全封闭碳纤维与高强钢丝复合拉索的弹性模量

Elastic modulus of fully-enclosed composite cable made of CFRP and high-strength steel strand

探讨了全封闭复合拉索的协调工作机理,即要求芯部高强钢丝束与碳纤维筋弹性模量接近或相等;研究了高强钢丝束捻距与弹性模量间的关系;推导了37股高强钢丝束弹性模量的计算表达式,通过有限元分析验证了表达式的正确性.试验表明,碳纤维筋弹性模量可以达到与高强钢丝束的弹性模量相近的要求.结论表明:复合拉索中的索力按照碳纤维筋与高强钢丝束的轴向刚度进行分配,全封闭复合拉索中碳纤维筋与高强钢丝束的弹性模量相等.在整体锚具的张拉下,复合拉索中碳纤维筋与高强钢丝束的变形一致,弹性模量相等决定了索力按照复合拉索中碳纤维筋与高强钢丝束的截面比例进行分配,能够确保复合拉索索体的协同作用.高强钢丝束的弹性模量与其捻距及扭转角相关,随着捻距的减小,扭转角的增大,高强钢丝束的弹性模量降低.

Coordination mechanism of the fully-enclosed composite cable is investigated,and the requirements that the elastic modulus of the high-strength steel strand and CFRP（carbon fiber reinforced polymer） should be equal is proposed in this paper.Firstly,the relationship between the twist and the elastic modulus of the high-strength steel strand is studied.Then,the calculation formula of the elastic modulus of the high-strength steel strand with 37 strands is derived.Finally,the correctness of the formula is verified by finite element analysis.Test results show that the elastic modulus of CFRP can reach that of high-strength steel strand.It is concluded that the force of the composite cable is distributed in accordance with the axial stiffness of carbon fiber and high-strength steel strand,and the elastic modulus of both CFRP and high-strength steel strand in fully-enclosed composite cable are equal.With the pull of the whole anchorage,the deformation of CFRP in fully-enclosed composite cable is consistent with the deformation of the high-strength steel strand.Equivalence of the elastic modulus determines that the force is distributed in accordance with the ratio of the cross-section of the carbon fiber and the high-strength steel strand,which can ensure the coordination mechanism of the fully-enclosed composite cable.The elastic modulus of the high-strength steel strand is associated with the twist and the torsion angle.With the decrease of the twist and increase of torsion angle,the elastic modulus of the high-strength steel strand decreases.