Research on the Numerical Calculation Method for Antiloosening Performance of Screwed Joints under Complex Working Conditions

Table 1

Testing systems and load extraction procedures.

Steps	Method	Example
1	Strain gauges are pasted onto the clamped parts.	Figure 5: strain gauges pasted onto the front suspension (Figure 5(a)) and rod-coil spring rear axle (Figure 5(b)).
2	Exerting forces on the clamped parts, collecting the strain gauge signals through the load calibration test, and determining the relationship matrix between the strain signals and the exerted forces.	Figure 6: exerting a lateral force on the left rear wheel (Figure 6(a)), a longitudinal force on the left front wheel (Figure 6(b)), and a lateral force on the left front wheel (Figure 6(c)). The test equipment and test method are described in [36].
3	Collecting the dynamic strain signals of the clamped parts during the vehicle road test; transforming the signals into load spectrums using the relationship matrix.	Figure 7: vehicle road test; Figure 8: vertical force spectrum and lateral force spectrum on left rear wheel under the braking condition.
4	Calibrating the dynamics simulation model through the relationship matrix and load spectrums, simulating the typical complex working conditions, outputting the loads acting on the SJSs corresponding to the coordinate system of the vehicle, and determining the ultimate working condition corresponding to the maximum load.	Figure 9: dynamics simulation model. Figure 10: working loads acting on the shock absorber-body SJS under the braking condition output from the dynamics simulation.