TESTING AND ANALYSIS OF MARINE COMPOSITE STRUCTURES IN ELEVATED TEMPERATURE CONDITIONS

摘要

A series of 1.8m long glass/vinyl-ester beam specimens has been tested in four-point flexure, at room temperature and at elevated temperature, in isothermal and non-isothermal conditions. The beams are typical of composite structures that would be used in shipboard applications, including solid fiberglass laminates as well as balsa core and foam core variants A finite element analysis was ten performed for each test condition, computing the time-history of temperature and structural response of the beams, including the effects of creep and reduction in elastic modulus at elevated temperatures. Predictions using temperature dependent material properties obtained from Dynamic Mechanical Thermal Analysis (DMTA) of coupon-size specimens yielded deflections that were not consistent with the 1.8m beam tests, suggesting a scale effect in the DMTA test results. Material properties obtained from the beam tests were therefore used in the finite element analysis. A key aspect of the finite element modeling was the use of a relatively coarse mesh density, suitable for modeling larger structures, such as a stiffened panel, a bulkhead, or an entire deckhouse. Comparisons with test results indicate that the finite element models may provide a suitable analysis tool for the design of marine structures that may be exposed to elevated temperature conditions, although the modeling was based on a very limited number of tests. Further verification efforts are in progress.