Determination of Cable Tension Force using Accelerometer

Abstract

Cable is the main element in a long span structure and is often used for special structures such as long span bridges, roofs and other structures that require a long span. The stiffness of the cable is determined by the amount of axial tensile force acting on the cable, and hence, the magnitude of the actual tensile force on the cable is an important factor to be determined and monitored. One simple method for determining the actual tensile force on a cable is to calculate the tensile force from the first natural frequency of the cable. However, it is important to ensure that the formulas used to calculate the tensile force are accurate. This research aims to determine the level of accuracy and the factors that influence the accuracy of the formula to determine the tension force of the cable from the natural frequency value of the cable. The methodology used in this research project was by applying free vibrations to the cable with given axial tensile load and measuring the acceleration that occurred with an accelerometer sensor. By using Fast Fourier Transform (FFT), the natural frequency value of the cable can be calculated and the actual tensile strength in the cable can be determined. From the experiment conducted, it was found that the length of the cable affects the accuracy of the measurement of the natural frequency and the magnitude of tensile force of the cable. The strain that occurs on the cable plays a very important role to the accuracy of the formulas used.