Advanced Materials Research Vols. 562-564

Abstract: Deficiencies are existed for currently formulas of mobility calculation for planar mechanism. They are not suitable for planar mechanism with virtual constraints and the number of general constraints equal to 4. To solve the problem, the new concepts of virtual loop, virtual-loop constraint and virtual pair are defined to establish a general f ormula for DOF of planar mechanism; the calculation method for virtual-loop constraint and the mobility of link-group are also given. It is proved that the new formula is correct, general, simple and effective through the mobility analysis of several different kinds of planar mechanisms.

Abstract: Based on mechanism of SLS, the scanning speed, laser power, preheat temperature and thickness of spreading layer are main factors to part quality in Selective Laser Sintering(SLS). With manufactured specimen pieces by Molding machine AFS-450, orthogonal experimental design and analysis of variance were adopted to post-treatment. Three indexes, including sintering strength, constriction percentage and sintering density, were studied. So an optimized project can be determined. This work can provide process parameters in SLS for ABS power. It will be of benefit to improve the part dimensional precision and strength.

Abstract: To find the changing regularity of stress and displacement, a 3MW wind-turbine main shaft was modeled and analyzed at startup time of operation. The results were verified by theoretical calculation. Parametric design of the shaft was used through orthogonal experiment method in which parameters were consisted of structural and load ones. The optimal regression equation, which indicated the relationship between the shaft stress or displacement and the parameters, was given by using polynomial regression with the test results.

Abstract: There are lots of practical problems which are related to the solution of Fredholm integral equations of the second kind. The present work proposes intervallic Coiflets for solving the equations. Illustrative problem involving dynamic stress and electric fields of a cracked piezoelectric excited by anti-plane shear wave is addressed. Permeable boundary condition has been used to obtain a pair of dual integral equations of the symmetric and antisymmetric parts which can be reduced to the solutions of two Fredholm integral equations of the second kind. The dynamic stress intensity factor is expressed in terms of the right-end values of two unknown functions in Fredholm integral equations. The two unknown functions are solved by intervallic Coiflets which have less the endpoints error. And intervallic Coiflets have low calculation cost and high accuracy due to the wavelet expansion coefficients are exactly obtained without calculating the wavelet integrations. The calculation results agree well with the existing method, which show the high accuracy of the estimation and demonstrate validity and applicability of the method.

Abstract: The balancing system of a four-bar mechanism is frequently applied for bucket staking-reclaiming machines. For this purpose, a Multi-objective optimum model is developed in this study. Moreover, Genetic Algorithm is used for optimal design of the derricking mechanism and further programmed using MATLAB toolbox. To this end, this approach improves the mechanism performance, loading condition and cost-efficiency.

Abstract: Created a standard involute spur gears which was interactive and paramatric by Pro/ENGINEER software. Set gear parameters, created involute profile, achieved 3D paramatric gear model and make an interactive automatic modeling interface with the help of VC++. The finished 3D model is of high precision and easy to modify. If the designed product which is standardized and serialized, the methods and skills of the paper involved are suitable to make a automatic 3D solid paramatric model.

Abstract: Aiming at the shortcomings of fixed coupling and flexible coupling with rubber component used in the diesel generator set, a new type of metallic-disc flexible coupling for diesel generator set of 500kW power was designed. The working principle and theory analysis of the metallic-disc flexible coupling were expounded in detail. The simulation analysis was carried out to determine the optimal numbers and thickness of the metallic-disc using ANSYS software. The relevant results can provide some guidance for the improvement design of domestic diesel generator set.

Abstract: The paper is to design a system that helps to select cutting parameters in standardization data and modular approach. The approach is based on industrial engineering methods defined by modular. The result is the parameters that take into account all the existing restrictive factors. First, a reasonable process to select cutting parameters is proposed. And then, the corresponding tools are designed. To achieve the standardization of the resources and process of cutting parameter selection, the resource contents and query actions are made in a uniform form. Finally, the selection of cutting parameters is realized within a management framework. It provides a scientific basis for selecting cutting parameters in actual production.

Abstract: The influence of the strain rate on the plastic deformation of the metals was significant during the high strain rate of loading. However, it was very difficult to obtain high strain rate data (≥ 104 s-1) by experimental techniques. Therefore, the finite element method and iterative method were employed in this study. Numerical simulation was used to characterise the deformation behavior of Hadfield steel during explosion treatment. Base on experimental data, a modified Johnson-Cook equation for Hadfield steel under various strain rate was fitted. The development of two field variables was quantified during explosion hardening: equivalent stress and strain rates.

Abstract: A class of problems is usually met in actual engineering, i.e., the low-speed motion of the slider of a linkage in a section of its stroke is required based on the prerequisite of ensuring the slider’s definitive working times. Through analyzing the mechanisms of low-speed Stephenson’s six-bar linkage, the main parameters of the slider’s low motion are found. The Stephenson’s six-bar linkage satisfying low-speed working requirements is designed through a mechanical press as an example.