Applied Mechanics and Materials Vols. 457-458

Abstract: For rotating machinery, a fault diagnosis method is proposed on the basis of the EEMD (Ensemle Emperical Mode Decomposition) and Correlation Coefficient Method. In the Vibration Signals and rotate speed of rotating machinery, the fault diagnosis method is achieved by Spectrum Analysis and real-time monitoring. The original signals are decomposed into several IMF components. Each IMF contains the local feature of the signal. Correlation coefficient method is used to select the appropriate Intrinsic Mode Function. Extract the fault feature through its envelope diagram. Experiment proves the feasibility of this method.

Abstract: through the use of single-chip microcomputer measurement CNC lathe cutting force, this paper focuses on the single chip microcomputer to implement continuous automatic sampling, A/D conversion, scale transformation and data processing methods. Introduces the principle of the measurement and control system, structure and data acquisition part of the program.

Abstract: Focusing on welding problems such as poor working environment, high pressure, appalling conditions in oil and gas pipelines, pressure vessels and other large welding, a 6R welding robot was proposed. Based on D-H notation, space kinematics model of robot was founded and the kinematical equations of the grinding robot wad derived. According to the kinematics model, The robot work space was obtained by Monte Carlo methods. Furthermore, control and software system was introduced for the arc welding robotic system.

Abstract: Manufacturing process problems in industrial systems are currently large and complicated. The effective methods for solving these problems using a finite sequence of instructions can be classified into two groups; optimization and meta-heuristic algorithms. In this paper, a well-known meta-heuristic approach called Firefly Algorithm was used to compare with Shuffled Frog-leaping Algorithm. All algorithms were implemented and analyzed with manufacturing process problems under different conditions, which consist of single, multi-peak and curved ridge optimization. The results from both methods revealed that Firefly Algorithm seemed to be better in terms of the mean and variance of process yields including design points to achieve the final solution.

Abstract: Based on tension tests for tower bolt, it was found that the pretension increased with the extension of torque retention time, and manifested characteristics of decreasing at early stage then increasing at later stage during the tension process, that provided guidance for bolt fastening.

Abstract: Clinching is a cold forming process for hard-to-weld materials joining in the field of automobile lightweight design and manufacture. The automatic crack detection for clinch joints in the loading test is an important monitor process. In this paper, the method of automatic crack detection on clinch joints by using digital image analysis technology was presented, and an image acquisition and processing platform coupled with a single shear pulling test machine was introduced. In order to insure the real-time of the calculation, multiple scan lines perpendicular to the potential crack strip was set, and threshold segmentation and edge detection with Sobel operator was used in the analysis. Results showed that the analysis procedure proposed in this paper is available for automatic crack detection for the loading of clinch joints and can get high computer speed.

Abstract: In practical applications, often using natural gas pipeline through the pipe shaft way, so conditions for shaft pipe stress analysis has a very important practical significance and economic value, and limit the tube length calculation is one of the key issues. Take advantage of this stress analysis software, combined with program design, the shaft condition of the pipeline depth simulation. The results show that: gas pipeline tunnel shaft limit pipe length and pipe material, wall thickness and operating conditions are closely related, the greater the steel yield strength and wall thickness, the smaller the operating pressure, the longer the tube length limit. In the actual design pipeline crossing, it should fully take into account the limits of the tube length limit, the limit calculated under different conditions, to ensure the normal operation of gas pipelines provide pipeline reliability and economic benefits.

Abstract: In order to solve the key issues such as the improvement of the movement smoothness of the center of mass and the movement coordination of each joint of the legs in the process the movement of the bionic hexapod robot, etc., establish bionic hexapod robot simulation model jointly by observing the movement characteristics and structural characteristics of the hexapod beetle and using three-dimensional modeling software SOLIDWORKS and mechanical system dynamics simulation software ADAMS and build the legs dynamic contact and collision model with the ground through the applied force constraint of ADAMS. Ultimately, form the global dynamics simulation model of the robot. Using the model the triangle gait of bionic hexapod robot is analyze, especially the straight and turning gait, which proves that the movement of robot is stable. The results lay the foundation for the further study and optimization of the bionic hexapod robot.

Abstract: Rubber track of Rescue Robot was dispersed into limited number of track blocks by the method of finite segment method used in flexible multibody dynamics. The two neighbor track blocks were connected by springs and dampers, then the moldel was become a multi-rigid-body system with flexible joint. Rubber track was modeled with the help of macro command used in the secondary development of virtual prototype technique software named ADAMS. Flexible connection was realized by the method of adding Bushing, and then a new method was proposed to build rubber track model. The obstacle-surmounting simulation of climbing the barrier of single step was carried out. It intuitively reflected the stress and deformation under the condition of climbing barrier. The method mentioned above laid good foundation for studying obstacle-surmounting abilities of the rubber-tracked robots and dynamic characteristic of the tracks.

Abstract: With an urgent need for energy conservation and pollution reduction, the trend of replacing traditional incandescent or fluorescent lamps with high-power LEDs is growing more and more popular. However, heat dissipation of high-power LED is the main bottleneck for its application. In this research, a kind of automotive headlamp low beam system model is designed with high power LED chips. Several different cooling devices are designed for headlamp cooling, the heat dissipation performances are simulated and analyzed both by the finite volume method (FVM) in FloEFD and experimental measurements. The obtained results indicate that loop heat pipe combined with fined heat sink is the most effective way for heat dissipation in the designed automotive low beam system, even in 80¡æ environmental temperature can ensure the LED headlamp system working stability. The research lays a theoretical basis for the follow-up study.