Applied Mechanics and Materials Vols. 37-38

Abstract: The large deformation of powder molding pressing machine in the load affects the accuracy of the machine. The model of powder molding press was simplified by finite element method. ANSYS software was employed to simulate the location of the frame deformation in load, deformation and stress distribution of the real case. The sizes and structures of the powder molding pressing frame were changed, such as adding stiffeners on the both sides of the frame support shelf to improve the support plate bending rigidity and resistance to flex capacity. The results showed that the increasing thickness of the steel plate can reduce stress concentration. The overall deformation reduced from the original 0.361688mm to 0.254033mm. The maximum deformation area transferred from the support rack of the frame to the edge of mold shelf. The deformation of Y direction is reduced from 0.336271mm to 0.186853mm. The optimized deformation of the rack and the mold shelf significantly is reduced.

Abstract: As the traditional calibration methods are difficult to ensure the calibration accuracy and system stability, a new optimization design of the secondary calibration based on Levenberg- Marquard (LM) algorithm is proposed. It is the optimization and correction of the first calibration results. The method introduces the optimization idea of the LM algorithm. The required objective function can be obtained by capturing the image of standard block after the first system calibration. The problem is solved satisfactorily with the optimization theory of LM algorithm. Experimental results show the optimized system accuracy is less than 0.01mm, RMS error is less than 0.02mm. The proposed algorithm has significant effect on accuracy improvement, and the system is more stable.

Abstract: In machines working under the effect of alternating stresses, the fatigue bending deflection occured occasionally. On the basis of the Fuzzy Reliability Theory and with full consideration of the fuzzy factors during mechanical process, the paper studied the fuzzy reliability optimal design for the hollow spindle of multi-functional jade carving machine and improved the design quality of the jade carving machine spindle by probing into the combined model constructed by the random variables and fuzzy variables. The design was approved to be advanced, reliable and practical in service and provided a new way for the design of multifunctional jade carving machine spindle and other mechanical products.

Abstract: In this paper, the connection parameters of HSK tool-holder are investigated. After simulation analyses, the results show that the positioning accuracy of tool taper face and flange face can be improved for mezzo magnitude of interference and medium-high pre-tighten force. Meanwhile, higher magnitude of interference and pre-tighten force are more favorable for the stiffness improvement of HSK tool. For the special spindle structure, the optimal priorities of the connecting system with different parameters are obtained with the analytic hierarchy process.

Abstract: The optimization of collaborative scheduling in supply chain was studied. Aimed at minimizing processing time, the model of collaborative scheduling in supply chain was established. The genetic algorithm using hybrid double-coding was applied to the model. By analysing suppliers’ scheduling, the scheduling results can direct suppliers to reasonably arrange the production and act as reference for manufacturers in distributing orders also. The numerical experiments show that the satisfactory solution can be obtained through optimization.

Abstract: How to acquire prior distribution is a key to Bayes method. Firstly, a nonlinear constrained optimal model of probability density function based on the principle of maximum entropy is set up. By using Lagrange multiplier this constrained optimal problem is transformed to a non-constrained optimal one, which is solved by standard particle swarm optimization (PSO) algorithm. Secondly, a new improved particle swarm optimization (IPSO) algorithm is proposed because standard PSO is slow on convergence and easy to be trapped in local optimum. IPSO introduces the hybrid method from genetic algorithm (GA) so that the overall searching ability is enhanced; then linear decreasing inertia weight is used to optimize particles. The simulation examples show that IPSO is simple and effective and it can rapidly converge with high quality solutions.

Abstract: The flat end face mechanical seals are widely used in shaft sealing at moderate rotational speed. The thermal deformation of the rotating and stationary rings initiated by friction heat of fluid film should be primarily considered in the design of mechanical seal. In consideration of the coupling effect among the thermal deformation of sealing rings, the fluid flow in the gap composed by end faces of sealing rings and the heat transfer from fluid film to sealing rings, the optimum design method for flat end face mechanical seal is established. The end faces are fabricated to form a divergent gap at the inner side of the sealing rings, and a convergent gap will occur at the outer side and a parallel gap will be obtained at where the original divergent gap is due to the thermal deformation. After optimization, the leakage rate can be reduced while the bearing force of fluid film is still large enough to keep the fluid lubrication of the end faces.

Abstract: This paper applies differential evolution (DE) algorithm to realize the output tracking control and synchronization of continuous chaotic systems. The output tracking control of single-input single-output (SISO) and multi-input multi-output (MIMO) chaotic system is investigated. Moreover, synchronization of chaotic systems with parameter mismatch or structure difference is also under discussion. Numerical simulations based on the well-known models such as Lorenz and Chen systems are used to illustrate the validity of this theoretical method.

Abstract: The study concentrated on a radial telescopic-type tire building drum, analyzed the frameworks and working principle. Make motion analysis and dynamic analysis for the frameworks, research the relations of speed, acceleration between them, and analysis the mechanical efficiency of them. Determine the main parameters that affect the motion and force transmission characteristics of the mechanism. On this basis, we optimize the parameters and make of general guidelines for preferences and design. Using the software SolidWorks to make three-dimensional entity modeling, assembling and motion simulation. By the check analysis of the software, improve and optimize the design.

Abstract: The accurate mathematical model is an important tool for simulation and design analysis of fuel cell power systems. Semi-empirical models are easier to be obtained and can also be used to accurately predict the performance of fuel cell system for engineering applications. Particle swarm optimization (PSO) is a recently invented high-performance algorithm. In this paper, a parameter optimization technique of PEMFC semi-empirical models based on DKPSO was proposed in terms of the voltage-current characteristics. The simulated and experimental data confirmed the validity of the optimization technique, and indicated that PSO is an effective tool for optimizing the parameters of PEMFC models.