Applied Mechanics and Materials Vols. 152-154

Abstract: In the present paper, large-eddy simulation (LES) based on commercial computational fluid dynamics (CFD) software FLUENT for prediction of flow and heat transfer in a mixing T-junction was completed. Mean and root mean square (RMS) temperature and velocity were defined to describe the distributions and fluctuations of temperature and velocity. Numerical results indicate that profiles between symmetrical planes are almost same and the root mean square temperature and velocity close to the center of the main duct in the downstream are larger than those near the main duct wall. The prediction of the fluctuations of temperature and velocity is significant to understand the knowledge of the cause of thermal fatigue in a mixing T-junction.

Abstract: The cantilever fluid conveying pipe which restrained by linear spring and cubic nonlinear spring at its free end was studied. Firstly, the model reference adaptive control system with parallel structural style was designed for the restrained cantilever pipe based on Lyapunov theory of stability. Then the vibration of the pipe system was under positive controlled making use of this adaptive control scheme. Lastly, the numerical simulating method was used to verify the effectivity of this control method and the influence of system parameters on control performance and control input energy were also investigated. The simulation results showed that the control effect of the control system was extremely distinct. In addition, the larger the Lyapunov function state feedback declinational gains were, the better the control effect had, and the shorter the required time that the controlled system entirely settled down needed. With the position of piezoelectric actuator moved to the pipe free end the required time that the controller entirely settled down would become longer and longer. Moreover, the effect of the length of piezoelectric actuator on the controlled system was relatively complicated, the required time that fluid conveying pipe system settled down and the control energy took on complicated variation regularities.

Abstract: The fractional volume of the reservoir sand shall be taken to the ground when the crude oil is brought up from the ground. With the deepening of the oil extraction the sand content of oil recovery is increasing. Although many measures have been used such as prevent sand, block sand and so on, the viscosity of heavy oil is big and the fractional of sand is carried into the crude oil gathering system inevitably, causing a series of problems at ground equipment, having a serious impact on the normal production and gathering of crude oil. The larger size of sand can be removed by the sedimentation and the smaller sand can be removed by hydrocyclone devices. Hydrocyclone is a separation plant used to separate non-uniform phase mixtures. It can be used to complete the liquid clarification and to wash particles, liquid degassing and grit removal, grading and classification of solid particles and the separation of two non-miscible liquids and others. Hydrocyclone separation technique is simple and convenient operation, high separation efficiency, no rotating units, small size and easy to realize automatic control. On the offshore platform，if the sand mixed with oil is discharged into sea unsatisfactory the standard, it will pollute the sea. It will cause a serious of marine pollution; this is a problem that should be solved quickly. This paper discusses the requirements for the design of the hydrocyclone desander equipment with compact structure, applicable to offshore drilling platforms，and carrying out CFD simulation, the results showing that the particle size of 75 of sand, grit removal efficiency above 90%.

Abstract: The theoretical principle of mode analysis was introduced. The finite element models of the empty and loaded car body of special gondola car were built, and then the mode analysis and verification of the two models were studied. The results show that the two finite element models of empty and loaded car body of special gondola car are accurate and reliable. Furthermore, a new way is provided to analyze the mode of car body embarked by bulk cargoes, and a solid foundation is laid for further dynamic researches.

Abstract: Objective To construct three-dimensional models of individualized femoral prosthesis by using computer-aided design and to verify whether individualized femoral prosthesis is superior to popular femoral prosthesis via simulating and contrasting mechanical study. Methods Two-dimensional images of fresh femurs were obtained by using total-length CT scanning and processed with computer edge recognition and three-dimensional contour extraction software to identify outer and inner contour of pulp cavity, extract contour data of pulp cavity and prosthesis, and construct three-dimensional models of femur and individualized femoral prosthesis. SolidWorks software was used to establish three-dimensional prosthetic models in common biological and bone cement types; moreover, bone-cement, biological, and individualized femoral prosthesis were replaced via simulating clinical surgery. Results Edge extracting was replaced by Canny operator, characterizing by stable running, credible outcome, and consistent with the primary request. Stress, femoral stress, interface stress, and primary micro-motion of individualized femoral prosthesis were significantly lower than biological and bone-cement femoral prosthesis (P Conclusion The computer-aided design is reliable to perform the assistant design of prosthesis; furthermore, biomechanical properties of the individualized femoral prosthesis are superior to those of popular femoral prosthesis.

Abstract: Objective To look for a suitable displacement range of acetabular medial wall following osteotomy by computer-aided design finite element analysis. Methods SolidWorks 2008 software was used to establish three-dimensional models of acetabular dysplasia pelvis. Acetabular medial wall displacement osteotomy was simulated to make acetabular medial wall bone displace from 2 mm bone contact to 7 mm bone contact in the pelvic cavity. One experimental group was set at 1 mm intervals, totally 10 experimental groups. The acetabulum in each group was split into four quadrants. The prosthesis acetabulum-bone interface in each group was analyzed by computer simulation contrast mechanics experiment. The Mises stress and shear stress values were measured between acetabular prosthesis and bone interface. Results In groups 1, 5, 6, 9 and 10, the Mises stress was unevenly distributed in posterior inferior, anterior superior and anterior inferior quadrants. In groups 2, 3, 4, 7 and 8, the Mises stress was evenly distributed in posterior inferior, anterior superior and anterior inferior quadrants. Of them, the stress was most even in the group 4. In groups 2, 3, 4, 7 and 8, the shear stress was evenly distributed in the above-mentioned three quadrants. The shear stress was lowest in the groups 7 and 8. These indicate that joint force in the acetabulum mainly focused in the posterior superior quadrant. With the displacement of acetabular cup, the contact area of acetabular cup and bone would gradually increase, which finally increased the Mises stress in the contact surface. However, shear stress decreased with displacement of acetabular medial wall. Conclusion the suitable displacement range of acetabular medial wall osteotomy is 1 mm away from the pelvic cavity and 1 mm complete embolism in the pelvic cavity. The optimal position was 1 mm complete embolism in the pelvic cavity.

Abstract: The paper analyses problems existing in integration models of product design and manufacturing in enterprises. Under the theory of product life cycle management (PLM) and via the platform of J2EE, it builds a framework for establishment of integration architecture in product design and manufacturing based on knowledge engineering. The paper gives a detailed introduction to the structure, function characteristics and realization forms of the architecture. On the basis of this, the paper then studies integration methods of the information system based on XML and explores key technologies in the knowledge base plus network safety of the architecture. Finally, the paper emphatically analyzes types of flow of traditional knowledge and digital knowledge in enterprise knowledge management. The proposed architecture has realized close integration of various sectors so that knowledge runs through the whole process of product life cycle. As a result, the architecture can satisfy modern enterprises’ demand for collaborative manufacturing, resource sharing and network integration while supporting knowledge management and technological innovation.

Abstract: Aiming at the problems that existed in the actual application of traditional measurement methods for large-size components, the size measurement and detection method of large-size components based on machine vision was researched and discussed, and the imaging model was built, of which on the basis, the feature edge detection method was applied into the large-size components measurement, thus the image stitching algorithm based on feature edge detection was pointed out, and after simulation, the simulation result shows that the image stitching algorithm based on feature edge detection has good real-time performance compared with the traditional corner detection stitching algorithm, and the former has better accuracy than that of the latter. So the image stitching algorithm based on feature edge detection could enhance the accuracy and efficiency by taking use of large-size components measurement based on machine vision, and it is significative for enhancing the application level of large-size components measurement based on machine vision.

Abstract: A new type hydraulic rotary cutting and pneumatic impacting rock drill is used to drill medium and deep hole. This rock drill is made up of three components: impact system, rotary system and dedust mechanism. The power is provided by hydraulic liquid and compressed air, and the hydraulic power is separated with the pneumatic power. The rotary system driven by hydraulic liquid transfers motion and force by its components: motor, input gear, mid-gear, revolving sheath, etc. The maximum rotary power is greater than the impact power. Compared with other drill, this new rock drill has a simple structure, high reliability, fast drilling speed, long service life of the drilling tools, easy maintenance, high performance-price ratio and other advantages

Abstract: This paper deals with the existing propulsion mechanism, analyzes the disadvantages of the flat key and the spline, studies the features of the logarithmic spiral profile shaft connection. In an existing chain propulsion mechanism, we change the fit of the inner hole of sprocket gear and the outer circle of intermediate shaft to get a logarithmic spiral profile shaft connection(a keyless joint), then introduce the propulsion mechanism with logarithmic spiral profile shaft connection. At last, applying Solidworks2010 software，we create the three-dimensional modeling of the propulsion mechanism, which would lay a solid foundation for the further study. This new propulsion mechanism has such advantages as self- centralizing, easy disassembly, low stress concentration, with a simple fit cross-section, transmitting big torque, suitable for the heavy loads of rock drilling.