GFRP-轻木夹芯梁弯曲蠕变试验及预测
Flexural creep test and prediction of GFRP-balsa sandwich beams
李晓龙 1方海 2吴鹏2
作者信息
- 1. 江苏开放大学 建筑工程学院,南京 210036
- 2. 南京工业大学 土木工程学院,南京 211800
- 折叠
摘要
以玻璃纤维增强复合材料(GFRP)为面层,轻木(Balsa)为芯材的GFRP-balsa夹芯结构在基础设施领域的应用范围不断扩大,但 GFRP-balsa夹芯结构具有粘弹性,易于发生蠕变变形.为此,在温度为(25±1)℃,相对湿度为 55%±5%的环境下,利用自主设计的弯曲蠕变加载装置对GFRP-balsa夹芯梁在 20%、25%和 30%荷载等级下的三点弯曲蠕变性能进行了 3 000～8 760 h的测试,并利用多种模型对GFRP-balsa夹芯梁的蠕变响应进行了模拟和预测.结果表明:在试验荷载等级下,GFRP-balsa夹芯梁表现出线性粘弹性;弯曲蠕变对GFRP-balsa夹芯梁的跨中挠度具有重要影响,所有试件在 3 000 h的蠕变系数均不小于 0.35;Findley模型适用于单一荷载等级下GFRP-balsa夹芯梁时变总挠度的拟合,在 3 000 h的拟合值与试验值之间的最大相对误差仅为 0.7%;Bailey-Norton模型和通用幂次律模型分别适用于荷载等级不超过 30%的GFRP-balsa夹芯梁蠕变挠度和时变总挠度的预测,在一年时,Bailey-Norton模型和通用幂次律模型预测值与试验值之间的最大相对误差分别为8.3%和5.9%.
Abstract
The application scope of the glass fiber reinforced plastic(GFRP)-balsa sandwich structure composed of GFRP facings and a balsa wood core is constantly expanding in the field of infrastructure.However,GFRP-balsa sandwich structures are susceptible to creep deformation due to their viscoelasticity.Under the controlled tem-perature of(25±1)℃and relative humidity of 55%±5%,the three-point flexural creep performance of the GFRP-balsa sandwich beams at 20%,25%and 30%load levels were tested for a period of 3 000-8 760 h using the self-designed flexural creep loading devices.Various models were used to simulate and predict the creep response of the GFRP-balsa sandwich beams.The results show that the GFRP-balsa sandwich beams exhibit linear viscoelasticity at the test load levels.Flexural creep has an important impact on the mid-span deflection of the GFRP-balsa sandwich beams,and the creep coefficients at 3 000 h of all the specimens are not less than 0.35.The Findley model is applic-able for fitting the time-dependent total deflection of the GFRP-balsa sandwich beams at a single load level,and the maximum relative error between the fitting value and the test value at 3 000 h is only 0.7%.The Bailey-Norton model and the general power law model are applicable for predicting the creep deflection and the time-dependent total deflection of the GFRP-balsa sandwich beams when the load level does not exceed 30%,respectively.At one year,the maximum relative error between the predicted value of the Bailey-Norton model and the test value is 8.3%,and the maximum relative error between the predicted value of the general power law model and the test value is 5.9%.
关键词
玻璃纤维增强复合材料/轻木/夹芯梁/弯曲蠕变/预测模型Key words
glass fiber reinforced plastic/balsa/sandwich beam/flexural creep/prediction model引用本文复制引用
出版年
2024
NETL
NSTL
万方数据