为研究钢纤维混凝土管片中钢纤维的细观分布和朝向特征对管片宏观承载性能的影响，基于球面概率密度函数，建立一种更准确的钢纤维投放算法；利用MATLAB编程和Abaqus联合仿真，建立钢纤维混凝土管片受荷变形和损伤的三维精细模型；
以钢纤维方向系数和纤维分布差异率作为变量，详细分析不同参数设置下钢纤维混凝土管片的力学特性和损伤演变规律。结果表明: 1)采用球面概率密度函数优化后的钢纤维投放算法能够有效解决投放不均的问题，并且显著提升模型预测的准确性。2)钢纤维的方向系数和分布差异对管片的抗弯承载力、韧性及延性等关键性能指标有着至关重要的影响；当钢纤维方向系数由1.0降至0.3时，管片的抗弯韧性下降约75.79%，延性也相应降低约4.18%；而当分布差异率从-0.25增至0.25时，抗弯韧性的降幅达到26.08%，延性则降低约6.72%。3）合理调整钢纤维的分布和朝向有助于增强结构的安全性与稳定性。
Herein, the impact of the mesoscopic distribution and
orientation characteristics of steel fibers in steel fiber-reinforced
concrete (SFRC) segments on the macroscopic load-bearing
performance are explored. First, a more precise steel fiber placement algorithm
grounded in spherical probability density functions is proposed. Then, a three-dimensional fine simulation model of load deformation and damage of
SFRC segments is established using MATLAB programming and Abaqus joint
simulations. Finally, the mechanical properties and damage evolution of SFRC
segments under different parameters are examined in detail by taking the
orientation coefficient of steel fiber and the difference rate of fiber
distribution as variables. The experimental results show the following: (1) The
steel fiber placement algorithm optimized by spherical probability density
function effectively solves the problem of uneven placement and significantly
improves the prediction accuracy of the model. (2) The orientation coefficient
and distribution difference of steel fiber crucially influence the key
performance indices such as flexural bearing capacity, resilience, and
ductility of segments. When the steel fiber orientation coefficient decreases
from 1.0 to 0.3, the flexural resilience of the segment decreases by about
75.79%, and the ductility decreases by about 4.18%. When the distribution
difference rate increases from －0.25 to 0.25, the
flexural resilience decreases by 26.08%, and the ductility decreases by about
6.72%. In summary, reasonable distribution and orientation of steel fibers are
beneficial to safety and stability of the segment structure.
