基于DIC的BFRC受压损伤特性及本构模型研究

Research on Compression Damage Characteristics and Constitutive Model of BFRC Based on DIC

采用数字图像相关(DIC)技术对玄武岩纤维混凝土(BFRC)受压过程中试件表面应变场进行计算,分析了试件表面水平应变云图变化情况,得到了BFRC受压损伤演化规律;通过对水平应变场统计分析,利用应变场标准差统计指标定义损伤演化因子,得到不同纤维掺量下BFRC损伤演化曲线;同时,基于应变等效原理及损伤演化因子,推导出BFRC单轴受压损伤本构模型,通过对比试验与模型曲线,发现两者吻合较好,该模型在峰值应变之前可有效描述BFRC单轴受压下损伤演化过程;对比曲线发现玄武岩纤维可有效提高混凝土峰值应力及峰值应变,提高其变形能力,并具有延缓损伤作用。

Through digital image correlation method,the surface strain field of basalt fiber reinforced concrete under pressure was calculated.The change of the horizontal strain cloud diagram about the specimen surface was analyzed,the evolution rule of compression damage about BFRC was obtained.By means of statistical analysis of horizontal strain field,the damageevolution factor was defined by using the statistical index of strain field standard deviation and the curve of BFRC damage evolution with different fiber dosage was obtained.At the same time,the constitutive model of BFRC uniaxial compression damage was deduced based on the strain equivalence principle and the damage evolution factor.The test resultis in good agreement with model curve,which couldeffectively describe the damage evolution process of BFRC under uniaxial compression before peak strain.Through the comparison curves,it shows that the basalt fiber can effectively improve the peak stress and peak strain of concrete.The ductility could also be enhanced.And the fiber still have the effect of delaying damage.