Key Engineering Materials Vols. 480-481

Abstract: In order to study the dynamic characteristics of a super-long-span cable-stayed bridge which is semi-floating system, the spatial finite element model of this cable-stayed bridge was established in ANSYS based on the finite element theory.Modal solution was conducted using subspace iteration method, and natural frequencies and vibration modes were obtained.The dynamic characteristics of this super-long-span cable-stayed bridge were then analyzed.Results showed that the super-long-span cable-stayed bridge of semi-floating system has long basic cycle, low natural frequencies, dense modes and intercoupling vibration modes.

Abstract: Safety risks management of safety potential information and hazard sources has been taken in Construction process. It is the most important measure to solve the current situation that safety accidents is frequent in Chinese Construction projects. The main reasons of frequent accidents were find out and the D-S evidence theory of multi-source information fusion method was used to reduce the accident rate in Construction safety in this paper. Through analyzing and predicting the engineering data and information in human, machine, environment and management four aspects in Construction, prediction model was built in Construction safety risks management, the possibility of dangerous and harmful level in the construction project can be known, preventive measures for specific situations were taken and promptly the safety state of the Construction will be ensured.

Abstract: The development of low-carbon economy is restricted and affected by the natural conditions, the economic stage as well as the industry technological level; and it needs a worldwide cooperation. The development of Chinese low-carbon economy should be established on the basis of the native condition and the national interest because of the uneven level of low-carbon emission, the exceedingly limited R&D and innovation ability of China; which will be the biggest challenge for Chinese “high-carbon economy “transiting into “low-carbon economy”. It’s the inevitable way to overcome the low-carbon economic difficulties by improving the following items: Governments’ cooperation, international organization coordination, energy consumption patterns, human being life styles, modern industrial rebuilding, eco-civilization and ecological economy’s establishment and the relevant system.

Abstract: Due to high rotation accuracy, high dynamic stiffness, high vibration damping and long life, high-speed spindles supported by hydrodynamic and hydrostatic hybrid bearings are widely applied in the field of high-speed precision machine tools. The basic structure and working principal was detailed introduced, and then demonstrated a series of models and specifications of motorized spindle manufactured by FISCHER company in Switzerland. The finite element model of high-speed motorized spindle was built up and carried out thermal analysis to study the heat generation and heat transfer. With the help of ANSYS finite element software, the temperature field distribution and the temperature rise condition for motorized spindle were analyzed. The result indicates that the front bearing has a higher temperature than that of back bearing. The maximum temperature of inner ring is bigger than that of outer ring.

Abstract: Laser Metal Deposition Shaping (LMDS) is a state-of-the-art technology that combines rapid prototyping and laser processing. There are many factors affecting the quality, precision, microstructure and performance of LMDS-deposited parts. Among them, substrate preheating is a significant one since it can change the heat history of the LMDS process. Preheating is often used to reduce the residual stresses and the risk of thermal distortion and cracking. In this work a set of substrate preheating device for LMDS system employed with dual-channel control, namely intelligent PID temperature control and realtime serial-port temperature acquisition and feedback control, is designed and developed. In addition, the heating up rule gained through the relative experiment is introduced to reduce the overshoot amplitude of substrate preheating device by cascade control method. The results show that not only can this substrate preheating device realize the dual-channel control and continuous adjustment of substrate preheating temperature, but also can realtime collect and record the substrate temperature.

Abstract: In this paper, the technology of semi-solid casting was to used are produced Sn-Bi alloy. The influence of agitating time at 125 °C on the microstructure and mechanical properties of of Sn-58Bi casting alloy were discussed. The eutectic Sn-Bi alloy was mechanically agitated during the casting solidification process. The results indicated that non-lamellar Sn-Bi structure with long plate shape, short strip, small size block and suborbicular block shape Sn phase was obtained for different stirring time. The elongation of Sn-Bi alloy with non-lamellar eutectic structure is improved prominently. Compared with the elongation of lamellar eutectic Sn-Bi alloy prepared by conventional die casting, the elongation of semi-solid Sn-Bi alloy with suborbicular block shape Sn phase is enhanced up to 45%.

Abstract: In this study, the goose meat was used as raw material and the formula of composite tender agent was optimized by Response Surface Methodology. Goose breast meat were soaked with exogenous protease of plants, phosphate and Ca2+ for 3 hours at 2 °C. The influence of different composite tender agent on the water-holding capacity was examined by statistical response surface methodology (RSM). The result showed that papain 6.16 U/g, compound phosphate 0.308 % and calcium chloride 0.133 % was helpful to increase the tenderization of goose breast. The results of our study would be used to improve the tenderness of goose meat and increase economic efficiency of goose industry.

Abstract: The coordination development between Manufacturing and Logistics is important for a district to ensure its healthy and sustainable development. In this paper on the basis of reviewing the research achievements about the relationship between manufacturing and logistics, constructing an evaluation index system about the relationship between manufacturing and logistics, based on the grey relation analysis, an empirical analysis about the quantitative evaluation of coordinating degree between manufacturing and logistics industry in Hangzhou is given to verify the novel evaluation methodology. The results have realistic significance for the government to provide an important scientific basis.

Abstract: Surface reconstruction by alpha geometric shape based on triangulation is a new idea and method in computer graphics and reverse engineering. In the process of Topology reconstruction, the points are reduced and projected to a middle slice plane. The adjacency among slices is established by section line subdivision, and triangle mesh is stored and called by the form of STL. The simplexes are classified and computed in order to obtain α interval by the external-ball radius and center of every simplex, and the data structure is designed to save them. Through the man-machine interactive selection modes, α-shape can be reconstructed by different α parameters. The surface reconstruction is completed.

Abstract: In position control system of hydraulic excavator, the uncoordinated speeds between joints make quite trajectory errors no matter how well each joint performs. In order to solve this problem, a cross-coupled pre-compensation method is introduced in and applied to hydraulic excavator servo control system to solve this problem. Furthermore, in order to compensate for the nonlinearities of excavator and friction resistance, a nonlinear controller with angle velocity error observer and acceleration feedback is designed. Experimental results show that the proposed control strategy is effective in improving tracking accuracy and response ability when subjected to external load.