High Tensile Fibers Research Articles

Measurement of Super-Pressure Balloon Deformation with Simplified Digital Image Correlation

A super pressure balloon (SPB) is an aerostatic balloon that can fly at a constant altitude for an extended period. Japan Aerospace Exploration Agency (JAXA) has been developing a light-weight, high strength balloon made of thin polyethylene films and diamond-shaped net with high tensile fibers. Previous investigations proved that strength requirements on SPB members are satisfied even though the net covering the SPB sometimes becomes damaged during the inflation test. This may be due to non-uniform expansion, which causes stress concentration, however, no method exists to confirm this hypothesis. In this study, we tested a new method called Simplified Digital Image Correlation method (SiDIC) to check if it can measure the displacement of the SPB by using a rubber balloon. After measuring the measurement accuracy of the Digital Image Correlation method (DIC) and SiDIC, we applied both DIC and SiDIC to a rubber balloon covered just with the net. Interestingly, SiDIC entailed a smaller amount of data but could measure the deformation more accurately than DIC. In addition, assuming the stress concentration, one part of the net was bonded to the balloon to restrict the deformation. SiDIC properly identified the undeformed region.

Natural history at the cutting edge

Natural history is a vast database useful for the discovery of new biological resources and when the logic of evolutionary biology and ecology is applied to it, an extraordinary diversity of commercial applications are revealed. Examples show that organisms as unexpected as ants, spiders and molluscs provide proven or potential resources for products as diverse as pharmaceuticals, high-tensile fibres and new construction materials while lowly worms and wasps provide services from environmental monitoring to biological control. These examples are the tip of the iceberg and a branch of ecological economics is proposed to develop the logical and systematic exploration of biodiversity for novel products and services. While the primary reasons for the conservation of biodiversity may be ethical and moral, the judicious use of natural history clearly demonstrates that the economic imperatives for the conservation of all species are far greater than previously imagined.