Papers by Keyword: Predicted Model

Abstract: Researching on the mathematic model of surface roughness in machining hardened steel was to provide the reference for the surface roughness prediction. The contrast experiments of dry turning hardened steel were carried out with ceramic tool (CC6050), cubic boron nitride tool (CB7025) and kentanium tool (GC2025), the surface roughness was measured using 2025 surface roughness tester, the predicted models of the surface roughness were built by Particle Swarm Optimization (PSO) algorithm, the reliability analysis was given out, the shape of chips was observed by scanning electron microscope (SEM). Results proved: the reliability of the predicted models built by PSO was to be verified, it could reflect the relation between the surface roughness and cutting parameters exactly. The feed rate was found out to be dominant factor on the surface roughness in turning with three tools. The saw-tooth chips could decrease the cutting temperature and improve the surface quality.

Abstract: It established a model for estimating the concentrations of heavy metals pollutants in exhaust gas and waste water from coal-burning power plants. By studying the sources, forming processes and the probable effects to environment of the main heavy metals pollutants(（Hg，As，Cd，Pb，Cr）)in exhaust gas and waste water from coal burning power plants. The prediction of heavy metals pollutants in exhaust gas was based on conventional calculating model. The key factors were ascertained, the material conservation theory and the on-line data of coal quality were used to build the formula for calculating the quantity and the concentration of the gas contaminants. The predict of heavy metals pollutants in water had aimed at the status of ash-flushing system in power plants, ash-water in two different types ash-flushing systems was researched separately. Not only the material conservation for macroscopically consideration, but also several chemical reaction that probably exit in ash-water were took into account. The power plant monitor and prediction software using VB and access database were developed based on the above prediction model.

Abstract: The effect of fly ash in improving the mechanical properties of concrete is investigated and the existing concrete strength development models are studied. Based on the chemic reactivity properties between fly ash and cement, an appropriate concrete strength model are chosen, and a new model for the fly ash strength factor combing Maturity method is built up and the factors are regressed by existing experimental datum. A total of 24 concretes, including two concretes were produced with two partial fly ash replacement ratios (23.7%, 32.7%). The cubic samples produced from ash fly concrete were demoulded after a day, and cured at standard temperature ( in GB/T 50081-2002) with 100% relative humidity until 28 days, then cured in water. The compressive strength tests were carried out on the cubic specimens at different ages. The compressive strength with time was evaluated by using the new predicted model. It was found that the calculated results by new method are fit the experimental data well.

Abstract: Thin-walled parts with complex configurations are extensively used in aerospace and precise instrument industry. However, because of low stiffness, cutting forces, clamping forces and residual stresses in cutting have been the main factors influenced on machining accuracy of thin-walled parts. Furthermore, biggish deviation exists between practical finished surface and theoretical value as a result of machining deformation caused by cutting force namely “cutter relieving” phenomenon; besides, direct relation exists between determination of clamping force and generation of machining residual stress and cutting force, so it is necessary to build up accurate cutting force prediction model to improve the machining accuracy of thin-walled parts. Therefore, cutting force prediction model based on Johnson-Cook’s flow stress model and Oxley’s shear angle model has been developed, which takes the property of high strain, high strain ratio in area of cut and high cutting temperature into account fully and determines shear angle more accurately on the basis of force balance principle; with different cutting and tool geometric parameters existing, perform simulation and experiment studies on cutting force prediction model, verify the validity of prediction model and obtain the response rules resulted from cutting force prediction model acting on cutting and tool geometric parameters.

Abstract: The modulus of elasticity of wood, fiberboard and wood-fiberboard composite was measured by nondestructive test (longitudinal transmission vibration method). The predicting model of the modulus of elasticity of wood-fiberboard composite was discussed. This study has shown that the wood ratio has substantial effect on the modulus of elasticity of wood-fiberboard composite. The modulus of elasticity of wood-fiberboard composite can be predicted from volume fraction of wood by simulation formula. The model Eq.(3) can be used to predict the modulus of elasticity of the wood-fiberboard composite from the modulus of elasticity and volume fraction of wood and fiberboard when M=0.92~0.97. The model Eq.(4) can be used to predict the modulus of elasticity of the wood-fiberboard composite from the modulus of elasticity and volume fraction of wood and fiberboard when M=0.97~0.99.

Abstract: During the Machining process of a part, along with the generation of new surfaces, various machining errors are produced. These machining errors depend on the characteristic of the manufacturing process system, as there are so many undetermined factors in the process system, it is very difficult to determine the machining accuracy of the workpiece. To the operator, the final accuracy of the part is very ambiguous, he can only consider the shape of the workpiece, and machining accuracy always be controlled by selecting different sets of cutting parameters. So the machining process is always time-consuming and costly. Therefore, it is very necessary to establish the accuracy predicting model to the workpiece. In this paper, According to the characteristic of turning, tool nose is abstracted into a “tangential point”, “three instantaneous centers” method is presented to get the reality shape of the workpiece. Using this method, and with the demarcating the errors in process system, the workpiece shaping model including multi-error is established. The model can not only describe the physical state of the workpiece, but also calculate the machining accuracy of the workpiece conveniently. In this paper, ‘three instantaneous centers’ method is developed to get a workpiece reality shape in turning. Using this method, the workpiece shaping model including multi-error is established. The model can not only describe the physical state of the work-piece, but also calculate the machining precision of the work-piece online.