Papers by Keyword: Mechanical Deformation

Abstract: Welding technology, as one of the process of manufacturing material in the permanent link, are already widely used in various kinds of aerospace ground launch equipment. Modern manufacturing industry is in rapid development phase, the welding automation is inevitable trend of production, which not only can greatly improve the efficiency of welding, but also what more important is to ensure the welding quality, thus to improve the operating environment. Modern welding is developing in the direction of mechanization, automation, intelligence, robot welding has become an important symbol of welding automation technology modernization. This paper focuses on regularity and influence of welding deformation, the welding deformation and deformation control, control and eliminate problems for research.

Abstract: Finite Element Method numerical simulation has been carried out to analyze mechanical deformation of thrust bearing under the point and line supporting condition. The simulation results indicate that the torsion deformation of the point supporting is the larger, torsion deformation is mainly radial bending deformation, and circumferential bending deformation is small, it becomes more and more obvious with the decrease of bearing pad length-width ratio under the same working conditions for the same pad. Line supporting torsion deformation is mainly the circumferential bending deformation, and the left and right sides are symmetrical along the circumferential, the radial bending deformation is small, torsion deformation related to the length and width of supporting, with their size increasing the torsion deformation decreased.

Abstract: The grinding process is currently used for most of the parts requiring good precision. However, the apparition of some damage related to this process is still uncontrolled. The major deterioration is from residual stress. In order to investigate the residual stresses caused by mechanical plastic deformation, thermal plastic deformation and phase transformation in ground components, a feasible numerical method was developed to accommodate appropriately thermal stress and phase transformation in a workpiece experiencing critical temperature variation during grinding. The change of the material properties was modeled as function of temperature history. The wheel velocity V_s is a key factor in determining the distribution of residual stress; both the surface residual stress and the depth of residual stress are induced with the increase of the wheel speed.

Abstract: Deformation of round castings due to thermal and/or mechanical strain may lead to the occurrence of their ovality defects during continuous casting. Presently, ovality defect from thermal deformation have been effectively controlled in actual casting process with the application of more advanced equipments and more sophisticated control strategies. But the control of ovality defect from larger mechanical deformation still cannot satisfy the need of caster design or higher qualified rate of castings. It is shown that excessive hot pressure while strand passes through tension leveler, is the main reason to generate larger mechanical deformation. With consideration of the characteristics of round caster and the requirement of safety production, a theoretical calculated model based on mechanical deformation analysis has been developed in the paper to eliminate ovality defect specially from the over large hot pressure. Calculation analysis suggests that groove design of drive roller and range of round section sizes should be the important consideration for the determination of hot pressure, and there always exists an optimum value for hot pressure when the machine equipments of round caster have been designed and installed. The model can provide a useful guideline for casting engineers to design the groove of drive roller and to determine reasonable safe hot pressure. Reliability of the model analysis has been verified by industrial application on a newly built round caster.

Abstract: Large scale computer simulations suggest that in nanocrystalline metals grain boundaries act as source and sink for dislocations. This suggestion has been the motivation for developing a new in-situ X-ray diffraction technique that allow peak profile analysis of several Bragg diffraction peaks during tensile deformation. Synergies between simulations and experiments are discussed including new applications of the in-situ technique.