11 results about "Contact theory" patented technology

The invention discloses a wear-vibration coupling modeling method and device for a roller linear guide rail pair system, and the method comprises the steps: dividing the movement process of a roller into an LC stage and two transition stages according to the contact load, deformation state and wear mechanism difference of the roller in a sliding block track; respectively establishing a sliding wear model and an impact-sliding composite wear model, and constructing a non-uniform wear depth expression taking space coordinates as input; the multi-state contact behavior is described by introducing roller compression deformation and contact angle change, and the actual contact area under different contact states is determined based on the Hertz contact theory; in combination with roller operational analysis and a coordinate transformation relation, mapping of the abrasion depth among a roller coordinate system, a sliding block coordinate system and a guide rail coordinate system is achieved, and the abrasion effect of each roller is accumulated through a time discretization method; a five-degree-of-freedom nonlinear dynamic model is introduced, coupling analysis of pretightening force degradation and vibration response is achieved, and dynamic performance changes of the guide rail system in long-term operation are predicted.

The present application relates to the technical field of seepage mechanics, and particularly relates to a conical sealing surface leakage rate calculation method based on Darcy's law, comprising the following steps: a W-M function is used to simulate the random topography of the workpiece surface at a microscale, and a normalization method is used to generate surface point cloud data meeting roughness requirements; according to the surface point cloud data, a contact mechanics model is used to solve the change law between the contact state and the external load, and according to the Hertz contact theory, the contact between the rough surfaces is reconstructed as the contact between a rigid plane and a flexible rough surface; the surface is discretized into a three-dimensional grid model, the effective porosity is screened and calculated by using the connected domain discrimination method; a micro-leakage rate calculation method for the conical sealing surface in the flared pipe joint is obtained based on the effective porosity and the seepage mechanics theory algorithm; the leakage rate of the conical sealing interface is calculated, and the sealing performance of the interface is quantitatively evaluated. The present application improves the comprehensiveness and accuracy of the sealing performance evaluation.

The invention provides a simulation research method for wear resistance of a nano-diamond ceramic coating. The invention aims to solve the problem that the existing wear simulation depends on a user subprogram, needs to empirically zoom coefficients and causes unreliable results due to grid-physical mismatch. According to the method, on the basis of Abaqus software, a high-fidelity contact-wear coupling model is constructed, the size of a local grid is determined in combination with the Hertz contact theory, and multi-cycle automatic control is achieved through a native * STEP CYCLING instruction; meanwhile, differentiated wear parameters are defined for the two contact faces respectively, and a termination criterion based on the accumulated wear depth is introduced. By means of the technical scheme, high-precision, efficient and stable abrasion evolution simulation of the nano-diamond ceramic coating can be achieved without external programming.

The invention provides a statics calculation and analysis method for a non-slip working condition of a tailstock of a numerically-controlled lathe, and relates to the technical field of statics analysis of structures of numerically-controlled machine tools. Firstly, the maximum static friction force between a sleeve and a tailstock body is calculated based on a mechanical model of the tailstock clamping mechanism; when the external load is smaller than the friction force, the non-slip working condition is judged; based on a fractal contact theory, respectively establishing nonlinear elastic restoring force models of a sleeve-tip conical surface joint surface and a tailstock-lathe bed guide rail joint surface, wherein the guide rail joint surface is discretized by adopting a slicing method so as to describe non-uniform contact deformation of the guide rail joint surface; and finally, integrating the sub-models to construct a system statics equation under the non-slip working condition of the tailstock, and obtaining the load-displacement response of the system under the non-slip working condition and the bearing characteristic of each joint surface through numerical solution.

The invention belongs to the technical field of bridge structure safety, and discloses a bridge suspender steel wire fretting corrosion fatigue life prediction method and system, and the method comprises the steps: obtaining the initial parameters of a steel wire, considering the stress non-uniform distribution and contact angle of the steel wire based on the Hertz contact theory, and carrying out the step-by-step iterative calculation, a steel wire fretting corrosion wear model is established, and the fretting corrosion wear depth and the fretting corrosion wear rate of each analysis step length are output; based on the fracture mechanics theory, the wear notch stress concentration and the multi-axis stress state of the steel wire are analyzed, a steel wire multi-axis corrosion fatigue crack propagation rate model is constructed, and the crack propagation rate is output; an equivalent initial crack method is adopted, the fretting corrosion wear rate and the crack growth rate are compared through cycle-by-cycle iteration, competition analysis of cracks and wear is carried out, a fretting corrosion wear dominant stage and a multi-axis corrosion fatigue dominant stage are divided, the service lives of the two stages are solved respectively, and the service life of the multi-axis corrosion fatigue dominant stage is calculated. The sum of the two is the total fretting corrosion fatigue life of the steel wire.

The invention discloses a logistic regression-based wheel-rail contact state evaluation method, and relates to the technical field of wheel-rail contact state evaluation. According to the logistic regression-based wheel-rail contact state evaluation method, based on a wheel-rail contact theory, the contact point distribution percentage number, the concentration ratio composite index and the 3mm equivalent taper are selected to represent the wheel-rail contact state more comprehensively and accurately through multi-dimensional parameters, so that evaluation deviation caused by one-sidedness of the parameters is avoided, and the evaluation accuracy of the wheel-rail contact state is improved. The logistic regression model is adopted as an evaluation core algorithm, the mapping relation between input and output of the model can be quantitatively explained through regression coefficients, the model is high in interpretability and adapts to engineering practice requirements, the model threshold value can be flexibly adjusted according to different line operation and maintenance requirements, and the evaluation accuracy is high. The method is advantaged in that potential safety risks are avoided, the method is adaptive to diversified railway operation scenes, intelligent grading evaluation of the wheel-rail contact state is realized, wheel-rail service life prolonging is facilitated, and operation and maintenance cost is reduced.

The application discloses a kind of ball screw contact stress calculation methods, solve the existing entity steel ball simulation exists and is assembled with the problem such as big, loaded law disorder, low solving efficiency etc. of discrete error, the method does not need rolling body, only through screw and nut modeling constructs assembly body, adopts spring to replace steel ball and is established finite element model in coordination Python batch processing, through function accurate control contact point, batch export spring normal contact force and coordinate before and after deformation, after conversion actual contact angle, contact stress is calculated in combination with Hertz contact theory.The application avoids initial assembly and discrete error, reduces the number of contact pairs, improves solving speed and stability, without repeatedly debugging model, greatly reduce research and development cost, shorten product iteration cycle, applicable to EMB braking system etc. the performance analysis of automobile field ball screw.

The application discloses a calculation method for the wear and vibration coupling characteristics of a screw nut pair, and provides technical support for the coupling characteristics research of the wear and vibration of the screw nut pair by means of the geometric structure parameters, material parameters and working condition parameters of the screw nut pair, a dynamic wear depth prediction model of the screw nut pair, a stiffness model of the screw nut pair considering the wear influence and a nonlinear dynamic model of the screw nut pair based on the Hertz contact theory and the Archard wear theory. The dynamic wear depth prediction model can replace the wear experiment which is time-consuming and high in cost. The nonlinear dynamic model can be used for solving the dynamic response of the screw nut pair under the wear action, and has important theoretical significance and engineering application value for enriching the dynamic characteristic research of the screw nut pair.

The application discloses a kind of online evaluation method of rail repair precision, including steps 1: calculating profile dynamic adaptation DPA;Step 2: calculating disease residual correction DRC;Step 3: calculating surface roughness standard degree SRC;Step 4: calculating polishing quality uniformity GUI;Step 5: calculating rail polishing quality comprehensive evaluation index CGQI, the present application fuses profile dynamic adaptation, disease residual correction, surface roughness standard, polishing uniformity these four dimensions, forms comprehensive evaluation system (CGQI), based on rail basic parameters and the contact pressure deduced based on Hertz contact theory, combined with laser profile measurement deviation, realize the dynamic evaluation of "the greater the contact pressure, the higher the deviation influence weight", it is in line with actual service working condition;Supplement microelement area division, profile alignment reference, deviation limit and other key rules, solve engineering landing pain points;Give consideration to macro profile, residual disease, micro roughness, polishing uniformity, more comprehensive evaluation.

The application belongs to the technical field of bridge structure safety, and discloses a bridge suspender steel wire fretting corrosion fatigue life prediction method and system, which comprises the following steps: obtaining steel wire initial parameters, establishing a steel wire fretting corrosion wear model through step-by-step iterative calculation based on Hertz contact theory and considering the stress non-uniform distribution and contact angle of the steel wire, and outputting the fretting corrosion wear depth and fretting corrosion wear rate of each analysis step; analyzing the wear notch stress concentration and multi-axial stress state of the steel wire based on the fracture mechanics theory, constructing a steel wire multi-axial corrosion fatigue crack propagation rate model, and outputting the crack propagation rate; adopting an equivalent initial crack method, comparing the fretting corrosion wear rate with the crack propagation rate through period-by-period iteration, carrying out a competition analysis of cracks and wear, dividing a fretting corrosion wear dominant stage and a multi-axial corrosion fatigue dominant stage, respectively solving the life of the two stages, and summing up the two stages to obtain the total fretting corrosion fatigue life of the steel wire.

The invention belongs to the technical field of mechanical dynamics, and discloses an improved spiral bevel gear bearing contact analysis method, a medium and an electronic device. On the basis of a gear tooth contact analysis method, geometric parameters of tooth surfaces of a large gear and a small gear are obtained, a spiral bevel gear pair bearing contact analysis model is constructed, and a tooth surface overall flexibility matrix, an overall contact flexibility matrix and a local contact flexibility matrix are calculated; establishing a deformation coordination iteration equation, analyzing the morbidity of the deformation coordination iteration equation, and establishing a preprocessing matrix to improve the deformation coordination iteration equation; solving the time-varying meshing stiffness and the tooth surface load after the improvement is completed; and based on the tooth surface load, calculating the main curvature of the tooth surfaces of the large and small gears by adopting an Euler analytical method and determining the main direction, and solving the contact stress in combination with the Hertz contact theory. According to the method, the problems that iteration convergence is difficult to guarantee due to the ill-conditioned property of a contact flexibility matrix under a low-load working condition in a traditional wheel tooth bearing contact analysis method, and the calculation precision and efficiency are low due to the fact that curvature calculation mostly depends on numerical value difference are solved.