Papers by Author: Li Yang Xie

Abstract: Notched fiber-mental laminates are susceptible to damage. Nowadays, damage detection mainly depends on visual inspection and C scan. But the two methods are limited to the technical skill of the inspectors, causing missed detection or even fault detection. This paper devotes to exploring the DIC monitoring technique to assess of the damage process taking place in notched (open hole) specimens under uniaxial tensile loading. Two-dimensional (2D) Digital Image Correlation (DIC) techniques are employed to obtain full-field surface strain measurements of GLARE3-3/2 and GLARE6-3/2 laminate with an open circular hole under tensile loading. Failure modes,damage initiation and progression of notched fiber-metal laminates are characterized and discussed.

Abstract: Hydraulic support is an important equipment of synthesis mechanization caving coal and safe production in modernization coal mine. According to the research object of ZF5000/16/28’s mould hydraulic support, stress distribution of dangerous parts is obtained by stress testing and ANSYS software. The relevant total displacement distribution rule and equivalent stress distribution rule of the type hydraulic support prototype were found. At the same time, reliability analysis of a single stent and stent system reliability prediction were carried out, which guides design and use of hydraulic support in theory better.

Abstract: Transverse vibration analysis is presented for Euler-Bernoulli beams carrying concentrated masses and taking into account their rotatory inertia at both ends. The dimensionless eigenfunctions for the problems are first obtained using the differential equations of motion and considering translational and rotatory springs at both ends. A numerical technique, the Newton–Raphson algorithm, is then used to solve vibration eigenfunctions of the beams. Finally, the influences of different non-dimensional parameters on frequencies are discussed.

Abstract: A model of the optimal maintenance period for repairable product after warranty expiration under renewing warranty is proposed. In the process to fulfilling warranty, the failures of product within warranty period happen randomly, the replacements of products successively failed with warranty period form a renewing process. Given failure rate of product, the period of fulfilling warranty is function of warranty period. User purchasing a product is considered an investment; the period of fulfilling warranty and the maintenance period after warranty make up the life cycle of product investment. Taking various cost factors into account, making model of the cost rate in life cycle of product investment under renewing warranty, the cost rate is function of maintenance period. Give the failure rate of product is an increasing function, it is derived that there is unique optimal maintenance period minimizing the cost rate. Finally, numerical example is given for illustration.

Abstract: The reliability of kinematic trajectory of manipulators describes the ability that manipulators keep kinematic accurate. It is an important parameter to evaluate the performance of manipulators. The kinematic accuracy of manipulators can be improved when piezoelectricity material are used as a transducer to suppress the vibration of flexible manipulators. First, a 3 degree-of-freedom parallel manipulator system and its dynamic equations are introduced. The theory and experiment of a vibration suppression system are then presented. The calculation method of both error and reliability of kinematic trajectory of manipulator is further implemented. Finally, the reliability of kinematic accuracy are calculated and analyzed for the 3 degree-of-freedom parallel manipulator with or without vibration suppressing control. The results show that the reliability of kinematic accuracy is improved using vibration suppressing control.

Abstract: Fatigue test were performed on 2024-T62 aluminum panels with MSD cracks, and the fatigue behavior of panels with MSD was analyzed. By the experiment results, the speed of crack growth increased stably in most time of life span, and crack growth rate curves were plotted. Then a rough method was presented to evaluate fatigue life of aluminum panels based a constant geometric factor from the curves and the evaluation is useful in engeering.

Abstract: A novel time-variant reliability model is developed after studying the traditional dynamic performance of mechanism. The expression of reliability is given based on stochastic process. A two-dimensional description of the error generating process is established by studying mechanism output kinematic accuracy. The reliability of mechanism output kinematic accuracy can be obtained according to this description. The model proposed can be used to calculate the reliability of mechanism directly, if the distribution of mechanism output kinematic accuracy is known.

Abstract: Residual strength degradation of 35CrMo alloy steel is investigated experimentally and theoretically in this paper. The experimental results were obtained by high-frequency fatigue testing machine and electro-hydraulic servo testing machine at room temperature. The experimental results showed the true tensile strength under static load and the residual strength under different cycle ratio, respectively. An exponential degradation model was proposed relating the initial strength, residual strength to the applied fatigue cycles and the constant amplitude stress. The residual strength distribution was described using three-parameter Weibull probability density function. The mathematical software MatLab was used for parameter estimation. Finally, the distribution function and failure probability density function of the residual strength was received, which was significant in fatigue reliability.

Abstract: With the qualities of smooth operation, high efficiency and small size, the planetary gear box was widely used in transmission field. In this paper, a 2-stage planetary gear box was studied. CAXA and Pro/E were used for modeling. The FEA analysis results were obtained by ANSYS, both the contact stress and the bending stress of the gear tooth root. The results showed that with the continuous action of cyclic loads, the excessive contact stress is the direct reason of the failure. Then, the system reliability evaluation was made, which can provide guidance for engineering practice.

Abstract: Flange is a common part in engineering, and it is tedious to build the 3D models of flanges repeatedly. Nowadays 3D modeling softwares are widely used in many engineering fields such as mining machinery, transportation and petrochemical. In practical engineering, it is necessary to compute the reliability of a flange. For these reasons a reliability design system of flange was developed with VC and Protoolkit. In this system, we only need to input several parameters to build a flange model and to compute its reliability. Also it is easy to determine the key sizes of a flange with an appointed reliability. The application of the software shown that using the software can improve the work efficiency and decrease the labor intensity of designers.