Effects of Subzero Temperatures and Seawater Immersion on Damage Initiation and Growth in Sandwich Composites; Interim rept. 13 Dec 2007-13 Jun 2008

摘要

Progress during the past six months is described. Efforts during this period have focused on (1) immersion studies of core and sandwich laminates, (2) the effects of environment on impact damage and fatigue response, and (3) debonding test development and toughness assessments. Ongoing studies in the first area indicate that there is no appreciable difference in the sea water absorption rate or saturation level for samples immersed at room temperature versus immersion at 0 C. In the second focus area, approximately 50% of the proposed test program has been completed, allowing a number of preliminary conclusions to be drawn about the effects of temperature, sea water saturation, and damage on the static strength, stiffness, fatigue life and fatigue strength of sandwich laminates. In the third focus area, work on validating a new, highly accurate debonding test is nearly complete. Specimens have also been manufactured and sea water conditioned in preparation for subsequent use of this test method to study the effect of temperature and sea water immersion on toughness.