Predicting crack propagation in the shaft dovetail of a generator rotor
First Claim
1. A generator rotor crack propagation prediction system, comprising:
- memory means;
interface means that inputs data and outputs results;
stress calculation means that calculates the mean stress in a generator rotor shaft dovetail and stores the stress in the memory means;
factor range calculation means that calculates the stress intensity factor range of shaft dovetail crack and stores the stress intensity factor range in the memory means; and
crack propagation amount calculation means that calculates an amount of the shaft dovetail crack propagation from the mean stress and stress intensity factor range stored in the memory means, and crack data.
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Accused Products
Abstract
An object of the present invention is to control crack propagation, either by predicting shaft dovetail crack propagation with high accuracy, or by determining operation conditions under which the crack does not extend. The crack propagation prediction system includes an operation processing unit, an interface unit, and a memory unit. The operation processing unit includes a stress calculation unit that calculates the mean stress generated in the shaft dovetail, a factor range calculation unit that calculates the stress intensity factor range for the crack in the shaft dovetail, and a crack propagation amount calculation unit that calculates an amount of the shaft dovetail crack propagation for an arbitrary time period, from the obtained mean stress and the stress intensity factor range, an operation pattern, an operation time, and data on the crack. The stress calculation unit includes as individual calculation units that calculate separately different types of mean stress, a contact surface pressure stress calculation unit, a thermal stress calculation unit, and a residual stress calculation unit, as well as a mean stress calculation unit that sums these mean stresses.
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Citations
7 Claims
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1. A generator rotor crack propagation prediction system, comprising:
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memory means; interface means that inputs data and outputs results; stress calculation means that calculates the mean stress in a generator rotor shaft dovetail and stores the stress in the memory means; factor range calculation means that calculates the stress intensity factor range of shaft dovetail crack and stores the stress intensity factor range in the memory means; and crack propagation amount calculation means that calculates an amount of the shaft dovetail crack propagation from the mean stress and stress intensity factor range stored in the memory means, and crack data. - View Dependent Claims (2, 3, 4, 5)
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6. A generator rotor crack propagation prediction method for predicting generator rotor shaft dovetail crack propagation using operation processing means that carries out calculations to predict crack propagation, memory means that stores calculation results, and interface means that receives data input and outputs results, the method comprising the steps of:
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calculating the mean stress in the shaft dovetail using the calculation means; calculating the stress intensity factor range for a crack in the shaft dovetail; calculating and storing in the memory means an amount of the shaft dovetail crack propagation from the obtained mean stress and stress intensity factor range, and crack data; and displaying the obtained calculation result using the interface means.
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7. A generator rotor crack propagation prediction program that predicts generator rotor shaft dovetail crack propagation using a computer, the program causing the computer to implement:
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a stress calculation function that calculates the mean stress generated in a shaft dovetail; a factor range calculating function that calculates the stress intensity factor range for a crack generated in a shaft dovetail; and a crack propagation amount calculation function that calculates an amount of the shaft dovetail crack propagation, from the obtained mean stress and stress intensity factor range, and crack data.
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Specification