Applied Mechanics and Materials Vols. 16-19

Abstract: Intelligent teaching system design has become an active research topic in education research community. How to manage the network teaching resource efficiently will have a direct impact on the teaching process and quality in the network teaching system. The semantic web can be a very promising platform for knowledge management systems in the intelligent teaching system design. In this paper, we have presented a framework for the network teaching resource knowledge base (NTRKB) based on semantic web, which includes network teaching resource knowledge representation, regular relation definition based on OWL, knowledge base modeling and construction based on RDF. The NTRKB can achieve knowledge sharing and intelligent retrieval for the network teaching resource, and these components will greatly benefit the development of the proposed intelligent teaching system.

Abstract: In this paper, ontology modeling language and reasoning engines are studied and applied, framework model of ontology-based expert system is built up, the model tree of classes and instances of fully mechanized caving used equipments is brought forward, OWL-based equipment knowledge base is created by using protégé tool, knowledge rules of mining equipments selection and matching are analyzed, and SWRL-based selection and matching rules are designed. Finally, the rule conversion and reasoning is realized in JESS environment.

Abstract: Technology of digital mockup is introduced and the application background and practical requirement of tunnel boring machine has been discussed in this paper. One type of EPB tunnel boring machine’s digital mockup is built. The kinematics simulation of working station is disigned base on it. And finite element analysis of some critical componants are operated in CATIA.

Abstract: The virtual prototyping (VP) technology is a new method for belt conveyor dynamic design. However the conveyor belt simulation is very difficult. There is no successful precedent of belt conveyor VP until now. Based on a new type of dynamic software – Recurdyn, the VP design plan is formulated, which comprises simplification of belt conveyor, 3D modeling, belt separation and belt blocks assembly. Then a simplified belt conveyor VP is given. The VP is simulated under working condition in virtual environment. The results show the correctness of simplified VP and the feasibility of heavy-duty belt conveyor VP. And an improved belt conveyor VP which can be used in design and research is completed in the end.

Abstract: Virtual assembly based on the virtual reality gives a low-cost and rapid prototyping method for products’ assembly, and tolerances have become a key technique of information integration in CAD/CAM. It will be a new task about how to integrate tolerances into virtual assembly. A toleranced product model based on the virtual reality is constructed for the virtual assembly, and the essential data is saved and managed in database. Model transform interface software is developed, which is a special software that users can get the essential data without any users’ acting. The geometric model of products is constructed in the virtual reality, and the method of getting assembly information, dimensions, and tolerances is proposed. A toleranced product modeling system based on the virtual reality is developed, and the using of tolerances is discussed by an example.

Abstract: The analytical stiffness equations of the 3-RPR planar parallel mechanism are derived in this paper based on the Conservative Congruence Transformation (CCT) stiffness matrix proposed in [1-3]. Stiffness maps of the 3-RPR mechanism are plotted in order to show the behaviour of the stiffness with and without external forces. The stiffness characteristics of the mechanism are analyzed and discussed in details. Numerical examples show that the stiffness in x and in y are well balanced, while the stiffness in tends to be lower.

Abstract: Complete contact is often used in assembling wheel hub and shaft which are used in the closed impeller assembly group of large turbine compressor. The interference is usually fixed. In the topic, based on the nonlinear contact theory and FEM, an impeller assembly is studied from finishing assembly to steady state, then the size and distribution of stress of the contact area between wheel hub and shaft is gotten. Then a structural optimization on the assembly is done. The stress distribution is changed reasonably when the structural redundancy is reduced. Then the incidence of shaft bending is reduced effectively and assembling performance of the impeller assembly structure is improved, the results can be used to offer reference for the design and manufacture.

Abstract: Virtual manufacturing technology has become an effective method for decision and planning in manufacturing. Due to ergonomics problems are widely concerned in assembly design planning, a human-centered virtual assembly system framework is proposed for ergonomics analysis for assembly operation in this paper. The six-layer framework integrates virtual human modeling, motion capture and recognition, ergonomics evaluation and virtual assembly process planning as an organic whole. Data exchanging and system function are discussed based on this framework. The work in virtual reality (VR) technology, motion capture technology, ergonomics method and optimization method for implementing the system is also described. The framework would provide a new approach for the combination of virtual manufacturing and ergonomics analysis in the future.

Abstract: The virtual maintenance technology based on the virtual reality technology has changed the traditional single-site maintenance means, and also overcame the shortcoming of manufacturing cycle length, high cost, and difficult to amend for the physical prototype. Furthermore, it can expose the problem during the early design. The key technologies of virtual maintenance include the maintenance process model, virtual maintenance prototype, virtual maintenance simulation, analysis and evaluation of maintainability. In this paper, the research object is aeroengine.The key technologies of virtual maintenance were analyzed.

Abstract: For the concrete pump truck, the movements of the arm and the hydraulic cylinder are analyzed respectively with multi-body dynamic theory. And with the applying of PD control theory, the dynamic equation of arm system is also built. And according to the numerical solution of the equation, it is proved that the dynamic equation can describe every dynamic character of the concrete pump truck well.