Applied Mechanics and Materials Vol. 251

Abstract: This paper researches on the data acquisition method in reverse engineering based on coordinate measuring machine. Firstly, it puts forward the data acquisition method of characteristic line based on the principle of path planning, then, it summarized the application scope of characteristic-line method by analyzing the examples of data acquisition of regular surface and free curved surface products, finally, it realizes the rapid data acquisition of product based on coordinate measuring machine.

Abstract: It takes the mouse surface for example and introduces the general process of reverse engineering combining with the advantage of Pro/E and Mastercam,including using CMM for the data acquisition, using Pro/E for data preprocessing and model reconstruction, using Mastercam for processing the cavity and arranging actual processing on CNC with wax model to achieve the End-entity. Thereby, it provides a practical approach on reverse engineering for complicated product.

Abstract: Computational simulation relies on valid and accurate representations of the geometry of objects being simulated. However, the Stereo Lithography (STL), one of the most commonly used formats for computational simulation, may be invalid with several kinds of defects when the geometry is too geometrically and topologically complex. In many cases, castings have the most complicated geometries in the world, and its geometries in STL format always contain some defects. The implicit surface is a much more robust geometry representation than STL. With the representation in the implicit surface, most of the defects in STL can be cleared and ignored. This paper presents a method to fast construct the implicit surface for arbitrary complex casting geometries in the format of STL.

Abstract: Taking the conjugate cams beating-up mechanism as an example to carry out three-dimensional parameterized design with Pro/Engineer secondary development accords to the equations of conjugate cams curves derived by the analytical method. Using the finite element software ANSYS the dynamic characteristic of beating rocker has been analyzed. And through the calculation the modal distribution and modal shapes of beating rocker are provided. It could provide references for design of future high-performance beating-up mechanism.

Abstract: In order to improve the shortcomings of the existing machine, a new laser pipe-blanking machining is designed. A 3D optimization designing method of pipe-blanking machine is presented through using Solidworks software as a design platform. The simulation and verification of design results is realized by the virtual assembly of whole machine, interference checking and motion simulation of machining process. On the basis of the analysis of simulation results, the structure and capability of the product is further analyzed and optimized in order to achieve the best design.

Abstract: This paper advanced a kind of method that put sensitivity analysis of target function and restriction conditions into robust optimal design of cycloid pinwheel speed reducer. An applied example showed that the method could improve feasibility robustness of optimal result and ensured design quality.

Abstract: The eutectic composite ceramic is composed of parallel lamellar inclusions distributed in the matrix. First, the recessive expression for the effective stress and the flexibility increment tensor of eutectic composite ceramic are obtained according to the four-phase model. Second, the analytical formula which contains elastic constant is given by applying Taylor’s formula. The eutectic composite ceramic is transverse isotropy, so there are five elastic constants. Third, the effective elastic constants of composite ceramics are predicted.

Abstract: Based on micro-mechanics and finite element theory, the stress field of fiber-eutectic was researched by using the ANSYS program. First, in order to study the interaction of fiber and interphase, fiber- eutectic can be simplified as representative volume cell. Then we use ANSYS program to construct the cell model and simulate the tensile stress field. The results show that the stress is uneven in the cell and the elements near the interphase with high stiffness will damage first. At last the stress change and damage evolution route are simulated by using the element birth and death technology.

Abstract: Interference-Fit Components, Especially under Rotating Bending Loads, Usually Suffer Fretting Fatigue, which Tremendously Reduces Service Lives of the Components. by Taking Specimens with Different Interference-Fit Parameters for Fatigue Test, their Fretting Fatigue Lives Could Be Obtained. and through Using Finite Element Analysis (FEA) Software ABAQUS, the Ruiz Fretting Damage Parameter K_(x) for each Tested Fatigue Specimen Were Achieved. then, According to the Test Data and the Results of Calculations, Two Fretting-Fatigue Life Prediction Models (model 1：N=c•K^-α, and Model 2：N=λN_{0—m•Kⁿ) )based on the Ruiz Fretting Damage Parameter Were Fitted, and their Ratλionalities and Validities Were Analyzed. at the same Time, the Influences of Interference-Fit Parameters -Interference Value (V), Casing outside Diameter (D), and Casing Length (L), Contact Pressure (p) and Friction Shear Stress (τ) on Fretting Fatigue Life Have Been Analyzed. the Results Showed that the Two Fitalic Textretting Fatigue Life Prediction Models Used in this Paper Were Valid, but, in Contrast, the Second One Was More Accurate and Rational; and that Fretting Fatigue Life (N) Decreased as V, D, L, P or τ Increasing.}

Abstract: MCMB were prepared from coal-tar pitch by pyrolysis condensation in the presence of graphite. The characteristics of the MCMB were studied by BET and optical textures of the pitch mixtures were characterized by polarized-light microscopy. Results show that the graphite addition contributes to an increase of MCMB yield. The pyrolysis conditions and content of graphite have notable effect on the structure and yields of MCMB. When content of graphite reaches 3% and the pitch are pyrolysated at 450°C for 4 h, the MCMB yield arrive at 32wt%.