摘要
玻璃纤维增强塑料(GFRP)材料的力学性能对工作环境温度很敏感,在设计时应充分考虑环境温度对此的影响。通过试验研究在不同工作环境温度(20℃～120℃)条件下GFRP筋拉伸力学性能的温度效应。加载设备采用MTS322电液伺服静动万能试验机,试验温度由环境箱进行自动控制。试验结果表明:试件在加载过程中,会因损伤而发出清脆响声,其表面出现白斑状裂纹,随荷载增加响声增大而渐密;破坏形态多为较大范围内发生片状裂开破坏,偶见某一断面断裂破坏,均为脆性破坏;GFRP筋的力学性能对环境温度非常敏感,极限抗拉强度、抗拉初始弹性模量、屈服应变和极限延伸率随着环境温度增加而下降,而抗拉屈服后弹性模量变化规律则相反;GFRP筋应力–应变曲线在20℃～80℃时为双线性,随着温度升高,其屈服点逐渐降低,在100℃,120℃时应力–应变曲线变为线性。通过试验分析,建立考虑环境温度影响的GFRP筋应力–应变关系及其相关参数同环境温度的关系;提出考虑环境温度影响的GFRP筋极限抗拉强度计算公式。试验研究成果为GFRP筋在不同环境温度条件下应用提供了科学依据。
Temperature is an important factor influencing the mechanical properties of glass fiber reinforced plastic(GFRP) material,and it should be considered sufficiently. Based on experiments,the mechanical properties of GFRP rebar at different environmental temperatures ranging from 20 ℃ to 120 ℃ are studied. The load is applied by MTS322 electro-hydraulic servo-controlled testing machine,and the test temperature is controlled by the circumstance box. Twenty six GFRP rebars are adopted in this test,which are 10 mm in diameter and 400 mm in the efficient pull-out length. The following conclusions can be drawn from the experiments. Firstly,during the loading process,white fleck cracks appear on the surface with hard noise caused by damage. The noise becomes louder with the load increasing. Flake crack in a big range is the main failure mode,and the rupture on a section is a rare occasion. Both are brittle failure modes. Secondly,the mechanical properties of GFRP rebar are sensitive to temperature. The ultimate tensile strength,the initial tensile Young′s modulus,the yield strain and the ultimate elongation ratio all decrease with the temperature increasing,but the elastic modulus after tensile yield is reverse. Thirdly,the stress-strain relationship of GFRP rebar between 20 ℃-80 ℃ is bilinear. With the temperature increasing,the yield point reduces gradually. At the temperatures of 100 ℃ and 120 ℃,the stress-strain relationship is linear. By the analysis of experiment,considering thermal effect,the stress-strain relationship of GFRP rebars and the relationships between correlative parameters and the temperature have been established. A formula has been developed to calculate the ultimate tensile strength of GFRP rebar. The experimental results supply scientific foundations for the GFRP rebars′ application at different temperatures.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2008年第S1期2707-2714,共8页
Chinese Journal of Rock Mechanics and Engineering
基金
广东省交通科技项目(2004–17)
关键词
岩土力学
玻璃纤维增强塑料
拉伸试验
力学性能
温度效应
rock and soil mechanics
glass fiber reinforced plastic(GFRP)
tensile test
mechanical properties
temperature effect
