Research On Cable Force Identification Method Based On Bending Wave

Cable force is not only an important indicator for bridge construction monitoring,but also an important indicator for assessing the health status of the bridge operation phase.In the construction of the cable-stayed bridge,the control of the cable force will directly affect the deformation and stress state of the structure.The premise of cable force control is to obtain the correct cable force value.The most widely used frequency method still has accuracy and Stability issue.In this paper,from the perspective of traveling wave,the dynamic characteristics of the cable structure are studied by the axial tension beam model.Several beam theories such as Euler-Bernoulli beam theory,Timoshenko beam theory and modified Timoshenko beam theory are systematically introduced and summarized.The propagation characteristics of the bending wave in the beam structure are studied.It is proved that the standing wave is equivalent to the propagation-reflection-superposition of the traveling wave under the condition of the truncated boundary.The research shows that there are two kinds of waves in the beam,one is the wave number of two.The near-field wave is the opposite of the pure real number,and the other is the traveling wave with the wave number being two opposite pure imaginary numbers.Selecting one sub-segment from the cable and arranging 4acceleration sensors can identify 4 The wave component coefficient,the premise is the cable force,the value of the bending stiffness is consistent with the actual.In this paper,by adding one sensor,the redundant equation is constructed,and the least squares solution of the wave component coefficient is obtained,aiming at fitting the minimum residual.The cable strength and bending stiffness are identified,and the accuracy of the method is verified by numerical simulation of hammering.Compared with the traditional frequency method,this method is not affected by the shock absorber because it is the cable force identification of the cable.But also reverse thrust position each cable tension cable,the cable tension to break the concept of a single value by subindex cable tension segments identified by the static analysis.