Effects Of Short-term Aging And Creasing On Uni-axial Tensile Properties Of Airship Envelope Materials

Airships have great development value in high-speed communication,precise positioning,early warning reconnaissance,ecological protection,hydrological monitoring,material transportation,and tour and sightseeing.In terms of structural system,airships are classified into two types of rigid airships;semi-rigid airships and non-rigid airships,of which the latter is currently the main form of construction.As an important part of non-rigid airships,aerostat airbags play an important role in maintaining the aerodynamic shape,structural rigidity and transfer force flow of the airship.The aerostat ballonet is made of envelope fabric material,so the mechanical properties of the envelope material are crucial for airship engineering design and structural calculation analysis.In this paper,the Uretek3216-LV airship's envelope material was used as the research object,and the short-term aging and creasing damage simulation test,as well as the uniaxial monotonic tensile and cyclic characterization tests were carried out.The uniaxial tensile properties of degradation of the envelope material under short-term aging and creasing damage were revealed.Firstly,the outdoor exposure tests and the flex durability tests that were carried out on the envelope material of Uretek3216-LV were in accordance to industry standards.The outdoor exposure tests(four batches materials were exposured to 1?3?8?12 months respectively)are used to simulate the natural aging of airship envelope material,and the flex durability tests(four categories flex durability tests which were flexed 20?270?900?2700 cycles respectively)simulate the creasing damage generated by the airship ballonet during manufacturing,transportation,storage,launch and service.Secondly,the uniaxial monoaxial tension and the uniaxial cyclic tensile tests were carried out on the four batches of aging test pieces and the four categories of flex durability test pieces respectively.The strength and elastic modulus test values of the two types of test pieces were obtained.The relationship between the short-term aging and the flex cycles on the uniaxial tensile strength and the tensile elastic modulus were obtained by carrying out the analysis of experimental data.The theoretical degradation model of uniaxial tensile mechanical properties of envelope materials by short-term aging and the flex cycles were established respectively.Finally,the uniaxial tensile strength and elastic modulus degeneration models of the envelope material under the combination of short-term aging and creasing damage were established by the principle of damage superposition.Uniaxial tensile strength and elastic modulus tests of shortterm aging and creasing(16 combinations)were carried out and the experimental data were used to verify and optimize it.