Biaxial Mechanical Properties of High-Strength Weldable Aluminum Alloys
The uniaxial mechanical properties of most structural metals tested at liquid-hydrogen temperature show the yield, ultimate, and weld strengths to be substantially increased over their room-tempe rature values. The tensile notch and impact strengths, however, are generally lower than their room-temperature values, indicating a tendency toward brittle behavior. Since notch and impact strength values are comparative data only and are not values which can be directly correlated with actual design problems, the question arises as to how this extremely low-temperature service affects the structural reliability of missile tankage. This question could be answered by the testing of a full-scale statictest article for each design. A full-scale static test with liquid hydrogen, however, is extremely costly and hazardous. A failure could result in a fire or in explosion and no conclusive information would be obtained, Therefore designers of liquid-hydrogen missile tankage systems are compelled to be conservative to ensure a successful static test. The resultant weight penalty is sufficient reason for the construction of a test fixture that closely simulates design conditions at cryogenic temperatures.
KeywordsImpact Strength Cryogenic Temperature Test Fixture Weld Strength Center Deflection
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