Applied Mechanics and Materials Vols. 201-202

Abstract: It is necessary to study the dynamics and load-bearing characteristics of ropes in order to guarantee the stability and reliability of hoisting equipments. Based on ADAMS, a parametric coupling model of rope winded along cylindrical helix is built by force field. An optimized simulation method, cooperating fixed joints with angle sensors under the control of script, is recommended. Studying on the construction system of deep vertical shaft wall, the bucket is placed at static equilibrium position by preload defined in force field and dynamics behaviors of the center of mass in bucket are researched. The results indicate that the displacement curve is successive and complete, thus it confirms that the driving method is reasonable and feasible. This method could not only guarantee the accuracy and stability but also increase simulation efficiency, providing a new simulation approach for one kind of flexible body such as ropes and cables.

Abstract: Shape transformations in sketches have been utilized as a way to address the reasoning process in design activity. The research on the representation of the reasoning process is still in its infancy. The purpose of this study is to explore the representation of the reasoning process of shape transformations in sketches by using shape grammar and ontology. In our framework, a shape grammar performs shape transformations based on information provided by the ontology. Shape grammar and ontology are both contain design rules, sketch related knowledge is captured in the ontology and processed by shape grammar to represent the reasoning process. The combinatorial nature of design rules encapsulated by shape grammar and ontology offers the possibility that reasoning process of shape transformation in the sketch can be represented explicitly.

Abstract: The lightning current parameters are very important for the lightning-line monitoring, they can provide important raw data for the construction of power grids and lightning protection engineering, conducive to the maintenance of high voltage transmission lines. But also provide the objective basis of the lightning accident analysis and statistics of lightning law. In this paper, we have Investigated parts of the complex and diverse terrain characteristics of Guizhou Province, we plan to design a simple, economic, effective data acquisition system for lightning current, timely and accurate grasp of the local lightning. we have done some research on the measurement mechanisms of lightning current strength. First, a novel lightning current strength detection program is proposed, and then we have done a lot of tests on the program and depicted the related parametric curve. Last, we verify the linearity of this sensor.

Abstract: The key point of the design of combinatory cam is the design of vice-cam contour curve. A series of dots on the follower’s path curve which driven by the unknown vice-cam were achieved by using the PROE’s curve modeling capabilities and motion simulation function. Then import these points into the curve fitting capabilities function of AutoCAD and a certain extent smooth curve that stringing every point were obtained. Finally, the curve we got from the last step was imported back into PROE, and the unknown vice- cam can be deduced.

Abstract: By research of the mix technology of VC++ and Matlab based on Matcom software, the insufficiencies of data processing in VC++ and visual programming in Matlab have been sloved effectively in signal processing. The own definition functions by matlab can be converted to the C code with Matcom,then the functions can be called anywhere if you need.Using this mix technology, the vibration signals collected by UA307 data acquisition card have been transformed by FFT and the results are consistent with Matlab’s. The mixed-program can operate independently without Matlab software and this method is a good reference to the development of the signal processing system.

Abstract: Working state of compressor valve plays a key role in compressing. Valve plate opening not timely or even chattering is a major problem in the process of air passed into the cylinder. This paper through the improvement of valve seat to increase the pressure exerting on the valve plate then to reduce or even to eliminate the phenomenon mentioned above is a good try. With the help of software to do simulating calculation of flow field for the contrastive models of the seat channel, proved that the improved structure achieves the goal designed. This may provide a new way to the valve improving designation and make certain significance in practice.

Abstract: Accurate detection of weld seam deviations from the desired path during laser welding process facilitates seam tracking monitoring and is thus of primary concern in performing successful weld. This paper proposes a novel method for real-time seam tracking monitoring during high-power fiber laser welding, as it investigates into the techniques of infrared image sensing and visual recognition. Molten pool images were taken by a high-speed camera arranged in the off-axis direction of laser beam. Accumulative grayscale variation based on a molten pool thermal distribution was extracted and used to determine the deviations between the laser beam focus and the weld seam center. The proposed algorithm was experimented on a butt joint laser welding of Type 304 stainless steel plates at a continuous wave fiber laser power of 10 kW.

Abstract: The tribological characteristics of nickel-aluminium bronze CuAl10Ni5Fe4 against 30CrMnSiA steel after the prior corrosion treatment was studied at the M2000A model wear tester. The wear rate of corroded specimen was less than that of uncorroded specimen at the early stage of prior corrosion treatment, while the wear resistances deteriorated and the average friction coefficient slightly declined with the extension of prior corrosion period. The tests of CuAl10Ni5Fe4 sliding bearing at PLS-100 swing tribometer were used to validate the results. The wear resistances of CuAl10Ni5Fe4 sliding bearing increased slightly after a short period of prior corrosion, and the average friction coefficient decreased slightly after a long term of prior corrosion. A suitable period of prior corrosion treatment can enhance the wear resistance performance of CuAl10Ni5Fe4 bearing. The tribological characteristics of CuAl10Ni5Fe4 sliding bearing tested by PLS-100 rack swing tribometer are consistent with the conclusions of the tests at M2000A model wear tester.

Abstract: Metamodeling techniques are commonly used to replace expensive computer simulations in complex engineering optimization problems. Due to the discrepancy between the simulation model and metamodel, the prediction error in predicted responses may lead to a wrong solution. To balance the predicted mean and prediction error, the efficient global optimization (EGO) algorithm using Kriging predictor can be used to explore the design space and find next sample to adaptively improve the fitting accuracy of the predicted responses. However in conventional EGO algorithm, adding one point per iteration may be not efficient for the complex engineering problems. In this paper, a new multi-point sequential sampling method is proposed to include multiple points per iteration. To validate the benefits of the proposed multi-point sequential sampling method, a mathematical example and a highly-nonlinear automotive crashworthiness design example are illustrated. Results show that the proposed method can efficiently mitigate the prediction error and find the global optimum using fewer iterations.

Abstract: The purpose of this paper is to explore a practical method of revolving machine’s field balancing and solve problems that the requirement of revolver balancing is high and the process is complicated in practical engineering. The paper introduces balancing principle of rotating machinery’s static balance and dynamic balance based on vibration test, and applicable conditions of different balance method. The paper mainly analyzes implementation steps and operation method of three point method field balancing based on vibration test, indicates points for attention in the process. There is no need for complicated testing equipment, just with common vibration meter, simple and practicable. In addition it is balanced in actual using condition, there won’t be problem that new imbalance comes into being after installation.