| Summary |
This study involved creating a large polyurethane model, scaled at 1/10 of a full-scale cylindrical pneumatic membrane dome with a spherical roof reaching a height of approximately 30 meters. The study aimed to estimate the required internal pressure to restore the original shape and avoid buckling of the pneumatic membrane structure under natural wind conditions. The experiments utilized motion capture to determine three-dimensional displacement vectors. By establishing an offset method that considers the sequential correlation between wind speed fluctuations and displacement vector variations, the actual displacement was identified, accounting for measurement zero-point shifts due to membrane expansion from initial internal pressure and wind speed effects. Measurements were taken with internal pressures of membrane structure varying incrementally from 9.1 Pa to 27.8 Pa in winds of 2.39 to 4.35 m/s, collecting 27 data sets equivalent to 10-minute averages. The results included obtaining the actual deformation diagrams in the wind direction at the lowest internal pressure of 9.1 Pa, where maximum displacement was expected, and comparing these deformations with previous wind tunnel experiments, yielding similar conditions. Based on these results, the offset method was used to estimate the required internal pressures P0 for three cases with different reference wind speeds for shape restoration. For buckling avoidance, the study could be estimated the required internal pressure P0b for one case by introducing the substantial minimum peak rate Ǩ0, based on the 3σ displacement variations located on the leeward side of themembrane. The obtained required internal pressures showed good approximation when compared to the simplified calculation method based on the rigid thin membrane structure discussed in Part 1 of this paper. Thus, the simplified estimation method for the required internal pressure presented in this paper was confirmed to be a sufficiently practical approach.
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