Impact damage characteristics of steel fiber reinforced cement matrix composites based on digital image correlation
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摘要: 本文采用数字图像相关（DIC）技术对钢纤维增强水泥基复合材料三点弯落球冲击试验过程中试件表面位移场和应变场进行计算与研究，基于开裂点附近位移变化确定初裂冲击次数，并对全场水平应变值进行统计分析，得到冲击过程的损伤程度因子（Df）表征曲线，进一步探讨纤维掺量对试件弯曲冲击损伤的影响规律。试验结果表明：钢纤维的掺入对水泥基材料破坏次数的提高较初裂次数更明显；Df曲线能够较好反映冲击荷载作用下试件弯曲冲击破坏各阶段；试件弯曲冲击损伤过程经历缓慢、加速、再缓慢三个阶段；纤维掺量越多，Df曲线发展越缓慢，冲击损伤三阶段中的再缓慢阶段所占比例越大，即钢纤维增韧作用主要表现在三阶段损伤过程中的再缓慢阶段。
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关键词:
- 混凝土 /
- 钢纤维 /
- 弯曲冲击 /
- 数字图像相关(DIC) /
- 损伤
Abstract: The surface displacement field and strain field of steel fiber reinforced cement matrix composites at three-point bending falling ball impact test were calculated and studied by the digital image correlation (DIC) technology. The impact times of initial crack was determined by the displacement near the crack point. And the whole horizontal strain was statistically analyzed to obtain damage factor(Df) characterization curve under impact. The influence law of bending impact damage with different fiber dosage was further investigated. The experimental results indicate that compared with the effect to the initial crack impact times, the steel fibers effect to the crack impact times is more obvious; Df curve can better reflect the impact of shock load and the bending impact of the specimen is destroyed, based on the damage factor characterization curve, the impact bending process has tardiness, acceleration and tardiness stages; The more fiber content, the slower Df curve development, the greater the proportion of the tardiness stage of the three impact damage stages. And steel fiber toughening effect mainly displays in the tardiness stage.-
Keywords:
- concrete /
- steel fiber /
- flexural impact /
- digital image correlation (DIC) /
- damage
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