Applied Mechanics and Materials Vols. 148-149

Abstract: The job-shop-like knowledgeable manufacturing cell scheduling is a NP-complete problem and there has not been a completely valid algorithm for it until now. An algorithm with self -learning ability is proposed through the addition of precedence constraint of operations on the basis of directed graph. A method based on support vector machine is constructed to choose accurately interchangeable operations by small samples earning to obtain the better scheduling. The classification accuracy can be improved by the continuous addition of new instances to the sample library. The results of simulation show that the algorithm performs well for the job-shop-like knowledgeable manufacturing cell.

Abstract: The present paper demonstrates a study of the impact of cutting condition on turning high strength steel 34CrNiMo6. Based on Taguchi method, a plan of experiments was performed with ceramic cutting insert. The first and second cutting force equations are developed through the response surface methodology (RSM) to investigate the effect of input cutting parameters (cutting speed, feed rate and depth) on cutting force. In term of input parameters, the cutting force contours are showed and the analysis of the predicted models is performed with aid of the statistical software package. In addition, the separate influence of individual cutting parameter and the interaction between these factors are also discussed in this study. In general, the results obtained from the mathematical model agree well with the experimental data.

Abstract: High purity aluminium and magnesium were exposed in the field. The meteorological data showed that the dew point remained at a constant level in the short period. The time dependence of corrosion mass loss of aluminium followed a logarithmic law, and that of magnesium did a linear law. The constant dew point corrosion test (CDPCT) was employed to investigate the effect of chloride deposition rates and dew points. Aluminium was insensitive to the change of chloride deposition rates and dew point. Magnesium corroded more in higher chloride deposition rates and lower dew points. The corroded surface area of aluminium slightly changed with exposure time, and that of magnesium increased gradually.

Abstract: The strip mining method is proposed to prohibit overlying strata and surface moving. The law of displacement and deformation damage of overlying strata and surface which is a sophisticated process of physical and mechanical dynamics is analyzed in theory. Based on the actual project data, the law is obtained by the numerical simulation with FLAC3D. Moreover, the strip reasonable mining method and interrelated parameters is presented according to the specific geology and mining conditions of coal. It is proved that the strip mining method can avoid geological damage effectively for overlying strata and surface movement in practice.

Abstract: Based on Interaction energy of solid ball, the new particle damper is designed which can be used in a high temperature and high shock energy. To verify the design of the damper, a falling weight Impact test rig is designed, a sensor, data acquisition card and computer hardware constitutes a signal test system. Experimental results show that the particle diameter is the biggest impact for the role of the particle damper , the characteristics of the displacement curves are increased at first and then decreased, the opposite effect of the time. At the same time filled with particles and the degree of damping rod embedment also have an impact on energy consumption.

Abstract: The stress concentration of trimaran’s cross-deck structure is serious and the problem of its fatigue strength appears particularly important. In this paper, the responses of ship motion and hydrodynamic pressure on ship’s surface in regular waves are calculated using 3D linear potential flow theory, then the stress responses of the hot-spots in regular waves with different wave angles are evaluated by finite element analysis of the global trimaran structure. Based on linear cumulative damage theories, the fatigue damage is calculated according to the direct calculate method used spectral analysis. The result can offer the reference for the trimaran’s design and development.

Abstract: The management and sharing of varied automotive intake and exhaust system data makes it imperative for modern automotive companies. Based on needs of a certain company’s NVH department, much work has been done to analyze the data management method and data features, then a web platform based on B/S model has been built and also the solutions to transformation methods between different data types, data visualization, processing of massive data and data dynamic expansion are presented. Based on the key technologies, a practical web-based information system is designed for the management of intake and exhaust system data, which remarkably facilitates the company’s data management work.

Abstract: In the machining process, the parts dimension, geometric shape and the formation of the relative position between the surfaces, depended on the position of the workpiece related to the cutting tool in cutting motion process, while the realization of this mutual position relationship is through locating points layout restricts parts DOFs. For this reason, this paper presents the conceptions of theoretical constrained DOFs and Practical constrained DOFs, at the same time the paper innovatively presents locating points layout determination algorithm for complex parts. Firstly, established the DOFs limit model according to the condition that parts of absolute velocity is zero in the machining precision requirements, theoretical constrained DOFs is expressed as the function relation of machining precision requirements. Secondly, establishing the model of locating points layout according to the constraint condition that parts of normal absolute velocity is zero in the position of locating points, and describing Practical constrained DOFs as the function relation between the position of locating points and normal vector. Then, according to the relationships between theoretical constrained DOFs and solves the model of locating points layout, constructed the automatic design algorithm of locating points layout. Finally, according to the proposed design algorithm, developed design and analysis modules of locating points layout by VC6.0 in the UG environment.

Abstract: In this paper, we researched a one-of-a-kind assembly production system where every product is unique (i.e. each product has its unique tree-like process route) and arrives one by one randomly with the exponentially distributed interarrival times. We proposed a new effective combined dispatching rule (ELFT rule) that is constructed by considering three factors: the latest finishing time (LFT), the remaining path size (RPS) and whether an operation is on the critical path (CP). We did many numerical experiments to compare the efficiency between the proposed rule and other rules that were reported in existing studies such as LFT rule and EDD rule. The performance analysis shows that the proposed dispatching rule is more effective in reducing the number of tardy products and total tardiness time.

Abstract: In allusion to climatic chamber which is the important device in reliability and environmental test, design a control system including S7-200 PLC and PC to realize conventional PID control. To obtain more precise test temperature goal, a setting of temperature tolerance belt is imported. And introduce SIMATIC S7-200 PLC communication protocol, design a PC human-machine interface based on VC++, use a ActiveX control named MSComm6.0 to realize data recording and control between PC and PLC.