Strength evaluation of bonding structures used in a cryogenic composite tank with polymer liner at cryogenic temperature
- Paper number
IAC-08.C2.4.5
- Author
Mr. Kouhei Takahashi, Tokyo Metropolitan University, Japan
- Coauthor
Prof. Eiichi Sato, Japan Aerospace Exploration Agency (JAXA), Japan
- Coauthor
Mr. Yuuki Kakimoto, Tokyo Metropolitan Institute of Technology, Japan
- Coauthor
Dr. Yasuko Motoyashiki, The Institute of Space and Astronautical Science / JAXA, Japan
- Coauthor
Prof. Kouichi Kitazono, Tokyo Metropolitan University, Japan
- Year
2008
- Abstract
Development of a carbon-fiber-reinforced plastic (CFRP) tank for liquid hydrogen propellant is indispensable for practical use of single stage reusable rocket. Now, Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (ISAS/JAXA) is developing a CFRP LH 2 tank onboard Reusable Vehicle Test (RVT). Since it is difficult to make the tank of only CFRP with low gas-barrier performance, the tank has a liquid crystal polymer (LCP) liner for gas-barrier in addition to Ti alloy mouthpieces for an interface of pipeworks. Thus, this tank has many adhesive bonding and fusion bonding whose fracture toughnesses are expected to decrease at cryogenic temperature. The strength of bonding structures of a tank would restrict the design freedom.In this paper, evaluation tests were performed on the specimens made of combinations of these materials as well as each material. Double cantilever beam (DCB), single lap shear (SLS), short beam shear (SBS) and tensile tests were performed at room and cryogenic temperatures. The results of DCB tests were analyzed based on the energy release principle to obtain the critical strain energy release rate.The bonding structure of CFRP and Ti alloy with epoxy adhesive was evaluated using DCB specimens made of two Ti beams having CFRP beam between them. Regardless of the test temperature, delamination occurred in the CFRP layer, but the pre-crack induced at the adhesive layer between Ti and CFRP did not grow. Interlaminar fracture toughnesses of CFRP were evaluated as 900 J/m^ 2 and 600 J/m^ 2 at room and cryogenic temperatures, respectively.On the other hand, cohesion failure was observed in the adhesive layer of the DCB specimens made of two Ti alloy beams bonded by epoxy adhesive. Fracture toughness of adhesive bonding was 200 J/m^ 2 and higher than that of CFRP interlaminer fracture at room temperature. However, it was 500 J/m^ 2 at cryogenic temperature, which is a little smaller than that of CFRP interlaminar fracture. In the both specimens, fracture toughnesses decreased at cryogenic temperature from those at room temperature.In the DCB specimens made of two Ti alloy beams fusion-bonded by LCP were evaluated as 200 J/m^ 2 and 350 J/m^ 2 at room and cryogenic temperatures, respectively. Its temperature dependence was different from others.
- Abstract document
- Manuscript document
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