Papers by Author: Li Yang Xie

Abstract: The informatization of manufacturing industry brings new requirements to the industrial design of electromechanical products with high degree of automation and high intelligence. One of the central design concerns is to guarantee reliability of the interactions between the operators and the products working in non-transparent conditions, and at the same time to provide pleasant user experience. Starting from the user’s behavior patterns and psychological needs, the paper analyzed human-machine interaction system of electromechanical products and the design principles of its constituent, and the suitability of the interactive environment of electromechanical products was provided.

Abstract: A computational model for position and posture error of 6-DOF parallel machines is proposed based on D-H transformation matrix and the inverse kinematics. The model is used to construct a linear least-square identification model for geometric parameter errors. Error identification program and compensation method are also presented. Simulation results indicate that the effects on position and posture of machines are almost equivalent from calculated least-square solution and from real values. The pose error of moving platform can be decreased up to 90% if error compensation is performed by modifying the input kinematic parameters of driving joints.

Abstract: Under variable amplitude load history the exact distribution of fatigue strength corresponding to a specified number of life cycles cannot be obtained exactly by test, fatigue strength distribution can be obtained from fatigue life distribution. According to statistical property analysis of Miner cumulative damage rule, probability distribution of fatigue life under variable amplitude load history is predicted based-on constant amplitude median Sa-Sm-N surface. In the end, a fatigue reliability model is established to calculate fatigue reliability according to stress distribution as well as fatigue life distribution function. The model is applicable to calculate fatigue reliability under stochastic load environments.

Abstract: During device applications being debugged, communications with device are need. Combining with real device brings inconvenience on debugging, and even hides bugs. Techniques and methods for debugging device applications combined with virtual device are discussed in this paper, and already proved to be feasible and effective by projects’ decrease of cost and increase of efficiency.

Abstract: Factors affecting the shape of failure rate curve are analyzed, and four elements including load, strength, degradation and lifetime index (namely, the number of load application and time) are proposed for calculating the failure rate of components. Taking the number of load application and time as the life index, respectively, the failure rate models of components consisting of four elements is developed, which can embody the effect of parameters of load, strength, degradation and life. Then, the rules that the reliability and failure rate changes as life index are studied. The result shows that the failure rate curves are partially or whole bathtub-shaped. For different parameters of load, strength and strength degradation, the curves of reliability and failure rate of components changing with time present different shapes. The models derived in this paper can calculate the failure rate of components as long as the parameters of load, strength and degradation and life index are known.

Abstract: A reliability analysis method for the shiplift gear according to the system-level load-strength interference model is presented. The gear is regarded as a series system with dependent failure and multiple failure models. Its reliability is obtained by calculating the probability that the minimum order statistic of the strengths exceeds the maximum order statistic of repeated random loads. The load probability distribution of gear is then obtained using Monte Carlo on the basis of load information. The contact strength and bending strength are calculated. On the basis of system-level load-strength interference analysis, system reliability of a gear is straightforward built up. Finally, system reliability of a gear is worked out, which shows a high reliability.

Abstract: Multiple site damage (MSD) is the occurrence of small fatigue cracks at several sites within aging aircraft structures. Focusing on this typical structure, an analytical method for calculating the stress intensity factor (SIF) of an infinite plate containing multiple holes was introduced in this paper. The properties of complex variable functions are used to evaluate the stress function. The approximate superposition method is applied to solve SIF problems on multiple holes. Some numerical examples of radial cracks appearing at the boundary of two circular holes are examined by this method. By comparing the analytical and finite analysis results it was realized that the analytical results are accurate and reliable. This modified analytical method is easier to apply than traditional analytical method and can provide SIF solutions for an infinite plate containing multiple holes.

Abstract: The traditional loading-strength interference model is used to calculate the reliability of components and system when random loading act once. In fact, components always work under repeated random loading, so it is important to derive a reliability model considering the frequency of loading. The two-dimensional distribution of random loading is proposed in this paper. In engineering practice, only a few samples of time-loading process can be obtained because of all kinds of limitation, so the reliability model based on transverse distribution of random loading. In addition, when it is difficult to know the exact distribution of random loading and strength, a discrete reliablity model is developed through the method of universal generating function. Finally, the reliability of system is analyzed considering common cause failure.