The lack of a comprehensive, validated, and easily accessible data base for the durability of fiber-reinforced polymer (FRP) composites as related to civil infrastructure applications has been identified as a critical barrier to widespread acceptance of these materials by structural designers and civil engineers. This concern is emphasized since the structures of interest are primarily load bearing and are expected to remain in service over extended periods of time without significant inspection or maintenance. This paper presents a synopsis of a gap analysis study undertaken under the aegis of the Civil Engineering Research Foundation and the Federal Highway Administration to identify and prioritize critical gaps in durability data. The study focuses on the use of FRP in internal reinforcement, external strengthening, seismic retrofit, bridge decks, structural profiles, and panels. Environments of interest are moisture/solution, alkalinity, creep/relaxation, fatigue, fire, thermal effects (including free...

Durability Gap Analysis for Fiber-Reinforced Polymer Composites in Civil Infrastructure

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Durability Gap Analysis for Fiber-Reinforced Polymer Composites in Civil Infrastructure | NIST

Continuous fibre reinforced thermoplastic composites are increasingly applied in aircraft structures. These high-performance thermoplastic matrices need processing at high temperatures; therefore, thermal residual stresses arise due to the mismatch in coefficients of thermal expansion between the fibres and the thermoplastic matrix. Since residual stresses are inherently present in virtually all composite materials and influence the properties of the composite structures significantly, it is of utmost importance that the residual thermal stresses are taken into account in both design and analytic modelling of composite structures. In order to understand the effects of residual stresses and find ways to decrease their magnitude or use them to our advantage, the factors responsible for the residual stress build-up need to be understood. This first part of a literature review discusses these factors, focusing on thermoplastic composites, and in particular the material properties of their constituents and processing parameters governing stress build-up.

Residual stresses in thermoplastic composites—A study of the literature—Part I: Formation of residual stresses

Seawater durability of glass- and carbon-polymer composites

The degradation of an IM7/997 carbon fiber-reinforced epoxy exposed to ultraviolet radiation and/or condensation has been characterized. Based on observations of physical and chemical degradation it has been established that these environments operate in a synergistic manner that causes extensive erosion of the epoxy matrix, resulting in a reduction in mechanical properties. Matrix dominated properties are affected the most, with the transverse tensile strength decreasing by 29% after only 1000 h of cyclic exposure to UV radiation and condensation. While, the longitudinal fiber-dominated properties are not affected for the exposure durations investigated, it has been noted that extensive matrix erosion would ultimately limit effective load transfer to the reinforcing fibers and lead to the deterioration of mechanical properties even along the fiber dominated material direction.

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Degradation of Carbon Fiber-Reinforced Epoxy Composites by Ultraviolet Radiation and Condensation

Written especially for first-time users of reinforced plastics. The book offers substantial introductory information with key concepts. Chapters examine the long-term threats to the integrity of reinforced plastics: outdoor weathering, solvent/water attack, high temperatures, and repetitive stress.

Geoffrey Pritchard

Papers

Reinforced Plastics Durability