Applied Mechanics and Materials Vols. 602-605

Abstract: Influence of different pre-hem paths on the flange geometry was studied first. Among these paths could be vertical, oblique, horizontal. The result of the simulation shows that the vertical pre-hem path leads to less creep. To avoid the hemming quality defects around the corner of the outer-sheet, influence of the structure of the pre-processing steel on the hemming force was studied. And finally the design scheme of the table-top hemming machine and the basic operating principle were presented.

Abstract: Rotary air preheater is adopted widely in large power plant boiler,due to poor working conditions, inside rotary air preheater,plugging ash and corrosion happens easily,causes the rise of exhaust gas temperature,fan resistance increases,causes serious damage to the safe and economic operation in power plants,so heat transfer and flow of the rotary air preheater remains to be further optimized.By studying the working characteristics of rotary air preheater, simplifies the rotational structure of the rotary air preheater to a cuboid wind tunnel,internal layouts more groups of heat transfer components,through periodic switching valve,changes the flow of hot air and cold air,alternating flushing heat transfer element,simulating the unsteady heat transfer process of rotary air preheater. Experiment with NF heat transfer components,getting the convective heat transfer coefficient and resistance coefficient of this heat transfer element under different wind speed,verifies the feasibility of experiment system research on the heat transfer and flow characteristics.

Abstract: For the Comprehension of the dynamic mechanical properties of the materials under the dynamic loading, Hopkinson pressure bar apparatus is used. During the compression testing of the low impedance materials the use of the hollow transmission bar is common. In the current work, the analysis is performed to analyze the effects of hollow transmission and incident bars on the specimen testing for the large diameter compression setup. Complete model of the setup is prepared using the ANSYS software and the simulation of loading is done using the LS-DYNA software. The results of analysis indicate that for the large compression testing setup, solid bars can be replaced with hollow bars. By using the hollow transmission bar the objective of high strain rate testing is also obtained.

Abstract: Hopkinson pressure bar apparatus is extensively used for the measurement of the dynamic fracture properties. For accurate measurement of the dynamic fracture properties we need to understand concepts and principles associated with the test setup. The understanding of stress wave in the bar and specimen is also very important. In the current work, ANSYS LS-DYNA software is used to simulate the propagation behavior of the time based loading and generation of stress wave. The stress and strain plots in the specimen and the incident bar are obtained as an output of the analysis. The analysis of the plots suggest that, for the same time duration the rising trend is observed for the plots of stress and strain of incident bar whereas a sine wave trend is observed for the plots in the specimen.

Abstract: The finite element model of flexible clamp multi-point stretch forming (FCMPSF) was set up, and extensive contradistinctive analysis of forming limit and forming accuracy between FCMPSF and RCMPSF were done. The results show that under the same forming conditions, spherical part formed by FCMPSF is not easy to fracturing, dimpling and springback, and is easy to fit the die. The reason for this was analysed. The non-fracturing limited graph, the non-dimpling limited diagram and the average springback value of spherical parts formed by FCMPSF and RCMPSF were obtained. Finally, the forming experiment and error analysis of spherical part formed by FCMPSF were done, the results indicate that 3D parts with large transversal curvature can be shaped by FCMPSF and the forming quality was guaranteed.

Abstract: Through interaction with online consumers, e-commerce websites can gather data reflecting consumer preferences. The available data on consumer preferences together with sophisticated analytical tools enables companies’ increases in profit through optimization of prices. We consider a class of models of consumer purchasing behavior, each of which affected the data on a consumer’s requirements and budget constraint to subsequent purchasing tendencies. We can study for the multi-product pricing problem based on the max budgets of consumers, and a customer data-oriented multi-product pricing model is presented. Proposed models were solved through genetic algorithms. Optimal solution of the given examples shows that this model is effective for enterprises.

Abstract: The development of modern advanced manufacturing technology greatly relies on the CAD / CAM technology. Many pieces of computer software with CAD/CAM function have been developed rapidly in recent years. Unigraphics (UG) is one of the outstanding representatives. It has a powerful design and CNC programming function, and CAD/CAM seamless connectivity. As an application example, a mouse model part which has complex surface was designed and trial-manufactured with CNC machine. First, the 3D model of the part was created in the modeling module of UG software. Then, the process scheme was developed after analyzing. In the manufacturing module of UG software, the NC machining parameters were set according to the processing requirements, the tool paths were generated, edited and checked, and the NC codes were generated by post processing. And then, the NC machining was simulated in YULONG software. Finally, the part was manufactured in a 3-axis CNC milling machine. It has desirable shape and high accuracy. The results show that UG has a perfect CAD/CAM function. The CAD/CAM technology based on UG makes the NC machining of complex surface part very convenient. It improves the efficiency of design and machining, shortens the manufacturing cycle, and reduces the cost, which reflects the importance of the CAD/CAM software in NC machining. The method described in this paper can provide valuable reference for processing similar parts, and it is also useful for related study.

Abstract: A new type of the precision flow pump is developed with the giant magnetostrictive materials as the driving source. Experiment has been conducted to test the performance of the pump with designed key components. The pump as the preloading mechanism, adopting an elastomer instead of a spring, not only simplifies the structure, but also improves the performance of the pump. A design is also made to some key components such as the giant magnetostrictive rod and driving coil. The result of experiment shows that the pump flow resolution records 1 ml/min~400ml/min and the maximum output pressure 0.6 MPa, which means the performance of this kind of pump is superior to ordinary diaphragm pumps.

Abstract: The traditional large-scale marine propeller processing equipments have such disadvantages as single-surface machining, propeller blade vibration, poor stiffness, repeated clamping and long processing time. The method of double-cutter & double-surface symmetrical machining is proposed for large-scale marine propeller based on the parallel-serial mechanism. The processing method can overcome proposed disadvantages, and improve machining efficiency and accuracy. The structural design of the processing equipment is introduced and the coupling kinematics parameters of the parallel spindle platform are analyzed. The inverse kinematics solution and improved forward kinematics solution are discussed in detail. And the forward kinematics solution can solve a troublesome problem about the selection of good initial parameters. A simplified prototype is built to verify the solution method which could be used in the future actual application as a foundation.

Abstract: In the present study, nonlinear bending problem of functionally graded material (FGM) cantilever beams resting on a Winkler elastic foundation under distributed load are discussed. Based on the large deformation theory and considering the axial extension of the beam, the equilibrium equations with geometric nonlinearity of FGM beams subjected to distributed load are established. In the analysis, it is assumed that the material properties of the beam vary continuously as a power function of the thickness. By using shooting method, the nonlinear boundary-value problem is numerically solved as well as the non-linear bending characteristic curves of the deformed beam versus the load are presented. The effects of material gradient property and foundation stiffness parameter on the bending deformation of the beam are discussed in detail.