دانلود کتاب Creep tests on GFRP pultruded specimens subjected to traction or shear

In this paper, experimental long-term tests on pultruded GFRP specimens are presented. Specimens havebeen subjected to constant traction and shear forces for about 760 days. The tests have been performedunder controlled temperature (20 °C) and humidity (60% RH) inside a climatic room. The specimensunder traction have been cut from plates and from the flanges of a wide flange GFRP pultruded beam;the specimens under shear loadings have been extracted from the web of the same beam. Moreover,some specimens have been stiffened by bonding CFRP sheets to both sides, in order to study how theirintroduction may reduce the specimen deformability under long term loading. Results from the unstiff-ened specimens have been interpreted by means of the Findley law, the reference model for creep inpolymers and FRP, in terms of strains and creep coefficient. A simple model has been finally proposedto predict strains in stiffened specimens and by taking stress redistribution into account.