Applied Mechanics and Materials Vols. 138-139

Abstract: In this paper, finite element method is compared with analytic method in the analysis of submarine cable fiber excess length. And the limitations of using analytic method are analyzed. Then the feasibility and advantages of using finite element method is discussed. We can control and design fiber excess length more reasonably and produce cables in a more scientific way by using finite element method in the analysis of submarine cable fiber excess length.

Abstract: The Simplified model of both calculating leakage magnetic field and mechanical force of windings at short circuit condition for a 120MVA/220kV power transformer is set up. The leakage magnetic field ‚ short-circuit force and stress in transformer windings are analyzed and their distributing characteristics are acquired respectively by using FEM. The calculation method and results are validated by withstanding short circuit strength test of the product. A number of useful suggestions are given for design of power transformers.

Abstract: In order to investigate the mechanism of the formation of the high pressure region which is caused by the type IV interaction, and to develop an alternate control method, the two-dimensional RANS equations were solved to simulate the interaction under the condition of free stream Mach number 3.45 and oblique shock angle 30°. The configuration of type IV interaction is well illustrated, and the mechanism of the formation of high peak values of pressure is revealed. The prediction of surface pressure without energy deposition is found to be in good agreement with experiments. Continuous energy injection is used to control the flow field to decrease the peak values of pressure. The result shows that the peak value decreased by more than 70%, which suggests that there is a potential for continuous energy deposition control of type IV interaction to protect the blunt leading edge.

Abstract: Aiming at adscititious magnetic field effect GTAW arc, decrease the maximum welding residual which by arc shape be changed, avoid the temperature excessive focus on welding pool, reduce temperature gradient and so on. Arc heat source model of GTAW under the magnetic field was established, also consider physical properties of materials varying with the temperature and the influence transformation, through the method of killing or activating elements treatment such as melting or solidification by welding pool, 3D FEM simulation analysis for the temperature gradient and residual stress size distribution to GTAW welded joints compared to on magnetic field or not. The results show that maximum weld longitudinal residual stress and transverse residual stress were respectively reduced by 12.3% and 13.6% when compared to no magnetic field, also have blind hole measuring method measure welding residual stress, Test measurement and simulation values were basically consistent.

Abstract: Aimed at the work condition and structure's characteristics of a large discharge emulsification pump's crankshaft, the load type of a low rotational speed and high load were determined, and the quality of a crankshaft is related with material, manufacture, heat treatment and so on. Based on unit production model during the research and development, the processes of the roughcast, manufacture and heat treatment were described: The roughcast was forged by a forging die in order to suffice a low rotational speed and high load. The crankshaft was manufactured by a universal machine tool, clamps and measuring tools in order to obtain the precision of specification after processing. Heat refining after rough cutting, nitrogen treatment and polishing after finish machining were selected in order to improve mechanical property, application life and cost reduction.

Abstract: Large diameter and super-long pile has found abroad application in high buildings, super high buildings, large bridges and port engineering, and its ultimate bearing capacity is increasingly demanding. Its ultimate bearing capacity is affected by many kinds of uncertainty factors, which is a complex grey analysis program. The influencing factors are analyzed by grey system theory such as pile diameter, pile length, socket length, the length to diameter ratio, the socket length to diameter ratio, rock strength and rock coefficient of weathering. The grey correlation analysis is combined with the tested statistical data of 19 large diameter and super-long piles in Zhejiang province based on the grey correlation model. With the objective to overcome the lack of objectivity in calculating correlation degree of the grey correlation analysis, this paper has improved the calculated formula of the correlation degree based on the distance analysis method. The paper has get and compared the corresponding result of the correlation degree and its rank of various influence factors with the improved calculated formula and the original formula respectively. The influence advantage factors found by grey correlation analysis, and the results can provide important reference for the future theoretical research and design application of large diameter and super-long pile, and show that the grey correlation method is effective and reliable.

Abstract: An improved higher order method was used in calculating the natural frequency of laminated composite plate. The function of equation of free vibration of laminated plate was established using Hamilton's principle and calculated the natural frequencies of plates. The influence of the laying-angle and thickness ratio and cross-elastic modulus ratio to the frequency of the plate were analyzed. It is shown that the natural frequency of antisymmetric angle-ply laminated plates and antisymmetric cross-ply laminated plate can be calculated by using this paper theory; in addition, it is feasible to calculate the natural frequency of the random form of laying laminate.

Abstract: In this paper, the possibility of applying non-obstructive particle damping (NOPD) into the vibration attenuation for heavy-duty machine tool was analyzed and the experimental study on the characteristics of damping vibration attenuation was then carried out. First, the finite-element model for heavy planer type milling machine was built and then the stress state excited by the cutting force in the presence of the holes for filling particles located in the stand column was calculated. Secondly, based on the experiment, the acceleration time-domain waveform and the frequency response function (FRF) between NOPD application and the traditional solid cast-iron column of the planer type milling machine were obtained. Finally it is indicated that NOPD can effectively reduce the amplitude of vibration of heave-duty machine tool and has a good damping effect. Meanwhile, it has some additional effects, such as cost reduction, energy conservation and emission reduction.

Abstract: With respect to different weather and sea conditions, the acoustic model under ocean environment was proposed by analyzing the interaction characteristics between sonar and environment. Based on the sonar equation, the performance mathematical models of active and passive sonar were produced with considering acoustic characteristics of the target and parameters of the marine environment. Simulation results of target detection performance for different target types, sonar parameters and sea conditions show the validity of the proposed model.

Abstract: This paper describes the effect of fiber diameter of fiber reinforced concrete (FRC) under fatigue behavior and its design method. Some researchers showed that the fatigue behavior of FRC is mainly governed by the bridging stress degradation, but little information is still available so far. We conducted fatigue tensile experiments of the FRC under constant strain amplitude first and the degradation of bridging stress was measured experimentally. Then, the micromechanics-based theoretical model is also developed, and the model is verified by the test results. The model accounts for the loss of fatigue ruptured fibers of which fatigue rupture is based on S-N relationships. The parametric study from the micromechanics-based theoretical model indicates that the best fiber diameter varies according to the number of cycles and strain level applied to the FRC specimen. The result suggests that we need to design FRC with considering the application and its loading conditions to utilize the capacity of FRC.