98 results about "Contact model" patented technology

The invention discloses an aggregate random distribution concrete PFC (Power Factor Correction) simulation method, which comprises the following steps: a model selection step: determining a parallel bonding model as a mechanical model for concrete material simulation; a cement mortar matrix generation step of generating a cement mortar matrix by using particles in a set size range in a set space range based on the model, and setting pore density, particle density and contact model parameters; a coarse aggregate random distribution simulation step: randomly covering and grouping original particles in the matrix in a grouping and range mode; a concrete numerical model construction step: determining particle classification so as to distinguish cement mortar and coarse aggregate; and a model reliability verification step: comparing indoor test results through a uniaxial compression test. According to the method, the simulation accuracy is improved, the randomness of aggregate is reduced, the model reliability is ensured, the matrix simulation refinement degree is improved, and a method is provided for concrete modeling and performance research.

The invention belongs to the field of geologic disaster prevention and control of geotechnical engineering, and provides a multi-scale numerical simulation method for a slope instability mechanism of a ductile shear zone, which comprises the following steps: acquiring physical and mechanical parameters of a rock-soil body material, and establishing a numerical model based on a particle flow discrete element method; a Johnson-Kendall-Robert contact model is adopted as a contact model between particles, the contact force between the particles is calculated, and meanwhile, a pressure interference parameter is defined to control the limit value of normal contact rigidity; performing dynamic modeling of the discrete element particle system based on a particle generator; static modeling of a discrete element particle system is carried out based on a Lagrange body continuous unit component; the acting force of discrete element particles is converted into equivalent grid node force through an equivalent node force conversion method, and surface attributes of all unit sets possibly involved in contact are defined in a solver.

The invention discloses an efficient identification method for connection rigidity of a steel pipe pole of a power transmission line, which relates to the field of structural health monitoring, and comprises the following steps: constructing a multi-scale finite element model of the steel pipe pole, acquiring displacement and frequency response of the structure to carry out parameter sensitivity analysis, and screening key correction parameters; constructing a key parameter-structure response sample data set, and training and optimizing an FEA-Net neural network model; and constructing a Bayesian correction framework, solving posterior probability distribution by adopting a TMCMC algorithm, and realizing the probabilistic identification of the connection stiffness and the systematic correction of the finite element model. By constructing a local refined contact model, a bolt pretightening force-connection rigidity corresponding relation is established, and an effective means is provided for verifying whether the rigidity of the corrected model is matched with the rigidity of an actual structure or not. The structure rigidity damage position can be accurately recognized, the rigidity degradation degree can be quantified, and a high-credibility model basis is provided for safety evaluation, digital twinborn construction and operation and maintenance decision making of engineering structures such as electric transmission line steel pipe poles and the like.

The application discloses a short-fiber reinforced ablative material bulk ablation simulation method, and belongs to the technical field of multifunctional composite materials and structure numerical simulation.The application comprises the following steps: constructing a discrete system composed of a series of spherical particle units by using a discrete element method; calculating the contact area, contact force and connecting force of the particle units by using a Hertz-Mindlin contact model and a parallel-bond model at each calculation time step; calculating the temperature of the particle units by using an energy conservation principle and a Fourier heat conduction law; calculating the displacement and angular displacement of the particle units by continuously integrating the momentum conservation equation twice; updating the velocity, displacement and diameter of each particle unit, and updating the porosity and pore pressure of the discrete system; iteratively solving and visualizing until a specific condition is met, and ending the simulation.The application characterizes the internal structure features of the short-fiber reinforced ablative material by using the discrete element method, so that the numerical simulation accuracy of the ablation process is improved, and the possibility of capturing the micro ablation mechanism is provided.

The application discloses a wheel fatigue life prediction method based on a rolling contact fatigue simulation technology, and comprises the following steps: establishing a finite element model of a wheel-axle-rail, performing grid encryption on a wheel-rail contact area, and performing static strength checking to obtain an initial finite element model meeting static force requirements; establishing a wheel-rail rolling contact model based on the initial finite element model, describing rolling motion of the wheel by using a hybrid Lagrangian / Eulerian description or a co-rotating coordinate system, and applying a wheel non-circularity excitation spectrum in explicit dynamics analysis to calculate a dynamic contact stress field under different axle loads and friction coefficients; and based on the dynamic contact stress field, a multi-axle fatigue damage model is used in combination with a linear cumulative damage criterion to calculate fatigue life, and an abrasion correction coefficient and a residual stress correction coefficient are introduced to correct the calculation results. The application significantly improves the prediction accuracy of fatigue defects such as wheel peeling, cracking and polygonization.

A method for constructing a dynamic model of a coupled system of high-speed railway train-track-substructure includes: experimentally obtaining key technical parameters with nonlinear and frequency-varying characteristics in the high-speed railway infrastructure system; constructing a novel wheel-rail contact model suitable for higher speed levels and integrating it into the vehicle-track coupled dynamic model; constructing a train vehicle model and track structure model based on the principles of multi-rigid-body dynamics and the finite element method; and using a self-developed program to realize the dynamic modeling of the train-track system; taking the ballastless track structure, subgrade, bridge, and tunnel structures of high-speed railways as research objects, and applying a finite element simulation platform to realize the construction of a refined finite element model of the track-substructure structure; this invention achieves a breakthrough in the theoretical modeling of the vehicle-track-substructure system of higher speed railways, providing a research method and platform for deepening the understanding of the coupled dynamic mechanism of complex systems of high-speed railway infrastructure with speeds of 400 km / h and above.

The application discloses a kind of discrete element modeling methods of multi-layer interpenetrating shear mixing drill and soil body, comprising: S1, the design parameter of multi-layer interpenetrating shear mixing drill is obtained, design parameter includes the pitch of blade, inclination, shape, size and quantity;Multi-layer interpenetrating shear mixing drill includes inner drill rod, multiple pairs of inner blades and outer frame arranged on inner drill rod;The outer frame includes multiple pairs of outer blades, two side plates and a collar arranged at intervals, and each pair of outer blades and each pair of inner blades are arranged at intervals;S2, the modeling of multi-layer interpenetrating shear mixing drill is carried out to obtain drill model;S3, establish soil model, import drill model, distribute contact model, and construct the coupling discrete element model between multi-layer interpenetrating shear mixing drill and soil particles;S4, simulation is carried out using coupling discrete element model, and quantitative analysis is carried out on mixing effect according to simulation result.The coupling discrete element model constructed by the above method has reliability and engineering applicability, and provides quantifiable basis for drill structure optimization.

The invention discloses a flexible wiping method and system of a flexible joint space robot based on dynamic adaptive impedance control, and the method comprises the steps: firstly, building a contact model between the flexible joint space robot and a wiped target; then, self-adaptive impedance control for dynamically updating impedance parameters is designed; and finally, performing comparison simulation on classical constant impedance, fixed update rate adaptive impedance control and dynamic update rate adaptive impedance control, and verifying the effectiveness of the method combining the dynamic update rate adaptive impedance control and singular perturbation control on friction force compliance control in the wiping process of the flexible joint space manipulator by a simulation result. The method is used for the field of on-orbit wiping of the flexible joint space robot, and accurate compliance force control can be conducted on the flexible joint space robot rapidly, efficiently and accurately; when the flexible joint space robot executes a task, necessary guarantee can be provided for the flexible joint space robot, and it is ensured that the space robot and a wiping target are not damaged, and meanwhile a good cleaning effect is obtained.

The invention discloses a gear pair meshing stiffness calculation method considering a thermoelastic coupling effect, which relates to the field of gear transmission, and comprises the following steps: establishing a gear temperature field model and a contact model by utilizing a finite element method, obtaining a gear heat conduction matrix and a structural stiffness matrix, and calculating to obtain gear meshing stiffness and tooth surface load distribution based on an actual tooth surface equation. Calculating tooth surface heat flux density based on tooth surface load distribution, tooth surface friction coefficient and relative sliding speed of each meshing position to obtain a gear thermal load matrix, calculating to obtain an equivalent node load matrix according to a gear heat conduction matrix and the thermal load matrix, and calculating to obtain tooth surface thermal deformation by combining the equivalent node load matrix with a gear structure stiffness matrix. And repeating the steps to obtain the meshing rigidity of the gear pair under the thermoelastic coupling effect. According to the method, the gear contact state iterative solution model based on the potential energy method, the matrix polycondensation method and the slicing thought is established, the requirement for computing equipment is lowered, and the solution efficiency is improved.

The invention relates to a concrete structure fault movement damage simulation method based on damage contact constitutive, which belongs to the technical field of geotechnical engineering numerical simulation, and has the technical key points that the method is based on a plastic damage constitutive theory proposed by A.D.Jefferson and is combined with a discrete element method to simulate the fault movement damage of a concrete structure. A contact model suitable for cracking evolution of the concrete lining structure under the fault shearing condition is constructed; the method comprises the following steps: establishing a contact surface force-displacement increment relationship and a failure criterion by introducing parameters such as normal rigidity, tangential rigidity, tensile strength, cohesive force, a friction angle and fracture energy, carrying out secondary development coding based on a 3DEC development port by utilizing a C + + language, and generating a constructed DLL module file; by constructing a typical engineering numerical model, the development process of concrete cracks under fault movement is simulated, and sensitivity analysis is carried out. The method can accurately capture a structural damage path and a stress concentration part, and is suitable for engineering application scenes such as tunnel crossing fault and high-stress area support optimization.

The invention relates to a heavy-load forming robot dynamic modeling method considering spherical pair gaps and connecting rod deformation. The heavy-load forming robot dynamic modeling method comprises the following steps that S1, the basic structure of a heavy-load forming robot is determined; s2, the movement position relation of the heavy-load forming robot component is determined; s3, constructing a ball pair clearance contact model of the heavy-load forming robot; s4, a kinetic equation of the heavy-load forming robot sliding block is determined; s5, a kinetic equation of a heavy-load forming robot connecting rod is established; s6, a kinetic equation of the heavy-load forming robot moving platform is determined; and S7, determining a total kinetic equation of the heavy-load forming robot. According to the heavy-load forming robot dynamic modeling method considering the spherical pair gap and the connecting rod deformation, more accurate prediction of the real-time pose of the robot can be achieved. According to the method, the dynamic model considering the spherical pair gap and the connecting rod deformation is established, the dynamic model is verified through a loading experiment, and the accuracy of the error of the moving platform can reach 70%.

The invention relates to an anti-deformation leveling algorithm based on a foot-ground contact model and a platform rigidity model. The anti-deformation leveling algorithm comprises the steps that a foot-ground interaction load-settlement model, a platform load-deformation rigidity model and a leveling algorithm with feed-forward compensation are established; a foot-ground interaction load-settlement model is adopted to describe foot-ground contact settlement behaviors, and the landing leg settlement amount is predicted by identifying ground rigidity parameters; secondly, establishing a platform structure stiffness matrix, quantifying a platform load-deformation relationship, performing simulation calculation on a platform system under a typical leveling pose by using a finite element method, and obtaining stiffness coefficient matrixes corresponding to different poses; and finally, designing a leveling algorithm with feed-forward compensation, and superposing the total compensation amount to leveling control output by predicting the landing leg settlement amount and the landing leg structure deformation amount so as to realize feed-forward control. According to the method, the foot-ground contact model and the platform load-deformation rigidity model are constructed, and rapid and stable leveling is realized through a dual-mode control algorithm.

Systems and methods related to generating video sequences containing physiologically realistic avatars are provided. In an example, an albedo for an avatar is received, a subsurface skin color associated with the albedo is modified based on physiological data associated with a physiological characteristic, and the avatar is rendered based on the albedo and the modified subsurface skin color. The rendered avatar can then be composited in frames of a video. In some examples, the video containing the composited avatar can be used to train a machine learning model to detect the physiological characteristic. The machine learning model can receive a plurality of video segments, where one or more of the video segments contain a composited physiologically realistic avatar generated with the physiological characteristic. The machine learning model can be trained using the plurality of video segments. The trained model can be provided to a requesting entity.

The invention relates to the technical field of particle breaking numerical simulation, in particular to a breaking simulation method and device for particles in irregular shapes. The method comprises the following steps: establishing a particle initial model with a real irregular form, and endowing each particle with an initial contact model and physical-mechanical properties; calculating the principal stress of the current particle based on the contact state of the current particle and the adjacent particle, and calculating the critical stress intensity of overall crushing of the current particle; according to the main stress intensity and the critical stress intensity, whether the current particles meet the overall crushing condition or not is judged through the intensity criterion, and if yes, an overall crushing cutting plane is determined; if not, carrying out corner breaking identification, and determining a corner cutting plane based on an identification result; and performing particle cutting according to the determined cutting plane. The method can solve the problems that an existing modeling method is inaccurate in simulation, high in calculation cost, unstable in numerical value and the like, and lacks unified and generalizable morphology recognition and evolution rules for common edge and corner breakage.

The invention discloses an asphalt mixture freeze thawing discrete element modeling method. The method comprises the following steps: S1, constructing an asphalt mixture initial discrete element model; s2, adding a contact model among model particles of the initial discrete element model of the asphalt mixture constructed in S1, and calibrating mesoscopic parameters according to indoor experimental data to obtain a complete sample model; s3, compiling a freeze-thaw cycle subprogram based on a water-ice phase change coupling expansion method to perform freeze-thaw cycle simulation on the sample model obtained in S2; and S4, performing freeze-thaw cycle simulation on the sample model obtained in S2 under different working conditions based on the freeze-thaw cycle subprogram compiled in S3. The frost heaving stress is simulated through a water-ice phase change coupling expansion method, and a way is provided for researching a frost heaving damage mechanism of the asphalt mixture; flexible setting of multiple parameters such as freezing and thawing temperature, rate and temperature difference is supported through a cosine temperature formula, and refined simulation is achieved; the freezing and thawing cycle result is high in precision, and the design of the asphalt pavement in the cold region can be guided.

The invention provides a collaborative robot motion control method and device and electronic equipment, in the process of executing assembly, a contact model between an assembly tool and an assembly body is constructed, a state variable is determined based on the contact model, and a system state equation is established based on the state variable. Extended Kalman filtering processing is performed based on the system state equation to obtain estimated environmental stiffness. And whether the estimated environment rigidity exceeds a preset threshold value or not is detected, and if the estimated environment rigidity exceeds the preset threshold value, the collaborative robot is switched to a torque mode. Damping in the admittance control algorithm is adjusted based on the estimated environment rigidity and the force sensor data, and assembling between the assembling tool and the assembling body is executed based on the adjusted admittance control algorithm. According to the scheme, under the condition that a sensor does not need to be additionally arranged or equipment does not need to be replaced, when the estimated environment rigidity exceeds the preset threshold value, the collaborative robot is switched to the torque mode, the damping parameters are adjusted in a self-adaptive mode, and therefore the oscillation phenomenon is avoided.

The invention discloses a local heat treatment optimization method for dent-free control of a heat transfer tube of a nuclear power steam generator, and belongs to the technical field of heat treatment numerical simulation. The method comprises the following steps: establishing a finite element stress contact model of a heat transfer tube and a piping system support plate simulation piece, applying a load to carry out deformation analysis, and determining a critical deflection angle of a piping system support plate when the heat transfer tube generates dents; establishing a finite element equivalent simplified model of the nuclear power steam generator, and performing local heat treatment numerical simulation to obtain a displacement field in the axial direction; extracting displacement data of symmetric surfaces of the piping support plates along any radial direction, and calculating and determining the maximum relative deformation angle of each piping support plate; and based on the fact that the maximum relative deformation angle of the piping system supporting plate is smaller than the critical deflection angle, the local heat treatment process is optimized. On the basis that the maximum relative deformation angle of the pipe system supporting plate is smaller than the critical deflection angle of the pipe system supporting plate when the heat transfer pipe generates the dents, local heat treatment process parameters are optimized, and heat transfer pipe dent-free quantitative analysis and control are achieved.

A friction stir welding analytical method according to the present invention uses an analytical model including: a first mesh for a Lagrangian analysis and corresponding to a welding tool, which is a first analytical target; and a plurality of marker particles disposed in an element where a welding target member, which is a second analytical target, is present in a fixed second mesh. The analytical method according to the present invention is characterized by comprising an analytical step for using a contact model and a heat generation model to perform a thermo-elasto-plastic analysis and a thermal conduction analysis on the first and second meshes, and a step for moving the marker particles in the second mesh in accordance with the node flow rate obtained in the analytical step, wherein at least one of a temperature, an acceleration vector, a velocity difference, an equivalent plastic strain, an identifier, a stress tensor, and a velocity vector, is moved together with the marker particles.

The invention belongs to the technical field of methods for simulating and evaluating the wear resistance of a screw, and particularly relates to a method for simulating and evaluating the wear resistance of the screw based on discrete elements, which comprises the following steps of: constructing a three-dimensional assembly model of the screw and a machine barrel, importing the three-dimensional assembly model into discrete element simulation software EDEM, and finishing parameter setting in the EDEM, a particle model is created through a particle generator, the density and Poisson's ratio of particles, the static / dynamic friction coefficient with the surface of a screw and particle size distribution are defined, the density, shear modulus, Poisson's ratio and friction coefficient of the screw and a machine barrel are input, and the contact model is used for describing mechanical behaviors between the particles and between the particles and the screw. The abrasion model is used for representing the screw abrasion process, determining the size and the feeding efficiency of a virtual feeding factory, adjusting the rotating speed of the screw according to equipment parameters, configuring simulation calculation parameters and then starting simulation calculation.

The invention provides an asphalt mixture mechanical property evaluation method based on discrete element numerical simulation, and relates to the technical field of road materials, and the method comprises the following steps: setting the unit radius and boundary unit radius of component particles of an asphalt mixture to be tested, adjusting the particle size distribution of the component particles and a contact model between different component particles, and calculating the mechanical property of the asphalt mixture to be tested; establishing an initial discrete element model; carrying out a semicircular bending test based on the initial discrete element model to obtain mesomechanical characteristic parameters of the to-be-tested asphalt mixture; sub-index matrixes corresponding to the damage dimension parameters, the force transmission dimension parameters and the structure dimension parameters are determined through an ideal solution sorting method, weighting is conducted on the sub-index matrixes in combination with an objective weighting method, and a comprehensive evaluation index is obtained through weighted fusion; determining the micro-mechanical properties of the to-be-tested asphalt mixture based on the comprehensive evaluation index; the sub-index matrix comprises a damage sub-index, a force transfer sub-index and a structure sub-index.

The application belongs to the technical field of the cross of artificial intelligence and computational mechanics, and particularly relates to a bagged sand cofferdam MPM simulation method and system based on artificial intelligence, a three-dimensional simulation system of the bagged sand cofferdam is constructed by combining the MPM method, a penetration state of the sand and the geotextile is detected by using a penetration tracking algorithm and a space hash acceleration, an artificial intelligence algorithm is introduced to design a reward function with the minimum penetration depth and penetration times as the target, penetration prediction of the bagged sand MPM particle is driven, further based on the predicted contact model and the artificial intelligence algorithm, the MPM particle velocity and stress are dynamically regulated to prevent penetration and ensure numerical stability, and the implicit integration and gradient descent method are adopted to improve the calculation precision, and the two-way coupling of the sand and the geotextile is realized through a visualization module. The problems of low coupling simulation efficiency, easy penetration and numerical instability of the sand and the flexible structure in the traditional method are solved, and the accuracy and reliability of the simulation analysis of the bagged sand cofferdam structure under complex working conditions are significantly improved.

The invention discloses a precise modeling and prediction method suitable for airplane thin-wall part riveting assembly deformation, and the method comprises the steps: carrying out the representation of a riveting surface of a thin-wall part through employing a W-M fractal function from the microstructure, and building a fractal model which accords with the actual surface statistical characteristics; then based on a fractal contact theory, establishing a micro-convex elastic-plastic contact model, expanding a microscopic contact behavior to the whole junction surface through a size distribution function, and constructing an analytical model of normal contact rigidity and contact damping; then, an equivalent modeling method based on a spring-damping unit is provided, rigidity and damping of the joint surface are distributed in a discretization mode, and accurate quantitative calculation of riveting assembly deformation is achieved.

The application discloses a gas turbine pull rod rotor wheel disc vibration analysis method, system and device, relates to the technical field of gas turbines, and comprises the following steps: constructing a three-dimensional finite element dynamics equation of a rotating component; considering rough contact characteristics of a contact interface, combining a micro contact mechanics model of the contact interface and a rough consolidated interface contact mechanics model based on a statistical theory, and deducing contact stiffness of adjacent contact units; considering stress strengthening effects, iteratively calculating a stress stiffening matrix and a contact stiffness matrix; considering local contact nonlinearity of a center pull rod end surface tooth structure, constructing an end surface tooth contact model considering collision separation; and adopting a degree of freedom reduction method to solve vibration response of the three-dimensional finite element dynamics equation; and the method can greatly retain geometric characteristics, contact surface characteristics and load actions of an original model without simplifying the pull rod rotor by establishing a vibration analysis model.

The invention discloses a high-pressure roller mill wear prediction and service life evaluation method based on DEM-FEM coupling simulation. The method comprises the following steps: constructing a roller mill simplified model through modeling software; the method comprises the following steps: simulating crushing and contact behaviors of grinding material particles based on a discrete element method (DEM), and quantifying interaction between the particles and interaction between the particles and a roller surface by adopting a Hertz-Mindlin contact model and a Tavaries crushing model; analyzing stress and deformation characteristics of a roll shaft structure based on a finite element method (FEM), mapping particle contact force output by discrete elements into a distributed load of a finite element model by utilizing a mechanical equilibrium equation, and solving roll shaft contact stress, strain and plastic deformation distribution; and calculating the instantaneous wear loss based on an Archard wear model, converting the instantaneous wear loss under multiple working conditions into a damage index in combination with a linear cumulative damage theory, and judging the service life of the roller surface when the total damage index reaches a threshold value. According to the invention, accurate prediction of roller surface wear and scientific evaluation of service life under the action of multiple working conditions are realized.

The application belongs to the field of circuit breaker testing, and specifically discloses a contact ablation method and system of a gas circuit breaker. The application converts the traditional high-energy-consumption and high-cost ablation experiment into a safe laboratory implementation scheme by proportionally reducing the contact model and calculating the equivalent current, thereby significantly reducing the experimental threshold. By introducing a controllable gas blowing device to simulate the dynamic airflow environment during actual breaking, the application solves the problem that existing static experiments cannot reproduce the actual ablation working condition, making the experimental results more realistic. Through the above means, the application realizes high-fidelity simulation of the ablation behavior of the contact of the gas circuit breaker under low-cost and low-risk conditions, and can reliably predict the ablation results and electrical life of the full-size product according to the experimental data, thereby providing an accurate basis for product reliability evaluation.

The invention relates to the technical field of water conservancy projects, and provides a fault section diversion tunnel reinforcement design method in order to accelerate the construction progress and reduce the project investment, through finite element analysis, the supporting effects of linings, sprayed concrete, anchor rods, steel bars and the like are considered, the interaction between tunnel linings and surrounding rocks is also considered, and the construction progress is accelerated. A more scientific and accurate structure stability evaluation result can be obtained, reinforcement is performed based on the result, the construction progress can be effectively accelerated, and the project investment can be reduced; according to the method, the contact stiffness is determined based on numerical simulation on the principle that calculation results of a lining structure under a surrounding rock-lining common node model and a contact model are consistent, the problem that the value of the contact stiffness is difficult is solved, and the determined contact stiffness is more accurate; and whether reinforcement is needed or not is judged based on the accurate contact rigidity, the reinforcement judgment accuracy is improved, the construction progress is accelerated, and the project investment is reduced.

The invention relates to the technical field of tire simulation design, in particular to a method, a system and equipment for calculating contribution of a tire part to return rigidity and a storage medium. The method is based on a tire finite element model, and comprises the following steps: firstly, establishing a tire-rim-road surface contact model under rated inflation pressure and load working conditions, and calculating to obtain the reference return rigidity of the whole tire; then target parts such as a tread, a belted layer and sidewall rubber are selected, the Young modulus of the target parts is reduced to 0.01%-5% of a design value, inflation, loading and lateral deviation simulation are repeated on the premise that the geometric structure and boundary conditions are kept unchanged, and the return rigidity after degradation is obtained. The return rigidity difference value before and after degradation is compared, the return rigidity contribution value and contribution rate of each component are calculated according to the occurrence frequency of the component in the tire structure, and therefore the overall return rigidity is finely decomposed to the component level. According to the method, quantitative stripping of the return rigidity contribution of the tire is achieved, the method has the advantages of being small in error, good in repeatability and high in applicability, and a reliable basis can be provided for tire operation stability performance optimization.

The invention discloses a calculation method and a prediction model for the invasion depth of rubber in contact with a rough road surface. The method comprises the following steps: establishing a rubber block and rough pavement contact model, and defining the surface of the rubber block in contact with the rough pavement as a feature contact surface S; boundary conditions of constraints and loads are applied to the rubber block and rough pavement contact model, and contact between the rubber block and the rough pavement in the loaded state is achieved; on the premise that the rough road surface contour is not changed, model parameters and loads representing rubber attributes are changed respectively, and the corresponding rubber block invasion depth H under the combination of the model parameters and the loads of different rubber attributes is calculated; and constructing a rubber invasion depth prediction model and verifying to predict the invasion depth H when the rubber is in contact with the rough road surface in a loaded state. The method has the advantages that the invasion depth of the rubber block on the rough road surface under the action of different loads can be effectively captured, so that theoretical analysis and numerical analysis of rubber friction characteristics can be better guided and corrected.

The application provides a motion analysis method and system based on image and foot bottom contact modeling, comprising the following steps: reconstructing the three-dimensional posture of the subject motion according to the identified 2D key points, and generating a personalized skeletal model matched with the subject according to the height data of the subject; obtaining the foot bottom image of the subject, and automatically generating a plurality of contact spheres in the foot bottom area according to the extracted foot bottom contour shape to approximately represent each area of the foot bottom contact with the ground, the positions and radii of the contact spheres are optimized and set according to the foot type of the subject, and a personalized foot bottom contact model is formed; solving the ground reaction force (GRF) consistent with the dynamics under the given kinematic conditions according to the personalized skeletal model, joint motion data and personalized foot bottom contact model; determining the moving path of the force point of action of the resultant force with time according to the force condition of each contact sphere of the double feet, and calculating the trajectory of the foot bottom pressure center (COP). The application can perform motion analysis based on image and foot bottom contact modeling.

The invention provides a yarn untwisting fluid-solid coupling modeling method and device based on cohesion friction, and relates to the technical field of textile. The method comprises the steps of obtaining yarn structure data, and constructing a three-dimensional spiral fiber bundle geometric model based on the yarn structure data; a cohesive contact model is introduced into a contact interface between cotton fibers, a shear traction force-separation displacement constitutive relation is constructed, and a target cohesive contact yarn model is obtained; aiming at an untwisting working condition, establishing a three-dimensional steady flow field computational domain, setting inlet, outlet and turbulence boundary conditions, and importing the model into a three-dimensional steady flow field model to carry out untwisting analogue simulation; establishing a fluid-solid coupling numerical model between the yarn and the flow field to obtain data and cloud pictures of displacement, stress, strain and speed of the yarn; and analyzing and correcting the breaking strength, the linear density and the twist of the yarn until the parameter convergence of the target cohesive contact yarn model is completed.