Bending fatigue life analysis of gear based on ABAQUS / FE-SAFE

ABAQUS / FE-SAFE is used for joint simulation. The analysis process is as follows: firstly, the fatigue analysis software FE-SAFE needs to input the analysis results obtained in ABAQUS finite element software, redefine the analysis results, and define the load of previous tests according to the gear bending fatigue test And 42CrMo material parameters and fatigue life calculation criteria. Its analysis process.

First, create material fatigue characteristic parameters. In FE-SAFE, you can edit them from the existing material library in FE-SAFE, modify and re-enter the specific parameters. 42CrMo is used as the material of the gear used in the test. From the existing material library in FE-SAFE, edit its tensile strength of 1080mpa and elastic modulus E = 210000mpa.

During the test, the gear teeth are under pressure due to pressurized force. The load loading form is sinusoidal pulsation, and the load spectrum form of the load loading process is shown in the formula:

Where: a – average load; B – load amplitude; FZ is the resonance frequency of the equipment.

The performance parameters of 42CrMo gear are used to edit the fatigue load spectrum, and the knot obtained from the previous numerical simulation is substituted into ABAQUS / FE-SAFE. The bending fatigue analysis is based on the “force strain” mode, and the maximum number of cycles is set to 10000000. Using Miller’s linear damage theory, that is, under the regular variable amplitude cyclic stress, the rapid damage can occur once, but it can be continuously superimposed through linear accumulation.

The condition of fatigue failure is that the sum of the damage rates of all stresses is equal to 1. Based on this principle, the software judges that when fatigue failure occurs in the gear teeth, the calculation of this element will terminate, and the calculation of other elements that do not reach fatigue damage will continue. When the number of cycles reaches the set value of 10000000, the calculation will stop.

In order to obtain the logarithmic fatigue life nephogram of gear, the fatigue life calculation results need to be imported into ABAQUS for processing to obtain the logarithmic fatigue life nephogram of 42CrMo gear under different loads when the reliability is 84.1%, as shown in the figure.

It can be seen from the figure that the fatigue life nephogram shows the results of gear teeth under different loads. The set limit fatigue life of the gear is 10000000. When the load f > 13kn, the set limit life is greater than the fatigue life on the tensile side of the tooth root, and the gear will fail. When the load f = 13kn, the gear tooth can realize theoretically infinite cycle. At the same time, according to the previous tests, the fatigue life of the tensile side of the gear teeth determines the fatigue life of the gear. Under the condition of 84.1% reliability, the logarithmic fatigue sea life of gear teeth under different loads obtained by numerical simulation is transformed into normal fatigue life. Compared with the results obtained by the two, the difference between the test fatigue life results and the numerical simulation fatigue life results is very small. Therefore, it can be concluded that it is feasible to verify the gear bending fatigue life by numerical simulation under different load conditions, and the gear bending fatigue life results obtained by ABAQUS / FE-SAFE software are true and effective.

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