Mechanical Properties and Strength Criteria of Fabric Membrane for the Stratospheric Airship Envelope
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Mechanical Properties and Strength Criteria of Fabric Membrane for the Stratospheric Airship Envelope Junhui Meng 1 & Mingyun Lv 1 & Zhipeng Qu 1 & Penghui Li 2
Received: 12 May 2016 / Accepted: 29 June 2016 # Springer Science+Business Media Dordrecht 2016
Abstract In this paper, specimens of a new kind of envelope material for the stratospheric airship with and without initial notches are tested under uniaxial and biaxial tensile conditions. It can be seen from the tests that the characteristics of nonlinearity and anisotropy are not so obvious, especially for the biaxial specimens. The damage process of the on-axial specimen is brittle failure, because the damage of the specimen takes place suddenly without any distinct phenomenon, and there is no obvious yield stage before the failure of the material. The failure strength and the damage mode of the envelope material are determined by the strength of the woven fabric and the off-axial angle, respectively. The simplified maximum stress criterion and a new modified Tsai-Hill criterion can be used to predict the failure of the envelope material under on-axial and off-axial tension, respectively. The results show that it is the number of the cutoff yarns but not the shape of the initial damage determines the failure strength of the envelope material. In addition, the stress concentration factor of the envelope material is much higher than the isotropic material, because of the difficulty to transfer concentrated stress around the initial opening hole.
* Mingyun Lv [email protected] Junhui Meng [email protected] Zhipeng Qu [email protected] Penghui Li [email protected]
1
School of Aeronautic Science and Engineering, Beihang University, No. 37 Xueyuan Road, Haidian District, Beijing, China
2
People’s Liberation Army Military Representative Office in No. 162 Plant, Anshun, China
Appl Compos Mater
Keywords Stratospheric airship . Envelope material . Strength criterion . Failure fracture . Stress concentration
1 Introduction The stratospheric airship (SSA) is a class of Lighter-Than-Air (LTA) vehicle with application potential in communication, investigation, science exploration and other fields [1–3]. Therefore, study in the SSA has become the focus in many counties in recent years [4, 5]. However, there is no mature and practical SSA in the engineering at the present stage. Lightweight and high strength envelope material is one of the bottlenecks for the development of the SSA, which directly determines the long endurance flight performance and loading deformation characteristics of the airship [4, 6–8]. Several experimental flight accidents have been happened because of the airship envelope tearing failure, such as the HiSentinel airship [9] and the Japanese experimental airship [10]. The envelope is a major part of the airship structure, which is used to contain lifting gas and keep the aerodynamic configuration. Because of the complex work condition and stratospheric environment, any kinds of materials with a single component cannot satisfy th
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