为模拟拉索各钢丝间的摩擦接触,放弃会带来极大计算量和高度非线性问题的常规接触单元而采用理想弹塑性弹簧单元,并推导了弹簧屈服力的计算公式.建立127丝平行钢丝束有限元模型,拉索钢丝间的摩擦接触采用理想弹塑性弹簧单元模拟,采用单元生死功能模拟钢丝断裂.计算分析结果表明:当拉索出现锈蚀断丝后,断裂钢丝并不会完全退出工作,经过一段发展长度后能恢复到正常应力水平.钢丝断裂后,各钢丝间会出现应力重分布,断裂截面断裂位置周围的钢丝应力增大,远离断丝侧钢丝应力减小,拉索合力作用点偏移拉索截面中心,故荷载恢复完成后拉索截面各钢丝平均应力并不均匀,恢复后拉索截面应力分布规律与断丝截面相反.随着断丝百分比的增加,断裂钢丝荷载恢复长度逐渐增大,相应的索力损失率增大.%In order to simulate the friction contact between the wires of the cable,the conventional elastic-plastic spring element is used to abandon the conventional contact element which will bring the maximum calculation amount and the high nonlinearity problem,and the formula of the spring yield force is deduced.The finite element models are implemented for parallel strands with 127 wires.Elasto-perfectly plastic spring elements are used to simulate the frictional contact.In addition,birth and death of elements can be used to simulate fracture of wires.Results show that broken wire can recover some carrying capacity after the development length,when internal cable wire breakage occurs.After that,stress redistribution occurs between wires.The stress of wires surrounding the broken wire is a maximum and decreases with distance from the break.The action point of resultant force of cable offsets the sectional center of cable,so the stress of wires in cross section where the recovery has completed for broken wire is not uniform,however,the stress distribution law in cross section of broken wire is opposite to it.With the increase of the percentage of broken wires,the recovery length of the broken wire increases gradually,and the corresponding cable loss rate increases.
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