Effect of controllable drawbead on the formability of high strength steel box

With the application of simulation technology and orthogonal test, the effects of controllable drawbead on the formability of HSS (high strength steel) box are researched through the simulation of HSS box with 6 different drawbead shapes and 3 different drawbead trajectories. Use the limit drawing height as the evaluate indicator, it is proofed that the controllable drawbead can improve the formability of HSS by analyzing the result data that three types of controllable drawbead trajectories indicators are bigger than the immovable ones. And the 2nd trajectory, ascent—halt—descent is determined as the optimal type. The improve scales of straight drawbeads is better than the oblique drawbead, whereas the latter ones have better target. The main influence factors are obtained by range analysis. At last the reason that accounts for controllable drawbead can improve the formability is got the answer by the forming force analysis.     

Deep drawing simulation for high strength steel box of controllable drawbead

As blank drawing resistance in sheet metal forming process can be significantly influenced by the changes of drawbead height, and high strength steel (HSS) is one of the materials difficult to be formed, so a controllable drawbead technology is proposed to improve the formability of HSS. A numerical simulation model and an experimental device of JAC590Y HSS box deep drawing with fixed drawbead are established. Comparative analysis of simulation and experimental results show that the difference of fixed height drawbeads has a significant effect on the formability of HSS. A controllable drawbead moving path of ascent halt descent is designed based on the variations of deep drawing force in the sheet metal forming process. Then the path is applied to the formation of an automobile engine tunnel side panel which is similar to the box deep drawing. Twenty group test schemes of good formation are obtained, in which the part smallest thickness is significantly influenced by controllable drawbead. Moreover, in the twenty group test schemes, the optimized combination of moving path and main influence factor H2 are found by range analysis of part average smallest thickness. Finally, the correlation between part smallest thickness and factor H2 is predicted by using GA BP neural network and regression analysis.     

Analysis and FEM Simulation of the Forming Process of Front Bumper Bracket

The processing characteristics of the front bumper bracket are analyzed,and a reasonable process scheme is worked out.The three-dimensional sheet metal forming analysis software PAM-STAMP are adopted to simulate the bracket's drawing process.Then the surface of die is proved fine through analyzing the FLD diagrams and the forming results.An economical and optimized die structure is decided,and a complete set of dies of the bracket is designed.The spacing block is added in the sizing mold,which control the size precision of end products and assembling columns actively,and finally the certified products.The material utility and the labor productivity are raised,the production cost is saved,and the mold design quality and the efficiency are improved effectively.     

Topology optimization for constrained layerdamping material in structures using ESO method

Topology optimization for constrained damping material in structures is investigated in order to suppress structural vibration through the optimal placement of constrained damping material in structure. A mathematical model to describe the topology optimization problem is established. In the topology optimization approach, structural modal damping ratio is designed as objection function, while constrained damping material consumption is considered as constraint condition. The sensitivity of modal damping ratio to the place is analyzed. An evolutionary criterion for placement of constrained damping material in a structure is presented. The formula of sensitivity is derived and used to determine the optimized placement of constrained damping material in structure. The topology optimization problem is further solved by evolutionary structural optimization (ESO) method. The numerical examples are given. The results show that a stable and dramatic increase of the modal damping ratio during the course of iterations can be observed. Therefore, an optimal layout of constrained damping material in structure is obtained. The comparison of amplitude frequency characteristics with the optimal and fully covered layout validates the effectiveness of proposed topology optimized approach.     

State and Prospects of Physics-Based Free-form Surface Modeling

Physics based modeling is one of the keen free form surface modeling method at present, and it should be a practical surface modeling method in the future. In Physics based modeling, the object is viewed as a physics and not a pure geometry model. According to its physics principle and math representation, the physics based models are mainly classified into two types:energy model and dynamic Lagrangian model. The fundamental theory is introduced, and the principle, development and application state of each model is reviewed. To provide designer more naturally design ability and to introduce more flexible geometric modeling methods are the prospect of future researches on physics based free form surface modeling is outlined at last.     

Energy Saving Principle and Design Experience of a New Type Curtain Wall

The energy consumption and sight pollution of glazing curtain wall are two problems to be urgently managed. Intelligent curtain wall is a new type one of energy conservation and environment protection, in which the thermal channel to save building energy consumption and automatic sunshade to adjust sunlight are adopted. Four engineering examples of oversea intelligent curtain wall are briefed. The construction and energy saving principle of ventilative curtain wall as the core technique of intelligent curtain wall are presented. The earliest ventilative curtain wall in China Mainland, and its test results of heat preservation in winter are stressed. The design experience of how to choose three key parameters: the width of thermal channel, the layout of inlet and outlet and the type of glass is discussed.     

Stability Analysis on Excavated High Slope of Mozong River Power Station in Wulong

The subject matter of this paper is to analyze the stability of excavated high slope. On the base of typical engineering case in Wulong, Chongqing, the geological conditions and potential failure pattern of the high slope are discussed. Then, the limit equilibrium method and the stereographic projection method are used to synthetically analyze the stability of excavated high slope. As a result, it indicates that the stability of the high slope in insufficient and some retaining structures ought to be adopted for the high slope as soon as possible.     

Comparison on Physical and Chemical Characteristics and Electric Properties of Three Types of Vegetable Insulating Oil

Three types of vegetable oil, transgenic rapeseed oil, transgenic peanut oil and cotton-seed oil, are used as raw materials in experiments to obtain the refined insulating oil. The dosage of reagent in experiments is studied for vegetable insulating oil refinement. Furthermore, basic physical and chemical properties of the three types of vegetable insulating oil are analyzed. The electrical properties including breakdown voltage, dissipation factor, dielectric constant, and volume resistance are studied and presented. By compared with each item of properties of the three types of vegetable insulating oil, rapeseed-oil-based insulating oil is considered to possess the best properties due to the fact that it is more abundant of mono-unsaturated fatty acid than the other two types of insulating oil.     

Environmental quality assessment model of urban soils based on improved BP algorithm

The input and output samples for the network are determined through random function and pre processed with scaling in interval (0.2, 0.8). The neutral units in the hidden layer is decided by the trial and error method and an a model of artificial neural network(ANN) with a structure of 7∶8∶1 are established for the assessment of environment quality of urban soils. BPANN model is simulated through programming in Matlab 6.0. It is found that the BPANN model is reliable for assessing accurately and objectively the environment quality of the urban soils. With Changchun as a case study, it is concluded that the environment quality of urban topsoil is generally good and about 81% of the area reached the first level of national environmental quality standard for soils. It should be mentioned that the heavy metals pollution in local area is serious and should not be neglected, and some effective control measures of reducing heavy metal pollutants discharges should be put forward to ensure the sustainable use of urban soil resources.     

Application of GA in Calculating Factor of Safety in SlopeStability

How to ascertain the sliding surface and the factor of safety(FS) is the key problem of slope stability.The failure model of a slope is supposed at first and then the sliding surface and the factor of safety are computed approximately during analyzing the slope stability all over the world.However,the hypothesis cannot reflect the real state of slope sliding.In this paper,the critical failure surface with the lowest value of FS is computed and the better result is got by means of GA.     

Discussion on Optimization of Tube Settling Process

The optimization of tube settling process should be confined within the optimization of whole water treatment plant design under the conditions of higher criteria on potable water.Tube settling process has a better suitability for the challenge of new regulation of drinking water quality. When optimizing tube settling process,the effects on which filtration and flocculation processes have been exerted should be considered.The design surface load of tube settling should be lower than that in existing design codes.The configuration of tube module can be selected as two-or multi-layer module to make full use of the separation capacity of tube module.The suitable cross-section type of tube is also needed to be selected carefully,adopting an excellent one which is knoumas square cross-section type of tube.The layout of tube settler,the arrangement of tube module,the connection between tube settler and flocculator,and the construction and operation management of tube settling process are also factors for the optimization of tube settling process.     

Optimum Design of Individual Foundation and Its Application

On the basis of analysing the defaults occuring in normal design,a new method of optimum design for individual foundation is put forward in this paper.This method can solve some problems successfully such as the strengh and deformation can be considered at the same time,which cannot be done in the current specification.The optimal mathematical models of individual foundation design and the bottom surface dimension design under eccentric load are derived.The optimal solution is decided by method of optimization and the method selected is penalty function and complex method, and the programs of optimum algorithm have been compiled and design and drawing of individual foundation have been completed. The final result suggests that a fair-sized economic efficiency can be obtained by using optimum method for foundation design.     

Research on QoS Strategy of Web Server Cluster Application Based on Request Classification and Request Admission Control

The increase of requests often results in performance degradation of the web server cluster. The quality of service (QoS) expected by users can't be guaranteed. This is the problem that service-level web server cluster must cope with. In this paper, two strategies are proposed including classification of the user requests and request admission control, the different quality of service can be reached and the QoS of service-level users is guaranteed. The simulation experiments proved, the load balance of the system is improved and average response time of the system is decreased.     

Sharing Rate of Cooling Load of Radiant Terminal Device and Air Supply Terminal Device in Residential Buildings——From the Perspective of Thermal Comfort and Indoor Air Quality

Taking residential buildings as the study objects, for three different residential load types such as low load, medium load, and high load type, indoor thermal environments of different load sharing-rates are simulated, respectively. Indoor thermal comfort and indoor air quality of different load sharing-rates are also analyzed and evaluated. And the appropriate range of cooling load sharing-rates are given from the view of both occupants thermal comfort and occupants health. When ωc (the sensible heat load sharing rate of the radiant terminal device) <0.7, the human thermal index in work region can be controlled within the range of thermal comfort standard. From the point of avoiding local discomfort, ωc is suggested to take 04~1. As regard to indoor air quality, for the constant air volume mode, ωc is suggested to take 0.5~0.9 under low and middle load conditions, and ωc is suggested to take 0.35~0.6 under high load conditions. For the variable air volume mode, the smaller the value of ωc is, the better indoor air quality is.     

Research and Application Perspective of Stay-green Mutants

Stay-green mutants of all botanical species have similar phenotypic features.The senescence is delayed,and chlorophyll degradation is blocked or slowed.Nevertheless,the molecular mechanism of stay-green in these mutants is quite different owing to different genetic basis.The authors summarize the progresses in research on the physiological and biochemical behaviors(mostly concentrated on the enzyme-catalyzed metabolic pathway of chlorophyll),hereditary features and molecular biological aspects in various stay-green mutants.They also describe the importance of stay-green mutation to the research of chlorophyll metabolism,leaf senescence,photosynthesis and other physiological processes in plants,as well as the perspective of exploiting the advantages of these mutants in many aspects of agriculture.Among the many types of stay-green mutants,the most promising and significant can be the functional Type A and Type B which are distinguished for their increased yields and improved resistance against stresses.Furthermore,thorough understanding of changes in the molecular mechanism of stay-green is a potential access to consummately solving the presenility problem of crops.     

Strategies for Improving the Overall Environmental Quality of Rivers Based on “Renovation and Restoration” Concept: A Case Study of Landscape Planning of Linjiang River,Yongchuan District,Chongqing City

The concept of "renovation and restoration" marks the transformation from urban and rural planning and construction to intensive development mode and to quality improvement stage.The environmental imbalance problem of emphasizing development and neglecting ecology in the past has become the focus of the current urban quality improvement stage.Rivers are related to the origin,development and evolution of cities,affect the layout,transportation and environment of cities,and bear the culture,economy and characteristics of cities.Taking the Linjing River of Yongchuan in Chongqing as an example and taking the concept of "renovation and restoration" as the guidance of the design of the overall environmental quality improvement of the river,this study analyzed and summarized the problems to be solved in the improvement of the environmental quality of the river based on the four river environmental impact factors of water pollution,water resource supply and demand,ecological environment and shore water waterfront type and the strategies of optimizing the aquatic environment management,constructing the ecological landscape pattern,shaping the regional cultural landscape and combining the economic development along the river were put forward in order to improve the overall environmental quality of Linjiang River and provide reference for relevant planning and design.     

Study on CAD System of Slope Pile-Anchor Retaining Structure

The process of designing the common slope pile-anchor retaining structure in Chongqing is analyzed, the finite element method is applied to calculate the force of the structure and design the anchor bar, pile and holding sheet. The CAD system is developed including fore-process, post-process, calculation of the structure and drawing by computer in order to make the designing of slope pile-anchor retaining structure more quickly, more economical and convenient. It has been applied in practice of the slope engineering with a good result.     

Design and optimization of the precision rollforging on a heavy truck front axle

The under-filling defect of I-beam in a heavy truck front axle which occurs in the process debugging of the precision roll-forging and die-forging is studied. Finite element models of precision roll-forging and die-forging are established based on FEM software and the previous productive results. Then, the mechanism of the under-filing defect in I-beam is studied. And the effects of the three variables including width B, radius R and slope A of I-beam in the third step on the forging quality are investigated. In addition, the roll-forging die constructions for I-beam in previous three steps are redesigned and manufactured. The productive results show that I-beam can be fully filled, the debugging cycle is reduced significantly and the products quality is guaranteed.     

Quick Modifying Method of NURBS Curve

Although there are modifying modules in the most CAD software, the parameters of entire curve must be computed again as the tiny local curve changed. The modification are not local and spending long time and difficult as the eurve is complex or large. A method can be applied to engineering designer easily has been proposed. There are only four segments have been ehanged along with the moving of a given point, and the speed is fast. It ean be used to CAD software and generalize the method to surface easily.     

Application of Fuzzy Mathematics in the Evaluation of MSW Compost Quality

Through selecting the index of MSW compost quality and establishing the evaluation grades of index, an evaluation system with the method of fuzzy mathematics has been framed in this paper. Then, based on the assessment of single factor and comprehensive effects of different factors, in this paper, the experimental data are taken for example to evaluate the MSW compost quality. The result shows that this method is successfully applied and also can be used as a simple useful method to the evaluation of MSW compost quality.