温度对纤维增强塑料筋力学性能的影响

摘要

将直径φ8的玄武岩纤维增强塑料(BFRP)和玻璃纤维增强塑料(GFRP)筋恒温30 min再冷却至室温,用钢套管固定BFRP和GFRP筋端头并对其进行拉伸力学性能试验.研究BFRP和GFRP筋受拉本构关系、拉伸弹性模量、极限抗拉强度、极限拉应变等力学性能,并拟合温度在20～120℃时BFRP和GFRP筋拉伸力学性能随温度作用后的变化规律.结果表明:随荷载增加到极限荷载65％ ～80％,BFRP和GFRP筋均发出清脆的声音,其表面纤维丝断裂而导致脆性破坏;随温度增加,BFRP和GFRP筋受拉本构关系呈线性变化;120℃与20℃相比,极限抗拉强度分别降低9.8％和10.6％;BFRP筋极限拉应变减少20.4％,而GFRP筋出现先减后稍增趋势;BFRP筋拉伸弹性模量提高5.4％和13.9％,而GFRP筋呈先增后减现象.%Maintained at different temperatures,the sensitivity of fiber reinforced plastic (FRP) bar's tensile mechanical properties to temperature was studied.BFRP (φ8) and GFRP (φ8) were retained at constant temperature for thirty minutes and then cooled to room temperature,and fixed by steel casing to test their tensile mechanical property.Mechanical properties of BFRP and GFRP bar's including tensile constitutive relation,tensile elastic modulus,ultimate tensile strength and ultimate tensile strain were tested,and the variation of BFRP and GFRP bar's tensile mechanical properties to temperature (20-120℃) was fitted.The results showed that when the load of BFRP and GFRP bar was increased to 65％-80％ of ultimate load,there was crisp sound,and surface filament broke,leading to brittle failure.With the increase of temperature,BFRP and GFRP bar's tensile constitutive relationship varied linearly.Compared 120℃ with 20℃,ultimate tensile strength decreased by 9.8％ and 10.6％ respectively;BFRP bar's ultimate tensile strain decreased 20.4％,while that of GFRP bars increased slightly after the first decrease trend;BFRP bar's tensile elastic modulus increased by 5.4％ and 13.9％,while that of GFPR bar increased firstly and then decreased.