73 results about "Contact theory" patented technology

The invention relates to a vibration response simulation analyzing method for a rolling bearing with single-point failures. On the basis of a Hertz contact theory, related knowledge about kinematics and kinetics are utilized to establish a five-degree-of-freedom nonlinear vibration mode of a rolling bearing and kinetic differential equations of the rolling bearing while influencing factors like slipping of rolling balls, oil slick rigidity and the like are taken into consideration, according to that the rolling balls change due to contact deformation is caused when the rolling balls roll through partial failures, a partial failure model of the rolling bearing is introduced into the kinetic differential equations of the rolling bearing, and the single-point failures of the rolling bearing are classified according to length-width ratios of the failures and size ratios between the failures and the rolling balls so as to establish different failure shape functions; the differential equations are solved by an ode solver in MATLAB (matrix laboratory) software, and vibration responses of the rolling bearing are simulated when an inner ring, an outer ring and the rolling balls of the rolling bearing are suffered from the single-point failures. By the aid of the vibration response simulation analyzing method, vibration responses of the bearings with failures in different sizes can be simulated. Compared with traditional methods for acquiring vibration responses of failed bearings, the vibration response simulation analyzing method has the advantages that an experimental period is short and experimental cost is saved. The computation for the vibration responses for the failed rolling bearings can lay the foundation of late failure diagnosis for the rolling bearings.

The invention belongs to the field of contact mechanics and relates to an extraction method of a load spectrum of a ball screw pair. The method comprises the following steps: setting up a load distribution model of a single-nut ball screw pair; setting up a nonlinear system of equations for load distribution of the single-nut ball screw pair based on a hertz contact theory according to the principle of deformation compatibility; solving the nonlinear system of equations for contact load of a single-ball model; setting up a solving model for dynamic contact characters of high-speed motion state of the ball screw pair and solving value of the nonlinear system of equations; calculating the change rule between contact load of the screw nut pair and positions based on relations of working positions and torque current of a servo motor with time; and working out the load spectrum of the ball screw pair. The extraction method of the load spectrum of the ball screw pair utilizes precisely-determined load spectrums of all components of the screw nut pair to provide reference for reliability design of a feeding system.

The invention provides an HSK100 main shaft handle's combined surface rigidity calculation method based on the condition of its high speed rotation, which belongs to the mechanical design and manufacturing field. The method considers the bearing changes of the HSK main shaft handle in different high-speed rotations because the connection performance of the handle is affected by a plurality of reasons. The contact of the handle's main shaft belongs to the non-linear research theory and if research is to be carried out on the connection performance of the connection parameters of the main shaft handle system, one should start from the non-linear consideration. However, the fractal geometry and optimized Hertz contact theory start to do research on the contact problem from the micro perspective to the macro perspective, and when fractal method is utilized to calculate the overall contact rigidity of the HSK100 main shaft handle's combined surface when the main shaft handle rigidity reaches the balanced state. The method raises the calculation of the rigidity of the HSK100 main shaft handle's combined part in high speed rotations through the use of the fractal theory and the Hertz contact theory for the first time. The method can provide a theoretical basis for the contact rigidity of the HSK100 main shaft handle and can better increase the HSK100 main shaft handle's precision and service lifetime.

A ball bearing reliability design method is based on the following prerequisites: 1, the contact between an antifriction bearing rolling body and internal/external raceway satisfies the Hertz contact theory, and the contact type between the rolling body and the bearing internal/external raceway is point contact or/and line contact; 2, the ball bearing reliability design method satisfies the following requirements: firstly building a deep groove ball bearing flexible multi-body contact dynamics model, simulating and parsing a deep groove ball bearing rotation process so as to obtain each part angular velocity and dynamic contact impact stress changing rules, and using obtained data to finish the ball bearing reliability design. The invention provides the reference method for ball bearing reliability design and fatigue life research; related principles can be promoted to all transplantable related technical fields; the ball bearing reliability design method has large latent economy value and social value.

The invention discloses a prediction method for crack initiation of a secondary surface of a heavy-load gear. The method comprises the following steps that 1, based on a hertz contact theory, the contact of a gear pair is simplified, a meshed position parameter is calculated according to geometric kinematics, and a contact analysis model is established; 2, based on the contact analysis model of the gear pair, by using a value calculation method, the surface contact pressure of the analysis model under the heavy-load condition is obtained; 3, a material constant related to the service life of crack initiation is solved; 4, based on a continuous damage mechanics theory, by using critical damage amount, whether or not a crack occurs on the secondary surface is judged, and a gear contact elastic-plastic constitutive equation of coupling damage is established; 5, the service life of crack initiation is calculated, and the position of crack initiation is obtained. According to the predictionmethod, the technical difficult problem which exists for a long time in the machinery industry is solved, the position and service life of crack initiation of the secondary surface of the heavy-loadgear can be effectively predicted, and the basis is provided for design, manufacturing and use of the gear.

The invention provides a force-position mixing control method for grinding and polishing of a force-controlled robot. According to the method, on the basis of a workpiece three-dimensional model, a grinding and polishing tool machining track and/or a five-axis NC program matched with a workpiece is generated according to different machining surfaces, and then a robot position control program is generated; based on a Hertz contact theory, suppose the pressure intensity of each position grinding and polishing contact point is the same, the grinding and polishing positive pressure of the contactarea is obtained according to the contact surface pressure stress distribution rule; the feeding speed is obtained through a feeding speed self-adaptive model; and in the grinding and polishing process, the position of the robot is controlled, the grinding and polishing pressure and the feeding speed of the grinding and polishing tool are controlled at the same time, so that the grinding and polishing precision and the surface uniformity of a complex curved surface workpiece can be effectively improved.

The invention discloses a prediction method of interface loading force in consideration of three-dimensional fractal. When two metal surfaces are contacted with each other, the formed interface contact is the contact among micro-bulges in fact from micro perspective. The loaded micro-bulges experience three stages of deformations of elasticity, elasticity-plasticity and plasticity in succession. In consideration of the three-dimensional fractal distribution characteristic of the micro-bulges in the interface, a prediction method of metal interface loading force under dry friction is provided based on fractal geometry theory and Hertz contact theory. The method considers three-dimensional fractal surface topography, friction coefficient and elastic-plastic deformation on the contact interface on the basis of the conventional contact analysis. The method makes the interface loading force which is hard to detect easy to obtain with simple calculation and easy operation, capable of being applied to interfacial dynamic characteristics analysis of precision machinery in projects.

The invention provides a method for allowing for using the maximum load of a rolling body to set a static load bearing curve of a blade bearing. The method comprises the following steps of: according to a hertz contact theory, obtaining an allowable maximum load [Qmax] of the rolling body, substituting the [Qmax] to obtain the axial load Fa allowed of the blade bearing and the static load computing formula M allowed of the capsizing moment; under a principle of selecting minimum values, determining the value of the epsilon 1 or the epsilon 2, and making the value meet two parallel conditions: 1, when the epsilon 1 is less than 1, the summation of the epsilon 1 and the epsilon 2 is equal to 1, and the epsilon 1 is more than or equal to the epsilon 2; and 2, when the epsilon 1 is more than or equal to 1, the epsilon 2 is equal to 0; calculating the Fa allowed value and the M allowed value according to the values of the epsilon 1 and the epsilon 2; and setting the static load bearing curve of the blade bearing by taking the axial dynamic load Fa allowed as the horizontal coordinate and the capsizing moment dynamic load M allowed as the vertical coordinate. By the use method for setting the static load bearing curve of the blade bearing according to the allowed maximum load of the rolling body, whether the lectotype of the blade bearing meets the use requirement can be validated, and the method can also be used as a reference for optimizing the design parameters of the blade bearing.

The invention discloses an interface ultrasonic reflectivity-pressure relation curve establishment method based on fillet plane contact theory and a loading test stand. The loading test stand includes a pressure display, a control terminal, an oscilloscope, a water logging ultrasonic transducer, a large cylinder, a small cylinder, an upper panel, a movable plate, a pressure sensor, a lower panel, an ultrasonic transceiver and a small cylinder connecting plate. Compared with the existing schemes, the interface ultrasonic reflectivity-pressure relation curve establishment method based on fillet plane contact theory and the loading test stand provided by the invention can construct a more accurate ultrasonic reflectivity-pressure relation curve, and the detection precision is high.

The invention discloses a modeling method for a soft climbing robot. The soft climbing robot comprises a deformation layer (1), a supporting layer (2), a restraining layer (3) and a central accommodating cavity (4) which are sequentially arranged from outside to inside. By using the minimum potential energy principle in elastic mechanics, the relation between deformation of points on a deformationlayer of a cavity and pressure intensity inside the cavity is analyzed so as to obtain the deformation needed by the contact theory formed by the deformation layer and a cable surface, and thereforethe optimal soft climbing robot conforming to the target performance can be easily obtained.

The invention relates to a thin-wall piece milling vibration restraining method based on a movable support. The mass, rigidity and a damping matrix of a workpiece are obtained through the finite element; equivalent stiffness and damping provided through the movable support are calculated through the contact theory and assembled to rigidity and a damping matrix of an initial workpiece; and finally,dynamics parameters of the workpiece at different tool position points are rapidly obtained through a numerical calculation method, and stability prediction is conducted. The functions of efficient restraining of vibration and rapid prediction of vibration stability in the whole machining process are achieved, and the material removal rate in the milling process is improved by 67% to the maximumin the embodiment.

The invention discloses a method for simulating contact pressure of friction plates with surface morphological information. According to the method, measure concepts of image processing and contact analysis are utilized to superpose surface morphological information into model grids so as to realize simulation of contact detail information of friction plates. According to the method, contact pressure of friction plates with surface morphological information can be simulated, and micro surface information is added onto a macro friction plate contact model, so that contact pressure simulation distribution of the friction plates is closer to the practical condition. Through combining a micro contact theory and macro practical engineering, the contact pressure simulation of the friction plateshas theoretical support and using meaning.

The invention discloses an aero-engine spindle bearing rated life calculation method considering backlash change, which comprises the following steps: analyzing the influence of interference fit, working temperature and rotating speed on a working backlash, and obtaining the working backlash by establishing a radial working backlash calculation equation of an aero-engine spindle bearing; based ona Hertz elastic contact theory, carrying out load distribution analysis of the main shaft bearing through a working clearance, and establishing a load distribution model; analyzing the motion states of the spindle bearing inner ring, the main shaft bearing outer ring and the rolling body to obtain a motion model of the main shaft bearing; and correcting the L-P fatigue life model through the loaddistribution model and the motion model, and calculating the rated life of the aero-engine main shaft bearing.. The method enables the prediction of the rated life of the aero-engine main shaft bearing to be more accurate.

The invention provides a prestressed pipeline friction loss test and calculation method. The test and calculation method comprises the following steps: (1) carrying out multiple times of asymmetric tensioning and symmetric tensioning operations on a prestressed steel bundle, and recording related data; (2) deducing a calculation formula of a friction influence coefficient of the prestressed pipeline based on a stress uniform distribution principle in a Hertz contact theory; and (3) according to the deduced calculation formula, calculating a friction influence coefficient of the prestressed pipeline by utilizing the elongation difference of the prestressed steel beams which are tensioned twice, and evaluating the prestressed friction loss. The method is based on the stress uniform distribution principle of the Hertz contact theory and skillfully utilizes the Hooke law; the test method is convenient and economical, can effectively and reasonably calculate the friction influence coefficient and the prestress friction loss value of the prestress pipeline, and is suitable for prestress concrete bridges with symmetrically arranged prestress steel beams; and the prestressed pipeline friction loss test and calculation method is convenient and fast in test, high in efficiency, low in cost, good in economy and high in accuracy.

The invention discloses a nonlinear correction method for an ideal linear coefficient of inertia of a ball screw type inertial container. First, based on Frenet frame theory and Hertz contact theory, relative sliding velocity and sliding friction moment between a ball of a ball screw pair and a raceway are deducted to obtain friction power of the sliding of the ball, the ratio between the friction power and exciting power is the efficiency of sliding friction of the ball; the efficiency of rolling friction of the ball is introduced, and finally the ideal linear coefficient of inertia of the ball screw type inertial container is corrected as the nonlinear coefficient of inertia. According to the nonlinear correction method, the nonlinear friction between the ball and the raceway in the ball screw type inertial container is considered, which is more in line with the actual situation. Compared with the correction method of the coefficient of inertia obtained by numerical simulation, the correction method is simple and reliable, can provide more accurate coefficient of inertia for the design of the ball screw type inertial container and the application in engineering vibration damping system, promotes and develops the theory and method of the inertial container, and has practical engineering significance.

The invention discloses a blocked analysis method for a large-size machine tool structural member. The method comprises the steps of establishing a combining surface rigid model based on a three-dimensional fractal contact theory, and identifying a normal stiffness and lateral stiffness; performing parameter modeling of the large-size structural member (crossbeam) based on a definite element method, and integrating the identified normal stiffness and the lateral stiffness into a large-size structural member three-dimensional model; and utilizing a parameter blocked designing method and a particle swarm optimization method, optimizing the dynamic performance of the large-size structural member (crossbeam), and designing the optimized large-size structural member (crossbeam) three-dimensional model by means of an optimization result. A re-manufacturing factor is taken into a designing period so that the structural member not only can satisfy function and performance requirement of a product and furthermore facilitates manufacturing, transportation, assembling and re-manufacturing. The blocked analysis method for the large-size machine tool structural member is deeply understood, thereby better guiding designing and application of the large-size machine tool structural member.

The invention discloses a rated dynamic load determination method for a roller needle bearing mounted on a bolt shaft cantilever. On the basis of the Hertz contact theory, the influence of the flexible deformation of the ferrule and the modification of the roller pin on the load distribution is considered, meanwhile, the influence of the inclination of the roller pin on the load distribution caused by the flexural deformation of the bolt shaft is considered, and a local flexible supporting roller pin bearing mathematical model installed on the cantilever bolt shaft is established. And accurateiterative solution is performed on the force balance equation by adopting a numerical analysis method to obtain load distribution of the roller needle roller bearing under the action of external dynamic load, and further the service life of the bearing is obtained according to a rolling bearing fatigue life calculation theory. And on the basis, a relation curve graph of the fatigue life and the external dynamic load is drawn, and then the rated dynamic load of the roller needle bearing is quickly obtained through the curve graph according to the definition of the rated dynamic load of the rolling bearing.

The invention provides a nanoindentation testing method for the elastic moduli of an austenite phase and a martensite phase of a shape memory alloy. The method comprises the following steps: multiple nanoindentation experiments at different depths; data processing by using the Oliver-Pharr method on the basis of experimental results; and regression analysis via empirical formulas obtained by using the Hertz contact theory and parameter analysis so as to obtain the elastic moduli of the austenite phase and the martensite phase. The testing method is simple in principles and easy in steps and can rapidly obtain the elastic moduli of the austenite phase and the martensite phase by implementing the nanoindentation experiments at different depths and using the calculation formulas put forward; and formulas used in the process of calculation are based on theories, experimental results are highly reliable, the process of a data processing algorithm is intelligible, and the data processing algorithm can be easily programmed.

The invention relates to a super hard material nanometer hardness measuring method considering press head elastic deformation, and belongs to the technical field of nanometer hardness measurement. Themethod comprises the following steps of 1, building two object elastic contact models on the basis of a Hertz elastic contact theory; deducing a hardness calculation formula according to the model; 2, loading a standard molten quartz sample by a press head at different press depths; correcting the area function of the press head according to loading and unloading data of the molten quartz samples; 3, calculating the data of tested samples obtained through nanometer press mark experiments by using the area function obtained in the step 2; obtaining the hardness of the sample to be tested. Thebuilt super hard material nanometer hardness measuring method considering press head elastic deformation has the advantages that the elastic deformation of the press head is considered by the built hardness calculation formula; the hardness of the tested material can be more accurately evaluated. The area function is the linear relationship between the contact area and the maximum press depth; thedata processing is simpler.