Advanced Materials Research Vols. 455-456

Abstract: Engine mounts are used to isolate the influence of the engine’s vibration on the frame and the body. Both rubber isolator and wire-net isolator are applied as engine mounts. In order to make comparison of their vibration characters correctly, theory of vibration was used to construct a six-degree freedom dynamic model of an engine mount system. Tests were also made on their vibration severity. Calculation and test showed that the dynamic model was correct and feasible. Test was further made on the vibration transfer efficiency of wire-net isolator. The wire-net isolator has better characteristics than that of the rubber isolator. The results have reference value in engine’s further design.

Abstract: Based on the combination of modal analysis technology and finite element method (FEM), the modal parameters identification of the main parts of a diesel engine (crankshaft ,connecting rod and oil pan) were tested using hammer beat method and calculated by means of I-DEAS software. The natural frequency and shake mode parameters of the parts were identified. The results could provide basis for structure dynamic analysis and control of noise of the diesel engine.

Abstract: Hydroplaning ranks a maior inducement of wet-weather road accidents. By way of CFD (Computational Fluid Dynamics) approach, this paper frames a finite-element meta-models for rib tires ranging in groove depth, aiming to figure out the wheel water pressures on tires under different traveling conditions, and to find out water velocities of the different parts of the tire tread. Analysis shows that the action coverage of the high pressure induced by hydradynamic pressure is correlated with the thickness of standing water, and the grooves fail to drain as designed in case of total hydraplaning. Based on the outcomes of the experiments, this paper frames the relation formula between hydradynamic pressure and traveling velocity, standing water depth and tire tread groove depth, and thus gives recommendations on speed range in wet weather driving, and also on measures for safe driving in wet weather conditions.

Abstract: This paper describes a general bearing profile for the water-lubricated rubber journal bearing. Characteristics of the most popular water-lubricated rubber journal bearing, the straight fluted bearing, were deeply analyzed. The bearing profile was expressed using subsection function and a parametric and controllable shape model was built. By adjusting the parameters of the shape model, the existing bearing profiles can be integrated into the shape model and some bran-new bearing profile can be generated from the model. The rigid film thickness equation was achieved using the shape model and the relationship between the load capacity and the parameters of the shape model was established with the neglecting of elastic deformation effect. It is seen that the dimensionless load capacity reduces with the increase of the transition arc radius, the flute radius and the number of flutes,. The Necessity of the research on the bearing profile and the correctness of the shape model are validated. The parametric and controllable shape model is the foundation to study the fluid-solid coupling effect and to carry out the multi-disciplinary cooperating optimization for the water-lubricated rubber journal bearing.

Abstract: Based on the damage scalar model and the sensitivity analysis of frequency and mode shape, the Combined Multiple Damage Location Assurance Criterion (CMDLAC) based on the change of frequencies and mode shapes was proposed. Then, the damage identification problem is transformed to the constrained optimum problem and the genetic algorithm (GA) is adopted for the damage localization of beam structures. At last, the numerical simulation results of a 3-span continuum beam structure verified the proposed method.

Abstract: Considering centrifugal force and Coriolis force caused by the real-time deformation of bridge, a vehicle-bridge interaction model is established. Take simply supported bridge subjected to an one-axle vehicle for example, the mass matrix, damping matrix, stiffness matrix and load vector of the vehicle-bridge system are derived via modal analysis method, thus the vertical motion equation of vehicle-bridge system, which can better reflect the operation characteristics of vehicles running on the bridge, has been established.

Abstract: This paper presents the design methods of CQU-DTU-B21 airfoil for wind turbine. Compared with the traditional method of inverse design, the new method is described directly by a compound objective function to balance several conflicting requirements for design wind turbine airfoils, which based on design theory of airfoil profiles, blade element momentum (BEM) theory and airfoil Self-Noise prediction model. And then an optimization model with the target of maximum power performance on a 2D airfoil and low noise emission of design ranges for angle of attack has been developed for designing CQU-DTU-B21 airfoil. To validate the optimization results, the comparison of the aerodynamics performance by XFOIL and wind tunnels test respectively at Re=3×106 is made between the CQU-DTU-B21 and DU93-W-210 which is widely used in wind turbines.

Abstract: The mechanical clinching process was a new alternative method for metal sheet joining technology which geometrically constrains two sheets by local deformation. The tools geometry was crucial since it directly influences the joint resistance. How to determine the value of the tools parameters was always the difficulty. In view of this, a fast and efficient tools design method was proposed in this paper based on the mechanical relationship of process variable and FE-analysis technology. Besides, the tensile test and shear test results were shown in this study for proving the validity of the method which indicated that this design method could meet the requirements of the joint resistance and would bring much more convenience in clinching tools design.

Abstract: In this paper, the support vecstor regression (SVR) approach combined with particle swarm optimization (PSO) is proposed to establish a model for predicting tungsten tensile strength base on the tension experimental data of tungsten alloy under two influential factors, including tungsten content and deformation magnitude. Comparing the prediction result of PSO-SVR model with that of back propagation neural network (BPNN) model, it is shown that the prediction precision of SVR model is higher evaluated by identical training and test samples. The mean absolute error (MAE), mean absolute percentage error (MAPE) and root mean square error (RMSE) of SVR model, all are smaller than those of BPNN. This study suggests that SVR is an effective and powerful tool for predicting the tensile strength of tungsten alloy.

Abstract: Based on the theory of FEM, the hooklift arm is modeled with the FEM software, and the structure of the device is optimized with genetic algorithm in a multi-objective/multi-parameter optimization environment, which results in an optimal design decision of the hooklift arm device under the engineering constraint. Comparison between optimized design decision and original design decision shows that the optimization is correct and the proposed multi-objective/multi-parameter optimization method is effective in improving the hooklift arm device.