7 results about "Dynamical friction" patented technology

The invention provides a device and a method for testing a sliding friction coefficient under a high-speed impact load, and relates to the technical field of sliding friction force testing. The device for testing the sliding friction coefficient under the high-speed impact load comprises an impact rod, an incident rod, a transmission rod and a compression-torsion coupling piece, strain sensors are attached to the incident bar and the transmission bar; one end of the pressure-torsion coupling piece is adhered to one end, far away from the impact rod, of the incident rod, a first to-be-tested material block is adhered to the other end of the pressure-torsion coupling piece, a second to-be-tested material block is adhered to the end part of the transmission rod, and the impact rod can impact the incident rod; the pressure-torsion coupling piece comprises two pressure plates and a plurality of inclined supporting rods, and the plurality of inclined supporting rods are arranged between the two pressure plates. And the technical effect of effective characterization capability of the dynamic friction behavior under the impact load is achieved.

This invention discloses a method for calculating the dynamic friction coefficient of a rough interface based on transient finite element method, belonging to the field of gear meshing interface friction and wear technology. The method first determines the calculation point on the gear tooth surface, extracts parameters such as load, sliding speed, roughness, and radius of curvature from the overall meshing transient simulation, establishes a local transient finite element model containing the rough morphology, and performs simulation. It then extracts the time-domain data of normal pressure and tangential friction resistance, calculates the transient friction coefficient through programming, and obtains the effective dynamic friction coefficient by taking the root mean square value. This invention fully considers the coupling effects of transient load, motion, vibration, and deformation in gear meshing, overcomes the limitations of experimental conditions, has high calculation accuracy, and a wide range of applications, providing reliable data for gear transmission efficiency analysis, power consumption calculation, and optimization design.

The invention provides a reservoir area landslide instability prediction method and a reservoir area landslide instability prediction device. The reservoir area landslide instability prediction method comprises the following steps: acquiring porosity, cohesion and slip mass density of target landslide slip zone soil; according to the rate dependence data of the residual friction coefficient of the slip band soil, a normal stress and rate dependence model is established, and a joint model is obtained through coupling; dispersing the target landslide into strip cylinders, calculating the self-weight stress, hydrostatic pressure, excess pore water pressure, water resistance, floating force, dynamic frictional resistance and cohesive force of each strip cylinder, listing and solving a dynamic balance equation, and obtaining the landslide acceleration of each strip cylinder; calculating the initial motion state of each column body by taking the rapid gliding moment of the landslide as an initial time point; the motion state, acceleration and speed of each cylinder at each moment are iteratively calculated, the friction coefficient measured by an experiment is utilized, the friction coefficient is obtained through experimental data, and the motion speed of the target landslide can be accurately calculated in combination with the excess pore water pressure.

The invention relates to the technical field of motion control of mining machinery, in particular to a physical simulation method and system for practical operation assessment of a bolter miner, and the method comprises the steps: obtaining working condition reference data, and constructing the working condition reference data into a working condition vector; and calculating the dynamic friction coefficient reflecting the real-time friction resistance of the contact interface between the drill bit and the rock debris by analyzing the physical characteristics, humidity distribution and pore structure of the rock debris in the working condition vector. According to the method, a fixed friction coefficient used in traditional simulation is abandoned, a dynamic friction model integrating rock debris physical characteristics, environment states and pore structures is established, and the friction coefficient dynamically adjusted along with changes of working conditions is calculated in real time; particularly, a humidity phase change function is introduced to accurately describe the nonlinear sudden drop characteristic of the friction force when the rock debris is transited from a dry state to a muddy state. The core problem of friction model distortion in virtual simulation is fundamentally solved, and the stress condition of equipment in a simulation environment is consistent with the real underground height.

The invention discloses a Ravigneaux type planetary gear transmission system fault dynamics modeling method. The method comprises the following steps: step (1), establishing a Ravigneaux type planetary gear pair time-varying meshing stiffness calculation formula containing a crack fault; (2) establishing a relative displacement formula of the Ravigneaux planetary gear pair containing the crack fault; (3) introducing a gear backlash nonlinear function under an elastic lubrication condition, and determining dynamic friction force on a meshing line of each gear pair; (4) establishing an oscillatory differential equation set of the Ravigneaux planetary gear transmission system containing the crack fault; (5) selecting different crack fault parameters of the Ravigneaux planetary gear, and inputting torque to solve nonlinear response characteristics of the system; the method has the beneficial effects that the nonlinear fault dynamics model of the Ravigneaux type planetary gear transmission system is established, and the related technical blank of fault dynamics modeling of the Ravigneaux type planetary gear transmission system at present is filled.

The invention discloses a device and method for measuring the dynamic friction coefficient of a pivot rail, and the device enables an armature to move in a chamber under the condition that an electromagnetic emission device is not powered on, can effectively reduce the complex stress condition in the chamber in the actual emission process, obtains the friction force of solid-to-solid contact in the emission process in cooperation with the use of a strain gauge, and achieves the measurement of the dynamic friction coefficient of the pivot rail. And a theoretical basis is provided for research of an actual electromagnetic track launching system. According to the method for measuring the dynamic friction coefficient of the pivot rail, the motor is selected to pull the steel wire rope to enable the armature to move in the chamber, the wire outlet end of the steel wire rope is wound on the inclined column of the sensor, the tension of the steel wire rope can be displayed in real time through the sensor, and the tension is friction force according to the law of conservation of mechanics. According to the measuring method, the dynamic friction coefficient of the pivot rail can be measured by using the self-designed power traction auxiliary device and the strain gauge, the device is reasonable in structural design, the measuring method is simple, and the measuring result is reliable.

The invention discloses a system for measuring the dynamic friction coefficient of a rolling linear guide rail pair. The system comprises a marble lathe bed, a driving module, a measuring module, a supporting module and a load adjusting module, the driving module drives the measuring module to reciprocate through the lead screw; the measuring module is provided with a tension and pressure sensor for collecting the pre-tightening force required for dragging the measured guide rail in real time; the load module applies an adjustable vertical load by adopting a pair of precise flat tongs and an opposite top type sliding block, and the load is monitored by a pressure sensor; during measurement, one end of the guide rail is clamped and arranged on the plane needle bearing through the connecting block, the other end of the guide rail is embedded into the opposite-vertex sliding block, and the supporting module adjusts the height to make the guide rail horizontal; the system calculates a dynamic friction coefficient based on a Hertz contact theory and a slide block skirt elastic deformation model in combination with actually measured dragging force and load data; the device has the advantages of being non-destructive, accurate in load, wide in applicable model, high in measurement precision and the like, and is suitable for dynamic friction performance testing of the rolling linear guide rail pair.