Computation model of bridging stress for flexible short fiber in asphalt at low temperature
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摘要: 分析了柔性纤维增强脆性材料特点, 建立了单根纤维从沥青中拔出时的受力模型。采用球面坐标系建立空间均匀分布短纤维桥联应力的计算模型, 计算了沥青断裂时短纤维产生的桥联应力。采用大尺寸的纤维沥青试件进行低温拉伸断裂试验, 实测短纤维的桥联应力。通过对桥联应力的计算值和实测值进行试算拟合, 修正了计算模型中的参数。分析结果表明: 桥联应力的实测值和模型计算值的拟合误差最大值为6.67%, 拟合效果比较理想。可见, 采用力学-经验方法可以研究低温下柔性短纤维桥联应力。Abstract: The characteristics of flexible-fiber-reinforced brittle materials were analyzed, and a mechanical model of single fiber pulled out from asphalt at low temperature was established.In spherical coordinate, a computation model of bridging stress for short fiber was established when short fibers uniformly distributed in asphalt, and the bridging stress was computed when asphalt ruptured.The bridging stress was measured by using tensile test and large size fiber asphalt samples at low temperature.The calculation model was corrected by fitting calculated and measured values of bridging stress.Analysis result shows that the maximal fitting error is 6.67%, so, the mechanics-experience method can be used to study the bridging stress of flexible short fiber at low temperature.
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Key words:
- pavement material /
- flexible short fiber /
- low temperature /
- asphalt /
- bridging stress /
- calculation model /
- tensile test
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图 1 单根柔性纤维从脆性材料中拔出时的典型受力曲线
Figure 1. Typical stress curve of single fiber pulled out from brittle material
图 2 单根纤维从沥青中拔出时的典型受力曲线
Figure 2. Typical stress curve of single fiber pulled out from asphalt
图 3 多根纤维从沥青中拔出时的典型受力曲线
Figure 3. Typical stress curve of several fibers pulled out from asphalt
图 4 单根纤维从沥青中竖直拔出的受力模型
Figure 4. Stress model of single fiber vertically pulled out from asphalt
图 6 考虑方向和埋入长度的单根纤维拉拔受力模型
Figure 6. Stress model of single fiber considering buried angle and depth
图 9 纤维埋置角度分布函数计算模型
Figure 9. Calculation model of distribution function of buried angle for fiber
表 1 拉伸试验值和数值计算值拟合结果
Table 1. Fitting result of tensile test values and numerical calculation values
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