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A Thermomechanical Fatigue Life Prediction Method Based on Low Cycle Fatigue for Metal Materials

A technology of thermomechanical fatigue and low cycle fatigue, applied in computer-aided design, geometric CAD, design optimization/simulation, etc., can solve the problems of large amount of experiments, low accuracy, high cost of time, manpower, and money, and achieve physical significance The effect of clarity, good universality, and good applicability

Active Publication Date: 2021-06-01
INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

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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  • A Thermomechanical Fatigue Life Prediction Method Based on Low Cycle Fatigue for Metal Materials
  • A Thermomechanical Fatigue Life Prediction Method Based on Low Cycle Fatigue for Metal Materials
  • A Thermomechanical Fatigue Life Prediction Method Based on Low Cycle Fatigue for Metal Materials

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 thermomechanical fatigue life of metal materials based on low-cycle fatigue, and belongs to the technical field of material science and engineering application. This method first establishes the quantitative relationship between the thermomechanical fatigue hysteresis energy of metal materials and the low cycle fatigue hysteresis energy of the same material at constant temperature (the upper limit temperature of thermal mechanical fatigue), that is, the difference between the two fatigue hysteresis energies is linear with the mechanical strain, and then through the energy method for life prediction. The method can realize accurate prediction of thermomechanical fatigue life under different mechanical strains through a small amount of low cycle fatigue and thermomechanical fatigue experiments. This method effectively reduces the amount of experiments required for thermomechanical fatigue life prediction, greatly saves time, money and labor costs, and has high accuracy. It can be widely used in high-temperature applications such as gas turbine blades, internal combustion engine cylinder heads and pistons. Thermomechanical fatigue life prediction for alloys and heat-resistant metallic 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 Patents(China)
IPC IPC(8): G06F30/17G06F30/20G06F119/04
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