1999 Vol.12(4)
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1999, 13(4).
Abstract:
The theoretical formula for estimating the side curling short-spiral chips is simplified. On the basis of experiment, a practical formula for forecasting the chip breaking length is obtained. It is proved by experiment that the result from the practical formula fits well with that from the experiments.
The theoretical formula for estimating the side curling short-spiral chips is simplified. On the basis of experiment, a practical formula for forecasting the chip breaking length is obtained. It is proved by experiment that the result from the practical formula fits well with that from the experiments.
1999, 13(4).
Abstract:
Based on the superfluous triangle material wrinkle model, the no-wrinkle limit criterion of cylindrical cup multi-deep-drawing is calculated as the prediction and control of the wrinkle limit. According to fracture model, the no-fracture limit criterion of cylindrical cup multi-deep-drawing is calculated as the prediction and conmtrol of the fracture limit. Combining the no-wrinkle limit criterion with the no-fracture limit criterion, the no-wrinkle and no-fracture limit criterion and diagram on cylindrecal cup multi-deep-drawing are given as the prediction and control of both wrinkle and fracture limits. In accordance with this can determine the limit deep-drawing coefficient and minimum deep-drawing coefficient, and can choose the deep-drawing coefficient of multi-deep-drawing, blank-holder force and deformation force by optimization choice method. Theory calculation and test data are highly consistent, and suitable for no-flange multi-deep-drawing and rigid punch expanding.
Based on the superfluous triangle material wrinkle model, the no-wrinkle limit criterion of cylindrical cup multi-deep-drawing is calculated as the prediction and control of the wrinkle limit. According to fracture model, the no-fracture limit criterion of cylindrical cup multi-deep-drawing is calculated as the prediction and conmtrol of the fracture limit. Combining the no-wrinkle limit criterion with the no-fracture limit criterion, the no-wrinkle and no-fracture limit criterion and diagram on cylindrecal cup multi-deep-drawing are given as the prediction and control of both wrinkle and fracture limits. In accordance with this can determine the limit deep-drawing coefficient and minimum deep-drawing coefficient, and can choose the deep-drawing coefficient of multi-deep-drawing, blank-holder force and deformation force by optimization choice method. Theory calculation and test data are highly consistent, and suitable for no-flange multi-deep-drawing and rigid punch expanding.
1999, 13(4).
Abstract:
The finite element method is employed to simulate incompressible viscous unsteady flow in two-dimensional channel with a sudden expansion. The streamline patterns and the velocity vector plots are presented at different expansion ratios and at different moment. The results obtained have certain significance to analyze the formation of eddies and energy loss in a sudden expansion channel flow and other complex channel flow.
The finite element method is employed to simulate incompressible viscous unsteady flow in two-dimensional channel with a sudden expansion. The streamline patterns and the velocity vector plots are presented at different expansion ratios and at different moment. The results obtained have certain significance to analyze the formation of eddies and energy loss in a sudden expansion channel flow and other complex channel flow.
1999, 13(4).
Abstract:
A method for the forced vibration and sound radiation of a rectangular plate with viscoelastic boundary supports is proposed. The method is based on damped complex modes analysis method. Using the damped complex modes of the plate system, the modal equation of the plate motion becomes completely uncouped. The sound radiation pressure is obtained by numerical integration of the Rayleigh integral. Effects of the viscoelastic boundary supports on the vibration response and the radiated sound pressure of the vibration plate are discussed by an example.
A method for the forced vibration and sound radiation of a rectangular plate with viscoelastic boundary supports is proposed. The method is based on damped complex modes analysis method. Using the damped complex modes of the plate system, the modal equation of the plate motion becomes completely uncouped. The sound radiation pressure is obtained by numerical integration of the Rayleigh integral. Effects of the viscoelastic boundary supports on the vibration response and the radiated sound pressure of the vibration plate are discussed by an example.
1999, 13(4).
Abstract:
Based on solid modeling, the geometry and the FE model of the hourglass worm gearing are established. By the hybrid method of FEM and penalty function, the load sharing among tooth pairs and the stress of contact teeth are calculated, the contact zones and the distribution of the contact pressure are investigated. The variation of the contact states with the load is investigated by comparision of its contact patterns under different loads.
Based on solid modeling, the geometry and the FE model of the hourglass worm gearing are established. By the hybrid method of FEM and penalty function, the load sharing among tooth pairs and the stress of contact teeth are calculated, the contact zones and the distribution of the contact pressure are investigated. The variation of the contact states with the load is investigated by comparision of its contact patterns under different loads.
1999, 13(4).
Abstract:
The key issues such as vision sensor, sampling planning are studied for reverse engineering. For the developed sensor, the low sensitivity to the incident angle and the high linearity between the output and the input are carried out. During digitizing, the adaptive sampling planning method based on the curvature of surface and the slope of tangent line of measured point is proposed. After integrating the vision sensor, CNC milling and relevant software, the reverse engineering system based on computer vision is developed. The experiment shows that this system is reliable and efficient.
The key issues such as vision sensor, sampling planning are studied for reverse engineering. For the developed sensor, the low sensitivity to the incident angle and the high linearity between the output and the input are carried out. During digitizing, the adaptive sampling planning method based on the curvature of surface and the slope of tangent line of measured point is proposed. After integrating the vision sensor, CNC milling and relevant software, the reverse engineering system based on computer vision is developed. The experiment shows that this system is reliable and efficient.
1999, 13(4).
Abstract:
A thermoelectric curve of GCr15-BN500 is acquired by rapid label way. The study on measuring the cutting temperature with PCBN cutter is done and the calculation formula is achieved. A serise of experiments about cutting tenperature are made for different hardness tempering bearing steel at the same time. The rule that cutting temperature increases with increasing of the cutting speed, feed, back engagement of the cutting edge is gained. It is known that the cutting temperature is highest under the condition that back engagement of cutting edge αp≥2.5mm and the machined material hardness equals to 50HRC.
A thermoelectric curve of GCr15-BN500 is acquired by rapid label way. The study on measuring the cutting temperature with PCBN cutter is done and the calculation formula is achieved. A serise of experiments about cutting tenperature are made for different hardness tempering bearing steel at the same time. The rule that cutting temperature increases with increasing of the cutting speed, feed, back engagement of the cutting edge is gained. It is known that the cutting temperature is highest under the condition that back engagement of cutting edge αp≥2.5mm and the machined material hardness equals to 50HRC.
1999, 13(4).
Abstract:
The grinding principle of plane envelope is demonstrated with the medium rack theory. The basic and general fixing patterns of grinding involute worms with plane envelope method are uniformed. The vector rotating method is originally applied to calculate precisely the grinding wheel fixing angles γh and γh under the general fixing pattern. It is proved with experiments that the method is feasible.
The grinding principle of plane envelope is demonstrated with the medium rack theory. The basic and general fixing patterns of grinding involute worms with plane envelope method are uniformed. The vector rotating method is originally applied to calculate precisely the grinding wheel fixing angles γh and γh under the general fixing pattern. It is proved with experiments that the method is feasible.
1999, 13(4).
Abstract:
The physical datum method that uses the laser beam as the physical datum is proposed. A high accuracy of the straight movement on the line above 0.01μm/100 mm is achived through applying the method of the closed-loop feedback control that uses the laser beam as the datum. The measuring accuracy above 0.05 μm is obtained by applying the self-making electric eddy displacement sensor to detect the geometric accuracy of the optical flat. It proves that the laser beam datum method can achieve the high accurcy of the straight movement and has the huge advantage.
The physical datum method that uses the laser beam as the physical datum is proposed. A high accuracy of the straight movement on the line above 0.01μm/100 mm is achived through applying the method of the closed-loop feedback control that uses the laser beam as the datum. The measuring accuracy above 0.05 μm is obtained by applying the self-making electric eddy displacement sensor to detect the geometric accuracy of the optical flat. It proves that the laser beam datum method can achieve the high accurcy of the straight movement and has the huge advantage.
1999, 13(4).
Abstract:
The concept of virtual manufacturing and measuring cell (VMMC) is proposed, the systematic architecture of the VMMC is extablished and two key problems:the error fusion in machining and the reconstructable modeling of wordpiece during virtual manufacturing and measuring, are discussed. An actual VMMC is presented as an example and its modularized frame is introduced.
The concept of virtual manufacturing and measuring cell (VMMC) is proposed, the systematic architecture of the VMMC is extablished and two key problems:the error fusion in machining and the reconstructable modeling of wordpiece during virtual manufacturing and measuring, are discussed. An actual VMMC is presented as an example and its modularized frame is introduced.
1999, 13(4).
Abstract:
An investigation is made to the friction chuch engagement control of automotive AMT systems based on a nonlinear dynamic model with double inputs. According to friction torque transmission characteristics during clutch engagement, an equivalent, fully controllable and linearized model and the feedback linearization control are derived from the original system with nonlinearities via homomorphic transforms. By the resulting mathematical modeling, computer simulations are made both for the original nonlinear and feekback linearized systems with incorporation of ordinary PID controllers to follow ideal vehicle dynamic responses. It has been shown by comparison between the two sets of numerical results that the feedback linearization control designed for the nonlinear system is of fine accuracy and robustness in model tracking behaviors of clutch engagements.
An investigation is made to the friction chuch engagement control of automotive AMT systems based on a nonlinear dynamic model with double inputs. According to friction torque transmission characteristics during clutch engagement, an equivalent, fully controllable and linearized model and the feedback linearization control are derived from the original system with nonlinearities via homomorphic transforms. By the resulting mathematical modeling, computer simulations are made both for the original nonlinear and feekback linearized systems with incorporation of ordinary PID controllers to follow ideal vehicle dynamic responses. It has been shown by comparison between the two sets of numerical results that the feedback linearization control designed for the nonlinear system is of fine accuracy and robustness in model tracking behaviors of clutch engagements.
1999, 13(4).
Abstract:
The response simulation is studied and the steering safety is evaluated by using finer integration method for driver-vehicle closed-loop system with stationary random road input. This algorithm ont only is precise, but also can shorten the evaluation period of steering safety and reduce the tremendous cost for real vehicle testing. The response simulation and the vehicle steering safety evaluation are also studied for the closed-loop system with evolutionary random road input. The study can more truly evaluate vehicle driving for including the slowly varying of vehicle velocity with time.
The response simulation is studied and the steering safety is evaluated by using finer integration method for driver-vehicle closed-loop system with stationary random road input. This algorithm ont only is precise, but also can shorten the evaluation period of steering safety and reduce the tremendous cost for real vehicle testing. The response simulation and the vehicle steering safety evaluation are also studied for the closed-loop system with evolutionary random road input. The study can more truly evaluate vehicle driving for including the slowly varying of vehicle velocity with time.
1999, 13(4).
Abstract:
The equations for calculating the deformation of parallelogram type flexible guide, which is caused by the external force, are derived. The correctness of these equations is verified by comparison with other research results and through the concrete design. These equations are applicable for flexible guides with any size.
The equations for calculating the deformation of parallelogram type flexible guide, which is caused by the external force, are derived. The correctness of these equations is verified by comparison with other research results and through the concrete design. These equations are applicable for flexible guides with any size.
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