authors: PASTURES/GRAZING 1. New annual pastures - quality and quantity for fodder conservation?, Sarah Pugh and Giles Glasson, Department of Agriculture Western Australia 2. Saltland Pastures: Dispelling some Myths, Ed Barrett-Lennard1,3, Hayley Norman2,3, Matt Wilmat2,3, Meir Altman,3, Kelly Pearce2,3, Sally Phelan4, David Masters2,3, 1. Department of Agriculture, Western Australia, 2 CSIRO Livestock Industries, Floreat, WA, 3. CRC for Plant-based Management of Dryland Salinity 4. Saltland Pastures Association 3. Pastures: Putting profit back into sandplain, Nadine Eva, Department of Agriculture Western Australia. 4. Pastures from Space R - Can be used to make profitable strategic and tactical management decisions on farm, Brad Wooldridge, Farmer Wagin WA, Stephen Gherardi, Lucy Anderton, Department of Agriculture Western Australia, Gonzalo Mata, CSIRO Livestock Industries, Wembley, WA 5. Are new farming systems based on perenial pastures in south west Australia more profitable?, P. Sanford, Department of Agriculture Western Australia, J. Young, Farm Systems Analysis, Kojonup WA 6. Sown fodders, rotational grazing and Merinos make money in a drought, Tim Wiley, Department of Agriculture Western Australia, Richard Quinlan, Planfarm, Geraldton 7. Lifetime Wool - The \u27best bet\u27 optimum condition score profile for Merino ewes lambing in winter. Chris Oldham, Mike Hyder, Mandy Curnow, Samantha Giles, Department of Agriculture Western Australia, John Young, Farming Systems Analysis Service, Kojonup, Andrew Thompson, DPI Victoria, Hamilton

Experimental analysis of stresses in bonded, pultruded composite structures

Pultruded composites are usually manufactured by pulling fibres that have been immersed in resin through a heated die. The material is layered, usually with the main component being a thick layer of unidirectional material (UD). This is often sandwiched between outer layers of a randomly orientated material. In the current work the outer layers comprise a chopped strand mat (CSM) material stitched on a woven roving mat, known as complex mat (CM). For protection purposes, a thin layer of material, known as a ‘surface veil’, that consists of thermoplastic fibres wetted with polyester resin is deposited on the surface. Investigations into bonded pultruded butt strap joints have been carried out by the authors showing that the joint efficiency was poor. This was attributed to damage initiating in the UD/CSM material interface, as a result of poor interlaminar mechanical properties, exacerbated by the large stress discontinuities at the adhesive/surface veil/CM and CM/UD interfaces. The failure essentially results in a detachment of the surface of the pultruded material. To identify a means of increasing the joint efficiency it is necessary to establish the stress distribution in the joint particularly at the interfacial layers in the pultruded material to define how the load is carried and transferred to each layer. To do this an experimental technique known as thermoelastic stress analysis (TSA) is used. TSA is a non-contact technique that provides a full field map of the stresses on the surface of a component. The application of TSA to composite materials is described in the paper. To obtain quantitative stress data from TSA it is necessary to ‘calibrate’ the materials; the calibration approach is also described in the paper. The TSA data provides a layer-by-layer map of the stresses from the joint interface on the surface through the complex mat layer into the UD. This approach has provided a new insight into pultruded joint behaviour and enabled improved validation of Finite Element Analysis (FEA)

Stress analysis of bonded joints in pultruded GRP components

Thermoelastic stress analysis is used to determine the stress field in an orthotropic pultruded material. An economical means of experimentally obtaining the thermoelastic constant and some mechanical properties of each of the constituent materials in the pultruded structure is devised. The stresses in a bonded joint are obtained using thermoelastic stress analysis. The calibrated thermoelastic data is used to validate a finite element model the joint. It is shown that to accurately interpret thermoelastic data from layered structure such as that of the pultrusion calibration is an essential step. It is also demonstrated that the thermoelastic approach provides an excellent means of validation of finite element models