Applied Mechanics and Materials Vols. 217-219

Abstract: In this paper, an intelligent water drop algorithm or IWD has been developed to optimise machining parameters in turning operation including a spring force model. Firstly, machining conditions are to minimise the production cost in conventional manufacturing processes. Several passes of rough machining are started on the turning operation with a final pass of a finishing. Various constraints are considered in each non-linear and non-convex model. The machining parameters in the turning consist of the depth of cut, cutting speed and feed. Finally, in a specialised manufacturing application on the spring force problem, an achievement of a specific goal may be the primary objective subject to some process parameter ranges. The computational results clearly showed that the proposed sequential procedures of the IWD have considerably improved the objective functions.

Abstract: A cellular automaton (CA) model was established to predict and control the microstructural evolution and flow stress characteristic during dynamic recrystallization (DRX). Values of model parameters were identified by a flow stress-based inverse analysis method; their variations with deformation conditions were estimated by the least square regression method and then integrated into the CA model. The effect of initial microstructure and deformation conditions on the microstructural evolution and flow stress behavior were investigated. The simulation agrees well with the experiment, which demonstrates the availability of the CA model.

Abstract: The particle motion in fluid has attracted much attention in material engineering concerned the particle effects such as the debris in lubrication and the particles deposition in material processing. By taking the hydrodynamic effect into account, the pressure distribution around particles in fluid in confined wedge space is analyzed. The influences of the particle position, particle shape and its velocity on the pressure distribution are also investigated. Results show that in confined wedge space, the fluid pressure around the particle in the side near the upper slope plate is larger than that in another side, which may make the particle move downwards. And the pressure discrepancy between both sides of the particle increases with the particle shape, the particle velocity and the particle coordinates in both directions of x and z. These special phenomenons may be used in structured surfaces fabrication based on particle deposition by constructing special fluid field.

Abstract: A phase-field approach which incorporates mass and momentum and solute conservation equations for simulation of Al-Si binary alloy solidification is studied. The effect of force flow on the dendrite growth and solute profile during the solidification of binary alloy were investigated. The results indicate that dendritic grows unsymmetrically under a forced flow, the growth velocity of the upstream tip is faster than the downstream tip. With the force flow, the upstream tip grows faster due the thinner solute boundary layer. The solute gradient in the solid/liquid interface regions of the upstream tip is higher than that of the downstream tip. The faster the flow velocity, the greater the solute gradients in the solid/liquid interface regions of the upstream tip, the thinner the diffusion layer before the upstream tip. The downstream tip is opposed to the upstream tip. The simulations agree qualitatively with the solidification theoretical results.

Abstract: Since it is difficult for ultrasonic vibration compound machining to get effective cutting mechanism mathematical model through dynamic analysis, and testing study is shown an effective method to solve this problem. Central Composite Design (CCD) testing was used to carry out following researches. Second-order relational model was established between tangential cutting force, surface roughness, and their main technological factors involved in SiC wafer vibration compound machining. Constraints of actual processing conditions on technological factors were discussed. Optimized target function was established to enhance processing efficiency of SiC wafer, which meant taking maximized sawing force as target. Particle Swarm Optimization (PSO) algorithm was designed to solve the issue, and obtain optimized process parameters meeting kinds of constraints.

Abstract: A prediction model of deflection is presented. The Artificial Neural Network (ANN) is adopted, and ANN establishes the mapping relation between the clamping forces and the position of fixing and the value of deflection. The results of simulation of Abaqus software is used for Training and querying an ANN. The predicted values are in agreement with simulated data and experimental data.

Abstract: The wind load on large cranes with great windward areas cannot be ignored. The simulation of wind field is to determine the accurate wind force acting on different parts of cranes and serves as the basis of the windproof design. Taking 300t shipbuliding gantry crane as the study object, this paper uses computational fluid dynamics, calculates the mechanical response of cranes by FLUENT, obtains the graphs of pressure, streamline, force distribution of cranes under different wind loads. Through the result analysis, dangerous force position is pointed out. And the ideas of structural methods to improve the windproof ability of cranes are also proposed.

Abstract: In this paper, according to the characteristics, dynamical behavior and the experimental data of the batch anaerobic culture, a parameter identification model was improved to describe the dynamical system for microorganism in batch fermentation. And some relative characters were introduced. Finally, a PSO algorithm with the inertia weight was used to get the best optimal parameter of the identification model. The results show that the model reduces the errors between the experimental data and computational values, and they can simulate the process of batch fermentation better.

Abstract: The drilling of multi-layered structural members has been a crucial process in aeronautic manufacturing. The burr formation on layer surfaces, especially on inter-layer surfaces, causes extra amount of deburring operations which waste time and cost. The inter-layer burr formation depends greatly on the size of the inter-layer gap which results from different deformations of the upper layers and the lower layers during a drilling process. Based on the theory of plates and shells, this paper discusses the drilling process of two stacked circular Al-2024T3 plates with edges built-in. The dependence of the inter layer gap formation on the pressing parameters and the axial drilling force is also discussed in this report.

Abstract: Based on fuzzy optimization design ideas, system fuzzy decision-making theory and fuzzy optimization theory are adopted to conduct optimal design on the drilling processing technique of main pin hole of vehicle front shaft in this essay. By analyzing controllable factors and boundaries fuzziness, confirming objective functions, a satisfying result has been acquired, which indicates that fuzzy optimization design theory has good application foreground in drilling processing industry.