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

Abstract

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.

Special Issue on Advances in Digital Image Correlation (DIC)

“…The question, addressed in [5], of the thermal environment is also central for the (thermo-)mechanical analysis of materials, and it raises a whole set of experimental problems (texture, acquisition, filtering, etc.). Regarding an atypical application, balloons, the authors of [6] recall that the field of (very) large deformation is still wide open and depending on the use case, special specific experimental configurations may help. It is also a theme addressed by [7] where calibrated targets were used to evaluate measurement uncertainties in this large deformation regime.…”

Application of Digital Image Correlation for Strain Mapping of Structural Elements and Materials

“…It finds application in both laboratory and outdoor field testing. The 3D version of the DIC method holds particular importance, especially in the examination of metals, plastics, thermoplastics [ 5 ], advanced polymeric composites [ 6 ], and biological materials such as tissues [ 7 ], carotid arteries [ 8 ], balloons [ 9 ], and many others. This tool enables the conduct of quasi-static loading tests.…”

Analysis and Testing of Variable Height Operating Characteristics of Super-Pressure Balloon Airbag Fan

“…Compared with aeronautical and astronautical platforms, a super-pressure balloon has significant advantages in terms of temporal and spatial resolution [4]. Researchers in many countries, including the United States, Japan, and China [5][6][7][8], have conducted multiple experiments on super-pressure balloons.…”