预应力钢筒混凝土管断丝检测数值仿真等效模型

有限元仿真常用于辅助分析预应力钢筒混凝土管断丝检测数据,在建模过程常遇到预应力钢丝螺旋结构网格划分困难,单元数量过多的情况。将预应力钢丝的螺旋结构模型等效成圆环模型以简化建模。针对含有阴极保护钢带的E型管道,对比分析了螺旋线结构+两条钢带模型、圆环+两条钢带模型和无钢带圆环模型的计算结果;针对L型管道,考虑了断丝时钢丝与钢筒之间脱开的效应。计算结果表明,对于含有阴极保护钢带的E型管道,圆环+两条钢带的模型与螺旋线模型等效效果最好,无钢带圆环模型等效效果较差;对于L型管道,圆环模型断口间距与螺旋线模型中钢丝与钢筒脱开的环向距离一致时,圆环模型和螺旋线模型等效。

Study on equivalent model of Prestressed Concrete Cylinder Pipe wire breakage detection based on finite element method

Finite element method is often used for the assistant analyses of the broken wire inspection data from prestressed concrete cylinder pipes. It is usually difficult to discretize mesh for the spiral model of the prestressed wires, which always results in too many elements for analysis. This paper tries to equivalent the spiral structure as the separate round rings for simplicity. As for the embedded type of pipe with shorting straps, analyses were carried out to compare the spiral model with two straps, ring model with two straps. ring model without straps. As for lined type of pipes, the effect of the disconnection between wires and the cylinder were discussed. The analyses results imply that for the embedded type of pipe with shorting straps, the ring model with two straps has the best equivalent effect while the ring model without straps is the worst. For the lined type of pipe, the spiral structure can only be equivalent as the ring model, in which the fracture distance has to be set as the circumferential distance of disconnection between wires and the cylinder.