18 results about "Thermo-mechanical fatigue" patented technology

The invention provides a special-shaped air film hole thermal mechanical fatigue simulation part design method, which comprises the following steps of: 1, analyzing the strength and the service life of a turbine blade, and identifying a key part of the service life of a special-shaped air film hole; 2, determining that the thermal mechanical fatigue simulation piece is of a hollow structure; 3, parameters of a clamping part of the hollow simulation piece are stipulated; 4, determining the mechanical stress of the key part through three-dimensional finite element simulation of the turbine blade; 5, verifying the included angle between the principal stress direction and the growth direction of the key part of the simulation part; step 6, measuring stress by using a strain gauge under a normal-temperature initial mechanical load, and verifying whether the load is compliant or not; 7, performing three-dimensional finite element simulation analysis on the temperature field of the test piece and calculating thermal stress; 8, controlling the thermal stress distribution of the section of the simulation piece by controlling the temperature distribution; step 9, when cooling gas is introduced into the inner cavity of the special-shaped gas film hole simulation piece, carrying out a thermal mechanical fatigue test by adopting an in-phase mechanical-temperature load; and step 10, optimizing the structure of the special-shaped gas film hole and analyzing the strength.

The invention provides a power module packaging structure and a packaging process thereof. The power module packaging structure comprises an upper substrate; the heat dissipation bottom plate is arranged opposite to the upper base; the AMB substrate is arranged between the upper base body and the heat dissipation bottom plate; the power chip is arranged on the AMB substrate, a source electrode of the power chip is electrically connected with an external terminal through a copper clamping piece, and interconnection between the copper clamping piece and the source electrode of the power chip is achieved through a non-pressure silver sintering layer. The copper clamping pieces are adopted to replace traditional bonding wires, the non-pressure silver sintering interconnection technology is combined, the module layout is optimized in a collaborative mode, the on-resistance and parasitic inductance of the power module are remarkably reduced, meanwhile, the heat dissipation capacity and the thermal mechanical fatigue resistance reliability of the power module are greatly improved, and the service life of the power module is prolonged. Therefore, the bottleneck of performance and reliability of the existing SiC MOSFET power module in a high-frequency and large-current application scene is successfully solved.

The invention discloses an automatic testing and screening method for electronic components, which relates to the technical field of electronic engineering and microelectronics and comprises the following steps: generating a multi-dimensional stress field through a temperature control module, a humidity control module and an electromagnetic interference simulation module; calling a preset extreme working condition combination sequence based on the target application scene of the component; under a dynamic coupling environment, dominant parameters and recessive parameters including a dielectric relaxation spectrum, a carrier mobility transient response and a thermoacoustic emission signal are synchronously collected; inputting the hidden parameter time sequence data into physical failure models including an electrochemical corrosion model and a thermal mechanical fatigue model; dynamically adjusting the passing threshold of the test item according to the model output; the step of applying accelerated degradation excitation to the screened component comprises the following steps of: circulating a set temperature for a set number of times; applying a bias voltage-temperature stress; and repeating the step S2 to monitor the implicit parameter drift amount, and eliminating the device with out-of-tolerance drift. The device guarantee is provided for the fields of new energy automobiles, aerospace electronics and the like.

The invention discloses a thermal mechanical fatigue crack growth rate testing method based on rigidity and a crack tip strain field. The method comprises the following steps: firstly, establishing a relation function between normalized crack length and normalized rigidity through finite element calculation; secondly, performing DIC speckle preparation for observing crack propagation and analyzing a strain field; then carrying out a thermal mechanical fatigue test, calculating the crack length based on a rigidity change result of the test, drawing an a-N relation curve in combination with a DIC synchronous observation result, and carrying out comparative analysis; and finally, calculating the crack growth rate through a three-point moving average secant method, and analyzing and determining the size of a crack tip plastic zone according to a DIC strain field, so as to accurately test the crack growth rate. The fatigue crack growth behavior under the thermal-mechanical coupling effect can be effectively tested, the thermal mechanical fatigue crack growth rate is accurately obtained by combining a crack tip strain field measurement method, and test data support is provided for damage tolerance design and structural integrity evaluation of high-temperature pressure-bearing equipment.

The present invention belongs to the technical field of material mechanical property testing, and discloses a method for testing the thermomechanical fatigue crack propagation of metal materials. First, the functional relationship between the crack length and the flexibility of the sample, as well as the functional relationship between the crack propagation driving force and the crack length are obtained by the finite element method; then, a crack is prefabricated using the constant load method under normal temperature conditions, and a thermomechanical fatigue crack propagation test is performed to obtain the test results; finally, the crack length corresponding to each cycle of the metal sample is calculated by the improved flexibility method, and the crack propagation rate is calculated in combination with the functional relationship between the crack propagation driving force and the crack length. The present invention can effectively simulate the working conditions of variable temperature and alternating load coupling that high-temperature components are subjected to during service, obtain the specific crack propagation rate and the evolution of the plastic zone in the crack propagation area, and provide important experimental data and theoretical basis for the damage tolerance design and safety verification of high-temperature structures under severe working conditions.

The present application relates to the field of material science and engineering application technology, specifically to a kind of metal material thermal mechanical fatigue life fast prediction method based on hysteresis energy density.First, hysteresis curve is used to calculate hysteresis energy density, then the quantitative relationship between shape coefficient, stress variation range and plastic strain range between low cycle fatigue and thermal mechanical fatigue is used, to achieve the purpose of predicting thermal mechanical fatigue hysteresis energy density under the same mechanical strain amplitude by low cycle fatigue, finally, energy accumulation damage model is used to predict thermal mechanical fatigue life.The method carries out two groups of experiments for low cycle fatigue and thermal mechanical fatigue respectively, realizes the prediction of thermal mechanical fatigue life under different mechanical strain amplitudes by low cycle fatigue, establishes the correlation between low cycle fatigue and thermal mechanical fatigue by using the similarity between them in the process of cyclic loading, effectively reduces the experimental amount required for thermal mechanical fatigue life evaluation, and is applied to the thermal mechanical fatigue life prediction of high-temperature alloy and vermicular cast iron and other metal materials.

The invention relates to the technical field of mechanical fatigue testing, and particularly discloses a turbine blade high-cycle vibration thermal mechanical fatigue testing system which comprises a power box, and a hollow frame is fixedly mounted on the upper end face of the power box; a second motor is fixedly mounted on the upper end surface of the power box in the hollow frame; under the action of a third motor, a first gear can drive a second gear to rotate, and in the rotating process, the second gear can drive a rotating connector to rotate, so that an electromagnetic vibrator can rotate, and single crystal blades on a vibration rod can incline at different angles; therefore, the fatigue test data of the single crystal blade in different states can be obtained. And secondly, under the action of a second motor, a first inserting rod and a second inserting rod, a rotating connector can rotate, so that an electromagnetic vibrator can be driven to rotate, the single crystal blade can rotate, and data of different states can be obtained.

The invention discloses an oxidation-thermal mechanical fatigue life prediction method based on a crystal plasticity theory. The method comprises the following steps: generating a representative volume unit with a grain boundary characteristic, importing the representative volume unit into abaqus software, and applying a boundary condition; based on a crystal plasticity constitutive theory and an oxygen diffusion control equation under thermal mechanical fatigue, corresponding UMAT and UMATHT subprograms are written; taking the UMAT subprogram and the UMATHT subprogram as abaqus calculation files, combining the abaqus calculation files with representative volume elements with grain boundary characteristics, and carrying out crystal plasticity finite element simulation under thermal mechanical fatigue; according to the finite element simulation result, fatigue damage and oxidative damage parameters under different working conditions are obtained respectively, the obtained parameters are substituted into the thermal mechanical fatigue life prediction model under the heat-force-oxygen coupling effect, and the predicted life is obtained. According to the method, the mechanical damage and the oxidative damage of the turbine disc under the service condition can be accurately simulated, and the prediction precision of the thermal mechanical fatigue life is improved.

This invention relates to the field of chip performance monitoring technology, and discloses a method for monitoring and evaluating the performance of chips throughout their entire lifecycle based on big data. This method first extracts key physical characteristics of each bare die at the manufacturing stage, generates individual chip quality factors, and writes them into a one-time programmable memory area. Then, at the application stage, it collects the junction temperature of each layer in real time, calculates the vertical temperature gradient vector and local absolute temperature, and constructs a thermo-coupled instantaneous interface mechanical damage rate model based on the quality factors to quantify the instantaneous interface mechanical damage rate. Furthermore, it introduces a business weight coefficient to couple electrical wear with cumulative thermo-mechanical fatigue damage, calculating the chip's remaining health. Finally, based on the health warning threshold, it executes a vertical wear balancing strategy to migrate the data of damaged layers to a safe level. This invention solves the problem that traditional chip performance monitoring cannot detect the risk of microscopic thermal mismatch within the stacked structure, and avoids sudden physical failures of the chip through proactive physical load redistribution.

The application discloses a thermal-mechanical fatigue crack propagation rate testing method based on rigidity and crack tip strain field, comprising the following steps: firstly, a relationship function between normalized crack length and normalized rigidity is established through finite element calculation; secondly, DIC speckle preparation is carried out for observing crack propagation and strain field analysis; then, a thermal-mechanical fatigue test is carried out, crack length is calculated based on rigidity change results of the test, an a-N relationship curve is drawn combined with DIC synchronous observation results, and comparative analysis is carried out; finally, crack propagation rate is calculated through a three-point moving average secant method, and the size of a plastic zone at a crack tip is determined according to DIC strain field analysis, so that the accurate test of the crack propagation rate is realized. The application can effectively test the fatigue crack propagation behavior under the thermal-mechanical coupling effect, and accurately obtain the thermal-mechanical fatigue crack propagation rate combined with the crack tip strain field measurement method, so as to provide test data support for damage tolerance design and structure integrity evaluation of high-temperature pressure-bearing equipment.

The present application discloses a method and storage medium for predicting the thermomechanical fatigue life of metal materials based on the influence of strain rate, wherein the method comprises: first determining the thermomechanical fatigue working condition and target temperature, conducting low-cycle fatigue and thermomechanical fatigue tests on the metal material, determining the relationship between the low-cycle and thermomechanical fatigue cycle hysteresis energy and the plastic strain and stress range, establishing a low-cycle fatigue energy model and obtaining relevant parameters; then introducing the fatigue-creep damage coupling index, correcting the strain rate, obtaining a thermomechanical fatigue life prediction model, and finally achieving prediction. The present application only requires a small amount of low-cycle fatigue and thermomechanical fatigue tests to achieve accurate prediction of thermomechanical fatigue life, and can also be used for low-cycle fatigue life prediction, while improving accuracy, significantly saving time, manpower and material resources. It can be applied to creep-fatigue coupled life prediction of high-temperature alloys and heat-resistant metal materials such as gas turbine blades and turbine disks, and internal combustion engine pistons.

The invention relates to the technical field of temperature control in a high-temperature mechanical property test, in particular to a sample temperature indirect control device and method for a thermal mechanical fatigue test. A first thermocouple is used as a main control thermocouple to realize stable tracking of a target temperature waveform; recording a follow-up temperature track measured and fed back by the second thermocouple; the second thermocouple is changed into a main control thermocouple, the follow-up temperature track is mapped into an instruction signal input into the temperature control module, and the follow-up temperature track is corrected through multi-round iteration of a track correction algorithm according to the deviation between the first feedback temperature track and the target temperature track; obtaining a final follow-up temperature track until the first feedback temperature track converges to the target temperature track; only a second thermocouple is welded at the same position of the fatigue specimen for the formal test, and the final follow-up temperature track is mapped into an instruction signal input into the temperature control module, so that indirect control that the temperature track of the gauge length section of the thermal mechanical fatigue specimen meets the target temperature track can be realized.

Systems and methods for estimating a thermal-mechanical fatigue in an electrical conductor in a thermal-mechanical fatigue assessment system include an electrical conductor having a cold resistance and a non-linear resistance when connected to an electrical power system, and a controller receiving temperatures of the conductor as inputs, wherein the controller is operable to estimate a service life of the conductor based on at least the input temperatures of the conductor and the cold resistance of the conductor.

This application provides a system and method for regulating the hysteretic heat generation of rubber. First, under preset dynamic thermomechanical fatigue test conditions, a correlation model is established between the rubber's loss factor and dynamic heat generation performance, and a target range for loss factor regulation is determined based on the target heat generation performance. Next, based on the target range, the internal structure of the rubber is synergistically regulated by adjusting the rubber's formulation or process to change its loss factor. Then, standard dynamic thermomechanical analysis tests are performed on the regulated rubber samples to obtain its loss factor data, and its predicted heat generation performance is evaluated based on the correlation model. Finally, for rubber samples whose predicted heat generation performance meets the requirements, dynamic thermomechanical fatigue tests are conducted under the preset fatigue test conditions, and the hysteretic heat generation performance is ultimately verified by measured temperature rise or heat generation data. The above scheme can achieve precise regulation of the hysteretic heat generation of rubber.

The invention discloses a heating and cooling rate adjustable thermal mechanical fatigue testing device, which comprises a hydraulic servo fatigue testing machine, a water cooling machine, a high-frequency electromagnetic induction heating system, a liquid nitrogen cooling system and a heating and cooling rate control system, and is characterized in that the hydraulic servo fatigue testing machine is used for applying a mechanical load to a sample and obtaining mechanical fatigue data; the high-frequency electromagnetic induction heating system is used for heating the sample so as to realize transient temperature rise; the liquid nitrogen cooling system is used for rapidly cooling the heated sample through liquid nitrogen; and the heating and cooling rate control system is used for obtaining the real-time temperature of the sample through a temperature sensor tightly attached to the surface of the sample, and controlling the work of the high-frequency electromagnetic induction heating system and the liquid nitrogen cooling system according to the real-time temperature, so that the temperature is linearly changed. According to the invention, the temperature change rate can be changed in a large range, and can be directly controlled through a control system, so that the influence of the temperature change rate on the thermal mechanical fatigue performance can be explored.

The present invention discloses a metal rubber vibration damper thermomechanical fatigue testing machine and a testing method thereof, comprising a resistance furnace motion control system, a resistance furnace heating and cooling system, a measurement and support system, a control system, a testing machine frame, and a circulating water cooling system. The heating system uses a resistance furnace to heat the metal rubber vibration damper specimen. The measuring system includes a temperature sensor, a force sensor, and a high-temperature extensometer, which are respectively used to measure the temperature distribution, force load, and deformation of the specimen; the control system includes a switch, a touch screen, an industrial computer, and a PLC test program. The circulating water cooling system includes a water pump, a water pump motor, a water tank, etc., which are used to cool the axial loading shaft of the testing machine to avoid damage to the sensors and other components of the testing machine due to excessive temperature. The present invention has high heating and cooling efficiency and can solve the problems of low accuracy and slow testing speed of existing thermomechanical fatigue testing machines.

This application discloses a heat-resistant eutectic Al-Si alloy material, which is obtained by adding strengthening elements Cu, Mg, Ni and microalloying elements Ti, Sc, and Zr to a eutectic Al-Si alloy and then subjecting it to ultrasonic treatment during the alloy solidification process. This application also provides a method for preparing the heat-resistant eutectic Al-Si alloy material. By controlling the formation of a nano-scale high-temperature stable precipitate phase, the thermomechanical fatigue performance and service performance of the Al-Si alloy material are improved; this addresses the technical problem that excessive Cu and Ni additions increase the volume fraction of intermetallic phases in the alloy microstructure, leading to increased brittleness and a mismatch between low-temperature plasticity and high-temperature strength, which is detrimental to the alloy's insufficient thermomechanical fatigue life during service.

The invention belongs to the field of electronic packaging, and particularly relates to liquid metal microcapsule modified pressureless sintering silver paste and a preparation method thereof. The pressureless sintering silver paste is prepared from the following raw materials in parts by mass: 90 to 95 parts of silver powder filler, 2 to 4 parts of liquid metal microcapsules, 2.3 to 5.5 parts of organic solvent, 0.20 to 0.27 part of dispersing agent, 0.05 to 0.08 part of rheological agent and 0.25 to 0.35 part of defoaming agent. The mixed powder of the flaky micron silver powder and the spherical nano silver powder is adopted, so that the sintering temperature of the silver paste can be remarkably reduced, and the sintering bonding strength of the silver paste can be improved. After being sintered, the pressureless sintered silver paste prepared by the method is high in shear strength, high in thermal conductivity and good in thermal mechanical fatigue performance, is suitable for packaging high-power devices, and has a relatively high practical value.