Deterioration Modeling of Large Glass Fiber Reinforced Polymer Composite Structures/Systems

The adoption of fossil-based hydrocarbon polymer composites has been successful in both the automotive and aircraft industries, and is rapidly expanding into buildings and civil infrastructure. One challenge to broader adoption of polymer composites in buildings and civil infrastructure is a limited ability to model the synergistic effects of the combined physical/chemical processes of environmental exposure and mechanical loading. Unlike other building materials, long-term experience and field performance data of polymer composites in buildings and civil infrastructure applications does not exist. The first and largest composite building system used in a high-rise exterior in the US is the facade of the San Francisco Museum of Modern Art (SFMOMA) completed 4 years ago in 2015. Since historical, experience-based service life models for composite building applications are not available, it is crucial to build multiphysical- based models in order to predict composite service life performance on a semi-centennial or centennial time scale. This paper begins to understand the thermochemical- mechanical degradation mechanisms of composite building materials at multiple length scales and proposes a computational model for service life prediction. This effort consists of two steps; (i) development of a theory of synergistic effects between two or more degradation processes (e.g., ultraviolet exposure and moisture exposure), and (ii) validate a computational model of this theory based on published accelerated degradation experiments. This effort extends the literature on composite degradation from empirical or observation-based models to new multi-physics-based models, and looks to assess the viability of new polymer composite building materials by leveraging both experimental and computational approaches.