Advanced Materials Research Vols. 706-708

Abstract: Based on the study of the working process for flexible collet, establish reasonable finite element model and set reasonable boundary conditions, a preliminary analysis for the deformation, strain distribution and the stress distribution in the working process of flexible collet is launched, then predict the possible locations of stress concentration and fatigue, which provide a reliable basis for optimum design of collet device.

Abstract: A simplified numerical approach based on the Finite Element Method (FEM) to compute the steady state temperature field and thermal stresses in a thermal roll of a calender machine is proposed. The temperature distributions of the working roll and thermal oil were investigated by fluid dynamics theory. With the acquired roll body temperature, the deformation and stress were calculated. This approach is suitable for fluid-structural and thermal stress problems and hence helpful for the design and improvement of such equipment.

Abstract: This paper studies the fracture mechanics of a thermoelastic medium with an internal circular crack subjecting to a prescribed thermal flux. The time varying crack tip thermal stress intensity factor is solved. Solution for the infinite medium under steady heat conduction is given in closed form. Comparisons between the non-Fourier results and the classical Fourier results are made. Numerical results show that the non-Fourier heat model predicts considerable high transient thermal stress intensity factor than the Fourier model. This paper, together with our previous paper entitled fracture of a finite medium with a circular internal crack under hyperbolic heat conduction-prescribed crack face temperature, completes the analysis of a finite medium with a circular internal crack under hyperbolic heat conduction.

Abstract: A novel kind of double-hemisphere rolling gear globoidal indexing cam mechanism was proposed，which can satisfy high speed and precision motion requirement. Fundamental principle and meshing characteristics were studied based on conjugate surface principle. Pure rolling of the transmision mechanism was applicated in engineering，and combination property was improved.

Abstract: Suspension model can be divided into vertical hysteresis characteristic model and suspension guide-mechanism model according to its function. The relationship of the force and displacement is described in the existing vertical characteristic model, which does not consider the impact of the frequency. In the existing guide-mechanism model, the centerline of suspension K&C experimental data is used as the basis of the spindle position and attitude correction, without considering the hysteresis area. The problems above will affect simulation accuracy of vehicle dynamic. In this paper, hysteresis characteristic model of suspension is built. The vertical hysteresis model consists of spring, Maxwell element and Dehl friction unit. While in guide-mechanism model, if the hysteresis region is not obvious, considering the asymmetry, upper and lower borderlines are used to instead the centerline, and if the hysteresis characteristic is obvious, the Fancher formula is used to describe hysteresis range. Results showed out that the model has a high accuracy and is able to accurately describe hysteresis characteristics of suspension by comparison with the suspension system K&C experimental results.

Abstract: Bounce time is one of the important factors of the ZNII vacuum capacitor switch. Study on the effects of contact wear on the bounce time can guarantee the performance stability of bounce during long-term operation. Through the analysis of closing bounce dynamics and motion simulation by MATLAB, get the conclusion that with the increasing of contact wear bounce time increases. Therefore, considering the influence of contact wear to the bounce time is very necessary in the design process.

Abstract: To improve the accuracy of attitude determination and control stabilization when simulating attitude motion of satellites in the space, the finite element model of the platform of 3-DOF spacecraft attitude control simulator was founded. Gravity field of air bearing testbed and formula for platform’s moment of inertia on the action of gravity was induced The result shows platform’s attitude accuracy error exist because of main principal axis of inertia change of direction.on the action of gravity, The more large value it is, the more error is .Error of inertia main axis changes as sine curve with the change of two horizontal Euler angle.

Abstract: In this paper, a novel method to recognize gear fault pattern was approached based on harmonic wavelet package (HWP), sample entropy and grey incidence. At first, the line structure element was selected for rank-order morphological filter to denoise the original signal. Secondly, different gear fault signals were decomposed into eight frequency bands by harmonic wavelet package in three levels; and sample entropy of each band was calculated. Finally, these sample entropies could serve as the feature vectors, the grey incidence of different gear vibration signals was calculated to identify the fault pattern and condition. Practical results show that this method can be used in gear fault diagnosis effectively.

Abstract: Digitization of CCT curves by systemically using common softwares was studied and practiced to rebuild the digital patterns for teaching purpose. As treated in PC procedure, the CCT images printed in books were transformed into the digital data points, which can be read and record clearly and precisely in computer, extremely changing the appearance and precision of raw images. As the digital data, this digitized CCT curves can be conveniently introduced into the courseware, drawing more attendance and interesting from students than raw images. On the other hand, these digitized data also can be used as the CCT database for industrial applications, which can introduce automation into the thermal treatment industry. That is, the digitization of CCT curves will take great advantage of the improvement of teaching and promote the producing depth.

Abstract: Stress and deformation analysis of 950 mill housing was done by means of ANSYS to calculate the maximum stress and deformation. Strength and stiffness of the mill roll were checked to meet requirements. Carries on the modal analysis to the rolling-mill housing, obtains its first 10 steps the natural frequency and the mode of vibration, through the vibration model diagram analysis frame of the weak link,and it is significant for similar mill housing designs.