9 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 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.

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.

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.

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.