Checking time forecast for torpedo based on maintain cost

Torpedo should be stored for a long time. It should be checked and repaired to satisfy the request of reliability when it is stored. How to make sure the rational checking time is very important. A grey model of disaster prediction is set up by selecting the catastrophe date sequence as the accumulate sequence of GM(1,1) model and the decreasing sequence of catastrophe date sequence as the original data. The date when the failure often appears can be forecasted. Then the reasonable checking time can be got. Result indicates that this model can achieve satisfactory precision. At the same time, it has practical value.