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Method for predicting thermal mechanical fatigue life of metal material based on low cycle fatigue

A thermo-mechanical fatigue and low-cycle fatigue technology, applied in computer-aided design, special data processing applications, instruments, etc., can solve the problems of large experimental volume, low accuracy, high time, labor, and money costs, and achieve a clear physical meaning. , good applicability, good universal effect

Active Publication Date: 2018-07-06
INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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Problems solved by technology

If the thermomechanical fatigue life prediction cannot be reasonably carried out, the service cost of components will be greatly increased, the service safety of components will be reduced, and irreversible damage will occur.
[0003] At present, the traditional thermomechanical fatigue life prediction can be divided into two categories: or the fitting method based on a large number of thermomechanical fatigue experimental data. Although the prediction accuracy is high, the amount of experiment required is large. Due to the complexity of the thermomechanical fatigue experiment process, Unpredictability is strong, and the cost of time, manpower and money are high, so this method has great limitations in application; or according to the physical and mechanical properties of materials, it can be calculated through complex theoretical derivation, and the accuracy is relatively low. Low, and the calculation complexity is extremely high, and some special parameters are obtained under harsh conditions, which is not suitable for industrial promotion

Method used

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  • Method for predicting thermal mechanical fatigue life of metal material based on low cycle fatigue
  • Method for predicting thermal mechanical fatigue life of metal material based on low cycle fatigue
  • Method for predicting thermal mechanical fatigue life of metal material based on low cycle fatigue

Examples

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Embodiment 1

[0034] This embodiment is to predict the life of cast iron materials under the reverse potential thermomechanical fatigue condition. The prediction process is as follows figure 1 As shown, the specific process is as follows:

[0035] First, the cast iron material is taken from the diesel engine cylinder head. According to the working conditions, it is determined that the required predicted thermomechanical fatigue temperature load is 125-400°C and 125-500°C, and the mechanical strain condition is ±0.1%-±0.4%.

[0036] Second, in this embodiment, for the working condition of 125-400°C, the target strain amplitude is ±0.15%, ±0.2%, ±0.3%; for the working condition of 125-500°C, the target strain amplitude Values ​​are ±0.15%, ±0.2%, ±0.3%. Here, multiple strain amplitudes are selected as the target strain amplitudes, the purpose of which is to compare with the experimental results.

[0037]Third, the low cycle fatigue test, the test conditions are: three tests at 400°C, with m...

Embodiment 2

[0053] This embodiment is to predict the life of the cast aluminum material under the condition of thermomechanical fatigue in the same direction.

[0054] First, the cast aluminum material is taken from the diesel engine piston. According to the working conditions, it is determined that the required predicted thermomechanical fatigue temperature load is 125-350°C, and the mechanical strain condition is ±0.1%-±0.4%.

[0055] Second, in this embodiment, for the temperature load of 125 to 350°C working conditions, the target strain amplitudes are ±0.25%, ±0.35%, ±0.3%, ±0.45%; multiple strain amplitudes are selected here , as the target strain amplitude, the purpose of which is to compare with the experimental results.

[0056] Third, the low cycle fatigue test, the test conditions are: four tests at 350°C, the mechanical strains are ±0.25%, ±0.35%, ±0.3%, ±0.45% respectively; calculate the median life hysteresis loop area of ​​each test data .

[0057] Fourth, thermomechanica...

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Abstract

The invention discloses a method for predicting the thermal mechanical fatigue life of a metal material based on the low cycle fatigue, and belongs to the technical field of material science and engineering application. The method includes the steps of establishing the quantitative relation between the thermal mechanical fatigue hysteresis energy of the metal material and the low cycle fatigue hysteresis energy of the same material at the constant temperature (thermal mechanical fatigue upper limit temperature), namely the linear relation between the difference value of the two types of fatigue hysteresis energy and the mechanical strain, and predicting the life through an energy method. By means of the method, the thermal mechanical fatigue life of different types of mechanical strain canbe accurately predicted through a small number of experimental tests of the low cycle fatigue and thermal mechanical fatigue. By means of the method, the experimental amount required for predicting the thermal mechanical fatigue life is effectively reduced, time, money and labor cost are greatly saved, high accuracy is achieved, and the method can be widely applied for predicting the thermal mechanical fatigue life of gas turbine compressor blades, internal combustion engine cylinder covers, pistons and other high-temperature alloy and heat-resistant metal materials.

Description

technical field [0001] The invention relates to the technical field of material science and engineering application, in particular to a method for predicting the thermomechanical fatigue life of metal materials based on low cycle fatigue. Background technique [0002] Metal materials, especially high-temperature alloys and heat-resistant materials, are widely used in high-temperature load-bearing components such as internal combustion engine cylinder heads, pistons, and gas turbine blades. During the operation of the engine, metal materials are simultaneously subjected to changes in temperature loads and mechanical loads. Therefore, failure is prone to occur. According to the failure analysis, the main failure mode is thermomechanical fatigue. If the thermomechanical fatigue life prediction cannot be reasonably carried out, the service cost of components will be greatly increased, the service safety of components will be reduced, and irreversible damage will occur. [0003...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F17/50
CPCG06F30/17G06F30/20G06F2119/04
Inventor 张孟枭庞建超张哲峰王猛邱宇
Owner INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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