Manufacturing Composite External Volumes with Enhanced Underwater Collapse Performance

Fiber Reinforced Polymer (FRP) composites have characteristics that have allowed for flexibility for application-specific customizations to isolate components inside the External Volumes (EVs) from exposure to the harsh marine environment.Ā However, if the EV implodes due to buckling, the collapse results in a pressure shock wave that can damage nearby structures and other EVs.Ā The Navy needs to improve control over the manufacturing and inspection processes to get a narrower tolerance of the collapse pressure prediction of the fabricated EVs.Ā Based on the manufacturing methods and the flaws that are found during inspection, a predictive model needs to be developed to bestow more confidence in the collapse pressure that will occur, which will eliminate the need to test the fabricated EVs up to their hydrostatic collapse pressure.Ā The Navy needs a better understanding of what have been fabricated using known manufacturing and inspection criteria by constraining the production quality requirements, and to understand the quality spectrum that is acceptable to meet the requirements in order to lower cost. Ā Inspection criteria need to be developed to identify manufacturing flaws and determine how flaw size, geometry, quantity, and location will change the collapse pressure to better understand which parts to reject and which to accept.Ā Texas Research Institute Austin, Inc. (TRI Austin) will develop and validate an approach for the translation of nondestructive inspection (NDI) defect detection into descriptions of the defects suitable for use in collapse prediction models that can calculate their effect on structural performance. The largest benefit to the Navy is in the reduction of engineering effort and unnecessary part rejection at defect sizes near the currently established limits for geometry tolerance and flaws.Ā TRI Austin will develop filament winding fabrication procedures and material requirements to manufacture high-quality composite pressure housings for EVs with the fewest flaws to control the collapse response.Ā Understanding how different filament winding methods will affect flaw distributions, which can compromise the collapse pressure, will be necessary to better control the collapse pressure.Ā TRI Austin will then non-destructively inspect the part geometries for wall thickness, diameter, out-of-roundness, and to identify and measure any flaws through the thickness.Ā TRI Austin will also test the hydrostatic collapse pressure of the filament wound EVs, perform quasi-static material characterization testing, and high strain rate testing.