Bolt Axial Force Measurement via Vibration Signal Analysis

The patent replaces the ultrasonic wave-based measurement system with a vibration-based measurement system. Instead of using ultrasonic waves that reflect off the bolt head surface, the invention uses vibration signals generated during the fastening process itself. This substitution eliminates the problem of non-planar surfaces causing erroneous echo signals, as the vibration signals are generated at the joint interface where the axial force is actually applied.

The patent utilizes mechanical vibration principles by measuring the vibration characteristics of the joint during fastening. The vibration sensor detects natural frequency shifts or damping changes that occur as the bolt is tightened, which directly correlate with the axial force development. This approach leverages the dynamic mechanical response of the joint structure itself to infer the axial force, providing accurate measurements independent of bolt head surface geometry.

The patent replaces the ultrasonic wave measurement system with a vibration-based system that monitors natural frequency shifts or damping changes during fastening. This substitution eliminates reliability issues caused by non-planar surfaces, as vibration signals are generated at the joint interface where axial force is applied, providing consistent and reliable measurements throughout the fastening process.

The vibration-based measurement system utilizes the fastening process itself to generate the measurement signals. The act of tightening the bolt naturally excites vibrations in the joint, and these self-generated vibration signals are captured by the sensor. This eliminates the need for separate measurement actions or external excitation sources, providing continuous reliable data throughout the fastening operation.

The patent replaces subjective human sensory detection with an automated vibration-based measurement system. Vibration sensors and signal processing algorithms objectively quantify the axial force by analyzing vibration characteristics during fastening. This substitution eliminates the limitations of human sensory assessment while maintaining operational simplicity through automated data collection and analysis.

The vibration-based system provides real-time feedback on axial force development during fastening. By continuously monitoring vibration signals and correlating them with axial force, the system enables operators to immediately assess whether the fastening is proceeding correctly and make adjustments if needed, providing objective precision that human sensory detection cannot achieve.