Papers by Keyword: Computer-Aided Simulation

Abstract: The work described in this paper pertains to the identification of some features of micro- and macroprofile formation of surfaces to be machined with flat face grinding, with inclination of the spindle axis. The question of the formation of machined surface profile at through-feed grinding and multiple-pass scheme are considered by using computer-aided simulations in COMPASS environment. More specifically, for flat face through-feed grinding, a generalized empirical equation exhibiting the dependency of concavity from the outer diameter of the face grinding wheel, the spindle axis inclination angle and the width of the surface of the workpiece is acquired. Furthermore, based on the maximum allowable value of flatness deviation and with pre-determined grinding wheel diameter and workpiece width, it is possible to identify the maximum inclination angle at which concavity falls within acceptable limits. For the case of multiple pass flat face grinding, the role of factors such as inclination angle of spindle axis, cross-feed and diameter of the grinding wheel on the height of residual ridges on the surface of the parts is determined through the proposal of an empirical equation. With the aforementioned equations the machinist may reasonably prescribe machining conditions in practice. The conducted research contributes to the expansion of ideas regarding technological possibilities of improvement of flat face grinding.

Abstract: The surface of a grinding wheel dressed by a diamond rotary dresser was generated by computer-aided simulation for the case of multipass dressing on the assumption that the grinding wheel is a homogeneous solid body and the dressing trajectories of the diamond grits are perfectly copied on the grinding wheel surface. The dressing process was visualized as a contour map of the dressed surface profile and the effects of the dressing strategy, i.e., down-cut dressing or up-cut dressing, on the grinding wheel removal process were investigated. It was found that the diamond grits remain the residual depth of cut on the surface of the grinding wheel, resulting in an actual depth of cut larger than that given by the rotary dresser.

Abstract: A computer-aided simulation was developed to visualize the three-dimensional topography of a grinding wheel surface dressed by a rotary diamond dresser (RDD), and the effects of up-cut and down-cut dressing on the roughness of the dressed surface were examined to demonstrate the effectiveness of the simulation. In the case of single-pass dressing, the roughness of the grinding wheel surface decreased with decreasing dresser feed rate and approached a constant value depending on the velocity ratio of the RDD to the grinding wheel. In the case of multipass dressing, up-cut dressing provided the grinding wheel with a surface topography which was much more stable than that provided by down-cut dressing.

Abstract: The product corrosion causes safety issues in flight vehicles and capital losses in aerospace industry. Since some geometrical surfaces and shapes such as hidden slot and pocket structure can easily contain moisture droplets and air impurity, the corrosion caused by chemical composite in aerospace products can be accelerated leading sudden flight vehicle failure and even personal fatal injury. Nanoparticle coating technology is a relatively new and efficient methodology in anti-corrosion since it can distribute very small material particles in complex geometrical structures to produce extremely durable and very strong surface coating to significantly decrease product corrosion. This paper studies the anti-corrosion mechanism in order to reduce corrosion damage by applying computer-aided simulation and prototype testing to verify nanoparticle coating performance. Both computer-aided simulation and prototype testing show close results which validate the methodology introduced in this research and demonstrate superior corrosion-resistant performance of nanoparticle coating to current regular coating methodologies.

Abstract: The main flaws of electric arc welds and factors determining the quality of the welded seams are considered in this paper. In practice, welding tools and their control systems are affected by some external factors causing deviation of the weld’s quality from the specified values. Currently used control systems of welding tools do not always satisfy the requirements for quality of welded joints. Major principles of developing the adaptive control system of the welding tool are considered here and the developed functional and block diagrams of microprocessor system are presented. General equations describing the welding process are also provided and the obtained transfer function of a closed system is described.