Durability and life prediction of a pultruded fibreglass flat sheet using an arrhenius method

This paper reports experimental findings from characterization work to understand the mechanical property changes of a pultruded fibre-polymer composite after exposure to hygrothermal aging. An ‘off-the-shelf’ glass/polyester plate of nominal 6.35 mm thickness at coupon level is investigated. Changes in tensile, compression, and pin-bearing properties are evaluated using test results from 75 coupons that had been immersed in distilled water at aging temperatures of either 25, 40 or 60 ℃ for 1278 days (3.5 years); this new data is combined with previous test results from characterizing 425 coupons for unaged and aging up to 224 days of hygrothermal aging. Compression strengths and moduli of elasticity and pin-bearing strengths with loading applied both in parallel and transversely to the direction of pultrusion were obtained from batches of five specimens per temperature. Whereas for the tensile loading batches of five specimens loading was only applied parallel to the direction of pultrusion. After the conditioning, short-term static tests to ultimate failure were conducted at room temperature. The effects of accelerated aging on the mechanical properties are discussed and an Arrhenius-based model is employed to predict the effective aging time for an average outdoor temperature of 9.97 ℃. This study presents insightful data into the long-term behavior of the pultruded material, thereby addressing a critical gap in existing knowledge that can be employed to categorize pultruded profiles for the design of structures having design working lives of, say 50 or more years.