Off-Axial Tensile Test and Analysis for Stratospheric Airship Envelope Material

The mechanical properties of envelope materials play a critical role in determining the service life of stratospheric airships. This paper investigates the failure analysis and strength criteria of a plain-woven stratospheric envelope material. First, a series of off-axial tensile tests were conducted, revealing that the material exhibits significant nonlinearity and orthotropic behavior under off-axial loading. Notably, the failure strength of the material decreases dramatically at small off-axial angles. Second, finite element simulations were performed to analyze the failure mechanisms of specimens at various off-axial angles and a potential explanation for the sharp decline in failure strength is proposed. Third, the predictions of several existing strength criteria were compared with experimental results, showing limited agreement. To address this, a new strength criterion is introduced to more accurately predict the failure strength of the envelope material across different off-axial angles. The results demonstrate that the proposed criterion offers a significant improvement in predicting the mechanical behavior of plain-woven stratospheric envelope materials