查看更多>>摘要：For the solutions to engineering equipment with pipes, unknown forces and unclear constraint conditions on the pipes result in the analysis limitation due to the high temperature and fluid pressure to pipes. In this paper, a new method for determining the loads is established to problems with many pipes. In the method, based on the combination of FEM and Successive Approximation Approach, pipes forces on the equipment are analyzed. By the analysis of suitable forces, the relationship between forces and stress can be obtained. The cycling process of "loading-solving-determining-adjusting" is carried out to approaching destinations based on hundreds of numerical results. Moreover, an evaluation scheme is built to evaluate groups of forces and guarantee equipment to work normally under some certain forces. The constraint condition from groups of forces can be also confirmed. A case study gave the verification of the method.
Wang Sheng-wuWen Ai-lingZhao Huai-ruiJin Xue-song...
845-848页
查看更多>>摘要：The 3D finite element simulations are conducted for the cold working of a fastener hole in a low carbon steel plate. The simulation models the actual cold working process where the hole edge is chamfered with die-press. The agreement of finite element method and experimental results is good enough. The residual stresses are analyzed under the different die-press parameters and contact conditions i.e. die-pressing depth, friction factor, the die taper. The main results in this work are as follows: With increasing in chamfer depth the maximum compressive residual stress shows an increasing within the chamfer range of C1.5; the compressive residual stress is decrease with increasing friction; with increase in die taper the maximum compressive residual stress shows the slow increase. The efficiency for enhancing the load-carrying capacity of structural components with cylindrical holes subjected to bending load has been proved by means of FE simulation. The study shows that the simulations of cold working are necessary for if predicted residual stresses are to be used to assess fatigue life and for design die-pressing tool, improvement of parameters of the process of DP working.
Wang Sheng-wuSun Shu-juanWen Ai-fingWang Wei-da...
849-852页
查看更多>>摘要：The fatigue limit of parts and components that have the multi-notches is important data for the design and manufacture of machinery and traffic equipment which are operated under the high speed or pressure. In this paper the rotating bending fatigue tests have been carried out to investigate the fatigue limit of specimen with double-notch that is constructed of step and blind hole, and analyzed the effect of stress concentrations at the double-notched bottoms on the fatigue limits, using three-dimensional elastic finite element method. Firstly, the fatigue tests of 8 group specimens have been performed for examining the of fatigue limits of the single-notched specimen and double-notched specimen, respectively. Additionally, the stress field interactions between two stress fields by the blind hole notch and step are discussed using three-dimensional elastic finite element method. The main results obtained in this study are as follows: The fatigue limit of the double-notched specimen are down comparison with the fatigue limit of the single-notched specimen; the fatigue limit of the double-notch specimen is insensitive to distance between the blind hole and step for the low carbon structure steel with better ductility; for the high-strength steel, superposition and intensification of the stress concentration by the blind hole and step mutually may be avoided so that their adverse effects on the fatigue strength may be become to minimize, as take appropriate distance between the blind hole and step. The results are significant for the design of engineering design of the multi-notched parts, and the study of fatigue strength.
查看更多>>摘要：The self-made metal cored wires with Fe-Si-Mn-Ti-B microalloyed series were adopted to directly form a part by gas metal arc welding (GMAW) surfacing rapid prototyping technology. The microstructure and microhardness of the part are both investigated. Its continuous metallographic microstructure along and vertical to the deposition direction shows layered characteristic, due to the special thermal cycles and cooling conditions. The microhardness values of intermediate sections of the part are much higher and stabler than those of surface sections. It is necessary to deposit a wear-resistant metal layer for enhancing the surface abradability. Among the microstructures of the part, the average nanohardness of acicular ferrite is 1.28 times than that of massive ferrite, but their Young's modulus values are almost equivalent, which indicates acicular ferrite possesses excellent mechanical property. Therefore, achieving acicular ferrite microstructures is an appropriate means to enhance the combination property of the formed parts.
查看更多>>摘要：In view of the current situation that landscape waterfronts are small, dispersed, increasing, and it is difficult for big mowers to cut aquatic grass, a small type submarine mower-SGW 1.2 type submarine mower, is developed for small waterfront. Based on the definition of the swath, the cut depth, the machine's outline size, productivity and other technical parameters, and combined with the knowledge of hydrodynamics and theoretical naval architecture and so on, the reciprocating cutters, propeller and auxiliary structures are selected and designed, and then the design of the submarine mower is accomplished. The experiments showed that SGW1.2 type submarine mower's cutting depth is adjustable among the required range, and all the parameters including the turning radius, the productivity, the speed and the fuel consumption meet the demands as anticipated. The average omission rate and average cutting leakage rate are small. The experiments proved that the submarine mower has a good ability for continuous cutting and harvesting, and is appropriate to cut aquatic grass in small-scale waterfronts.
查看更多>>摘要：To effectively control and monitor the quality of aquatic products, a supply chain traceability system of multi-user and multi-authorities has been established. In this paper, current situation of traceability system was firstly introduced, and then a general system architecture, function modules, data model and encoding scheme were discussed. This system was constructed on the ASP.NET platform, using the C# programming language and SQL server 2000 database technology. Through this system, a platform was provided for exchanging information of producing, circulating and consuming among supply chain participants, products quality control on the whole chain and traceability was then achieved.
查看更多>>摘要：Bending fatigue is one of the main failure modes of gears. The method of gear fatigue design was discussed in many papers. Most of them are based on GB/T3480-83.But study shows that the method current widely used only fits for the single side loaded gear. For double sides loaded gear, only a mean stress modification coefficient is concerned compared to single side loaded gear. A new formula based on fatigue theory is given to modify the mean stress in consideration of the load character of doubled sides loaded gear. The method given in the paper is an addition to the traditional gear design method.
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