Abstract: Hot-stamping molding for ultra-high-strength steel have some similarities with traditional cold-stamping molding in the aspects of molding process and die design. But due to the effect of temperature variation of blank, hot-stamping have some differences in ultra-high-strength products design, material selection and forming process design. Some special forming defects, such as local thinning, cracking and wrinkling, could appear in hot-stamping process due to these differences. In order to obtain uniform phase structure and get high-quality products, it is very important to be able to predict and control the blank temperature and the consistence of blank cooling rate. The thermo-mechanical characteristics of hot-stamping are studied with the material of ADVANCE1500 (22SiMnTiB). Based on the results of simulations and experiments, conclusion are drawn that the complexity of the product and the blank which contacts with die asynchronously causes the uneven distribution of the blank temperature. This is the key factor that leads to the poor mobility of the blank material and local thinning, cracking, wrinkling and other defects in forming process. Proper clearance between punch and die can reduce the probability of defects which could contribute to the improvement of hot-stamping process.
Abstract: According to the requirements of high-speed machining, the feed rate control algorithm based on the acceleration-deceleration control and dynamics conditions is proposed. This algorithm not only satisfies the continuity of displacement, feed rate, acceleration and jerk of the feed movement, but also meets the dynamics condition of high-speed machining. Furthermore, the algorithm is applied to NURBS curve interpolation and optimizes the acceleration-deceleration intervals. At last, the algorithm is verified by simulation. This interpolation algorithm of feed rate control reduces the impact, machine vibration of feed, and improves the surface accuracy and quality of high-speed machining.
Abstract: The accurate spatial 3D models and corresponding coordinates of every key point are needed to determine the sizes, shapes, and locations of installation for all curtain wall elements in the process of production and construction. To solve the transition problems between architectural design and construction design of curtain wall system, four kinds of single-constrained computer-aided 3D modeling algorithm for spatial point-line models were discussed in detail. Then, a multi-constrained iterative 3D modeling process was proposed by considering coupling relationships amongst the various constraints. A 3D modeling system named T3-CW-CAD was developed and applied to the Shenzhen Airport Terminal 3. The application results showed that the presented-algorithm can meet the overall demand for automatically generating multi-layer 3D models according to spatial point-line model, along with sizes and other restraints amongst curtain wall elements, therefore playing a key role in guiding the production and construction of curtain wall system.
Abstract: The compact storage and efficient evaluation of feasible assembly sequences is one crucial concern for assembly sequence planning. The implicitly symbolic ordered binary decision diagram (OBDD) representation and manipulation technique has been a promising way. In this paper, Sharafat’s recursive contraction algorithm and cut-set decomposition method are symbolically implemented, and a novel symbolic algorithm for generating mechanical assembly sequences is presented using OBDD formulations of liaison graph and translation function. The algorithm has the following main procedures: choosing any one of vertices in the liaison graph G as seed vertex and scanning all connected subgraphs containing seed vertex by breadth first search; transforming the problem of enumerating all cut-sets in liaison graph into the problem of generating all the partitions: two subsets V1 and V2 of a set of vertices V where both the induced graph of vertices V1 and V2 are connected; checking the geometrical feasibility for each cut-set. Some applicable experiments show that the novel algorithm can generate feasible assembly sequences correctly and completely.
Abstract: The distortion of the cylinder liners of internal combustion engines has a significant affect on engine operation. It can affect the oil consumption, the blow-by, the wear behavior and, due to friction, the fuel consumption. In order to achieve future requirements regarding exhaust emissions and fuel consumption, the development of low distortion engine blocks will play a significant role. Finite element method with experimental data were used to calculate and analysis the temperature field and machine assembly of a 150 engine cylinder liner in this paper. It can provide a theoretical basis for the controlling of the cylinder liner deformation.
Abstract: CAD / CAE technology has led traditional product design and analysis to digital. However, commercial CAD / CAE software also has its problems. Problems in the application of commercial CAD / CAE software are summarized in these this paper. From perspective development of software engineer, new technology such as integrated design, design reuse, intelligence and automation, workflow customization, application development, experimental and simulation complement each other are introduced to overcome these problems in this paper.
Abstract: To satisfy the manufacturing requirement of tyre tread pattern mold, the problem of machining region planning in the computer aided manufacturing of tyre mold is introduced. And it is analyzed that the core technology is the definition of inner and outer contours for machining region planning and tool-path planning. According to the defect of traditional constructed way of machining region, an auto recognition method of inner and outer contour is studied based on the inclusive test method.The detail step of the method is illustrated.Thinking about the special condition of the method, corresponding strategy is given. This method is applied in the computer aided manufactuing of tyre tread mold, by which machining region planning can be solved effectively.
Abstract: The structural characteristics of a laminating press were analyzed, and the corresponding finite element model was built with some essential simplification. By structural analysis, the distributions of stress and strain were obtained, based on which the rationality of the frame design can be verified. According to the complex structure and loading conditions of the laminating press, four analytical schemes with different models and boundary conditions were adopted, then the results of different analytical schemes were compared, and the causes resulting in the calculation differences were analyzed. The result shows that in analyzing different parts of the laminating press frame, different models and boundary conditions were required.
Abstract: To reduce the weight of the electric scooter frame, magnesium alloy is used to replace the steel. At the same time, the frame structure and tube thickness are redesigned by using topology optimization and size optimization respectively. In addition, static analysis and mode analysis of the frame are carried out to realize the application capability and dynamic capability. Compared with the original steel frame, mass of the magnesium alloy frame after optimization has been reduced by 60%, and the natural frequency has been improved greatly. The results show that the strength and the rigidity of the new structure can meet the designed demand.