Papers by Author: Run Jie Shen

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Authors: Ming Ma, Run Jie Shen, Bing Fang, Ming Wei Sun, Wen He
Abstract: In this paper, based on the analysis of white noise generation, equably distributed pseudo-random numbers are generated by a method of mixed congruency. In the case that the pseudo-random numbers are taken as the phase spectrum and the amplitude spectrum is equally set, the waveform array of frequency-domain is made up. The array is transformed from frequency-domain to time-domain by the IFFT before stored into the external data memory. Based on the wave generating technology of DDS, the timer interruption of DSP2812 is installed to change the frequency for generating wave .Then the number is taken out from the external memory. The limited white noise is formed by the way of D/A and zero-section maintenance .This generator can be used as signal source in the noise simulation experiment.
Authors: Zuo Chao Rong, Wen He, Run Jie Shen
Abstract: In the centrifuge of the multi-parameter combined environmental testing device, the three-phase induction motor could not be started directly at the frequency of 50Hz due to the large moment of inertia of the centrifuge rotor. Therefore, large torque output of the three-phase induction motor was required at low frequencies. And the specimen needed stepless rotational speed adjustment (40-130r/min). A set of frequency control system was developed based on vector control with PG, inverter and LabVIEW to solve these problems. The principle of the centrifuge was present. The principles of vector control with PG of three-phase induction motor were analyzed. Based on the mechanical characteristic of three-phase induction motor, vector control with PG was employed in the system. The system control software based on LabVIEW was presented, which realized stepless speed adjustment of the centrifuge on a computer. Experimental results show that the developed system could realize the stepless regulation of the specimen’s centrifugal acceleration.
Authors: Guan Hua Xu, Wen He, Run Jie Shen
Abstract: A novel design of a temperature test chamber in multi-parameter combined environmental test was introduced, in which thermoelectric coolers were adopted to achieve both high and low temperature. Multiple distributed actuators and temperature sensors were used for improving the evenness of the temperature field. A well performed cooling system for waste heat dissipating was designed based on air-cooled radiator and circulating water flow. A temperature control system based on PC and MCU with wireless communication modules was designed. The thermoelectric cooler was driving by H-bridge circuit, whose power was controlled by PWM signal. PID algorithm was applied and average temperature was adopted to be the controlled variable. Measurement and control software on the PC and MCU was analyzed and its flow diagram was given. Influenced by centrifugal acceleration, unevenness of the temperature field would increase. A fan was mounted at the bottom of the chamber to improve the evenness of the temperature field. The experiment results show that the temperature environment with other combined environment is realized in the test chamber based on the above technology.
Authors: Zuo Chao Rong, Wen He, Run Jie Shen
Abstract: The centrifugal acceleration generated by centrifuge is used to simulate the linear acceleration in multi-parameter combined environmental test. To resolve the problems of current centrifuges, such as difficulty to maintain the balance of their arm and difficulty to install many devices on their arm, as their arm was cantilevered, a disc centrifuge which had large capacity of its arm was developed in this paper. The structure of the centrifuge was described in detail. To perform as a platform for other environmental test devices, power and compressed air for the devices on the centrifuge arm were supplied by slip ring and swivel joint respectively. Finite element analysis on the key parts of the centrifuge was performed to ensure their stiffness to meet the requirements. The control system and the precision of the centrifuge were also analyzed. Experimental results show that the centrifuge is slow to start and stop, and works smoothly, and that the acceleration generated by the centrifuge is stable, and that there is little influence on the power network when the centrifuge starts. The linear acceleration is simulated by the centrifuge quite well.
Authors: Jian Yi Zheng, Wen He, Run Jie Shen
Abstract: A practical electropulsing treatment device has been developed based on capacitor energy storage and discharge technology. The device was controlled by a pair of charge and discharge switches which close in turn to produce high density electropulsing. The electropulsing treatment experiment was carried out by capacitor discharging while an exponential damping oscillatory waveform was produced. A group of 45 steel quenched specimens were connected into the discharge circuit with copper electrodes through a vacuum contactor switch. At last, a typical waveform of electropulsing was detected by a DS5062MA digital storage oscilloscope. This waveform demonstrates that the first peak of electropulsing has reached 23 kA, and the discharging process has concluded within 0.6 ms. Results indicate that the energy density of electropulsing treatment is very concentrated because of the waveform of high peak value and short duration. The device is now being used for the stress relief processing of metals.
Authors: Bing Fang, Run Jie Shen, Ji Feng Guo, Wen He, Ming Ma
Abstract: This paper aims to simulate the sound field of rectangular small enclosure excited by panel loudspeaker with FEM. Firstly, in order to testify the fluid-structure interaction theory in the field of acoustics calculation, coupled modal and uncoupled modal of loudspeaker and air were established. Result of harmonic response analysis shows that the vibration amplitude of uncoupled case is larger than the coupled case. The result just is in harmony with the fact. So when modeling the sound field, fluid-structure coupling should be taken into account. Secondly, for more accurate sound field simulation, different from most researchers’ modeling method that supposing the vibrating plate’s boundary of the loudspeaker is simply supported, this paper provide a more practical way that the boundary is elastic supported. The comparison shows that the resonance of air in enclosure is more severe under elastic boundary on condition of same driving force. Thereby the sound pressure is higher.
Authors: Jian Yi Zheng, Wen He, Run Jie Shen
Abstract: The butt welding of 45 carbon structural steel has been analyzed using a nonlinear transient finite element (FE) model. With numerical analysis technology, welding heat transfer and thermal elasto-plastictity have been progressed. Also the effects of welding seam growth with heating source movement have been studied using the birth and death technique. For this purpose, a 3-D structural and thermal direct-coupled solution has been used to obtain the temperature changing curves and residual stresses distributions. In addition, the variations of physical properties of material with temperature have been taken into account. Results indicate that the heating speed of welding is rapid, and the distributions of residual stresses are not symmetrical along the welding seam’s centerline, and the residual stresses are change along the welding direction and also in the plate-thickness. It has been shown that use of 3-D direct coupled-field and nonlinear transient model will lead to more accurate and realistic results.
Authors: Wen He, Bang Ping Gu, Jian Yi Zheng, Run Jie Shen
Abstract: Considering that most of the research on vibratory stress relief (VSR) is excited by low-frequency vibration at present, high-frequency-exciting VSR on small Cr12MoV quenched specimens was studied. A high-frequency vibration table system was adopted as the exciter of the VSR. To increase the vibration level, a novel vibration level amplifying device was put forward. High-frequency VSR on the same group of small Cr12MoV quenched specimens was carried out under various vibration levels. The residual stress before and after vibration was comparatively analyzed. The results showed that the high-frequency vibration had the better effect on eliminating and homogenizing the residual stress and that increasing the vibration level of high-frequency-exciting could improve the effect of high-frequency VSR.
Authors: Yuan Lai Zhou, Wen He, Run Jie Shen, Min Liu
Abstract: Considering the requirement of the multi-parameter-combined environment testing device, a kind of multi-parameter measure and control system based on wireless communication technology was studied in this paper. First, the overall structure of the multi-parameter measure and control system based on wireless communication in combined environment device was put forward, which was made up of six control subsystems: a host computer, the centrifuge and dynamic balance system, the vibration and rectification system, the temperature system, the air pressure system and the sound pressure system. Then, the communication protocol and hardware structure of the multi-computer communication system based on wireless transmission were mainly studied. And software design technology of multi-parameter measure and control system was studied in succession. Finally, the five-parameter-combined environment testing was carried out. The experimental results show that the measure and control tasks of the combined environment testing can be well finished by the multi-parameter measure and control system.
Authors: Chun Yu Wang, Wen He, Run Jie Shen
Abstract: The coupling between vibration and centrifugal field is quite strong in multi-parameter combined environment test system. The motion part of vibration table deviates from its original operation position by the action of centrifugal force, which ends in the stuck of armature and causes damage to vibration table. In order to solve such problem, an air-push-type armature redress system with displacement feedback was proposed, which provided a recovering force to counteract the centrifugal force and pushed the motion component to its designed operation position. Some improvements were also made to enhance its reliability. The result of simulation and test about the armature redress system demonstrates that the system has an excellent performance and meets the requirement of counteracting the centrifugal force, which guarantees that the vibration table could work in centrifugal field and multi-parameter combined environment.
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