Tear Propagation of a High Performance Airship Envelope Material

Maekawa, Shoji; Shibasaki, Kouichi; Kurose, Toyotoshi; Maeda, Toshiyuki; Sasaki, Yoshitaka; Yoshino, Tetsuo

doi:10.2514/6.2007-7829

Cited by 14 publications

(39 citation statements)

References 3 publications

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“…Thus, it is most important to reduce the structural weight, and lightweight envelope materials are needed. Many envelope materials have been developed and their basic material properties have been obtained, and the density is from 203 to 157 g/m 2 (Maekawa and Yoshino, 2008; Nakadate et al , 2009). Solar cells are one of the key enabling technologies for a solar powered airship.…”

Section: High‐altitude/long‐endurance Airship Parameters Sensitivity Analysismentioning

confidence: 99%

“…(Colozza, 2003; Khoury and Gillett, 2004; Seely and Smith, 2002; Agte and Cohen, 2008; Nickol et al , 2007; Wanggu et al , 2006), and the solar cell efficiency might be higher than 15 percent in the future (Miller et al , 2005). Based on an overall consideration of the papers (Maekawa and Yoshino, 2008; Nakadate et al , 2009; Colozza and James, 2005; Haifeng et al , 2006; Barbir et al , 2003), the trends concerning several technological enhancements in airship in the future which are summarized in Table II.…”

Section: Effects Of Technology Advances On Airship Performance Parametersmentioning

confidence: 99%

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Configurations analysis for high‐altitude/long‐endurance airships

2010

Aircraft Engineering and Aerospace Technology

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PurposeIn recent years, high‐altitude/long‐endurance airship platforms have generated great interest as a means to provide communications and surveillance capabilities. The purpose of this paper is to develop a model for airship conceptual design and help provide insight into the viability of high‐altitude/long‐endurance airships.Design/methodology/approachA configuration analysis model with the consideration of pressure difference, temperature difference, and helium purity, etc. was developed. The influences of the airship payload, size and area required of solar cell with environment and operation parameters, such as operation latitude, pressure difference, temperature difference, helium purity, seasons, latitude, and wind speed, etc. were analyzed.FindingsThe results show that the area of solar cell required for stratospheric airship is very large under the condition of low altitude, high latitude, wind, and in winter, etc. which might make the design of high‐altitude/long‐endurance airship an elusive goal. They also show that the solar cell efficiency is the key technology in the control of solar cell area required for airships, and the technology advances in regenerative fuel cells and propeller efficiency have significant effects among on the airship payload, size, and solar cell area required for airship.Originality/valueThe paper analyses the energy balance of the high‐altitude/long‐endurance airship.

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Section: High‐altitude/long‐endurance Airship Parameters Sensitivity Analysismentioning

confidence: 99%

Section: Effects Of Technology Advances On Airship Performance Parametersmentioning

confidence: 99%

Configurations analysis for high‐altitude/long‐endurance airships

2010

Aircraft Engineering and Aerospace Technology

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“…According to the test results, he derived a formula to describe the relationship between tear strength and crack length. Afterward, Maekawa et al 8 carried out a similar test on a cylinder measured 4000 mm in length and 900 mm in diameter ( Figure 1) and the initial crack lengths range from 70 to 200 mm. He proposed a new empirical formula to demonstrate the relationship between tear strength and initial crack length.…”

Section: Introductionmentioning

confidence: 99%

“…First of all, the influence of specimen width on tear strength was investigated theoretically. Specimen width was introduced into Maekawa's empirical formula (MEF), 8 and a modified formula was derived. Uniaxial tear tests were then conducted.…”

Section: Introductionmentioning

confidence: 99%

Investigation of tear strength of an airship envelope fabric by theoretical method and uniaxial tear test

Chen

Ding

et al. 2019

Journal of Engineered Fibers and Fabrics

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This article proposed a new convenient method to obtain tear strength of an airship envelope fabric, which is a laminated plain weave fabric with the ultra-high molecular weight polyethylene fibers. First, a modified formula based on Maekawa’s empirical formula was derived. Uniaxial tear tests were then conducted on three series of single-edge notched specimens with varying widths and their critical tear stresses were measured. The experimental result showed that critical tear stress decreases with the reduction of specimen width when initial crack length is fixed. Afterward, the tear stresses of the fabric were simulated by Maekawa’s empirical formula, the modified formula, and Thiele formula. By comparing the theoretical results with the experimental results, the modified formula was verified to be consistent well with the test data. Finally, an equation was derived, which shows tear strength of this fabric decreases as initial crack length increases. For instance, when the initial crack length is 31.75 mm, the tear strength is only 44.52% of the tensile strength.

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“…Such polymer materials will bear long-time highlow temperature cycle, UV radiation, ozone aging and other environment factors in the near space during the flying-time of NSV, and most of these environment factors will affect the properties of envelope materials, especial the ozone, which is a strong oxidants and also strong catalyst, so it has strong oxidizing and chemical activity and could accelerate the aging and embrittlement of envelope materials of NSV and result the lifespane shorten of NSV. The research of the ozone aging of polymer composites mainly focuses on the rubber materials, while for the envelope materials of near space vehicles, the ozone aging research is quite limited [5][6][7]. Shoji Maekawa and Atsushi Takegaki [7] have studied the 24h-ozone aging (the ozone concentration is 50±5ppm) Keywords-ozone aging; PE-EVOH; tensile strength; FTIR spectra; AFM Abstract-The ozone aging of PE-EVOH (ethylene-vinyl alcohol copolymer) films, which is a kind of envelop material of near space vehicle, is studied in the paper.…”

mentioning

confidence: 99%