Advanced Materials Research Vols. 314-316

Abstract: Based on the combination of modal analysis technology and finite element method (FEM), the 3D model of a diesel engine’s connecting rod was established with UG software, and then a free modal analysis of it was carried out with ANSYS. Through the analysis, the inherent frequencies and mode shapes of first 5 order modes were obtained respectively. The free modes of the connecting rod were verified by testing using hammer beat method.

Abstract: In order to provide the wetting processing and the design of thermal moisture comfort of fabric with micron-scaled pore size data, this paper reports on an experimental investigation on the pore size distribution of 6 kinds of fabrics with the method of seft-proposed weight-classification method. This paper focuses on the effect of fabric structure and component on the pore size distribution . Histograms reveal the relationship between various factors. For cotton fabric, the peak area of the histogram of 1/2 twill weave fabric (TWF) is wider and higher than that of plain weave fabric (PWF) due to fewer structure points and more loose structure. This leads to wicking rate increase. For the polyester fabric, the difference between the peak area shapes of the TWF and PWF is not obvious. This may arise from that smaller warp/weft density of both the samples inhibited by the change in inter-yarn gap leading to the similarity. For polyester-cotton fabric, with the increase in the ratio of hydrophilic cotton component, pore size range significantly expanded, showing more uniform wicking and capillary condensation.

Abstract: CAM (Computer Aided Manufacturing) software, one of important aid means of numerical control machining, improves the automatic level of processing with its application in numerical control machining industry. According to the character of woodworking curved jaw (WCJ), limitations of secondary development with existing CAM software were analyzed, and the advantages and basic principles of CAM which was independent development were introduced. In this CAM, dxf files as graphic information input for WCJ. Finally, CAM for WCJ was developed with VC++ and OpenGL.

Abstract: For the weaknesses in the precision machining to leaves, the overall structure model of TX-6 CNC abrasive belt grinding machine was established by the soft of Inventor, and the grinding trajectory was planned. The finite element model, static stiffness and modal analysis of the machine were established. The design of TX-6 CNC abrasive belt grinding machine have been approved.

Abstract: In this paper, numerical simulation was carried out for the tube bundle of a float-head heat exchanger with concentration on the effects of tube stiffness and tubesheet thickness on the thermal stress of the tubes and tubesheet. It is found that decreasing the tube stiffness by using corrugated tubes can reduce the axial thermal stress at the tubes and, thus, decrease the possibility of strength failure of the connection between the tubes and tubesheet. Decreasing the tubesheet thickness can reduce the thermal stress at the tubesheet, which is meaningful for the heat exchangers with large temperature difference between the shell-side fluid and tube-side fluid and under small pressures.

Abstract: As the blade surfaces of the centrifugal impeller are normally twisted in design to achieve the required performance, it can cause overcut and collision problems during machining. In order to comprehend the design concepts of impeller and create the capacity of the manufacture, the objectives of this paper are the regeneration of impeller profile and the studies of the five-axis NC machining. The geometry of the impeller is modeled according to the reverse engineering firstly. In the machining process, the flank cutting technique and the point cutting method are applied to rough and finish machining processes. Through the application of CAM software, the interference-free toolpath and the cutter location for five-axis NC machining are generated. To avoid collision between machine tool components, the generated toolpath is verified before actual machining through solid cutting simulation. It is also verified through the real cut with model material on a five-axis machine tool.

Abstract: A multiresolution approach is presented for NURBS curve fairing based on nonuniform semiorthogonal B-spline wavelets built. This method provides greater flexibility and applicability than uniform B-spline wavelets for multiresolution curve fairing. An example is presented to validate effectiveness of this multiresolution fairing method. Furthermore, the algorithm can be easily applied to NURBS curves in three dimensions as well as in two.

Abstract: Because of the difficult problem about exchanging and sharing products information between the CAX system and CNC machine, STEP-NC was proposed by EC（European Community）. The domestic research about STEP-NC was still in starting stage, the most of them were the second development of the software provided by the United States STEP Tools company. Based on the research about AP203 and STEP-NC standard, using VC + +6.0 as development platform, programmed directly to read AP203 file, extracted the geometry and topology information of the workpiece, automatically identified manufacturing features. It’s the foundation for the conversion from AP203 to STEP-NC programs.

Abstract: Currently, some manual segmentation problems exist in multi-beam waterjet cutting process drawings, such as low efficiency, incomplete segmentation and so on. In order to solve the problems, this paper designs a set of criteria for multi-beam cutting process and proposes the method of partition-classification trim, then uses the secondary development tool which is embedded in AutoCAD to program three user-defined commands, and these commands can partition the drawing by region, classify and trim the entities in the cutting process drawing. Through inputting the three simple commands on the command lines, it can realize automatic segmentation of cutting process drawings. Finally, the feasibility of this method is proved by a segmentation experiment. It can effectively solve the problems which exist in manual segmentation and greatly improve work efficiency.

Abstract: Marine propeller is a kind of typical part with free-form surface. The surface shape of propeller blade is very complex, and it is difficult to be described by general mathematical expressions, so that the modeling of propeller is very cumbersome and error-prone. To solve this problem, firstly, three-dimensional point data of propeller blade is calculated by VC/MFC programming technology and access technology of database based on projection principle of propeller blade. And then, automation and parameterization of solid modeling for propeller of different map forms are realized by programming with the interactive programming language of UG/Open Grip based on UG software. The parametric modeling system provides accurate three-dimensional model for automatic programming, dynamic simulation and numerical analysis of propeller, and improves the design efficiency of systematic propeller, and has very good practical value.