Development of a test facility for measuring the mechanical properties of materials under cryogenic environment: 1st Report uniaxial mechanical property testing
Structures Research Group, Institute of Aeronautical Technology, Japan Aerospace Exploration Agency (JAXA)
Structures Research Group, Institute of Aeronautical Technology, Japan Aerospace Exploration Agency (JAXA)
The recent application of composite materials in the cryogenic propellant tanks of a rocket structure is expected to result in significant structural weight reduction, a factor considered essential to the improvement of a rocket’s launch capability. Previous research and development activities have highlighted the importance of propellant leakage in addition to composite material strength during the design of cryogenic propellant composite tanks. The development of a test facility for measuring cryogenic biaxial mechanical properties is currently in progress at JAXA IAT(Institute of Aeronautical Technology) with the aim of developing a data of leakage results for composite materials under cryogenic conditions. Although the final goal is to develop a test facility for cryogenicbiaxial mechanical properties, a cryogenic environmental chamber for uniaxial mechanical property testing has been developed as a first step to overcoming a range of technical challenges. This report summarizes the development of a cryogenic environmental chamber for uniaxial mechanical property testing. In this development, composite specimens were cryogenically cooled using a refrigerator for the specimen instead of liquefied helium as a cryogen due to the difficulties with measuring propellant leakage from helium leak detectors. The specimen cooled by the refrigerator was subjected to uniaxial tensile load by a biaxial testing machine. During tensile testing, thespecimen was maintained at a cryogenic temperature by the refrigerator and vacuum insulation. In this development, it was difficult to design the interface to apply the tensile load to the specimen gauge area, which was positioned inside the cryogenic environmental chamber combined with vacuum insulation. In addition, there was a concern that the reaction of the specimen fracture might give the damage to the cryogenic environmental chamber and the refrigerator. Therefore, the cryogenic environmental chamber was equipped with protection mechanisms to avoid the damage to chamber and the refrigerator from the shock of the specimen fracture. The results of the performance tests reveal that the environmental chamber has the capability to cool the specimen below -196 C and enables the cryogenic fracture tensile testing of the composite materials with a biaxial testing machine.
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内容記述（英）
Physical characteristics: Original contains color illustrations
極低温環境力学特性用試験設備の開発: その1 単軸力学特性試験
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