3 results about "Modal damping ratio" patented technology

This invention discloses a method for optimizing the multimodal damping ratio of a cable-composite damper-cable-end damper system, comprising the following steps: S1, constructing a coupled system of cable-composite damper-cable-end damper; S2, calculating the damped vibration frequency, damping ratio of each mode, and mode shape of the coupled system; S3, optimizing the multimodal damping ratio of the coupled system. This invention constructs a coupled system consisting of a conventional damper, a damped damper, and a cable-end damper working collaboratively. Then, using the average normalized damping ratio of the multimodal damping ratio as the optimization index, the method systematically optimizes key parameters such as the stiffness and damping of the composite damper, the damping coefficient of the cable-end damper, and its installation position to achieve an overall and balanced improvement in the damping level of each mode.

The invention relates to the technical field of numerical control machining and intelligent manufacturing, and discloses an intelligent machining control method and system for automobile part milling. The method comprises the steps that a vibration signal and stress data are obtained and preprocessed to obtain a time domain sequence; resolving the time domain sequence to obtain a modal damping ratio time-varying characteristic sequence; analyzing rigidity fluctuation and a critical state, and predicting a damping ratio trend to lock an advanced intervention opportunity point; generating a variable parameter control instruction sequence according to the intervention opportunity point; screening an optimal control parameter combination based on an efficiency and life model; and outputting a final flutter suppression signal in combination with real-time vibration feedback. According to the method, the dynamic change of the damping ratio can be tracked in real time, the flutter is accurately intervened in advance, and the production efficiency and the service life of the cutter are both considered while the machining stability is guaranteed.

The present application relates to a kind of transmission line galloping critical wind speed prediction method based on L-P perturbation method, comprising the following steps: S1, the physical characteristics and aerodynamic parameters of transmission line are obtained by wind tunnel test as basic data;S2, establish the motion control matrix equation of transmission line based on modal displacement;S3, explicit solution of modal frequency, damping ratio and modal characteristics of each modal branch is derived based on L-P perturbation method;S4, iteratively solve modal frequency, on this basis directly solve damping ratio, amplitude ratio and phase difference, observe the change of modal damping ratio ξ in each direction with wind speed U, determine the critical wind speed of galloping;The explicit closed solution of the existing three-degree-of-freedom galloping start-up condition needs to be calculated multiple times iteratively on modal frequency, damping ratio and mode shape, and it is difficult to clearly explain the influence of structural parameters and aerodynamic parameters on aerodynamic instability, and the critical wind speed of transmission line galloping cannot be well predicted.