An accurate frequency-based method for identifying cable tension while considering environmental temperature variation

In this work, we study the influences of environmental temperature variation on the static and dynamic behaviours of cables, and we develop a very accurate method for identifying the tension of a cable while considering environmental temperature fluctuation. The dynamic equation of a cable that includes the sag effect, the inclination angle and thermal fluctuations is derived, and the numerical solution of temperature-dependent dynamic equations of the cable is obtained by using the finite difference method. The derivatives of the cable's dynamic characteristics with respect to the cable's systematic parameters and the environmental temperature are derived, which furnish an accurate parameter sensitivity method for identifying the tension of a cable subjected to a changing temperature environment. The results indicate that, when the sag-to-span ratio of a cable is between 10−3 and 10−1, the environmental temperature exerts a very important influence on the dynamic behaviours of the cable, not only because it changes the cable's tension but also because it changes the deformation of the cable's sag. In this case, the method proposed in this study is useful and practically important.