考虑端部约束效应的短索索力动力识别方法与影响参数分析OA

Accurate identification of cable force is of paramount significance for safety assessment and health monitoring of cable-supported structures.For short cables,the effect of flexural stiffness is non-negligible,and the actual boundary constraints typically reside between theoretical fixed and pinned conditions.Existing methods often rely on fitting parameters derived from specific experimental data,failing to precisely reflect the intrinsic mapping between cable force and dynamic characteristics,which limits their general applicability.To address this,this study introduced the elastically restrained dynamics theory,accounting for both end-constraint effects and short-cable characteristics.A one-dimensional wave equation for short cables was established,incorporating realistic boundary constraints and stiffness effects.Based on this,a cable force identification method was proposed,integrating finite difference discretization,Fast Fourier transform(FFT)for dominant frequency extraction,and bisection method inversion.This approach achieves a robust mapping from first-order frequency to cable force with reliable convergence.Validation through experimental results and finite element simulations demonstrates that the method achieves stable convergence under complex boundary conditions,with force identification errors maintained within 1%.Furthermore,a parametric analysis was conducted to investigate the influence of relative slenderness ratio(3-50),linear density(1-10 kg/m),moment of inertia(1×10-8～1×10-7 m4),and cable force(10-200 kN)on the first-order frequency response under varying rotational stiffness(0～1×106 N∙m/rad).The results indicate that the proposed cable force identification method,which considers the elastic fixity effect and the stiffness characteristics of short cables,can accurately reveal the key mechanisms governing the dynamic characteristics of short cables.Under the conditions of low relative slenderness ratios(ξ<39.87)and lightweight cables(m<3 kg/m),the elastic restraint effect exerts a decisive influence on the dynamic characteristics.Conversely,when the relative slenderness ratio exceeds 39.87,the effect of elastic restraint becomes negligible.The impact of elastic restraint on frequency is further amplified by decreasing the relative slenderness ratio or linear density,and by increasing the moment of inertia or cable force.The findings provide an effective technical framework for cable force detection and dynamic performance evaluation in complex engineering applications.