Applied Mechanics and Materials Vol. 137

Abstract: Abstract: The durability and safety of the bridge are paid more attention to and the design,construction,operation and maintenance are investigated and discussed by the bridge engineers and researchers. From the aspect of fatigue accumulated damage of the structures,and from the construction stage to operation stage or the life cycles of the bridge, the damage effect of the bridge in all stages would be analyzed systematically. By numerical FEM way,such as stress amplitude and displacement amplitude，the damage effects and fatigue characters from the accumulated damage would be demonstrated by the means of the determine and fix quantify.

Abstract: The key component of the spindle box for using the fuzzy optimization method for high-speed vertical machining center was optimized. Through the analysis of the fuzzy information of the components, the membership functions of the constraint were determined, and the satisfactory results were obtained according to the characteristics of the actual problems or decision-makers intention. Through fuzzy finite element method, the optimal solution in the space was adjusted, the design of multiple choices was provided for designers, and the favorable conditions for other design of parts were created.

Abstract: Prediction of welding distortion of stainless steel welding joint in reasonable time is meaningful in welding industry. In this paper, a three dimensional thermo-elastic-plastic finite element method (FEM) is developed to precisely predict welding distortion on bead on plate welding with 304 stainless steel. Meanwhile, the corresponding experiments are carried out to validate the predicted results. Research results show the predicted results by FEM match the experimental results very well. In the condition of different welding heat input, the welding heat input play an important role on welding distortion. While, material properties of stainless steel play a larger role on welding distortion when welding heat input is same. Further, for bead on plate welding of thin plate, both large distortion theory and small distortion theory are computed. The results show that using large distortion theory is more accurate in prediction welding distortion on thin plate welding.

Abstract: Analysis of real-time measuring data of stress points layouted on the quayside container crane, a new technology of real-time fatigue life estimation for quayside container crane is presented in this paper based on the study of feature of crane’s structure and theories of fatigue danmage. This technology can real-time estimate quayside container crane’s total fatigue life and remaining life at any moment in whole process from it put into use to the last scrap stage,the estimation is more credible and more accurate, and it provides a basis for structure maintenance, strengthening and rehabilitation.Compared with traditional structural fatigue life estimation, this new technology reduces downtime, creates greater economic benefits for the enterprise and has great application value.

Abstract: A fluid-structure interaction numerical simulation technique based on CFD has been developed to study the vortex-induced vibration behavior of steel arch bridge hanger. Above all, wind acting on bridge hanger is simulated by using Flunet and then vortex-induced dynamic motion of hanger is solved by method in the User Defined Function (UDF). Finally hanger’s transient vibration in wind is achieved by dynamic mesh method provided by Fluent. Using this technique, the vortex-induced vibration behavior of hanger of the Nanjing Dashengguan Yangtze River Bridge is analyzed, including vibration amplitude, vibration-started wind speed and vortex shedding frequency. The study also considers influences of different section type (rectangle, chamfered rectangle and H) of hanger. The following conclusions are obtained. Firstly hanger of different section has different vibration behavior. Secondly vibration-started wind speed of different section hanger differs with each other. Thirdly relation between vibration amplitude and incoming wind speed varies obviously. At the same time, numerical results are compared with those of one wind tunnel test and the out coming is satisfied. Relation between vibration amplitude and wind speed in both numerical simulation and wind tunnel test is similar because vibration-started wind speed in numerical result has only 10% discrepancy with that in wind tunnel test while vibration amplitude’s discrepancy is only 15%. Consequently, analysis results show the reliability of this numerical simulation technique.

Abstract: This study presented a case study of Pearl River Delta(PRD) region. Using basic data of land use and transport network, the extraction of land use information and the analysis of transport network accessibility were performed to comprehensively analyze the land use and transport accessibility of PRD region. Moreover, suggestions on the optimization of regional spatial structure were also made. By this empirical process, the combination of accessibility with land use factors in regional spatial planning was investigated.

Abstract: A novel prediction method which combined evolutionary strategy with least-square support vector machine is presented and applied to the trend prediction of hydraulic liquid leakage in this paper. In order to improve the prediction performance, the evolutionary strategy is employed to optimize the internal parameters of least-square support vector machine. Through the experiment study, the result validated the effectiveness of the prediction method, and it is also demonstrated that the method is able to do the short-term fault prediction for the hydraulic system.

Abstract: According to the quayside container crane, the pitch angle of the front crossbeam only can be used to classify the states of the whole crane into operating and non-operating. The Vibration Carpet Value (VCV）is presented in this paper. By means of VCV, the motor states including working and non-working can be correctly classified. Based on the classified result, by the methodology of Wavelet Packet Quantization Analysis Technique based on EMD, the real-time monitoring and evaluation of the motor condition are more correct and effective.