Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
ULTRASOUND METHOD TO EVALUATE THE FORCE IN BOLTED JOINT
Submission Author:
Rafael Tavares , SP , Brazil
Co-Authors:
Rafael Tavares
Presenter: Rafael Tavares
doi://10.26678/ABCM.COBEM2021.COB2021-0286
Abstract
The present study aims to investigate the method that estimates the force exerted by the screw on bolted joint, proposing a possible replacement of the conventional load cell. Based on the pulse-echo ultrasonic technique, the wave propagation time in a rectified screw is checked before and after being subjected to a normal load. The time difference related to the measured force by loaded cell was performed after applying the tightening torque on the fixation elastic region. Additionally, the screw samples were rectified at their parallel ends and the ultrasonic apparatus was magnetically coupled under the screw using water-based gel as a coupling, thereby verifying the time shift of the echo signal that is detected by a threshold amplitude of that signal. Moreover, the pulse-echo flight time in the isotropic medium was the object of the study to relate to the force measured in a cell that measures force (kN). Using equipment that basically is formed by cell of longitudinal and torsional load with electronic transduced torque wrench to define the gradual tightening, the time difference of the ultrasonic pulse was caused by a longitudinal effort after a tightening torque applied in the elastic region of mechanical resistance of the screw in the simulated joint. According to formulas at ISO16047, this equipment is currently used to check the friction of threaded elements and the numerous possibilities of contact surfaces, such as nuts and bolts. This method could evaluate the loosening force through a remote monitoring on bolted buildings, specifically bridges, oil and gas pipelines, wind energy towers, vehicles, engines, mats, maintenance of equipment, etc
Keywords
Ultrasound, echo-pulse, force, Load, bolt, nut
