Advanced Materials Research Vols. 971-973

Abstract: Machine tool bed, which supports headstock, tailstock and other functional components, is one of the important structure parts of machine tools. Precision grinding machine tool beds are designed by the authors with artificial granite and cast iron respectively for research. Their three-dimensional models were established via software SOLIDWORKS and then imported into the finite element software (ANSYS) to simulate for the first eight modal frequencies and the corresponding vibration modes. Simulation results show that the first eight order natural frequencies of artificial granite bed are better and the corresponding maximum amplitude of vibration modes are decreased significantly than cast iron bed. The dynamical properties of artificial granite bed are obviously better than grey cast iron bed.

Abstract: In order to solve the problems that the vibration and deformation of grasping steel machine’s boom can affect machine’s reliability and stability under complex work conditions, the crawler electric grab steel machine JK321-GD is taken as the research object. And then the three-dimensional modeling is established by UG software, the modal analysis of grasping steel machine’s boom is also conducted using ANSYS Workbench, arriving at the the dynamic characteristics of the boom, including the natural frequency, the maximum amplitude and the main vibration direction. These provides theory basis for further optimize design.

Abstract: according to the heat load of diesel engine piston, to set up the finite element model and the corresponding thermal boundary conditions of 3D thermal models of the diesel engine piston, Through the finite element analysis , simulating the temperature field. Through the above finite element analysis,getting the temperature field of diesel engine piston, to build a theoretical basis for the development and design of other diesel engine piston.

Abstract: By analyzing stress contours and deformation contours of the primary bracket, we can know that bracket material is more, contours proves too safe for bracket strength and stiffness. To improve the material utilization rate, topology optimization for bracket is carried by using topology module (DOE) of finite element analysis software workbench14.0. the main design parameter was set up, accordingly to accomplish analysis about the relationship between design parameter with quality. on the basis of analysis results, we improved primary structure that made the bracket quality reduced by 10% and executes verification, we obtained the reasonable structure finally.

Abstract: With the development of nondestructive testing (NDT) technology for wire ropes, various detection methods are constantly refined and improved. The primary and representative NDT methods are suitable for the detection of wire ropes including manual inspection, acoustic emission method,acoustic-ultrasonic method,eddy current method,electromagnetic method and metal magnetic memory method. Meanwhile, the research results of our laboratory based on the theory of the magnetic flux leakage to detect wire rope’s fault detection will be displayed. Through comparisons of methods’ merits and weaknesses,it also has brought forward the new trends about adopting metal magnetic memory to predict the lifetime of the steel wire ropes,which has greater value in theory and application for improving the precise detection of the in-service ropes.

Abstract: NC machine creeping failure usually occurs in the mechanical part and feed servo system of NC machine tool feed system, because of low speed creeping phenomenon often depends on the characteristics of mechanical transmission parts. Crawling is generally due to transmission of machine tool stiffness is insufficient, friction and dynamic friction coefficient difference and friction damped oscillations caused by too small. This paper establishes the physical model and the mathematical model, through theoretical analysis and numerical simulation of machine movement components that crawl main reason, put forward to prevent the moving parts of the main measures of creeping.

Abstract: This paper introducesmulti-component Gas Kinetics Scheme(GKS), when dealing with multi-componentsproblem, the assumptions of the same temperature and speed are meet at the cellinterface among components. The numericalsimulation of inclined air/SF₆ interface instability experiment wascarried out and the SF₆ densitydistribution at different time and the displacement history of inclinedinterface feature location are presented. The numerical simulationresults and experimental comparisons show that the gas kinetics scheme has a good ability for simulation ofinclined interface instability problems.

Abstract: Based on the background of the subgrade in Dalian of Dalian-Haerbin Passenger Dedicated line and combined the local climate condition and geological data, the thermal field in subgrade was simulated by finite element software, and the distribution of thermal field in subgrade of different month in winter and different years were analyzed. The results indicated that: The main areas of subgrade appeared negative temperature in winter, and the sunward and shady aspect should be considered in the distribution of thermal field in actual analysis. The negative temperature of thermal field in subgrade decreased with the increasing of the years in the same period, and the global warming have a significant effect on the distribution of thermal field.

Abstract: Withthe use and popularization of the tangential longitudinal axial combineharvester,the cleaning device of high loss rate and impurity rate continuouslyemerging.In order to analyses the reason of cleaning performance is low,thestudy for airflow field distribution of thetangential-longitudinal axial combine harvester has been carried out.Based onhomogenization when Reynold continuous equation and navier-stokes equation andthe renormalization group (RNG) kappa epsilon turbulence model predominateconstitute a closed equations,Using CFD simulation software simulated thecleaning shoe airway airflow.The simulation results show that the cleaning shoeair distribution is symmetrical in the screen surface width direction.Along thescreen surface height direction airflow velocity decreases gradually,Along thescreen length direction ,at the front of the sieve air velocity is low,Near themiddle of the screen as to achieve the maximum of air velocity.And for cleaningshoe air flow field were measured experiment, verify the accuracy of flow fieldsimulation.

Abstract: Based on actually collecteddata ofturbine blade, a 3D model was formed according to NURBS curved surface theory modelingmethod. Analyzing this model using UG^,s analysis ability, andcomparing with real turbine blade ,which shows if the model can be up to thereal component.The result shows that this method can offer precise data forblade manufacturing and maintenance, and it can also provide an advanced way forblade design.