Abstract
The reliability of a motion mechanism is affected by corrosion, wear, aging and other components’ performance degradations with the extension of service time. This paper tackles this problem by proposing a time-varying reliability analysis method for uncertain motion mechanisms. First, a model of motion mechanism error is constructed by assessing the difference between actual and expected motion. A time-varying reliability analysis method for a motion mechanism is proposed. The time-varying performance function is discretized into several static performance functions, which are further approximated with several normal variables. Then, the correlation coefficient matrix and probability density function of these normal variables are calculated, and the time-varying reliability of a motion mechanism is obtained via high-dimensional Gaussian integration. The study demonstrates that the proposed method successfully transforms the time-varying reliability problem into several time-invariant reliability problems for analysis, and handles the time-varying reliability problem of a nonlinear motion mechanism involving random variables and stochastic processes, and significantly increases the computational efficiency. Finally, the proposed method’s effectiveness is verified by two numerical examples and one practical engineering problem.
Highlights
A mechanism is defined as a mechanical device composed of several components used to transfer force and motion and realize specific functions and actions [1]
This paper proposes an efficient time-varying reliability analysis method for motion mechanisms
This paper deals with the problem of the overall degradation of the motion mechanism’s component performance with the extension of service time
Summary
A mechanism is defined as a mechanical device composed of several components used to transfer force and motion and realize specific functions and actions [1]. The mechanism’s manufacturing, assembly, boundary conditions, environmental loads, material properties, and artificial assumptions commonly give rise to uncertainties [2,3,4] These uncertainties may result in undesirable consequences such as reduced motion precision and increased fault rate, which further cause the mechanism’s failure and safety problems [5,6]. Friction coefficient, dimension error, and other relevant factors, Lai et al [13] modeled a plane four-bar mechanism based on the multibody dynamics and gap collision theory and proposed a reliability analysis method for motion mechanisms. Li et al.[15] proposes a new higher-efficiency interval method for the response bound estimation of nonlinear dynamic systems This approach uses Chebyshev polynomials to help the interval analysis applied on the estimation, analyzed the offshore boom crane with three degrees of freedom motion mechanisms numerical example
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