766 results about "Mechanics model" patented technology

Techniques for determining and using a thermodynamic model that characterizes a thermodynamic response of an enclosure conditioned by an HVAC system are disclosed. To determine a thermodynamic model, temperature information when the HVAC system operates in a first state may first be received. A response interval may then be determined where the response interval indicates an estimated time between when the HVAC system begins operating in the first state and when the temperature within the enclosure begins to change in a direction associated with the first state. Weighting factors corresponding to basis functions may then be determined, where the weighted basis functions characterize the temperature trajectory of the enclosure in response to the HVAC system operating in the first state. The basis functions may include a first basis function that is evaluated from a time that the HVAC system begins operating in the first state until a time when the response interval ends, and a second basis function that is evaluated beginning at the time when the response interval ends.

The invention discloses a physical prediction method for wind power station power based on a computational fluid mechanics model. The physical prediction method comprises the following steps: establishing a computational fluid mechanics model; performing discretization on wind conditions of a wind power station, and taking the discretized wind as boundary conditions for conditions numerical simulation of the computational fluid to obtain space flow filed distribution of the wind power station at the discretized wind conditions; establishing data base of hub height, wind speed, wind direction and generated power of wind generation sets under the discretized wind conditions; and taking numerical weather prediction parameters as input data, and utilizing the data base to figure out the wind speeds and the wind directions of the wind generation sets so as to figure out the generated powers of the wind generation sets, and accordingly obtain predicted value of the wind power station power. According to the invention, the physical prediction method is applicable to multiple wind power stations, has small calculated amount in the power prediction stage and has short calculation time.

A method and apparatus for predicting the performance of a drilling system for the drilling of a well bore in a given formation includes generating a geology characteristic of the formation per unit depth according to a prescribed geology model, obtaining specifications of proposed drilling equipment for use in the drilling of the well bore, and predicting a drilling mechanics in response to the specifications as a function of the geology characteristic per unit depth according to a prescribed drilling mechanics model. Responsive to a predicted drilling mechanics, a controller controls a parameter in the drilling of the well bore. The geology characteristic includes at least rock strength. The specifications include at least a bit specification of a recommended drill bit. Lastly, the predicted drilling mechanics include at least one of bit wear, mechanical efficiency, power, and operating parameters. A display is provided for generating a display of the geology characteristic and predicted drilling mechanics per unit depth, including either a display monitor or a printer.

The invention provides a multi-constraint locus planning method of a spatial free floating mechanical arm. The method can satisfy requirements for dynamic coupling, joint driving capability limitation, arresting opportunity and multiple optimizing indexes of a spatial robot. A driving joint motor realizes an autonomous arresting task to a non-cooperative object. The multi-constraint locus planning method comprises the steps of establishing a multi-member dynamic model of the spatial robot; establishing the locus of each joint of the mechanical arm based on a Bessel curve, converting constraint and optimizing index functions in a joint locus designing process to function of a Bezier curve control point, so that locus programming is finally represented by the Bezier curve control points as a nonlinear optimization problem of the optimizing parameter; converting the locus planning problem of the spatial robot to a multi-constraint and multi-object optimization problem, performing searching on the optimization problem by means of a nonlinear optimization method, obtaining an optimal solution, and finishing multi-constraint locus planning of the spatial free floating mechanical arm.

The invention relates to a soft tissue deformation simulation method based on smooth particle hydrodynamics, belonging to the technical field of graphic processing. In the method, a smooth particle hydrodynamics method is selected, and a viscoelastic mechanics model is used for reflecting the biomechanical characteristics of soft tissue. The method comprises the following steps of: constructing a series of equations related to soft tissue deformation simulation according to the viscoelastic model; selecting a proper support domain search strategy and a smooth kernel function, approximately calculating each related item of the equation by adopting the particle approximation method, and calculating the variation values of the density, the position, the velocity and the like of each particle along with time through the display integration method; and dynamically outputting the status of each time step size of the particle model to a screen, rendering texture irradiation, and displaying the real-time deformation process of soft tissues and organs under stressing conditions. The method does not need troublesome grid computing, thereby increasing the accuracy and the real-time performance of soft tissue deformation simulation.

The present invention relates to a method for measuring steel structure bridge life by utilizing fracture mechanics. It includes an ultrasonic inspection process of steel structure bridge member, and utilizes actually-measured data to correct analog data so as to raise accuracy of structural calculation. Said measurement method includes seven steps: structural mechanics modeling, mechanical model correction, traffic load modeling, traffic load correction, ultrasonic inspection, member fracture mechanics model modeling and bridge structure technical state judgment.

A satellite dynamics simulation system and method based on a satellite dynamics model library relates to the technical field of computer simulation. The invention solves the problems of high development cost and long cycle because the existing dynamics simulation systems need repetitive building of simulation models to complete modeling. The satellite dynamics simulation system comprises a satellite dynamics model library and a model management system, wherein the satellite dynamics model library is used for providing various orbit dynamics simulation models, various spatial environment simulation models, various attitude dynamics simulation models, various sensor measurement simulation models and various basic algorithm simulation models; and the model management system is used for calling and controlling various models in the satellite dynamics model library according to the simulation tasks so as to realize satellite dynamics simulation. The invention is application to satellite simulation.

The invention provides an unconventional oil and gas reservoir horizontal well section three-dimensional rock mass mechanical modeling method and device. The method includes the steps of determining an unconventional oil and gas reservoir horizontal well section object region; obtaining three-dimensional earthquake prestack gathered data in the object region; conducting elastic parametric inversion by adopting the three-dimensional earthquake prestack gathered data and obtaining a three-dimensional space elastic parameter data body in the object region, wherein the three-dimensional space elastic parameter data body comprises a rock mass poisson ratio and Young modulus; calculating a rock mass brittleness index according to the rock mass poisson ratio and the Young modulus; establishing a rock mass mechanical parameter model based on three-dimensional grid nodes according to the three-dimensional space elastic parameter data body and the rock mass brittleness index. The unconventional oil and gas reservoir horizontal well section three-dimensional rock mass mechanical modeling method and device can simply, effectively and accurately obtain an unconventional oil and gas reservoir rock mass mechanical model.

The invention relates to a model-constraint-based mechanical arm energy optimal trajectory planning control method and device. The model-constraint-based mechanical arm energy optimal trajectory planning control method comprises the steps that initial conditions are set and mechanical arm joint angle position description with respect to time is calculated and obtained through a cubic spline interpolation algorithm; on base of the mechanical arm joint angle position description and in combination with a dynamics model, a continuous function of moment with respect to time is obtained; a nonlinear constrained planning model taking mechanical arm movement energy consumption as the optimizing target is established, and in combination with the mechanical arm joint angle position description, thecontinuous function of the moment with respect to time and friction force energy consumption, energy consumption of a target function is solved; and on base of the nonlinear constrained planning model taking mechanical arm movement energy consumption as the optimizing target, the minimum value of energy optimal trajectory planning is iteratively solved adopting a sequential quadratic planning algorithm, and a mechanical arm optimal trajectory is obtained. Compared with the prior art, the model-constraint-based mechanical arm energy optimal trajectory planning control method and device do notneed a large number of complex calculation and have good real-time performance, and energy consumption is least.

The invention discloses a method for establishing a rock material ageing and elastic-plastic mechanics constitutive model. The method includes the steps that the triaxial short-long term test result of rock is used as the basis first, and the volumetric strains of a rock test piece under different test conditions are calculated; by drawing a stress-axial and lateral strain relation curve and a stress-volumetric strain relation curve, the yield criterion, the non-associated flow rule and the hardening criterion of the rock are determined, and an elastic-plastic mechanics model is established; then by combining material micro and fine damage attenuation ageing evolution dynamic equilibrium, the micro and fine ageing damage rule of the rock is determined, the model is popularized, a relation matrix of strain increment and stress increment at the ageing-elasticoplastic deformation stage is established, and accordingly the rock material ageing and elastic-plastic mechanics constitutive model is obtained. According to the model, the mechanics significance is definite, the expression is unique, the number of parameters is small and can be obtained based on the test results, hence, solving uniqueness and accuracy are guaranteed, and wide applicability and expansibility are achieved.

The invention relates to a calculation method of ultimate bending capacity of reinforced severe damage beam with fiber reinforced polymer, comprising the steps of the geometrical relationship that S1, going through the cross section of beam strain, the material stress- strain relationship, the establishment of mechanical model, calculating the relative compression zone height; S2, reducing the compressive strength of the concrete in the compression zone; S3, adopting the axial compressive strength of the concrete after the reduction, according to the above steps to recalculate the height of the compression zone; S4, calculating the ultimate bending moment; and S5, calculating the ultimate bending load capacity. The invention provides a prediction for the design and research of the ultimate flexural capacity of the RC beam with a single section of the reinforced concrete with a single rib, and saves the measured cost and a lot of test timeso as to make the ultimate bearing capacity of the reinforcement structure design more accurate;accurately calculating the ultimate bending capacity of the reinforced beam, which makes the engineering and technical personnel more accurate and convenient to control the loading process of the fiber reinforced concrete beam; The method has great economic benefit.

The invention provides an automobile chassis part weight reduction method based on multi-body dynamics and a topological optimization technology for the purpose of solving the problems that in existing automobile designs, a clear and feasible weight reduction method is unavailable, and an automobile chassis part still has a large weight reduction space. The automobile chassis part weight reduction method comprises the following steps: step 1, a finished automobile multi-body dynamic model and an object part finite element model of an object automobile type for weight reduction are established; step 2, multiple typical working conditions are selected, and an equivalent static load borne by an object part under each typical working condition is extracted; step 3, the equivalent static loads extracted in the step 2 are used as optimization boundary conditions, a flexibility weighting coefficient of each typical working condition is selected, the minimum total weighting flexibility serves as an objective function, and topological optimization is conducted with a constraint function including modality and stress; step 4, a threshold value is selected for a topological optimization result, and the position of a material to be removed is guided. The automobile chassis part weight reduction method based on the multi-body dynamics and the topological optimization technology combines a fatigue strength design with a static strength design, thereby having high reliability, portability and operability and being capable of effectively shortening the development cycle.

The invention discloses a dynamical model modeling method of vehicle driven on mountainous road, for solving the technical problem in the current vehicle dynamical model modeling method that has bad adaptability caused by a plane driven vehicle. According to the technical solution, the vehicle dynamical model driven on the mountainous road is built by means of an operation dynamical model and a tire model of the vehicle, a longitudinal velocity and a normal load of each vehicle wheel; the stability of the model is analyzed and the traffic safety of the vehicle on the mountainous road is evaluated according to the built vehicle dynamical model, the acquired vehicle driving state data and the road geometrical information. In the model, the slope angle of the mountainous road, the side rake angle of the road surface while turning and the dynamic change of the normal load of each tire while turning are considered so that the invention reduces or prevents the traffic accident and increases the driving safety of the vehicle on the mountainous road.

The invention discloses a moving load analog loading method and device for a rail transit wheel axle. A plurality of actuators are distributed above sleepers along a rail direction, the bottom of each actuator is connected in the span middle of a distribution girder, the bottoms of two ends of the distribution girder are arranged above steel rails at two sides, two continuous steel rails are laid on the sleepers and are respectively cut into mutually independent sectional steel rails above the positions of the sleepers, and each pair of sectional steel rail and sleeper is connected by a fastening system. Vertical pressure and upward pulling force are applied on the actuators by an anti-drop external member. A stress load time travel curve of a single fastening system under the effect of the wheel axle moving at different moving speeds is determined according to a train-rail-roadbed theoretical model and is used as a load exciting curve of each actuator, and the adjacent actuators are dynamically excited sequentially in the same time interval along the moving direction of the wheel axle so as to realize the analog loading of the moving load of the wheel axle at different speeds. The invention provides a reliable and convenient loading platform for developing a rail traffic dynamic model test research.

The invention provides a human-vehicle coordinative steering rolling optimization control method based on the driver in the loop. The method specifically includes the following steps of firstly, establishing a vehicle two-freedom-degree kinetic model and a vehicle kinetic model; secondly, determining an intervention degree coefficient through danger evaluating fuzzy logic; thirdly, establishing ahuman-vehicle coordinative steering system model; fourthly, designing a human-vehicle coordinative steering system controller through a model predicting method; fifthly, conducting driving authority distributing and calculating the control amount for completing control. By means of the method, a driver can be assisted in operations online in real time when the driver drives a vehicle and dangers probably happen, the operations of the driver cannot be intervened in when the driver normally operates the vehicle, the driver has vehicle steering absolute control authority when the vehicle is driven in a safety area, the controller absolutely does not intervene in the correct steering operations of the driver, and the controller decides the intervention degree in real time and assists the driver in completing the steering operations according to the operation behaviors of the driver and the position of the vehicle when the vehicle is driven out of the safety area.

The invention relates to the technical field of calculation, simulation and estimation of dynamic stress of a bearing structure of a high-speed tracked vehicle, in particular to a method for simulating and calculating dynamic stress of a vehicle body structure of the high-speed tracked vehicle. The method comprises two implementation steps of constructing a finished high-speed tracked vehicle system rigid-flexible coupling model based on a modal comprehensive method and calculating the dynamic stress of the vehicle body structure based on a modal stress recovering method. An integrated rigid body suspension system model, a propelling system model and a high-speed tracked vehicle rigid-flexible coupling complex dynamics model with a vehicle body structure finite element model are built by adopting a modal comprehensive technology, and the characteristics of the coupling dynamics between the vehicle system dynamics and the structure dynamics are accurately reflected. The method can obtain structural edge load at a designing and development stage of the high-speed tracked vehicle and simultaneously obtain structure dynamic stress, and provides effective means for design and improvement of a system structure of the high-speed tracked vehicle.

The invention discloses a calculation method of a tilt corridor of a tilt four-rotor aircraft with periodic variable pitch at constant rotational speed, which comprises the following steps: establishing flight mechanics models of various parts of the aircraft, converting all forces and moments into a body shaft system, and establishing a six-degree-of-freedom balance equation; determining the tiltcontrol mode; solving the upper and lower boundaries of the pitch angle by taking the lift characteristics of the wing as the limiting factor; obtaining the control variables and attitude angles under different state conditions by optimal trimming; finding the corresponding wing lift characteristic limit minimum speed boundary and wing lift characteristic limit high speed boundary; obtaining theavailable power limiting high-speed boundary by solving the required power at different state points. The invention is based on a flight mechanics model, takes into account the parameters of each aspect of the aircraft design, and reflects the specific attributes of each feasible flight point. The invention is also applicable to the tilt corridor calculation of tilt four-rotor aircraft under different control modes.

The invention discloses a method for constructing an elastoplasticity-damage coupling mechanical constitutive model of a rock material. The method comprises the following steps of obtaining the rock material on an engineering site, and manufacturing a standard cylinder sample; carrying out conventional triaxial compression mechanical tests under different confining pressures; obtaining a rock yield criterion, a plastic hardening criterion and a non-associated fluidity rule in combination with a test result; calculating a rock damage variable according to the stress-strain curve, and obtaininga rock damage evolution equation according to a damage variable-axial strain evolution rule; deriving a constitutive equation based on an elastic-plastic mechanics theory and an irreversible thermodynamic damage constitutive theory; combining the test data to obtain model parameters; writing the mechanical model into a UMAT subprogram, embedding the UMAT subprogram into ABAQUS finite element software, and carrying out triaxial test numerical simulation, so as to verify and improve the model. The method is clear in mechanical significance, simple in parameter acquisition, wide in application range and relatively high in accuracy.

The invention provides a system and method for determining nonlinear membrane stress. According to the invention, a membrane material is taken as a multilayer board shell structure to perform mechanic modeling so as to define the deflexion, cross section corner, middle plane internal displacement or curvature variation on the middle plane of the multilayer board shell structure as well as nonlinear geometric relationship to describe the deformation of the membrane material. Shape measuring equipment is adopted to measure the deformation of the membrane material caused by membrane stress, and the deformation is represented as the deflexion, cross section slope, middle plane internal displacement or curvature variation of the thin-film material. The finite elements of the multilayer board shell structure are adopted to discrete the geometrical model of a detected object, the measured values of degree of freedom of all or part of finite element nodes are given in a direct measurement or indirect interpolation manner, the least square fitting condition between the deformation generated by membrane stress at the nodes and the measured deformation is created, and the membrane stress is reversely solved through nonlinear iterative computations. As for membrane temperature mismatching stress belonging to part of the membrane stress, the nonlinear temperature mismatching stress of the membrane material with a deformed base body is calculated and considered at the same time under the condition of given temperature variation.

A GNSS ultra-tight coupling (UTC) receiver architecture applicable to space borne orbit platforms is described. A receiver in accordance with this architecture retains the rotational motion sensors typically found in an inertial measurement unit (IMU) of a conventional UTC receiver, but replaces the IMU accelerometer sensors with precise orbital dynamics models to predict the translational motion of the platform center of gravity (CG). Drag and radiation pressure may be modeled as well. The various models can be implemented in software. The IMU rotational sensors are retained for compensation of the GNSS antenna lever arm effect due to platform rotation.

The invention discloses a method for predicting multi-axis titanium alloy milling force of ball-end milling cutters. The method includes building multi-axis milling force models with consideration oninfluence of inclined angles of cutters on cut-in angles and cut-out angles on the basis of mechanics models of the three-axis ball-end milling cutters; carrying out cutting experiments; identifying milling force coefficients by means of linear regression according to measured cutting force at different feed speeds; carrying out simulation analysis on influence of machining parameters and geometric parameters of the cutters on the cutting force. The method has the advantage that certain theoretical bases can be provided for optimizing multi-axis milling machining technological methods.

The invention relates to a hypersonic speed reentry guidance method based on an analytical solution of a smooth and steady glide trajectory. The method includes the following steps that firstly, a flight vehicle dynamics model is established; secondly, a restraint model is established; thirdly, an initial descent stage guidance method is performed; fourthly, a smooth and steady glide stage guidance method is performed; and fifthly, a height adjustment stage guidance method is performed. The hypersonic speed reentry guidance method based on the analytical solution of the smooth and steady glidetrajectory has the advantages that prediction correcting of the longitudinal travel and the transverse travel is performed based on the analytical solution of a three-dimensional trajectory, the calculation amount is greatly reduced, the calculation speed is increased, and real-time application to an airborne system is facilitated. Transverse movement is determined by twice heeling reversing points, the first-time reversing point position is corrected to control the terminal transverse travel error, and the second-time reversing point position is corrected to meet the terminal speed restraint. Compared with a traditional method controlling transverse movement through a course error threshold, the number of heeling overturning times is reduced, the energy utilizing efficiency is improved,and the requirement for a control system is lowered. A proportional guidance thought is utilized in the height adjustment stage to make the terminal heeling angle converge to 0, and the target striking effect is enhanced.

The invention provides a method for analyzing and measuring the safety of a petroleum pipeline suspended on seabed and carrying out analysis and measurement on a limited simulation platform, comprising the following steps of collecting original data, detecting the buoyancy of integrally internal and external pipelines, establishing a cyber three-dimensional initial mechanics model of a marine petroleum pipeline by using a state that the marine petroleum pipeline is vacantly and horizontally arranged on a virtual and totally horizontal seabed surface, calculating the initial deformation caused by residual paving tensile force of the internal pipe by a finite element method, applying the loads such as pressure, temperature force and the like step by step on the internal and external pipe, thus obtaining the final deformation of the marine petroleum pipeline, and outputting the obtained calculation results. The analysis and measurement method can correct design at severe suspending sections under the prearranged seabed line on which the safety may be affected for the marine petroleum pipeline, and can also provide basis for carrying out remedial treatment at the severe suspending section under the built seabed line on which the safety may be affected.

The invention relates to a joint simulation method for a vehicle-road coupled vibration system. The method comprises the following steps of S1, building a vehicle dynamics model according to a dynamics equation; S2, building a pavement dynamics model according to a structural mechanics finite element equation; and S3, loading the vehicle dynamics model in the pavement dynamics model to generate a tire-pavement contact model, and finishing dynamics analysis of the vehicle-road coupled vibration system. According to the method, joint modeling of the vehicle-road coupled vibration system is realized by adopting efficient engineering software Matlab and Ansys; and by taking Matlab as control software and performing secondary development on Ansys, joint simulation of Matlab and Ansys is realized, and dynamics analysis of the vehicle-road coupled vibration system under complex road and vehicle conditions is finished.