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4052results about "Sustainable transportation" patented technology

Interior noise analysis and prediction method of high speed train

The invention discloses an interior noise analysis and prediction method of a high speed train. The method comprises the following steps: establishing a train reconditioning train body model, a statistical energy analysis model of a body in white structure and an interior and exterior vocal cavity statistical energy analysis model, and carrying out simplification and subsystem division; obtaining the statistical energy analysis parameters of the train body structure and an interior vocal cavity model, and loading the statistical energy analysis parameters onto a train body structure model plate subsystem and a vocal cavity model subsystem; and obtaining exterior vocal excitation source energy borne on the train body, applying the exterior vocal excitation source energy onto the exterior vocal cavity statistical energy analysis model, causing the exterior vocal excitation source energy to reach an interior vocal cavity after the exterior vocal excitation source energy is attenuated by the sound insulation property of a structural plate in a body in white structure model so as to obtain structural noise energy radiated into the train by the reconditioning train body under the function of the two-line suspension force of a compartment, and then, carrying out interior noise analysis and prediction. The problem that the interior noise of the train is difficult in prediction and the problems of the upper limit boundedness of a frequency domain, complex calculation flow, incomplete motivation consideration in the traditional method are overcome, calculation efficiency and prediction accuracy are improved, and development and test cost is lowered.
Owner:ZHEJIANG UNIV

Pneumatic elastic mechanical characteristic analytical method of hypersonic speed aircraft in thermal environment

The invention relates to a pneumatic elastic analytical method, and provides a pneumatic elastic mechanical characteristic analytical method of a hypersonic speed aircraft in thermal environment. According to the method, the piston theory is used for carrying out frequency domain nonsteady aerodynamic calculation on a full-aircraft finite element model of the hypersonic speed aircraft; on the basis, the pneumatic thermal effect on the model in the hypersonic speed thermal environment is considered; the weak coupling effect of pneumatic thermal input in aerodynamic input and elastic force input is ignored; only the structure temperature steady-state characteristics under the pneumatic thermal load effect are considered; after the steady aerodynamic calculation, the thermal flux density on the surface of the aircraft is obtained by adopting a reference enthalpy method; further, the steady temperature distribution on the surface of the aircraft is calculated; the practical equivalent rigidity matrix of the structure at the moment is obtained; and the critical flutter speed is calculated by an engineering method. The pneumatic elastic mechanical characteristic analytical method has the advantages that the pneumatic elastic analytical problem of the hypersonic speed aircraft in the pneumatic thermal environment is solved, and the pneumatic elastic performance of the hypersonic speed aircraft is improved through flutter speed analysis.
Owner:ANHUI JINSANHUAN METAL SCI & TECH

PoF (physics of failure) based method for calculating mission reliability of electronic product

A PoF based method for calculating mission reliability of an electronic product comprises steps as follows: step one, information of all mission profiles of the product is collected, and an environment profile of each mission is determined; step two, thermal simulation and vibration simulation of environmental stress of each mission are performed, and a local response of the product to an environmental load is obtained; step three, a product simulation model is established; step four, simulation calculation of the product in all the mission profiles is completed, and the mean time to failure and a main failure mechanism of the product are obtained; and step five, the mission reliability of the product is calculated according to the mean time to failure. According to the PoF based method for calculating the mission reliability of the electronic product, all missions of the product during lifetime use are considered, the environmental stress of each mission is simulated, and the mean time to failure and the mission reliability of the product are comprehensively calculated. By means of a PoF model, the direction relation between parameters of a product material, structure, process and the like and the reliability can be obtained, and a design improvement direction is clearly and directly provided for the product.
Owner:BEIHANG UNIV

Digital ship model planar motion mechanism experimental method based on CFD software

The invention provides a digital ship model plane motion organization experimental method based on computation fluid dynamics CFD software FLUENT. The method includes applying a FLUENT pre-process software GAMBIT to establish a research object model and a control domain; arranging a triangle grid on the model surface, then arranging a unstructured grid in the control domain; setting the boundary condition, joining an user-defined function UDF document, introducing dynamic grid technology, using a finite volume method based on the complete unstructured grid, realizing a pure swaying movement, a pure rising and falling movement, a pure oscillatory movement, a pure pitching movement and a pure rolling movement carried on by a plane motion organization experiment; applying a science computation software MATLAB to do Fourier expansion of a force and a moment coefficient obtained by the FLUENT, being fitted by EXCEL least squares method, obtaining a hydrodynamic force coefficient of a vertical plane and a horizontal plane as well as the related hydrodynamics analysis by dimensionless. The invention carries on the digit plane motion organization experiment using the CFD software, can satisfy the request of hydrodynamic force data in the design initial period of a submersible.
Owner:HARBIN ENG UNIV

Helicopter aerodynamic layout optimization method capable of reducing adverse effect of aerodynamic interference

The present invention discloses a helicopter aerodynamic layout optimization method capable of reducing the adverse effect of aerodynamic interference. According to the method, aiming at the defects of a wind tunnel test and a CFD method and based on a discrete vortex method and a surface element method, a coupled aerodynamic interference high-precision analysis model for a helicopter is set up, so that the influence of aerodynamic interference on the helicopter can be considered only by simulating calculation without carrying out the wind tunnel test; compared with the CFD method, the method has the advantages of greatly reducing the requirements of a simulation model for computing resources and shortening computing time. In order to further reduce calculated amount and a optimization region, a helicopter fuselage shape parameter model is set up by a parametric method and a combined optimization method based on an agent model is adopted, so that the optimal helicopter aerodynamic outline and layout are obtained and the purpose of reducing aerodynamic interference to improve the flight characteristics of the helicopter is achieved. The helicopter aerodynamic layout optimization method can be applied to the conceptual design phase of the helicopter so as to improve the flight characteristics, the balancing characteristic, stability and manoeuvrability of the helicopter.
Owner:NANJING UNIV OF AERONAUTICS & ASTRONAUTICS

Multi-objective optimization design method for wheel

ActiveCN107145663AImprove performanceAvoid defects where performance does not meet requirementsGeometric CADSustainable transportationTopology optimizationEngineering
The invention discloses a multi-objective optimization design method for a wheel, relates to the technical field of vehicle engineering and aims at solving the problems that the optimization space is limited and automatic optimization design is not carried out through joint transferring of calculation software with various properties due to the fact that only limited performance of the vehicle is analyzed and optimized and parametric modeling is lost at present. The method comprises the steps of topological optimization of a wheel fatigue test, combined topological optimization modeling, fatigue performance analysis, impact performance analysis, aerodynamic performance analysis and multi-objective optimization. Five working conditions of a dynamic bending fatigue test of the wheel, a dynamic radial fatigue test, an impact test of an impact hammer opposite to a spoke, an impact test of the impact hammer opposite to a window and air dynamics analysis of the wheel are set; the properties, such as the strength, the rigidity, the vibration characteristic, the fatigue life, the fatigue life security coefficient, the impact performance, the air dynamic property and the lightweight performance of the wheel are comprehensively considered; various performance parameters are calculated through finite element software emulation; and optimization design is carried out on the wheel by setting the performance parameters to be constraint conditions or objective functions.
Owner:JILIN UNIV

Full-firing-direction autonomous reentry guidance method based on three-dimensional reentry trajectory analytical solution

The invention discloses a full-firing-direction autonomous reentry guidance method based on a three-dimensional reentry trajectory analytical solution. The full-firing-direction autonomous reentry guidance method comprises the following steps of 1, building of a kinematical equation and a dynamical equation, 2, summarizing of the reentry guidance method, 3, descent stage guidance strategies, 4, steady gliding stage guidance strategies and 5 height-adjustment stage guidance strategies. The full-firing-direction autonomous reentry guidance method has the advantages that reentry guidance of an aircraft with the large lift-drag ratio can be guided effectively, low-damping and long-period trajectory oscillation caused by the high lift-drag ratio can be restrained effectively, the peak value ofthe heat flux density is reduced, and tracking of a reference track is facilitated; inertia force caused by earth rotation and actual aerodynamic force are combined into equivalent aerodynamic force,an equivalent aerodynamic section is planned through the analytical solution, and thus the aircraft has the omni-directional reentry task processing capability; and an equivalent aerodynamic section fitting formula based on the inverse proportional function is put forward, the reentry trajectory analytical solution based on the complex equivalent aerodynamic section form is further deduced, and thus high precision, all-dimensional applicability and high robustness are achieved.
Owner:BEIHANG UNIV

Method for designing water-spraying boost pump hydraulic model for efficient and large-power-density ship

ActiveCN104112040ABreak the monopoly high speedBreaking the Game for High-Performance Marine Waterjet Propulsion ApplicationsSustainable transportationSpecial data processing applicationsImpellerCavitation
The invention discloses a method for designing a water-spraying boost pump hydraulic model for an efficient and large-power-density ship. The method comprises the following steps that type selection design of water-spraying boost pump hydraulic parameters is conducted, two-dimensional axial face projective geometry is determined, three-dimensional geometrical shapes of an impeller and guide blades are obtained according to a parameterized ternary reversal design method, a three-dimensional geometrical shape of a shrinkage nozzle is obtained through circumferential rotation, the three-dimensional geometrical shapes of the impeller, the guide blades and the shrinkage nozzle are combined to obtain the water-spraying boost pump hydraulic model. The method has the outstanding advantages that the design period is short, the design quality is high, and the water-spraying boost pump hydraulic model which has the advantages of being high in efficiency, compact and large in power density can be rapidly and reliably designed. The geometrical shapes of the impeller and the blades are obtained according to the parameterized ternary reversal design method, so that on the condition that the water-spraying boost pump hydraulic model is kept compact, the efficiency is improved, cavitation is restrained, and the power density is increased in the researching and developing process of a high-speed ship water-spraying boost pump.
Owner:NAVAL UNIV OF ENG PLA

A method for analyzing fatigue life of steering knuckle

The invention discloses a method for analyzing the fatigue life of a steering knuckle, comprising the following steps: 1) obtaining the fatigue load of the steering knuckle; 2) carrying out uniaxial tensile material test on the use material; 3) if the fatigue load is under the static load condition, the elastic-plastic finite element analysis method is adopted to solve the problem; or, if it is the actual pavement load spectrum, the elastic-plastic finite element analysis is carried out on the points exceeding the yield strength by elastic finite element method and linear superposition method,and the modified stress-strain results are obtained. 4) analyzing the biaxiality of the obtained stress response in time domain to determine the load state of the steering knuckle; 5) calculating thedamage accumulation and life of steering knuckle. The present invention solves the problem of time-consuming finite element solution under the input of actual pavement load spectrum, at the same time, the stress and strain of the material entering the plastic phase are considered, so that the result is more accurate, and fatigue analysis is carried out by combining the static load condition or the single channel static load condition, and more references are provided in the design phase.
Owner:SOUTH CHINA UNIV OF TECH

Design method of hydraulic model of shaftless drive type integrated motor pump jet

The invention discloses a design method of a hydraulic model of a shaftless drive type integrated motor pump jet. By means of the method, the propeller which is equal to a seven-blade highly skewed propeller in open water efficiency and lower in radiation noise can be designed, wherein a motor and the pump jet are completely integrated. The method comprises the steps of a pump fluid channel hydraulic parameter type selection design, a parametric three-dimension reversal design of pre-positioned stator and post-positioned impeller blades, non-air-gap pump jet open water performance checking, and propelling, cavitation and noise performance and strength checking of the integrated motor pump jet. The pump jet which is composed of a thick guide pipe of an embedded motor stator, a motor annular rotor, an air gap, a pre-positioned stator and a post-positioned impeller is designed. The propelling efficiency is 0.589, the power is 3.7 MW and the pump jet can propel submersible vehicles with the navigational speed being 16 knots. The number of the stator blades is 13, the number of the impeller blades is 9, an NACA 16 wing type thickness distribution method is adopted for the stator blades and the impeller blades, and the impeller is highly skewed. The design method can be directly used for realizing shaftless electric propelling of unverwater vehicles, and is also suitable for shaft type pump jets and torpedo post-positioned stator type integrated motor pump jets.
Owner:NAVAL UNIV OF ENG PLA

Modal synthesis dynamic modeling and analysis method for automobile driving axle system

The invention relates to a modal synthesis dynamic modeling and analysis method for an automobile driving axle system. The method is characterized by comprising the steps that 1, a finite element model of all components of a driving axle is established, boundary nodes are defined according to the connecting relation between the components, a modal synthesis model of all the components is established, and a modal synthesis rigidity matrix and a mass matrix of all the components are obtained; 2, a connecting relation model of all the components is established; 3, the modal synthesis rigidity matrix and the mass matrix of all the components are assembled according to the connecting relation, a complete modal synthesis dynamic model of the driving axle system is established, and a rigidity matrix and a mass matrix of the driving axle system are obtained; 4, natural vibration frequency and a regular vibration mode of the dynamic model of the driving axle system are calculated, and a mode superposition method is adopted to calculate the dynamic response of the driving axle system under excitation of dynamic engaging force of gears of a main reducing gear. In the whole modeling process, high universality and calculating efficiency are achieved, and the method can be widely applied to dynamic analysis of a gear transmission system.
Owner:TSINGHUA UNIV +1

Hypersonic velocity aircraft wing spar structural reliability analysis method based on stress-strength interference theory

The invention discloses a hypersonic velocity aircraft wing spar structural reliability analysis method based on a stress-strength interference theory. The method comprises the steps that according to a geometric structure, proposed by NASA, of a six-degree-of-freedom hypersonic velocity aircraft universal model and an aerodynamic derivative equation, a stress analysis model of a wing spar root is built; flight constraint conditions of different flight phases are determined according to a flight envelope, the structural strength of the wing spar root is analyzed by combining material strength characteristic parameters at different temperatures; a stress-strength interference model is built according to a random load capacity and strength analysis data, and under the situation that the structural strength degrades along with increasing of flight frequency, the structural reliability of the model is calculated. According to the hypersonic velocity aircraft wing spar structural reliability analysis method based on the stress-strength interference theory, the frequency of the random load action on wing spars of an aircraft in the flight course is organically combined with wing spar structural strength degradation, and the accuracy of the reliability analysis is improved.
Owner:NANJING UNIV OF AERONAUTICS & ASTRONAUTICS

Positive real synthesis and passive implementation method of vehicle ISD suspension electromechanical network system

The present invention belongs to the field of vehicle passive suspension vibration isolation, and relates to a positive synthesis and passive implementation method of a vehicle ISD suspension electromechanical network system. The method comprises: Step 1: determining a dynamic model of vehicle suspension vibration and a performance evaluation index thereof; Step 2: establishing a vehicle ISD suspension electromechanical network system; Step 3: according to the performance optimization target, under the positive real inequality constraints, using the improved multi-PSO algorithm to optimize thesolution of the vehicle ISD suspension electromechanical network system to obtain the corresponding impedance transfer function coefficients; Step 4: carrying out positive real synthesis on the impedance transfer function obtained from the vehicle ISD suspension electromechanical network system; and Step 5: carrying out passive implementation on the vehicle ISD suspension electromechanical network system based on the electromechanical inertia. According to the method disclosed by the present invention, the limitation of the ISD suspension structure type design method and the difficult problemthat the impedance type design method cannot implement can be effectively solved, and a new method is provided for the structure design and implementation of the suspension.
Owner:JIANGSU UNIV

Aerodynamic stability predicting and estimating method of aerial engine under counter thrust state

Disclosed is an aerodynamic stability predicting and estimating method of an aerial engine under a counter thrust state. The method comprises the following steps of, firstly, performing aeroplane/engine integrated counter thrust air turbulence field fully-three-dimensional numerical simulation under the counter thrust state and obtaining the distortion maps and the distortion indexes of the inlet flow field of the engine under the counter thrust state; under the premise of obtaining the distortion indexes of the inlet flow field of the engine under different skating speeds of the aeroplane in the counter thrust state, performing integral stability computing analysis on influence of inlet flow field distortion on the aerodynamic stability of the engine in the counter thrust state; thirdly, taking the engine inlet flow field distortion maps obtained through three-dimensional flow field computing as the target to design an inlet flow field distortion generator used for aerial engine bench tests; fourthly, performing engine bench tests through the engine inlet flow field distortion generator, during the tests, starting a counter thrust device to measure the working state of the engine in real time and further to estimate the engine aerodynamic stability in the counter thrust state when inlet flow field distortion exists.
Owner:上海航数智能科技有限公司
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