Advanced Materials Research Vols. 201-203

Abstract: A tolerance synthesis model is established based on degree of freedom of geometric variations of features in this paper. The method allows a designer to analyze the relationship between geometric variations of features of a part and functional requirement of assembly (FRA). Firstly, tolerance is modeled with DOFs of geometric variations of features and the tolerance zone is expressed with six kinematic DOFs in three-dimensional (3D) space. Secondly, the stack-up of geometric variations of features is formulated as explicit tolerance analysis equations using kinematical coordinate systems associated with each feature. To express mathematically the relationship between given FRA values and the corresponding DOFs of geometric variations of features, the reverse synthesis equations are obtained using a matrix inversion scheme of the tolerance analysis equations. Finally, a case study is used to illustrate the proposed method.

Abstract: With the good ecological functions, the raw-soil structures attract attention of the people all over the world recently. According to surveys, more than 30 million farmers in China still choose to build their house using raw-soil. Since the advent of CAD/CAE techology, it became easier for engineers to design better buildings. However, for lack of adequate research on raw-soil structure, existing domestic and oversea softwares are incapable of solving the detailing work of this structure. In this paper, characteristics of the raw-soil structure and software function requirements are analyzed; the framework, data structure kernel are designed for a specialized detailing CAD information system based on BIM (Bulidgin Information Modeling). Finally the raw-soil software is developed with Object ARX technology and AutoCAD graphics platform, and an example is introduced to show the main functions.

Abstract: High speed cutting (HSM) is one of the main trends of cutting machinery. In our country, the relevant research of HSM starts later, the actual machining and experiment on the machining technology and the machining parameters of HSM are few, the reasonable machining parameters selection scheme and the appropriate cutter choice method are lack. The paper established the HSM cutters management system based on BP artificial neural networks to facilitate optimized database system and to improve cutting efficiency. The result shows the system is very helpful to select cutting parameters and the value of prediction fits with the test very well.

Abstract: According to the meshing principle of non-circular gears, the meshing characteristic and digital manufacturing technology of Limacon type gears is studied. Based on analyzing the parameterized modeling of pitch curve, transmission characteristics and convexity-concavity analysis on Limacon type gears, the transmission feasibility of this type gear is proved. Through tooth shape design, CAM calculation and analysis with example, and processing simulation, the validity and manufacturability of theoretical design method on this type gear is proved. The research results can provide more systemic theory basis for the design, manufacture, measure and application of Limacon type gears.

Abstract: The turbulent flow in the near-wall region affects the wall heat transfer dominantly. The farther it is from the wall, the less effect it has. So a two-step mechanism of the turbulent wall heat transfer is released: first, the energy is transferred to the outside of the viscous sub-layer by the rolling of the micro-eddy; secondly, the energy gets to the wall by conduction. Then, a theoretical model of wall heat transfer is developed with this concept. The constant in the model is confirmed by experiment and simulation of the transient turbulent heat transfer in pipe flow. Finally, the model is used to predict the local heat flux under different conditions, and the results agree well with the experimental results as well as the simulation results.

Abstract: Based on the geometrical property of the toroidal cutter, an improved local gouge detection method for 5-axis sculptured surface machining was presented here. By alternately taking full advantage of point projection principles on curve and surface, the minimum distance between the circular curve of the toroidal cutter and the design surface was firstly calculated. Then the local gouge detection was accomplished through comparing the minimum distance with the corner radius of the toroidal cutter. The maximum interference quantity required for correction was also gotton. Results of an example showed the new method was correct and stable.

Abstract: Especially from the perspective of geometric simulation, through the combination of CAD/CAM software Pro/e with professional numerical control machine tool simulation software Vericut, achieve the virtual processing of cylinder mold. Numerical control programs will be transferred to the virtual machine tool, producing products meet the requirements. Proving the combination of Pro/e and Vericut for the research of virtual machine technology is a possible method.

Abstract: In this paper, we study the boom of truck-mounted concrete pump from a company. After analyzing, we determine that the four booms extending horizontally is the most dangerous working conditions. We use the software Solid Works to design three-dimensional entity. With the help of Cosmos Motion which is a part of Solid Works, realizing the kinematic simulation. This paper study and analyze the problems during the simulation process, and collect a series of curves of kinematic simulation, mainly including the place-time curve, velocity-time curve and force-time curve, and analyze these curves detailedly.

Abstract: To realize the variant design of assembly containing standard component, both type characteristics and parameter characteristics of standard component are studied. With complex network theory, the parameters of assembly are analyzed. A method of assembly variant design is presented. UG (Unigraphics) is re-developed with VC++ and UG/Open. A variant design module is developed, and assembly variant design is realized.

Abstract: An algorithm for nearest neighbor query of Line Segment based on the R*S-tree is proposed. The dynamic spatial indexing structure for spatial line segments was constructed based on the R*S-tree, and the k-nearest neighbor of the target line segment were obtained by the hollow ball. The distance between the target line segment and the neighbor line segments was computed, and the neighbor line segments were sorted by the distance. The result shows that the algorithm can obtain nearest neighbor line segment accurately and effectively and has the strong adaptability of data type.