The assessment examined abnormal grain growth in the metallic liner of a composite overwrapped pressure vessel. NESC evaluated the liner's mechanical response, including its strain amplification factor, using custom-designed coupons that combined metal and composite overwrap. [S1]
The coupon approach was effective and practical for characterizing strain localization under various conditions, and its results showed strong correlation with modeling. Preliminary investigations also found phase coherence imaging, an ultrasonic technique, promising for detecting abnormal grain-growth microstructures; the technique needs further development. [S1]
Source documents
- TB 26-02 Effects of Large Grain Size in Composite Overwrapped Pressure Vesselhttps://www.nasa.gov/centers-and-facilities/nesc/tb-26-02-effects-of-large-grain-size-in-composite-overwrapped-pressure-vessel/