| Typical core power equipment such as gas turbines and aero-engines require smooth and safe operation due to their importance,but their working environment is very harsh,subjected to a variety of complex loads,prone to cracking,and further cracking after cracking.It poses a huge risk to the normal operation of the equipment.Therefore,it is necessary to study the crack propagation law in the rotor.Based on the stress intensity factor of the crack tip region,the calculation formula of the stress intensity factor is given,and the commonly used numerical method for calculating the stress intensity factor is deduced.The accuracy of the calculated stress intensity factor is verified by the example.It is seen that the calculated stress intensity factor has high accuracy,which lays a foundation for the subsequent study of crack crack propagation law and evaluation of rotor life.Taking the cracked rotor as the object of study,the variation of stress intensity factor under the condition of linear crack front is studied firstly,and studied the variation of SIF near the edge and in the middle of the crack front when the crack depth and the ratio of length to width of elliptical crack are changed under the condition of elliptical crack front.The remaining working life of a cracked rotor with different crack front shapes is compared.Then,an Aero-Engine Turbine disk is modeled accurately,and its stress distribution under various loads is studied,and the stress concentration position is found out and listed as a dangerous area.Firstly,after inserting pre-cracks into these dangerous locations,the crack propagation law is studied based on XFEM method.Finally,by solving the stress intensity factors at the front of cracks at different locations and predicting the life of cracks at different locations to dangerous depth based on Paris formula,the shortest dangerous location of life is determined,which provides the corresponding reference for the operation of the actual unit. |
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