Applied Mechanics and Materials Vols. 130-134

Abstract: Multi-axial low cycle fatigue was the main failure mode of turbine disk. Critical plane approach was an idea method for the prediction of multi-axial fatigue life. A lot of models based on critical plane approach have been put forward, but there is not a universal prediction model. In order to find a model for turbine disk, linear heteroscedastic regression analysis of the standard low cycle fatigue data was carried out to obtained fatigue parameters. After verifying the accuracy of the finite element model, the stress and strain history of the danger point was obtained based on elastic-plastic finite element analysis. The critical plane and the damage of it was found by the method of coordinate transformation. The fatigue life of turbine disk was estimated by different models, and the results were quite different. SWT-Bannantine model was more suitable for the turbine disk.

Abstract: The dynamic equations derived based on the actual rotor system with two asymmetric disks. In the analysis, the eccentric, rubbing fault characteristics and internal damping effects is considered, and all the analysis is established based on nonlinear oil film force model and coupled bending-torsional differential equations. The Rugge-Kutta method is used to solve numerical model, the torsional displacement response, torsion angle and Poincare map are obtained. The results show torsion amplitudes with initial phase difference π / 2 is larger than initial phase difference of π and 0. In order to eliminate the rigid rolling component the relative torsional angle must be considered.

Abstract: Design for product family is an efficient way to guarantee the idea of mass customization to be implemented successfully. This paper presents an approach to architecting a product family that aims to provide methodological guidance for enterprises which plan to implement strategy of product family design. Based on the conventional methodology of designing for a single product, this paper respectively demonstrates the methods of requirement modeling, function-principle modeling and structure modeling in details according to the characteristics of product family design, and also some key approaches in different design processes are presented.

Abstract: To investigate the effect of air flow in an pneumatic splicer on splicing performance, a computational fluid dynamics (CFD) model has been developed to simulate the air flow characteristics in an splicing chamber. Three-dimensional numerical simulation is conducted and standard K-ε turbulence model is used. Velocity distributions in the chamber are presented and analyzed. The computational results show that the velocities in the chamber are transonic. The air flows in the chamber are two swirling flows with opposite directions. This work also shows that CFD technique can provide a better understanding of the behavior of the high speed air flow in the air splicing chamber.

Abstract: In order to obtain the collision damping of blades’ tips characteristics, around a blades for a 300MW steam turbine, the COMBIN40 element of ANSYS was adopted. The collision damping among blades' tips is equivalent to a damping of spring and friction with a gap. Under the conditions of exciting force and rotating blade natural frequency ,the vibration of a harmonic response was analysed, the nonlinear impact damping of blade response characteristics and the vibration damping mechanism of collision was got.

Abstract: A parametric designing program which is used for the analysis of metal bellows’ stiffness, strength and fatigue life is developed basing on the software’s which contain Ansys, MSC.Marc, MSC.Fatigue and UGII in this paper. A designing and analyzing system with highly automation and standardization is established combined with VC++ and other programming languages compiling system interface,arranging the process automatically and generating the results automatically.

Abstract: He sensing of the weld pool and controlling of torch at the center of the groove are important problems in back welding of GMAW (Gas Metal Arc Welding) for pipeline, furthermore, the gap of the groove perhaps is varied, which needs an intelligent control strategy to obtain the high welding quality. Fuzzy neural network control method based on BP algorithm is proposed in this paper, from the module of image processing, the corresponding gap location and width can be obtained. Then determine corresponding swing width and speed when weld gap is varied by the network fuzzy inference and calculating Euclidean distance for GMAW variable gap backing welding process. Experiment results show that the designed control method can improve the welding quality compared with traditional fixed swing and the traditional auto swing.

Abstract: A dynamic modal of the milling of ball end milling is presented for the simulation and analyzing the influence of the milling parameters on milling in order to avoid the vibration. The milling cutter and constrains are simplified to be a system with the two modes of vibration, the modal is developed considering effective cutting area of the cutting edge and regenerative effect, which directly reflects the cutter-in and the cutter-out. The mode testing and identifying determine the equation coefficients. It is found that reducing the milling depth can improve the stability and avoid self-excited vibration milling when the depth less than the critical milling depth, the frequency of the milling system will change while changing the rotate speed of the spindle, the self-excited is prone to occur when the frequency is close to the natural frequency. The results of simulation are benefit of the milling and optimal design of the parallel machine tools.

Abstract: Technology of pyrolysis rotary furnace for oil sludge was conducted in this paper, which feature with natural gas as fuel, multi-combuster for heating controlling and novel dynamic-static sealing structure at both ends of the rotary furnace. A complete set of technical process was designed and operated with processing scale of 10 tons/day of oil sludge (The sludge moisture content is 80%). The result indicates that the system meets the standard of safe running. Recovery rate of the oil in sludge is more than 80%, while the oil content of pyrolytic residues is less than 0.3%. The main components of non-condensable gas include methane and hydrogen, occupying 35% and 40% respectively. There are high content of lightweight fractions in pyrolysis oil, such as gasoline, kerosene and diesel oil, in which the C10-C15 is near to 50%-60% and aromatics can be up to 60％. Finally, due to the high contents of carbon and aluminum salt in residue, it is much worth for the carbon and aluminum salt recovery.

Abstract: The use of a variety of means of control in the engine combustion temperature in the low load has been more widely used. Although the opacity of the filter paper on smoke (FSN) was used as a standard in many laboratories PM quality parameters measured, but cannot be measured under different conditions the engine size and number of particles in a major change, especially in smaller size The particles on the human body more dangerous trends. So a study of particle size distribution of a heavy diesel engine emission was investigated under the condition of different intake valve closing timing, different EGR, different injection timing and multiple injections.