Applied Mechanics and Materials Vols. 55-57

Abstract: SpaceWire is a high-speed data transmission bus standard proposed by ESA for the aerospace applications. Hosted by the National Astronomical Observatories, Chinese Academy of Sciences, the Space Solar Telescope project takes the SpaceWire bus standard as space communication link. The SpaceWire communication circuit implemented by our group is a part of the SST project. In order to improve the fault detection and fault correction capacity and the reliability of the SpaceWire bus, we add a more error analysis and data storage module into the original six state modules of the standard protocol in the exchange layer.We adopt the formal verification method based on the model checking to verify the finite state machine of the SpaceWire control module. The properties expressed by the high-order temporal logic formula are verified automatically to be true by the SMV model verifier of the Cadence Company. Verification results show that our SpaceWire bus implementation and the additional error analysis and data storage module are faithful to the protocol specification. Therefore, we also can integrate SpaceWire bus circuit into the SST project.

Abstract: The purpose of this study is to develop a methodology as to the knowledge management of concept structure for learners. Fuzzy clustering is adopted to implement classification so that learners of the same cluster have homogeneity and display common features of cognition diagnosis. In addition, fuzzy clustering is based on information of concept scoring and caution index from polytomous student-problem chart. In the study, the empirical data is the assessment of statistics concepts from university students. The results show that there are four clusters and each cluster has its own cognitive characteristics. To sum up, the methodology can improve knowledge management in classroom more feasible. Finally, some recommendations and suggestions for future investigations are also discussed.

Abstract: Contrary to the general connection style, the vibration characteristics of the ship foundation vibration is researched under the arrangement style of isolators acted on it. And the influence of the parameters of rigidity and damp to the excitation force characteristic is studied too. Based on the real ship data and the finite element method, the study is shown that the excitation force from the device to the foundation is not only related to the rigidity, damp of isolators and the natural frequency of device-isolator-foundation system but also the related to arrangement style of isolator. When the excited frequency is lower it had little effect on the vibration characteristics relatively. However that the frequency is higher, it had significant effect on the vibration.

Abstract: Military electronic components apply in high temperature conditions has become one of the hot research field of reliability field, then the temperature characteristics of the military electronic components are known by designers is key to guarantee high reliability of military equipment under high temperature conditions. So, a scheme of the high temperature dynamic test based on low consumed power test circuits and PC is worked out in this paper. It can be used for test the temperature performance of the military electronic components, and feasibility of the schemes are tested and verified by experiment. And the changing law of the components parameter are got in this conditions which found out components parameters approximate linear in 25°C～200°C, of nonlinear in large range in the very high temperature of 200°C～350°C conditions, which can offer some reference value to prolong lifetime of military electron device.

Abstract: Hydraulic motor with swinging bevel gear is a new kind of hydraulic motor. There are many advantages of it over other kind hydraulic motor. The decelerating ratio is big, moment work ratio is high, energy consuming is low, and decelerating function is good. Compared with other general liquid presses motor, this type of motor has the all new construction with the function, being applicable to the low turning the soon big turning the moment specially, high- efficiency realm. A principle for studying this kind of new motor with realize technique, include go together with to flow to convert the technique, adjust soon principle with method, the wheel gear theories matches the function with many cogwheels engaged, whole machine is excellent to turn the design, the kind machine manufactures experiment etc. with function on a trial basis to.The item's research for the country inside blank, spread to move to the host simplification, economize the energy, decline the low cost having got the important meaning.

Abstract: A new kind of hydraulic motor suitable for the low velocity, large torque, high efficiency and mutable velocity output have been researched and developed in this paper. There are a series of creations and in advantage, such as, the oil flow distribution, the principle of reducer, the output mechanics and the total structure. It features in the simple in construction, small of size, large ratio of reducer, high f ratio of torque-power, and low in energy consumption. It is suitable for all the occasions with hydraulic supply and all the fields when low velocity, large torque, high efficiency and mutable velocity output ware needed. Such as the construction mechanics, ship mechanics, heavy machine tool, heavy capstan and so on. The frequency of the hydraulic system is about 1000—2000/min, the reduced ratio of the planetary drive of swinging bevel gear is about 20-100, with 150 the maximum. This paper introduced the fundamental principle of the transmission of this mechanics, designed the basic structure of this mechanics, and analyzed the movement and forces.

Abstract: This paper presents a new way to determine the base circle of a cam by using the displacement and velocity graphs. This is a simple method to guarantee the obtained pressure angle aless than the allowed pressure angle [a], while the work of calculation is reduced dramatically.

Abstract: The concept of worm transmission with inconstant addendum is presented in this paper. Compared with the ordinarily cylindrical worm transmission, the contact area is increased dramatically. With these advantages, it is hopeful to substitute the Double Envelope Hourgrass worm gear transmission.

Abstract: This paper presents a new method to design and to determine the inertial moment of the fly wheel, according to the allowed maximum and minimum angular velocity. The advantage of this method is: in the same time of the dynamic analysis of the the mechanics we can fulfill the design of the fly wheel. With this method, the inertial moment of fly wheel is determined precisely. In the traditional method, first we have to determine the inertial moment of fly wheel, then, make static-dynamic analysis of the mechanism and find out the react force of the connect pair. For example, after work, one first goes home and then has to go shopping. But if we choose not to go home directly, while on the way home in passing do some shopping then go home. Even though it is not the shortest way, but in total we can shave time and rod. It is the same occasion with our design method too. Even though the process of calculation is more complicated than the formal method, but we can determine the reaction on the connect pair at the same time. So that in total decreased the amount of design work.

Abstract: With Pro/Toolkit of Pro/E and ADO(ActiveX Data Object) database technology, part parametric CAD system is developed and an successful instance is introduced in the paper. In the CAD system, interface between Pro/E and VC++6.0 is created correctly using Pro / Toolkit and user interface for part parametric designing can be achieved by means of dll( dll dynamic link) library built in VC++6.0 .Meanwhile ADO database is applied in the CAD system to manage all part parameters and thus part revising and updating can be realized quickly. The developing method in the CAD system not only is applicable to typical mechanical part designing but also be helpful to establishing standard part library.