108 results about "Static stress" patented technology

The invention relates to a fatigue life prediction system for a vehicle body structure of a vehicle in the technical field of vehicle design. The prediction system adopts a road spectrum fitting module to establish a combined road spectrum suitable for a field test; a vehicle body loading spectrum acquisition module is adopted to establish an entire vehicle multi-body rigid-flexible coupled model so as to extract the load-time-history at a connecting passage of the vehicle body and a chassis as the input of vehicle body excitation; an automobile body structure dynamic response analysis module is adopted to establish a finite element model of the vehicle body so as to obtain the static stress history generated by gravity and the dynamic stress history generated by road surface excitation of the vehicle body when the vehicle is under the excitation of the combined road spectrum; a dangerous position identifying module of low fatigue life of the vehicle body is adopted to quickly search dangerous positions of low fatigue life through an S-N method and a Miner linear accumulated damage model, and determine the multiaxial stress state of the dangerous positions by using 'biaxiality' analysis; and a fatigue life prediction module of the vehicle body structure is adopted to predict the fatigue lives of the dangerous positions accurately. The fatigue life prediction system for the vehicle body structure can improve the speed and the precision of the fatigue life prediction for the vehicle body structure so as to provide a reference for a real vehicle test.

The invention provides experimental equipment for simulating impact-type rock explosion. The experimental equipment comprises a rack and a specimen box assembly as well as an X-axis-direction loading mechanism, a Y-axis-direction loading mechanism, a Z-axis-direction loading mechanism and a control system which are installed on the rack. The loading mechanism in the first direction comprises four support pillars, a first frame, a second frame, a loading hydraulic cylinder and a screw rod, wherein the four support pillars are arranged in a rectangular shape; the first and second frames are aligned to each other and are respectively fixed at two ends of the four support pillars; and the loading hydraulic cylinder and the screw rod are arranged on the two frames respectively. The experimental equipment is capable of loading static stress and disturbing load on a rock specimen in the three mutually vertical directions in a three-dimensional space, so that the experimental equipment can be used for an experiment for simulating the impact-type rock explosion. In addition, as the structures of the three loading mechanisms are almost same and have good symmetry, the operation of loading stress or disturbing load on the rock specimen in the three directions is easier to control, and the accurate control on the operation is easy to achieve.

The invention discloses a core stress sensitivity measuring method based on nuclear magnetic resonance. Core stress sensitivity is measured on the basis of conventional displacement experiments and nuclear magnetic resonance testing methods. The method includes the steps that core pretreatment is conducted; a core is subjected to pressurized saturation to simulate formation water; the core is placed in a non-magnetic core clamp to be fixed to an NMR coil; confining pressure is set to test the nuclear magnetic resonance T2 relaxation spectrum of the core; stress values are set for repeated testing at intervals; the highest static stress values are sequentially reduced from 20 MPa to 2.5 MPa, each stress value is kept for a certain period of time to test the T2 spectrum, and the current conventional permeability and NMR permeability are obtained through computation; a core conventional stress sensitivity curve is drawn. By means of the method, people can understand the core stress sensitivity change rule from the micro perspective, characteristics such as pore size distribution, porosity changes and NMR permeability in the experiment process are provided, and change rules of microfracture compact matrix limestone pore size distribution, porosity and permeability in stress sensitivity testing can be effectively detected.

The invention relates to a method for testing residual stress of a steel rail. The method is characterized by comprising the following steps of using a steel rail with the length of 1m, taking one point (namely a center position) 500mm away from the end of the steel rail, drawing a line which is arranged at the point in the circumferential direction vertical to the axis of the steel rail, sequentially and alternatively taking 14 points from the center point of the rail bottom to the center of the rail head in the linear direction, attaching each point with a strain sheet, measuring the initial value of the residual stress of each point by a static stress-strain gage, using the line drawn on the steel rail as a center line, cutting steel rail into 20mm thin sheets at each 10mm part of the two ends of the center line in the direction vertical to the axis of the steel rail, and then measuring the final value of the residual stress of each point by the static stress-strain gage. The method has the advantages that by adopting the multi-point testing, the stress distribution conditions of the rail bottom, the rail waist, the rail head and other parts are acknowledged, the stress change of each point is analyzed, then the pressing amount of a rolling machine is corrected, and the distribution of the residual stress is adjusted, so the steel rail is qualified.

The invention discloses a testing device and a testing method for rock cracked through coupling of dynamic static load and water pressure. The testing device comprises a Hopkinson pressure rod device and a manual pressure pump. The Hopkinson pressure rod device comprises a high-pressure air tank, a punch, an incident rod, a data collecting processing system, an extension rod and an axial static pressure loading device. A testing piece and a water pressure loading pressure head are arranged between the incident rod and the extension rod, and the manual pressure pump with a pressure meter is connected with the water pressure loading pressure head through a sleeve. The method includes that first, axial static pressure is exerted on the testing piece through the axial static pressure loading device, then water pressure is exerted on the testing piece and adjusted to a preset value through the manual pressure pump with the pressure meter, the high-pressure air tank drives the punch to impact the incident rod, and finally collected data is processed. The testing device and the testing method achieve testing of dynamic mechanics characteristics of the rock in a laboratory under the condition of the coupling of water pressure seepage and dynamic and static stress and can better simulate deep excavation conditions.

Light from a light source device is polarized through a polarizer and is caused to impinge obliquely onto an object to be inspected. The resulting scattered light is received by a CCD imaging device having an element for separating scattered polarized light disposed in a dark field. Component light intensities are worked out for an obtained P-polarized component image and an obtained S-polarized component image and a polarization direction is determined as a ratio of them. The component light intensities and the polarization directions are determined from images obtained by imaging of the light scattering entities in a state where static stress is not applied to the object to the inspected and in a state where static load is applied thereto so as to generate tensional stress on the side irradiated by light. The component light intensities and the polarization directions are compared with predetermined threshold values.

The invention discloses a method for evaluating resistance of sandy soil on an embedded submarine pipeline under the action of waves. The method comprises the steps that soil body samples with different relative densities are prepared by obtaining sandy soil samples; different initial static stress ratios are selected for soil body samples with the corresponding relative densities, different dynamic cyclic stress ratios are applied to the soil body samples, the frequency of dynamic cycle and loading time are controlled, and a dynamic stress-strain change rule curve and a cyclic strength change rule curve are obtained; according to the dynamic stress-strain change rule curve and the cyclic strength change rule curve, a sandy soil dynamic strength-deformation and pore water pressure growth mode theoretical model is established, horizontal force and vertical force are applied to the pipeline, the size of constraint force of a sandy seabed on the embedded submarine pipeline is further obtained according to a load-displacement relationship, and a basic theoretical method is provided for design of embedding the pipeline in the seabed and evaluation of stability.

The invention relates to a method for evaluating the FOD resistance of an aero-engine blade. The method comprises steps of carrying out impact dynamics simulation of foreign object damage on a simulated blade numerical model; obtaining the relation between the macroscopic characteristics of the notch and the foreign object type, the impact speed and the impact angle, determining foreign object damage test conditions on the basis of the relation, carrying out an external simulated object damage test on the simulated blade by using an air cannon, and observing the macroscopic characteristics ofthe impact notch; Taking the static stress and the dynamic stress under the working load at the dangerous position of the front edge of the blade as the initial static load and the dynamic load of thehigh-cycle fatigue test, carrying out the high-cycle fatigue test on the damaged simulated blade, obtaining the high-cycle fatigue strength of the blade through a stepping method, and evaluating theFOD resistance of the blade according to the result of the high-cycle fatigue test; And carrying out foreign object damage simulation and high-cycle fatigue test on a small number of real blades to obtain the high-cycle fatigue strength of the real blades so as to verify the conformity of the simulated blades and the real blade test result.

The invention belongs to the technical field of testing simulation, and provides a method for obtaining circumferential load distribution of a friction plate tooth part through variable-contact-rigidity testing. The method aims at carrying out testing on static stress on the friction element tooth part, accordingly achieving mutual verification of two distribution rule testing results, and providing theoretical supports for dynamic strength simulation and design of a friction element. According to the method, the mass data synchronous collecting problem difficult to solve can be solved, middle testing links and a data processing link are omitted, the distribution characteristics of circumferential loads of the friction plate tooth part can be directly obtained through a variable-contact-rigidity curve obtained through the testing, and the accuracy of the testing results is improved; the testing method is simple, practical and high in testing result accuracy.

The invention relates to a method for estimating the state of charge of a soft package lithium-ion battery. The method comprises a step S1 of acquiring battery surface dynamic stress and a battery working state signal that includes first data for indicating that a battery is in a charging, standing or discharged state; a step S2 of determining whether the battery is in a standing state, if so, executing a step S3, and otherwise, executing a step S4; the step S3 of taking the previous estimation result as the current state of charge of the lithium-ion battery; the step S4 of obtaining battery surface static stress according to the battery surface dynamic stress, and executing a step S5; and the step S5 of estimating the state of charge of the lithium-ion battery by combining a corresponding function of the static stress and the state of charge according to the obtained battery surface static stress. Compared with the prior art, the invention achieves the estimation of the charge of charge of the lithium-ion battery by using a method based on stress measurement, and reduces the system complexity while improving the system accuracy.

The invention discloses a photodetection mechanics test device for simulating deep rock explosion cracking, which comprises a static load system and an explosion load device, wherein the static load system can perform test sample stress load along the horizontal direction and the vertical direction, and the explosion load device is used for generating dynamic loads. The static load system comprises a vertically arranged base plate, four push plates and a pressure supplying system, wherein the four push plates are distributed on one side of the base plate along the upper direction, the lower direction, the left direction and the right direction, and the pressure supplying system respectively provides pressure for the push plates in the upper direction, the left direction and the right direction. The push plates tightly clamp the test sample during the moving process, the explosion load device exerts dynamic load on the test sample and really simulates an initial static stress field in a deep rock body and a dynamic stress field generated during the explosion process. With the combination of a photodetection mechanics test method, the photodetection mechanics test device achieves observation of phenomena of explosion cracking, cracking expansion and the like of the rock body under deep high land stress, and is a simple, convenient and practical device for scientific and accurate research.

The invention discloses a finite element analysis method for a T-shaped blade root pre-twisted blade of a steam turbine, and relates to the technical field of computer-aided engineering. The method solves a problem of requirements on blade strength, vibration frequency and blade pre-twisting characteristics in finite element analysis of T-shaped blade root pre-twisting blades in the prior art. Themethod comprises the following steps: 1, performing geometric model processing, selecting components of blades, gap filling strips and rotors to manufacture a geometric model in a sector; 2, performing CAE model processing, specifically, drawing a hexahedral mesh model after cyclic symmetry part cutting is conducted on the geometric model, defining materials, boundaries, loads and the like of blades, rotors and gap filling strips according to requirements, and submitting and calculating; and 3, performing CAE post-processing, analyzing the static stress of the blade under each working condition, analyzing the blade frequency by using a frequency SAFE graph, and analyzing the contact area and the contact stress of each contact surface. The static strength, the vibration characteristic andthe pre-twisting characteristic of the blade under different operation conditions of the steam turbine can be effectively analyzed, and the working efficiency can be improved by 30%.

The invention discloses a flange type torque sensor, which comprises a flange shaft, left and right flange plates arranged at both ends of the flange shaft, the left flange plate is connected with the power input end, the right flange plate is connected with the load detection end, and the left and right flange plates are connected with the load detection end. The flange has an outer ring connected to the power input end or load detection end, and an inner ring connected to the flange shaft. The flange shaft is provided with a shaft hole, and the inner wall of the shaft hole is provided with an elastic body and a strain gauge. The outer ring It is integrally arranged with the inner ring, and the end surface of the left flange and/or the right flange is provided with an isolation part for isolating the outer ring and the inner ring. In this way, when the left and right flanges are respectively connected between the motor and the load to be detected, after the isolation part is set between the outer ring and the inner ring, the bolt link position on the flange is isolated from the position directly connected to the flange shaft in the middle, Avoid the above-mentioned static stress from being transmitted to the strain gauge, so as to minimize its deformation under the influence of non-detection stress, that is, minimize zero drift.

The invention discloses a design method for rock biaxial compression blasting. The method includes the following steps: step S1, obtaining the basic mechanical parameters of rock; step S2, performingtheoretical modeling on the dynamic mechanical response of blast holes during the propagation of cylindrical surface blast waves under a biaxial compression condition; step S3, utilizing a classic Kirsch method to calculate the static stress distribution at the peripheries of the blast holes when the rock is subjected to uniformly distributed horizontal confining pressure Px and vertical confiningpressure Py under plane strain and plane stress conditions; and step S4, adopting a Laplace transform method to solve the dynamic response of the blast holes when the inner walls of the blast holes are subjected to the action of explosion loading under the plane strain condition; Thus, the problems of lack of theoretical basis and guidance of experimental parameter design, large workloads and easy destruction on rock samples by confining pressure loading modes of previous testing methods can be solved.

The invention relates to a testing technique for stress wave propagation law, in particular to an experimental method and device for stress wave propagation in a rock-like material under gradient static stress. The invention proposes a combined loading method for realizing axial dynamic stress and gradient static stress of large-sized rock-like material specimens, and designs an axial gradient static stress loading device for rock-like materials, wherein the device is capable of realizing static stress gradients of different sizes, and furthermore, the test of stress wave propagation in the rock-like materials under gradient static stress is realized through the combination with the dynamic loading device and a data acquisition and analysis system. The experimental method and device provided by the invention are simple and easy in operation, and compared with the prior art, the experimental method and device are greatly improved in static stress gradient size, dynamic loading size, test accuracy and other aspects, and can provide more effective guidance for relevant theoretical researches and engineering practice.

The embodiment of the invention relates to a method and device for obtaining and verifying constitutive parameters and dynamic failure parameters. The method comprises the steps of: performing a quasi-static tensile experiment of an aluminium alloy material, and obtaining the quasi-static stress-strain curve of the aluminium alloy material; obtaining the dynamic stress-strain curve of the aluminium alloy material in different strain rates; obtaining the constitutive parameters of the aluminium alloy material by fitting according to the quasi-static stress-strain curve and the dynamic stress-strain curve; analyzing the fracture generated when the aluminium alloy material is tested, and determining the dynamic failure parameters of the aluminium alloy material; and, performing simulation calculation according to the constitutive parameters and the dynamic failure parameters, verifying the accuracy of the constitutive parameters and failure strain of the aluminium alloy material, simulating quasi-static stress-strain and dynamic stress-strain of the aluminium alloy material, then, obtaining the constitutive parameters and the dynamic failure parameters of the aluminium alloy material,and finally, verifying the constitutive parameters and the dynamic failure parameters.

The invention discloses an intelligent online monitoring device and method for a circuit breaker operating mechanism. The intelligent online monitoring device comprises two displacement sensors, a baffle plate, a supporting plate, a hinge pin, a spring, a pull rod, an LC oscillation circuit, a shaping circuit and a CPU (Central Processing Unit), and is characterized in that the positions of the two displacement sensors correspond to the position of the supporting plate and the position of the end part of the baffle plate at a compression state of the spring, connecting lines at two ends of a detecting coil of each displacement sensor go through an iron core and are led to the LC oscillation circuit, the output of the LC oscillation circuit is connected with the shaping circuit, and the output of the shaping circuit is connected with a high-speed counting interface of the CPU. The frequency of the LC oscillation circuit is calculated through a count value of a high-speed counter within a set timing time, so that inductance of the detecting coil is acquired, thus the distance between each displacement sensor and the baffle plate is calculated, and deformation of the supporting plate and the baffle plate after energy storage of the spring is calculated. The intelligent online monitoring device acquires a static stress value of the operating mechanism by adopting the non-contact displacement sensors, and is free of mechanical abrasion and long in service life.

The invention relates to a dynamic stress accelerated life test profile compilation method. The method comprises the following steps that 1, on the basis of a damage equivalent principle, dynamic stress is converted into static stress within a certain time interval; 2, on the basis of the step 1, an equivalent relation of a dynamic stress accelerated factor and a static stress accelerated factor is obtained; 3, the dynamic temperature stress is adopted as the dynamic stress, and on the basis of an Arrhenius model, dynamic temperature accelerated stress accelerated factor computational formulais obtained; 4, the dynamic temperature accelerated stress profile is compiled, and three parameters including a dynamic temperature accelerated stress mean value Tm*, a dynamic temperature accelerated stress amplitude Ta* and a dynamic temperature accelerated stress cycle period w* are determined. According to the method, the dynamic stress accelerated life test profile can be designed accordingto the dynamic change environment actually adopted by products, the reality degree simulated by the environment conditions in the accelerated test is improved, and it is ensured that the product failure mechanism in the test is consistent to that under the actual service condition.

The embodiment of the invention discloses a point switch fault prediction method and prediction system. The point switch fault prediction method comprises the steps of obtaining the mechanical part stress information of a point switch, wherein the mechanical part stress information at least comprises the bearing pedestal static stress; at least comparing the bearing pedestal static stress with a bearing pedestal static standard stress, wherein the bearing pedestal static standard stress is the difference between the standard close contact force and the current actuating rod driving force; andwhen the static stress of the bearing pedestal exceeds a first early warning range of the static standard stress of the bearing pedestal, carrying out tight attachment force early warning. According to the embodiment of the invention, the problems that the existing turnout switching equipment cannot carry out close contact force fault early warning and the manual maintenance wastes time and laborare solved, the detection and early warning of a mechanical structure in the point switch are achieved, it is guaranteed that the turnout switching equipment can be overhauled in time before breakingdown, and the traffic accidents caused by the turnout switching equipment can be effectively avoided.

The invention relates to a method for detecting paper honeycomb board core, belonging to the honeycomb paper board performance detection and application field, which comprises: using a detector to detect the solid modulus of a honeycomb paper core; building a relationship curve between standardized energy adsorption in unit volume and standardized stress; building an energy adsorption curve of approximate linear form; building a dynamic compression maximum acceleration speed static stress curve, under dynamic compression, analyzing the energy adsorption curve formed by connecting the shoulder points of the energy adsorption curve corresponding to the ratio between the thickness of the honeycomb paper board and the span, to obtain an energy adsorption picture for detecting the performance of the paper honeycomb board core. The energy adsorption picture of the invention can be applied for detecting the performance of paper honeycomb board core, to quickly and accurately optimize the structure and material selection of honeycomb paper boards, thereby providing accurate reference data for the manufacture of honeycomb paper boards under different conditions and realizing energy-saving high-efficiency package.

A method and a test fixture for evaluating a battery cell composed of a cell body having a plurality of electrode foils, a positive terminal and a negative terminal, wherein the positive terminal and the negative terminal are each joined to the cell body at weld junctions. This includes retaining the cell body of the battery cell in a first clamping device. The terminal is grasped in a terminal gripper. A dynamic stress end effector coupled to the terminal gripper applies a vibrational excitation load to the terminal. A static stress end effector applies a static load to the terminal. Integrity of the weld junction is evaluated based upon the applied static load.

The invention discloses a method for preventing cracks of a runner blade of a mixed-flow water turbine. The method includes the following steps: A, for different dynamic stress conditions of surface opening defects and internal defects, drawing a relation curve of maximum allowable equivalent defect size and static stress; B, according to the stress level, dividing the water outlet edge of the runner blade into several different areas, and searching the maximum allowable equivalent defect size in the relation curve in the step A according to maximum static stress and dynamic stress; C, performing nondestructive inspection on each area of the water outlet edge of the runner blade, finding out the surface opening defects or internal defects larger than the maximum allowable equivalent defect size of each area, and repairing the defects. By the method, the size of the allowable defects of key areas of the blade is determined according to fracture mechanics and failure analysis and based on combination of working stress of a target runner, so that quality requirements of the key areas are guaranteed effectively, and cracks are avoided during operation of the runner blade of the mixed-flow water turbine.

The invention discloses a construction method of an impact prevention and shock absorption supporting structure of an ingate, and belongs to the technical field of mining shaft building. The construction method comprises the main steps that firstly, after the ingate is formed through excavation, an anchor cable grouting project is implemented to form an anchor cable grouting reinforcement layer; then, a composite foam metal cushioning layer is fastened to a concrete sprayed layer through long iron nails to form a main energy absorption and shock absorption cushioning layer; finally, double layers of steel bars are erected on the outer side of the composite foam metal cushioning layer, and high-tenacity concrete is poured into the composite foam metal cushioning layer to form a high-tenacity steel bar concrete poured layer. Through the combination of the high-tenacity steel bar concrete poured layer, the composite foam metal cushioning layer and the anchor cable grouting reinforcement layer in sequence, the strong-weak-strong supporting structure is formed and can support static loads under high stress as well as resist dynamic loads of stress waves caused by excavation, detonation and the like, and the disasters that due to large deformation caused by highly-concentrated static stress of the ingate and damage caused by dynamic impact loads, surrounding rock is damaged and fractured and a supporting structure is unstable are avoided.

The invention discloses a method for determining an available limit of crack-type hard object damage of leading and trailing edges of a blade by taking high and low cycle fatigue into account. The method comprises the steps: firstly, extracting high-cycle-fatigue loads and low-cycle-fatigue loads from high/low-cycle composite loads borne by the blade, and respectively establishing a crack/tear-type hard object damage crack non-extension equivalent curve relevant to a stress ratio under a series of high-cycle-fatigue loads and low-cycle-fatigue loads; then, determining a static stress and a dynamic stress on a position of each point of the leading and trailing edges of the blade by using a finite element numerical analysis method; and finally, comparing positions of the static stress and the dynamic stress in the crack non-extension equivalent curve to determine a crack size corresponding to the equivalent curve, namely the available limit of crack/tear-type hard object damage at the point of the leading and trailing edges of the blade. The invention not only provides the simple and effective method for determining the available limit of the hard object damage, but also forms a normalized available limit formulation process for the crack/tear-type hard object damage of the leading and trailing edges of the blade.