摘要: A numerical simulation of high-speed forming of tubes on the die in electromagnetic forming (EMF) system is presented to study effects of some electromagnetic parameters. Simulations of electromagnetic and structural parts of EMF process are carried out. Calculated currents in this process are in agreement with experimental results measured by Rogowsky coil. But calculated and simulated currents at first peak are a little more than the experimental value. Effects of material and process parameters on bead depth are investigated in detail with this validated code. It deduced that shape of the bead is affected by discharge voltage and coil parameters. As a result, the bead depth increases with the increase of the discharge voltage and decrease of number of windings.
摘要: Machine tool vibrations have great impact on machining process. In this paper the dynamic behavior and modal parameters of milling machine is presented. For this purpose, the CAD model of the milling machine structure is provided in CATIA and then Natural frequencies and mode shapes of the machine tool structure are carried out through FEM modal analysis under ANSYS Workbench. The model is evaluated and corrected with experimental results by modal testing on FP4M milling machine. Finally, the natural frequencies and mode shapes obtained by both experimental and FEM modal analysis are compared. The results of two methods are in widely agreement.
摘要: Extrusion is one of the youngest processes in metal forming. In this proceeding the influence of the form and the angle of the die in the process of direct warm extrusion of aluminum is studied. Utilizing FEM and different forms of the curves of the die form, we have analyzed the various angles with the use of FVM; the improved angle and form of the die have been extracted from the findings. Having been modeled in the domain of Pro/Engineer, the dies are analyzed with the use of SuperForge2004 and Ansys6.1 softwares. To prove the correctness of the modeling and the analysis, we have compared our findings with available conclusions. So, with these methods we can model real industrial processes with minimum simplification and take effective steps in designing processes and reducing difficulties in manufacturing and improving the products.
摘要: In this paper, the plasma arc welding is studied and stainless steel temperature field is gained in this process. The available heat source models, either planar one like Gaussian or body ones like double-ellipsoidal and rotary Gaussian modes, are unable to describe the keyhole PAW process accurately. Based on the configuration feature of keyhole PAW welds, a combined heat source model is proposed for the numerical analysis of temperature fields in keyhole PAW process. Numerical simulation of welding process in SIMPELC method and by ANSYS software for gaining the temperature field of stainless steel, the effect of parameter variation on temperature field and process optimization for different cases of plasma and shielding gases(Argon, Helium), are done.
摘要: 3D information exchanging and sharing are difficult between CAD, CAPP and CNC systems. To solve this problem, under the support of the National High Technology Research and Development Program, a new approach is brought forward. In section Ⅱ of our explorative paper, a CAD/CAPP/CNC integrated system based on lightweight 3D model is established to manage the information of the whole process of product manufacturing. Fig. 1 in the full paper gives the system’s architecture and functions. In section Ⅲ, we establish an integrated information model based on lightweight 3D model by analyzing each system’s functions and requirements of manufacturing process and the process of data flowing. In order to extract manufacturing features from design features in lightweight 3D model, a feature convertor is established in section Ⅳ. And a 3D feature recognizing prototype system was established and the feasibility of this method was verified.
摘要: In this paper, thermo mechanical modelling of cutting process has been developed using a commercially available finite element analysis software, ABAQUS. A 2-D orthogonal cutting has been modelled using Arbitrary Lagrangian-Eulerian (ALE) formulation. The Johnson-Cook plasticity model has been assumed to describe the material behaviour during the process. This study is aimed at temperature and stresses distributions during machining of AISI 1045 steel with different rake angles; α=0° and α= -10°. The results showed that the maximum stress for 0° and -10° are 963MPa and 967MPa while the maximum temperature results shown that 771°C and 347°C.
摘要: Aluminum extrusion die design involves with two critical parts; die features and its parameters. Presently, die design process is performed by adaptation approach. The previous dies together with their parameters are collected and stored in a database under the well-memory organization. Case-Based Reasoning (CBR) has been applied and enhanced the design productivity. However, the CBR method has an excellent ability only that an exact or similar design features are existed. Reality, aluminum die design requires regularly changed according to the profile changes. Therefore, it needs to predict optimum parameters to assist in the process of aluminum profile extrusion. This paper presents the redesign process using adaptive method. In this case, CBR & ANN method are combined and development. The CBR uses for die feature adaptation; whereas the ANN is used for parameter adaptation and prediction to a new profile and die design. The actual production yield is given and the ANN will find the best size of billet length in order to receive the maximum yield.
摘要: Contaminant materials in lubricants are signs for prediction and measurement of wear in engines. Therefore oil monitoring is considered as one of the most effective techniques for maintaining the heavy equipments. However based on oil analysis data, the identification of engine problem is very hard due to different contribution factors. Hence, this paper is purposed to analyze the wear behavior of some sets of selected heavy equipment engine based on documented oil analysis data during two years in different conditions to track engine failures using trend analysis. Furthermore the selected equipments are divided into two major groups (plantation and forestry, and general construction) based on their environment, to show the effects of conditions on the engine wear behavior.
摘要: Most of the fatigue damage in aircraft structures can be linked to the stress concentration arising at the rivet joints. Interference-fit riveting of a flush rivet can form the uniform interference fit. Thanks to the uniform interference fit, large stress concentration can be avoided. The radial deformation, which is directly relative to interference fit, is therefore of prime importance. Parameters associated with a riveting process that directly affect the quality of rivets must be taken into account to observe the effect on radial deformation at rivet holes. This paper presents an effective variation analysis to calculate radial deformation at rivet holes by assuming that the axial stresses are constant both along the axial and radius of the rivet slug. Firstly, the rivet process model is built before variation analysis. Secondly, theoretical relationships between radial deformations and contact loads are proposed using elasto-plastic analysis. Later, the expressions of the contact loads are given according to geometrical relationships and analysis of deforming forces. Thirdly, an instance made up of the rivet, top sheet and bottom sheet is used to verify the analysis model. The model paves an efficient way to study the deforming law of the riveting press process and build the pre-estimate model of the rivet deformations and the parameter optimization model.
摘要: In order to describe the forming grinding principle of screw rotor, the mathematical model of screw rotor’s helical groove and forming grinding wheel are established by differential geometry theory and numerical analysis method. And the contact line equation is derived. To optimize the traditional method of calculating forming grinding wheel by known rotor end section profile, a numerical analysis method (Accumulated Chord Length Parameter Method) has been presented in detail. This method can improve the efficiency and reliability of the calculation of forming grinding wheel axial profile. Taking the asymmetry linear screw rotor (female) as an example, this paper calculates the grinding wheel axial profile and draws it using special designed software. The simulation examples are done by CAD (Computer Aided Design) based on the secondary development technology of UG. This study provides a precise 3D model which can be used in areas such as finite element analysis and virtual testing experiments.