Most view articles
2019, 47(7):1-5.
DOI: 10.3969/j.issn.1001-3881.2019.07.001
Abstract:
Stainless steels and PEEK composites are frequently used in key friction pair of seawater hydraulic components. The stainless steel has an important influence on tribological properties of stainless steel/PEEK composite pairing. Focused on AISI 316L, AISI 630 and S32750, tribological tests were conducted under seawater lubrication. Friction coefficient and wear rate of the three kinds of stainless steels sliding against PEEK were comparatively investigated. The tribological mechanism of the friction pairs were explored through observing and measuring the worn surfaces of samples.It is shown that the average friction coefficients of the three kinds of stainless steels have little difference; compared with AISI 316L, wear resistance of S32750 and AISI 630 is admirable, and wear rate of AISI 630 is less affected by load; wear resistance of S32750 and AISI 316L is positively correlated with their hardness, while high carbon content in AISI 630 will weaken its corrosion resistance and affect its friction and wear properties in seawater.The research provides reference for selection of stainless steel material in key friction pair of seawater hydraulic components.
Stainless steels and PEEK composites are frequently used in key friction pair of seawater hydraulic components. The stainless steel has an important influence on tribological properties of stainless steel/PEEK composite pairing. Focused on AISI 316L, AISI 630 and S32750, tribological tests were conducted under seawater lubrication. Friction coefficient and wear rate of the three kinds of stainless steels sliding against PEEK were comparatively investigated. The tribological mechanism of the friction pairs were explored through observing and measuring the worn surfaces of samples.It is shown that the average friction coefficients of the three kinds of stainless steels have little difference; compared with AISI 316L, wear resistance of S32750 and AISI 630 is admirable, and wear rate of AISI 630 is less affected by load; wear resistance of S32750 and AISI 316L is positively correlated with their hardness, while high carbon content in AISI 630 will weaken its corrosion resistance and affect its friction and wear properties in seawater.The research provides reference for selection of stainless steel material in key friction pair of seawater hydraulic components.
2019, 47(24):103-111.
DOI: 10.3969/j.issn.1001-3881.2019.24.018
Abstract:
Torque converter is widely used in all kinds of transmissions such as cars, buses, wind turbines and engineering machinery. Due to poor accuracy and adaptability, the traditional design method no longer suits the needs of torque converter design and optimization, and 3D flow field simulation is widely used in torque converter design. With the increasing interest in the coupling of computational fluid dynamics and modern optimization techniques, an urgent need in finding an appropriate algorithm in torque converter design has risen. To this end, this paper employed four popular algorithms to optimize the performance in terms of blade numbers on a response surface. We compared and contrasted the algorithms in terms of the ability of searching for global optimum and handling constraints. The results indicated that AMGA exhibited the best search ability which is mainly attributed to the use of a large external archive. NSGA II outperformed the other algorithms in handling constraints. Due to the use of neighborhood crossover, NCGA has difficulties converging to global optimum as well as preserving diversity. No optimizer is clearly best overall, but this study demonstrated the merits and drawbacks of each optimizer and this may help the designer in choosing an appropriate algorithm considering their actual needs.
Torque converter is widely used in all kinds of transmissions such as cars, buses, wind turbines and engineering machinery. Due to poor accuracy and adaptability, the traditional design method no longer suits the needs of torque converter design and optimization, and 3D flow field simulation is widely used in torque converter design. With the increasing interest in the coupling of computational fluid dynamics and modern optimization techniques, an urgent need in finding an appropriate algorithm in torque converter design has risen. To this end, this paper employed four popular algorithms to optimize the performance in terms of blade numbers on a response surface. We compared and contrasted the algorithms in terms of the ability of searching for global optimum and handling constraints. The results indicated that AMGA exhibited the best search ability which is mainly attributed to the use of a large external archive. NSGA II outperformed the other algorithms in handling constraints. Due to the use of neighborhood crossover, NCGA has difficulties converging to global optimum as well as preserving diversity. No optimizer is clearly best overall, but this study demonstrated the merits and drawbacks of each optimizer and this may help the designer in choosing an appropriate algorithm considering their actual needs.
2017, 45(1):1-4.
DOI: 10.3969/jissn1001-3881201701001
Abstract:
A kind of similar ruled surface integral impeller flank milling machining method was proposed based on inspection at original position. Firstly，the similar ruled surface was reconstructed for approximate ruled surface；then the similar ruled surface integral impeller flank milling judge conditions were proposed. For tool axial vector solved question of nondevelopment ruled surface，analytical method was proposed. Finally similar ruled surface tool path simulation and actual numerical control (NC) machining experiments were carried out, which verify the correctness of the algorithm.
A kind of similar ruled surface integral impeller flank milling machining method was proposed based on inspection at original position. Firstly，the similar ruled surface was reconstructed for approximate ruled surface；then the similar ruled surface integral impeller flank milling judge conditions were proposed. For tool axial vector solved question of nondevelopment ruled surface，analytical method was proposed. Finally similar ruled surface tool path simulation and actual numerical control (NC) machining experiments were carried out, which verify the correctness of the algorithm.
2021, 49(1):51-55.
DOI: 10.3969/j.issn.1001-3881.2021.01.011
Abstract:
The position servo system has higher and higher requirements on response speed, positioning accuracy and antidisturbance performance. Traditional PID control is easy to implement, but it depends on the object model and its performance is limited, so it is difficult to meet the high requirements. Sliding mode control does not depend on the object model and has strong applicability. Therefore, a fuzzy adaptive sliding mode control method for position servo system was proposed, by which the exponential reaching rate was adaptively adjusted. Taking the position servo system as the object, the simulation and experiments for position control and antidisturbance performance were carried out by using the methods of PID control, sliding mode control and fuzzy adaptive sliding mode control. The results show that the fuzzy adaptive sliding mode control is superior to the PID control in fast position and antidisturbance performance; compared with the ordinary sliding mode control, the fuzzy adaptive sliding mode control has better dynamic performance. Therefore, the proposed fuzzy adaptive sliding mode control has better applicability and certain application value in those applications where need fast response and strong antidisturbance performance.
The position servo system has higher and higher requirements on response speed, positioning accuracy and antidisturbance performance. Traditional PID control is easy to implement, but it depends on the object model and its performance is limited, so it is difficult to meet the high requirements. Sliding mode control does not depend on the object model and has strong applicability. Therefore, a fuzzy adaptive sliding mode control method for position servo system was proposed, by which the exponential reaching rate was adaptively adjusted. Taking the position servo system as the object, the simulation and experiments for position control and antidisturbance performance were carried out by using the methods of PID control, sliding mode control and fuzzy adaptive sliding mode control. The results show that the fuzzy adaptive sliding mode control is superior to the PID control in fast position and antidisturbance performance; compared with the ordinary sliding mode control, the fuzzy adaptive sliding mode control has better dynamic performance. Therefore, the proposed fuzzy adaptive sliding mode control has better applicability and certain application value in those applications where need fast response and strong antidisturbance performance.
2019, 47(7):105-109.
DOI: 10.3969/j.issn.1001-3881.2019.07.024
Abstract:
Networked remote control of workshop information brings user convenience while accompanied by security risks, in order to eliminate the potential threat of mobile terminal access workshop information system communication process, in view of the possible security problems in mobile terminal access workshop information system, the security mechanism of identity authentication, access control, abnormal behavior detection, black and white list filtering and access to the audit was designed, and a three layer to protect the security of information system was established. The test results show that the designed security mechanism can effectively improve the security of the mobile terminal access workshop information system, and can prevent the possible malicious attacks on the mobile terminal access workshop information system.
Networked remote control of workshop information brings user convenience while accompanied by security risks, in order to eliminate the potential threat of mobile terminal access workshop information system communication process, in view of the possible security problems in mobile terminal access workshop information system, the security mechanism of identity authentication, access control, abnormal behavior detection, black and white list filtering and access to the audit was designed, and a three layer to protect the security of information system was established. The test results show that the designed security mechanism can effectively improve the security of the mobile terminal access workshop information system, and can prevent the possible malicious attacks on the mobile terminal access workshop information system.
