基于Weibull分布函数的FRP退化模型研究

Study on deterioration model of fiber reinforced polymer by Weibull probability distribution

为进一步认识纤维增强复合材料(FRP)在不同使用环境下的长期性能,通过已有FRP耐久性试验研究,引入二参数Weibull分布函数,在试验样本与参数估计的基础上,对比例参数η与形状参数β二参数进行分析,建立FRP等效Weibull分布退化模型。分析结果表明:在不同环境下,拉伸强度比例参数η随退化时间的延长而逐渐降低,且退化前期下降较快;而形状参数β对不同环境与退化时间均较不敏感。将退化模型与试验结果及现行规范取值对比分析表明,本文模型与试验结果吻合良好,可较好地预测FRP在不同环境下的长期性能。在此基础上,简化得到相应的环境影响修正系数κ_(env),并对现行规范中存在的问题进行探讨,为FRP材料加固混凝土结构的耐久性设计提供参考。

In order to further understand the long-term performance of fiber reinforced polymer composites(FRP)under different exposure circumstances,a new degradation model,based on existing durability of experimental data and analysis of the scale parameterηand the shape parameterβ,is proposed to describe long-term deterioration of FRP characteristics by using two-parameter Weibull distributions.Based on the result,the scale parameterηof tensile strength is found to decrease significantly with increasing time,and the decline is faster in the early stage of degradation;and the shape factorβis insensitive to different exporsure circumstances.The prediction of probabilistic model are compared with experimental durability data and characteristics value,and the results indicate that the proposed model can well predict the long-term characteristics of FRP.Finally,the environment reduction factor κ_(env) is suggested,which serves as important reference in strengthening design.