In order to understand mechanical characters and find out a calculating method for preflex beams used in particular bridge engineering projects, two types of simply supported preflex beams with variable crosssection, ...In order to understand mechanical characters and find out a calculating method for preflex beams used in particular bridge engineering projects, two types of simply supported preflex beams with variable crosssection, preflex beam with alterative web depth and preflex beam with aherative steel flange thickness, are dis- cussed on how to achieve the equivalent moment of inertia and Young＇ s modulus. Additionally, methods of cal- culating the equivalent bending stiffness and post-cracking deflection are proposed. Results of the experiments on 6 beams agree well with the theoretical analysis, which proves the correctness of the proposed formulas.展开更多
To analyze a certain type of trees crusher working condition, to consider the limitation of electric, the motor driven pulverizer can only work in a fixed place. Therefore, a set of hydraulic system is used to replace...To analyze a certain type of trees crusher working condition, to consider the limitation of electric, the motor driven pulverizer can only work in a fixed place. Therefore, a set of hydraulic system is used to replace the motor. So it can get rid of electricity, and move conveniently, applying to the suburbs, parks, roadsides, which means expanding the range of application. Secondly, in view of the pulverizer speed higher than the motor speed, it is necessary to add the auxiliary speed regulating device. Besides , to adjust speed is more troublesome, and the hydraulic motor can directly drive the pulverizer. Therefore to adjust the flow of the hydraulic motor can change the speed of the pulverizer. In addition, base on the characteristics of work start, and stop, with a long time, big moment of inertia for Pulverizer, and it is the growth process of the motor driving pulverizer. The rotary inertia equivalent to the motor end will increase the square of the reduce ratio, and the load of the machine obviously. Driving by hydraulic motor straightly, and this problem will be avoided. Finally, in the light of the large start-up torque, and the high speed at working time of the pulverizer, the constant power pumps is choosed to meet the work demand. Constant power pumps can adjust the flow and pressure according to the different load automatically, thus more energy are saved. Hydraulic system simulation model is established based on the AMESim simulation, which verify the scheme is feasible展开更多
基金Sponsored by the Subsidization Plan for Outstanding Young Teacher of Ministry of Education
文摘In order to understand mechanical characters and find out a calculating method for preflex beams used in particular bridge engineering projects, two types of simply supported preflex beams with variable crosssection, preflex beam with alterative web depth and preflex beam with aherative steel flange thickness, are dis- cussed on how to achieve the equivalent moment of inertia and Young＇ s modulus. Additionally, methods of cal- culating the equivalent bending stiffness and post-cracking deflection are proposed. Results of the experiments on 6 beams agree well with the theoretical analysis, which proves the correctness of the proposed formulas.
文摘To analyze a certain type of trees crusher working condition, to consider the limitation of electric, the motor driven pulverizer can only work in a fixed place. Therefore, a set of hydraulic system is used to replace the motor. So it can get rid of electricity, and move conveniently, applying to the suburbs, parks, roadsides, which means expanding the range of application. Secondly, in view of the pulverizer speed higher than the motor speed, it is necessary to add the auxiliary speed regulating device. Besides , to adjust speed is more troublesome, and the hydraulic motor can directly drive the pulverizer. Therefore to adjust the flow of the hydraulic motor can change the speed of the pulverizer. In addition, base on the characteristics of work start, and stop, with a long time, big moment of inertia for Pulverizer, and it is the growth process of the motor driving pulverizer. The rotary inertia equivalent to the motor end will increase the square of the reduce ratio, and the load of the machine obviously. Driving by hydraulic motor straightly, and this problem will be avoided. Finally, in the light of the large start-up torque, and the high speed at working time of the pulverizer, the constant power pumps is choosed to meet the work demand. Constant power pumps can adjust the flow and pressure according to the different load automatically, thus more energy are saved. Hydraulic system simulation model is established based on the AMESim simulation, which verify the scheme is feasible
