24 results about "Contact theory" patented technology

The application discloses a gear time-varying meshing stiffness measurement method, which comprises the following steps: S1, a measurement model between current and time-varying meshing stiffness is established based on Hertz contact theory and Ishikawa formula; S2, a closed circuit is formed by connecting a driving gear, a driven gear and a power supply in series, and time-varying current of the circuit is measured; and S3, the time-varying current measured in S2 is substituted into the measurement model to obtain time-varying meshing stiffness of the gear. The application improves the measurement precision and efficiency of the gear time-varying meshing stiffness.

The invention provides a force thermal electric field coupling method based on an inclined crown spring connector, and belongs to the field of electric connector design and optimization analysis, and the method specifically comprises the following steps: S1, building a single-terminal parameterization CAE model of an inclined crown spring large-current connector, material attribute setting, grid division, contact pair definition, boundary condition and solver configuration are completed through an APDL language; s2, executing transient mechanical field simulation, and extracting normal contact force, geometric deformation and contact area of each contact at the moment when the pin is completely inserted; s3, based on the Hertz contact theory, calculating a contact resistance theoretical value according to the normal contact force of each contact, and deducing the contact conductivity and the contact heat conductivity; and S4, reconstructing a reed geometric model according to a mechanical field deformation result, and fitting the shape of the contact into an ellipse or a circle according to the contact area. The method is used for solving the problem that coupling simulation convergence is difficult due to a complex structure, and the multi-physics field coupling calculation difficulty is reduced.

The invention relates to the technical field of numerical control machine tool assembly stress detection, and discloses a method for acquiring contact stress of a machine tool assembly interface. Based on the real mapping of the contact resistance to the contact stress, the contact stress of the to-be-detected assembly interface is obtained by detecting the contact resistance value of the to-be-detected assembly interface, the contact stress obtaining process of the machine tool assembly interface is simplified, accurate obtaining of the contact stress of the machine tool assembly interface is achieved, and the working efficiency of the machine tool assembly interface is improved. And the method has high reliability and universality. According to the method for acquiring the contact stress of the machine tool assembly interface, a mapping relation model of the contact resistance and the contact stress of the assembly interface is constructed, the model considers the influence of the contact stress on the contact resistance, and the contact stress of the assembly interface is acquired through a micro-convex body distribution density function and a Hertz contact theory. And the real mapping of the contact resistance to the contact stress is realized by defining the transmission characteristic of the current passing through the rough assembly interface.

The invention belongs to the field of uncontained bearing load calculation, and discloses a load calculation method for a civil aircraft flap needle roller bearing. On the basis of the Hertz contact theory, a bearing outer ring is regarded as a flexible outer ring, the influence of bending elastic deformation of the bearing outer ring under an external load on load distribution is considered, a comprehensive deformation calculation formula between a roller pin and a roller path is established, then the roller pin is subjected to slicing discretization treatment along the axis of the needle roller bearing, and according to the obtained deformation, the bearing outer ring is subjected to deformation calculation; the contact load generated between the slice unit and the inner and outer raceways is calculated, then a static equation set of the flap needle bearing is established, the deformation amount of each position of the needle bearing is solved through a Levenberg-Marquardt algorithm, and the load distribution of the needle bearing can be calculated. On the basis, a relational expression among the maximum contact stress, the load and the displacement is established, and the maximum contact stress distribution of the needle bearing is obtained through a numerical iteration method.

The invention provides a sandwich structure battery pack bottom guard plate energy absorption evaluation method and system based on strain energy analysis, and relates to the technical field of power battery pack protection, and the method comprises the steps: preparing a laminated sandwich structure bottom guard plate; calculating strain energy per unit volume of the composite material skin, the foam core material and the embedded steel plate; determining a deformation area volume based on a Hertz contact theory; the total absorption energy is obtained through superposition integration; and optimal structure parameters meeting energy absorption requirements and deformation constraint conditions are determined through gradient optimization. According to the invention, the energy absorption performance of the battery pack bottom guard plate can be effectively evaluated, lightweight design is realized, and the safety of the battery pack is improved.

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 application provides a sandwich structure battery pack bottom protection plate energy absorption evaluation method and system based on strain energy analysis, relates to the power battery pack protection technical field, and comprises the following steps: preparing a laminated sandwich structure bottom protection plate; calculating the unit volume strain energy of a composite skin, a foam core material and an embedded steel plate; determining the deformation region volume based on the Hertz contact theory; obtaining the total absorption energy through superposition integration; and determining the optimal structure parameters under the energy absorption requirements and deformation constraint conditions by using gradient optimization. The application can effectively evaluate the energy absorption performance of the battery pack bottom protection plate, realize lightweight design, and improve the safety of the battery pack.

The invention discloses a ball screw contact stress calculation method, and solves the problems of large assembly and discrete errors, disordered loading rules, low solving efficiency and the like in the existing entity steel ball simulation. According to the method, a rolling body is not needed, an assembly is built only through modeling of a lead screw and a nut, a spring is adopted to replace a steel ball, a finite element model is built in cooperation with Python batch processing, contact points are accurately controlled through functions, spring normal contact force and coordinates before and after deformation are exported in batches, and after actual contact angles are converted, the contact stress is calculated in combination with the Hertz contact theory. According to the method, initial assembly and discrete errors are avoided, the number of contact pairs is reduced, the solving speed and stability are improved, repeated model debugging is not needed, the research and development cost is greatly reduced, the product iteration period is shortened, and the method is suitable for ball screw performance analysis in the automobile field of EMB braking systems and the like.

The present invention relates to the research field of the waterproof performance of shield tunnel joints under the action of sealing gaskets, and proposes a method for predicting the long-term waterproof performance and leakage rate of shield tunnel joints, the steps of which include: conducting an assembly force test on the sealing gasket to obtain a nonlinear relationship between the compression strain of the sealing gasket and the equivalent compression modulus; performing a morphological scan on the sealing gasket contact surface through an AFM test to obtain the surface morphology parameters of the sealing gasket rubber; utilizing multi-scale contact theory and percolation theory to obtain the percolation pressure considering long-term aging behavior; combining the self-sealing effect of the sealing gasket to obtain the critical leakage water pressure of the joint; obtaining the critical hydraulic opening under the contact of the sealing gasket based on the Persson model, and predicting the leakage rate of the sealing gasket at each stage under different joint opening and dislocation forms and the influence of long-term rubber aging based on the cubic law. The present invention can improve the existing shield tunnel joint waterproof design method and provide guidance for the waterproof performance of the sealing gasket under the influence of long-term aging.

The invention discloses a blade deterministic robot grinding and polishing method based on a mixed B spline curve, which comprises the following steps of: pre-fitting a section contour line of a blade by adopting a three-time non-uniform rational B spline curve, carrying out curvature analysis on a pre-fitted track curve on an accumulated arc length, setting a curvature change rate threshold value, screening out a high-curvature curve region, and carrying out grinding and polishing on the high-curvature curve region by adopting a three-time non-uniform rational B spline curve. Carrying out five times of secondary fitting of a non-uniform rational B-spline curve on the areas so as to obtain an interpolation fitting trajectory curve of the mixed non-uniform rational B-spline curve; a contact model of the blade surface and the abrasive belt surface is simplified and analyzed through the Hertz contact theory, so that a relational expression of curvature and speed is established, and finally establishment of an accumulated arc length-curvature-speed relation model is achieved; the speed boundary is flexibly managed in different B-spline curve segments, and the curvature distribution on the path is combined, so that the efficient processing of the path corner and edge is realized.

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 relates to a railway ballast track bed rigidity calculation method. The method comprises the following steps that ballast particle material parameters are obtained, and a track bed equivalent Young modulus expression is obtained according to the constitutive relation of isotropic discrete materials; obtaining a railway ballast contact stiffness expression according to a Hertz contact theory; the average normal contact force is adopted to represent the normal contact rigidity; the method comprises the following steps: obtaining stress changing along with depth in the vertical direction based on the fact that a load distribution form in a ballast track bed diffuses at a fixed angle in each direction, and calculating an equivalent Young modulus according to the stress; calculating the stiffness coefficient of the ballast bed based on the equivalent Young modulus; and calculating the dynamic stiffness of the ballast bed under different frequencies based on the constant damping and the stiffness coefficient. The equivalent Young modulus and rigidity are calculated based on the internal stress of the ballast bed, the nonlinear relation between the rigidity and the thickness of the ballast bed can be accurately reflected, the rigidity of the ballast bed can be calculated under the condition of different ballast bed thicknesses, the dynamic rigidity of the ballast bed under high frequency can be accurately calculated, and the method is suitable for the field of railway ballast bed dynamic analysis and rolling noise prediction.

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 invention provides a method and a system for judging a circumferential crack initiation condition of a wheel tread of a railway wagon. The method comprises the following steps of: establishing a railway wagon dynamic model; based on the action relation between the circumferential cracks and the shear stress borne by the wheels, the bogie working condition with the suspension failure is set in the railway wagon dynamic model; on the basis of the railway wagon dynamics model, statistics is conducted on the dynamics simulation result of each wheel of each bogie working condition, the bogie working condition when transverse force and transverse creep force borne by the wheels are maximum is obtained, and the bogie load working condition when circumferential cracks are generated is judged; based on the preliminarily judged bogie load working condition when the circumferential crack is generated, the maximum Hertz contact stress borne by the wheel is calculated through the Hertz contact theory; based on a dynamic simulation result, the maximum Hertz contact stress borne by the wheel and the shear yield limit of a wheel material, a wheel stability diagram is drawn by combining a stability theory; and judging the mechanism of circumferential crack initiation by analyzing a wheel stability diagram.

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 relates to the technical field of pressure-maintaining coring, in particular to a pressure-maintaining coring point load-based rock true parameter acquisition method, which comprises the following steps of: after pressure-maintaining coring is finished, directly carrying out point load test on a pressure-maintaining rock core in a high-pressure closed environment through point load test equipment integrated with a pressure-maintaining coring device; obtaining a load displacement curve by combining a load and displacement monitoring system; dividing the load displacement curve into a first section of arc curve and a second section of linear curve, and synchronously extracting a plurality of true parameters such as an intensity index, a contact elastic modulus and a point load elastic modulus based on load-displacement full curve analysis. A curve is divided into an arc-shaped section and a linear section, and a Hertz contact theory and an empirical coefficient conversion method are adopted respectively, so that the elastic modulus of the rock is accurately calculated.

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.

The invention discloses a ball cage type constant velocity universal joint contact stress calculation method, and belongs to the technical field of constant velocity universal joints, and the method comprises the following steps: obtaining a pre-constructed raceway geometric model; geometric parameters of the steel balls are obtained according to the raceway geometric model and the geometric relation; according to the raceway geometric model and the geometric parameters of the steel balls, the curvature sum of contact points of the steel balls and the raceway is obtained; and according to the Hertz contact theory and the curvature sum, the maximum contact stress of the ball cage type constant velocity universal joint in contact with the raceway is calculated. The method can solve the problems that an existing calculation method is large in calculation amount, time-consuming and high in requirement for calculation resources.