This paper presents an accelerated life testing method to solve the problem of in-pipe robot reliability in quantitative analysis. By established inverse power law probability density function model based on Weibull distribution, the results of accelerated life testing can be used to extrapolate reliability features of in-pipe robot under the normal condition, especially for single or rare prototype. The experimental results are in agreement with theoretical analysis, this forecast the mean time between the failures of the in-pipe robot and avoid its lost caused by online failure. Keywords-in-pipe robot; quantitative accelerated life test; inverse power law; acceleration factor; reliabilityI.

Based on derivation of fluid inertia velocity distribution, the paper proposes an analytical model for pressure distribution of squeeze film damper (SFD) in long bearing assumption under impact loading. Compared with numerical simulation and test results, the model is reasonable. The model analysis results reflect the reversion behavior about SFD radial force. Therefore, a design rule of synchro-response for SFD is recommended, and then an expression of SFD parameters is given which is in accordance with the rule. These results are useful for design and for real-time active control of SFD-rotor-system, and are helpful for further theoretical investigation on oil film dynamic behavior also.