Quasi-static and dynamic properties of unidirectional glass fiber/epoxy laminate for structural strengthening

Glass fiber reinforced polymer (GFRP) shows excellent mechanical properties and high cost performance, and has been extensively used for structural retrofit. Considerable research has demonstrated the effectiveness of using GFRP composite to retrofit deficient engineering structures. Nowadays, the increasing interest in using GFRP composite to retrofit structures against impact and blast loadings makes it essential to have a comprehensive knowledge of its dynamic properties for precise prediction of the dynamic behavior of GFRP retrofitted structures. Therefore, the quasi-static and dynamic properties of commonly used GFRP were investigated. The stretching process of the GFRP specimen was captured using a high-speed camera, and the images were post-processed with a digital image correlation technique to derive the strain time curve. The strain rate ranges from 6E-5 to 260 s(-1). It was found that the tensile strength, Young's modulus and failure strain of GFRP show an apparent strain rate sensitivity, which might be due to the different failure modes of the specimen under various strain rates. Empirical equations for predicting the dynamic increase factor in terms of strain rate are proposed according to the testing results of this study and collected from other research.

Automated summary

Glass fiber reinforced polymer (GFRP) is widely used for structural retrofit due to its excellent mechanical properties and cost performance. This study investigates the quasi-static and dynamic properties of commonly used GFRP and finds that its tensile strength, Young's modulus, and failure strain show strain rate sensitivity. The findings provide valuable insights for predicting the dynamic behavior of GFRP retrofitted structures.