Tribological tests play an important role on the evaluation of long-term bio-tribological performances of prosthetic materials for commercial fabrication.Those tests focus on the motion simulation of a real joint in v...Tribological tests play an important role on the evaluation of long-term bio-tribological performances of prosthetic materials for commercial fabrication.Those tests focus on the motion simulation of a real joint in vitro with only normal loads and constant velocities,which are far from the real friction behavior of human joints characterized with variable loads and multiple directions.In order to accurately obtain the bio-tribological performances of artificial joint materials,a tribological tester with a miniature four-station tribological system is proposed with four distinctive features.Firstly,comparability and repeatability of a test are ensured by four equal stations of the tester.Secondly,cross-linked scratch between tribo-pairs of human joints can be simulated by using a gear-rack meshing mechanism to produce composite motions.With this mechanism,the friction tracks can be designed by varying reciprocating and rotating speeds.Thirdly,variable loading system is realized by using a ball-screw mechanism driven by a stepper motor,by which loads under different gaits during walking are simulated.Fourthly,dynamic friction force and normal load can be measured simultaneously.The verifications of the performances of the developed tester show that the variable frictional tracks can produce different wear debris compared with one-directional tracks,and the accuracy of loading and friction force is within ？5%.Thus the high consistency among different stations can be obtained.Practically,the proposed tester system could provide more comprehensive and accurate bio-tribological evaluations for prosthetic materials.展开更多
The recent rapid development of electronics and continual increase of the complexity and variety of electronic circuits (chips, packets, micro- and embedded systems) creates a demand for viable test and diagnostic met...The recent rapid development of electronics and continual increase of the complexity and variety of electronic circuits (chips, packets, micro- and embedded systems) creates a demand for viable test and diagnostic methods. These recent developments have led to a great deal of research interest in electronic diagnostic systems, especially of effective diagnosis methods of detection, localization and identification levels of hard (catastrophic) and soft (parametric) faults in analog circuits. At present, the majority of electronic devices (embedded systems) are designed based on digital circuits;however a lot of them also contain analog components that require more complicated testing techniques. This paper presents a novel, electronic components tester board with inside, outside of circuit under tested. The design is first simulated by using the electronic work-bench software Multisim 11 in order to obtain satisfactory theoretical results for each standalone element of the design. Thereafter, the design is practically implemented and experimentally verified to show agreement with the simulated results.展开更多
基金Supported by Funding of State Key Laboratory of Mechanical Transmissions,Chongqing University,China(Grant No.SKLMT-KFKT-201504)National Natural Science Foundation of China(Grant No.51275381)Science and Technology Planning Project of Shaanxi Province,China(Grant No.2012GY2-37)
文摘Tribological tests play an important role on the evaluation of long-term bio-tribological performances of prosthetic materials for commercial fabrication.Those tests focus on the motion simulation of a real joint in vitro with only normal loads and constant velocities,which are far from the real friction behavior of human joints characterized with variable loads and multiple directions.In order to accurately obtain the bio-tribological performances of artificial joint materials,a tribological tester with a miniature four-station tribological system is proposed with four distinctive features.Firstly,comparability and repeatability of a test are ensured by four equal stations of the tester.Secondly,cross-linked scratch between tribo-pairs of human joints can be simulated by using a gear-rack meshing mechanism to produce composite motions.With this mechanism,the friction tracks can be designed by varying reciprocating and rotating speeds.Thirdly,variable loading system is realized by using a ball-screw mechanism driven by a stepper motor,by which loads under different gaits during walking are simulated.Fourthly,dynamic friction force and normal load can be measured simultaneously.The verifications of the performances of the developed tester show that the variable frictional tracks can produce different wear debris compared with one-directional tracks,and the accuracy of loading and friction force is within ？5%.Thus the high consistency among different stations can be obtained.Practically,the proposed tester system could provide more comprehensive and accurate bio-tribological evaluations for prosthetic materials.
文摘The recent rapid development of electronics and continual increase of the complexity and variety of electronic circuits (chips, packets, micro- and embedded systems) creates a demand for viable test and diagnostic methods. These recent developments have led to a great deal of research interest in electronic diagnostic systems, especially of effective diagnosis methods of detection, localization and identification levels of hard (catastrophic) and soft (parametric) faults in analog circuits. At present, the majority of electronic devices (embedded systems) are designed based on digital circuits;however a lot of them also contain analog components that require more complicated testing techniques. This paper presents a novel, electronic components tester board with inside, outside of circuit under tested. The design is first simulated by using the electronic work-bench software Multisim 11 in order to obtain satisfactory theoretical results for each standalone element of the design. Thereafter, the design is practically implemented and experimentally verified to show agreement with the simulated results.
