The Interplay between Seawater Absorption, Temperature, and Stress on Marine Composite Degradation
Abstract
Polymer composites are appealing for naval vehicles due to their high specific stiffness and strength and great impact and corrosion resistance. However, limited knowledge of their long-term performances under service conditions leads to inefficient designs of naval structures, which can compromise their reliability and survivability in harsh environments. Current challenges in predicting theservice life of marine composites are attributed to: (1) real-time testing for characterizing mechanical properties of composites relevant for long-duration missions (> 20 years) is unavailable and also impractical; (2) the hierarchical structures and material heterogeneities of composites when exposed to coupled mechanical loading and harsh environments lead to multiple time-dependent degradation and complex failure mechanisms; (3) naval vehicles are of complex geometries that can result in high gradients of fluid concentration, temperature, and stress when exposed to service conditions, leadingto localized damages that are difficult to detect.This project aims at investigating the multiple time-dependent degradations of carbon fiber-reinforced polymer composites exposed to seawater absorption, temperature cycle (-5 to 80oC), creep, and cyclic loadings, and their interactions on the creep and fatigue performance of composites. The team will perform immersion of specimens in seawater under varying mechanical loading (creep, cyclic, and hydrostatic pressure) and temperature and measure the subsequence changes in the physical properties of the composites. Accelerated testing techniques for predicting long-term creep and fatigue performances of the composites in different environments will be developed. The team will use multi-scale modeling and testing to study the influence of composites# microstructures (woven fabric architecture, unidirectional fiber architecture, and additively manufactured microstructural topology) and constituent properties on the creepand fatigue failures of the composites under exposure to harsh marine environments. Composites of different geometries, i.e., planar, rod, tube, and curbed beam, will be studied to examine the effect of spatial variations in the fluid sorption, heat generation from the long-term cyclic loading, and localized stress on the degradation of the composites. The team will train undergraduate and graduate students with knowledge of composite durability relevant to naval vehicles through research projects and Capstone Design courses. The team also plans to participate in summer camps to introduce composites to high-school students.The outcomes of this research are (1) the scientific explanation of how the coupled seawater absorption, temperature, and stress affect the degradation evolution and long-term performance of marine composites and (2) the identification of failure mechanisms in composites driven by their microstructural architectures and physical properties of constituents. The potential impact of thisresearch will enable the design of composite structures that can meet the demands of long-duration navy missions and promote the condition-based maintenance of naval vehicles, with a potentially large reduction of operational and maintenance costs.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Nov 08, 2024
- Source ID
- N000142412476
Entities
People
- Anastasia Muliana
Organizations
- Office of Naval Research
- Texas Engineering Experiment Station
- United States Navy