Research On Axis Force Of Bolt Tightening Based On The Ultrasonic Measurement Technology

High strength bolts are used extensively on machine equipment, vehicle, aviation, railway and building structure as a connector. To guarantee the reliability and security of the steel construction, it is very importantly that measures the clamping force of high strength bolts directly and accurately. Referring to the sonic-elasticity principles, we research six kinds of structural bridge bolt from Changxing central road steel beam bridge and the main research achievement is showed as follows:1. The thesis lucubrate the economy, precision, repeatability and reproducibility of commonly bolts, fastening methods. Emphasis on the sonic-elasticity principles, the principle and application of permanent mounted transducer system technologic bolts (PMTS) are pertinently researched.2. On the basis of research, characteristic curves have been analyzed between the torque/clamp force stress state and single axial force state. The correction methods of characteristic curve have been put forward under the single axial force state, different clamping length and different bolt temperature.3. Author build up the test platform, test the performance of samples, research the influence of bolt’s clamping force based on bolt material status, clamping length, bolt temperature, bolt surface condition, size, and personnel operating conditions. We focus on analyzing the ultrasonic measurement effect of clamping force under the same batch bolt, different clamping length and different temperature conditions. Also we put forward the relationship between the clamping force and ultrasonic flight time difference, clamping length, temperature of the same batch bolt.4. Finally the author has set up the test bolt according to this research method. The results show that the clamping force precision of test bolt has met installation requirements.