35 results about "Equivalent static load" patented technology

A topology optimization method. Characteristics of a structure to be designed are differentiated to calculate equivalent static loads. A relative fraction of material is adopted as a design variable. It is determined whether or not an element exists based on an objective function and constraints. Design topology is derived through a linear static analysis that processes the equivalent static loads as multiple loading conditions. Topology of the structure to be designed is compared with the design topology, and thereby the progress of optimization is determined. The topology optimization processes are terminated when a difference of the compared result is less than a setup value, and are returned to an initial step when the difference is greater than the setup value, and the equivalent static loads are calculated using the design topology as a new structure to be designed.

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 relates to a dynamic response topological optimization method implemented by application of improved bi-directional evolutionary structural optimization (BESO) to an equivalent static load method. In the method, improved BESO is applied to the equivalent static load method to form an optimized iteration method for replacing an original variable density method, and establish a new convergence condition in order to improve a dynamic response topological optimization flow. By adopting the method, optimization time of a design circulation stage of which k is greater than 1 can be reduced effectively, and CPU (Central Processing Unit) total time needed by optimization in two examples is reduced by 21.8 percent and 25.3 percent compared with an original method; the method has the characteristics of high computation speed and simple optimization flow; along with the increase of external load acting points and the expansion of the optimization scale, design circulation times needed by optimization are increased, and the method has greater advantages.

The invention relates to a power distribution network comprising a direct-current distributed power supply and an analysis method of comprehensive load characteristics of the power distribution network. The power distribution network comprises static loads, a dynamic load bus and comprehensive loads, wherein the static loads are equivalent static loads formed by combining static load elements and the direct-current distributed power supply, a model structure of the comprehensive loads is a generalized comprehensive load model structure and comprises a reactive compensation device, static loads, induction motor loads, an equivalent power supply, a power distribution network equivalent impedor, the reactive compensation device, the static loads, the equivalent power supply and an induction motor are connected in parallel and are connected to an external system through the power distribution network equivalent impedor. The model structure of the comprehensive loads adopted in the power distribution network can integrally describe various load characteristics of nodes, and the problem that after a large number of distributed power generation devices are connected to the power distribution network, the power distribution network affects the comprehensive load characteristics is solved.

The invention discloses a nonlinear topological optimization method for car body welding spot arrangement. The method comprises the steps that a vehicle crash simulation finite element model is established, LS-DYNA calculation is submitted, and displacement values of crash performance key attention nodes are output; a white car body linear rigidity simulation finite element model is established, and GENESIS optimizing calculation is submitted; entity units are adopted for modeling of relevant welding spots in a crash model and a white car body model; an equivalent static load method is adopted for transforming crash nonlinear conditions into linear static conditions for topological optimization design; the welding spots are set to be topological variables, obtained welding spot density values are updated into the crash finite element model, and a new round of crash simulation analysis is conducted; lastly, a convergence result is postprocessed. According to the method, the entity welding spots are subjected to topological optimization, car body welding spot arrangement is realized on the premise that crash properties at all important moments are met, reasonability of car body welding spot arrangement is ensued, redundant welding spot arrangement is avoided, the number of the welding spots is reduced, manufacturing cost is lowered, and production efficiency is improved.

The invention discloses a method for designing a hybrid fiber composite anti-explosion tank. The hybrid fiber composite anti-explosion container tank is obtained with an anti-explosion tank mechanical property determining method and a fiber hybrid ratio determining method based on anti-impact performance. The method is characterized by including the steps that impact loads of the anti-explosion tank during an explosion are obtained through the incoming overpressure, the reflecting overpressure and the power coefficient generated during a TNT explosion with an equivalent static load method; the stress borne by fibers is calculated through a grid theory in cooperation with a direct cylinder section and an end socket section of the anti-explosion tank, and the thickness of the wound fibers is obtained; the anti-impact performance in the fiber level is evaluated by introducing fiber energy absorption, and an anti-impact performance judgment criterion in the equivalent anti-explosion structure level is obtained; and the fiber ratio generated when the anti-impact performance is highest is selected as the optimal hybrid ratio by controlling the mass and the elastic modulus of the anti-explosion tank. According to the method, due to the anti-impact performance judgment criterion and the hybrid fiber anti-explosion tank optimal hybrid ratio determining method, powerful bases are provided for designing and manufacturing of the hybrid fiber composite anti-explosion tank.

The invention discloses a battery bin anti-collision beam topological optimization method based on an equivalent static load method. Time steps of equivalent static load extraction points are cleared,the mass of an anti-collision beam is adopted as a target function, displacement is adopted as constraint, and the optimal anti-collision beam structural mode is finally obtained through uninterrupted iterative optimization process. In other technical fields, extraction of equivalent static loads is performed in the whole dynamic process, only first six time steps before collision ending are extracted from the equivalent static loads, the optimization efficiency is improved, and by adopting topological optimization based on a variable density method, the passenger car battery bin anti-collision beam with the optimal structure can be obtained finally.

An air conditioner load modeling method based on least squares parameter identification is characterized in that air conditioner load is simulated by equivalent static load and equivalent dynamic load, a non-linear state equation is used to describe the equivalent mechanism model of the compressive load of the air conditioner load; and the steady state constraint condition of the air conditioner load is set and added into a weighing matrix for calculation; the working principle of the load modeling method based on the steady state constraint weighing least squares parameter identification, and corresponding detailed parameter identification steps which can be implemented by a computer are provided. The method has the advantages that a precise air conditioner load model can be provided, simulation results approximate to actual situations can be acquired, influence of the air conditioner load to a power grid can be identified favorably, and searching of methods for reducing air conditioner load damage is helped; the situation that no air conditioner load modeling exits is changed, the defects that the air conditioner load model cannot consider both steady state and transient state, and air conditioner load model accuracy is increased.

The invention belongs to the technical field of automobiles, and particularly relates to an automobile bumper mask size optimization method based on an equivalent static load method. According to themethod, the total mass of the automobile bumper mask is taken as an objective function, displacement is taken as a constraint, and the thickness of the mask is taken as a design variable to carry outsize optimization design on the bumper mask. According to the method, a final optimization result is required to meet a convergence condition and a displacement constraint condition, and the optimization result is more accurate. In addition, only the equivalent static load of the time step with the maximum displacement is calculated, the equivalent static load of all the time steps does not need to be calculated, and the calculation efficiency is high. All the functions are integrated through matlab, automatic solving is achieved, besides basic model preprocessing, finite element software doesnot need to be opened any more to solve the model, a running program directly calls a related solver to solve the model, and operation is convenient.

The invention discloses a method for carrying out structural topological optimization on nonlinear dynamic systems of high-speed light-load mechanisms. According to the method, the number of linear static structure optimization iterations in an ESLM (equivalent static loads method) is restricted according to the minimum number of iterations required by the structural topological optimization, so that the modifier in the optimization is restricted, the model error caused by equivalent load is reduced, and the structural topological optimization of the high-speed light-load mechanisms on the basis of structure restricted modified ESLM. According to the method, the equivalent load is considered as a function of a design variable, the optimization model is reconstructed, and a corresponding solving method is proposed, so that the residual amplitude is reduced as much as possible while the optimization condition is satisfied, compared with the standard equivalent static load, the amplitude under the same movement condition can be reduced by a half, the performance of the high-speed light-load mechanisms can be greatly improved and different design requirements of the high-speed light-load mechanisms can be satisfied.

The invention relates to a method and a device for detecting stability of transient voltage of an electric power system. The method comprises the following steps of reading offline load parameters of a synthetic load model, wherein the offline load parameters include rotor impedance, stator impedance and excitation reactance of an equivalent motor and impedance of an equivalent static load; reading voltage at a load bus and active power at the load bus in real time; computing rotating speed of the equivalent motor at the next moment according to the offline load parameters, the active power at the load bus and the voltage at the load bus; computing recovery time of the rotating speed of the equivalent motor according to the offline load parameters, the rotating speed of the equivalent motor at the current moment and the rotating speed of the equivalent motor at the last moment; and determining stability parameters of the transient voltage according to the recovery time of the rotating speed of the equivalent motor. The method and the device put forward quantitative evaluation indexes for analysis of the stability of the transient voltage of the electric power system and have the advantages of simplicity, rapidity, high efficiency and the like.

The invention belongs to the structure and equipment impact resistance design technology field and relates to a method of determining an impact-load equivalent static load. The method comprises the following steps of step1, according to the following formula which is defined in the description, calculating a dynamic scaling coefficient lambda, wherein TD is duration of an impact load, and fn is a fundamental frequency of a structure to be impacted; and step2, according to the following formula, calculating an equivalent static load Ps of the impact load, wherein the formula is Ps=lambda P, and the P is a peak value of the impact load. A lambda value acquired through calculation in the scheme can be greater than and less than 1 according to a change of TDfn, which is really equivalent to the impact load, and a truth degree of the equivalent static load is increased.

The invention discloses a high speed light-load mechanism nonlinear dynamic system structure evolution optimization method. The method aims at a nonlinear kinetic analysis to directly calculate sensitivity information of element strain energy and directly obtain the element strain energy at each time point, the strain energy at all the time points is superposed after normalization processing, the comprehensive sensitivity for measuring all discrete points is obtained, structure modification is performed by adopting an evolutionary structural method, then the structure is updated, the nonlinear analysis is performed again, and the process is repeated until an optimal object is realized. According to the method disclosed by the invention, the equivalent load calculation is omitted, and the change on inertial load by structural modification is directly reflected into a model to obtain a more optimal optimization result. According to the method disclosed by the invention, the equivalent static load is considered as a function of a design variable, and a corresponding calculation method is proposed, compared with a standard equivalent static load, the amplitude in the same movement condition can be lowered by half, and the performance of the high speed light-load mechanism is greatly improved.

The invention discloses a structural designing method for a robot multiple-speed translation mechanism and belongs to the field of mechanical equipment. The structural designing method includes simulating load borne by a main beam in actual working condition and analyzing to acquire dynamic load; applying the dynamic load onto the main beam, and calculating equivalent static load of the main beam; taking the equivalent static load of the main beam as a boundary condition to adopt a variable density method to perform topological optimizing design on structure of the main beam. By taking the equivalent static load of the main beam of the robot multiple-speed translation mechanism as the boundary condition, optimal material distribution of the main beam is acquired on the basis of the variable density method, and finally a multiple-speed translation mechanism with optimal comprehensive performance is acquired, so that maximum deformation can be reduced while structural weight is reduced, and working requirements on high speed and high accuracy of a robot are met.

The invention relates to a wind load simulation test method for a double-pitched roof mobile house in the technical field of wind resistance detection of mobile houses. The wind load of the mobile house is converted into multi-point loaded equivalent static loads applied to main bearing components of a windward side and a north wind side through a transverse wind load analog loading device and a wind suction analog loading device; a step-by-step multi-point loading test is carried out so as to measure the displacement and the strain of each stressed beam column under each stage of wind load; the wind resistance performance of the prefabricated house structure is evaluated and verified, the loading mode and the graded loading process in the test process are simplified, graded loading and graded testing are conducted on main bearing components in a targeted mode, the safety of the test process is high, and meanwhile the problem that implementation of a large prefabricated house wind resistance test and a wind tunnel test is limited is solved.