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

作　　者：李晓龙 方海[2] 吴鹏 LI Xiaolong;FANG Hai;WU Peng(School of Architecture and Civil Engineering,Jiangsu Open University,Nanjing 210036,China;College of Civil Engineering,Nanjing Tech University,Nanjing 211800,China)

机构地区：[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

出　　处：《复合材料学报》2024年第7期3813-3821,共9页Acta Materiae Compositae Sinica

基　　金：国家自然科学青年基金(52108215)。

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3000~8760 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3000 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3000 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GFRPbalsa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%。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 temperature of(25±1)℃and relative humidity of 55%±5%,the three-point flexural creep performance of the GFRPbalsa sandwich beams at 20%,25%and 30%load levels were tested for a period of 3000-8760 h using the selfdesigned 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 3000 h of all the specimens are not less than 0.35.The Findley model is applicable 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 3000 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 

分 类 号：TB332[一般工业技术—材料科学与工程]