No abstract

No abstract

, 94 pages The service lives of dies in forging processes are to a large extent limited by wear, fatigue fracture and plastic deformation, etc. In hot forging processes, wear is the predominant factor in the operating lives of dies. In this study, the wear analysis of a closed die at the final stage of a hot forging process has been realized. The preform geometry of the part to be forged was measured by Coordinate Measuring Machine (CMM), and the CAD model of the die and the worn die were provided by the particular forging company. The hot forging operation was carried out at a workpiece temperature of 1100°C and die temperature of 300°C for a batch of 678 on a 1600-ton mechanical press. The die and the workpiece materials were AISI L6 tool steel and DIN 1.4021, respectively. The simulation of forging process for the die and the workpiece was carried out by Finite Volume Method using MSC.SuperForge. The flow of the material in the die, die filling, contact pressure distribution, sliding velocities and temperature distribution of the die have been investigated. In a single stroke, the depth of wear was evaluated using Archard's wear equation with a constant wear coefficient of 1× 10-12 Pa-1 as an initial value. The depth of wear v on the die surface in every step has been evaluated using the Finite Volume simulation results and then the total depth of wear was determined. To be able to compare the wear analysis results with the experimental worn die, the surface measurement of the worn die has been done on CMM. By comparing the numerical results of the die wear analysis with the worn die measurement, the dimensional wear coefficient has been evaluated for different points of the die surface and finally a value of dimensional wear coefficient is suggested. As a result, the wear coefficient was evaluated as 6.5× 10-13 Pa-1 and considered as a good approximation to obtain the wear depth and the die life in hot forging processes under similar conditions.

No abstract

SFF and EFF are meshed with hex elements and the This paper describes the structural analysis carried out on honeycomb panels are meshed with solid brick and shell the main stiffened and honeycomb panels of the RASAT elements. For the calculated gRMS value the static analysis had satellite. The analysis here supports the design process and been conducted in each axis of the panel assembly. For the aims to ensure that the panels survive structural qualification dynamic case, the same finite element mesh and material testing. This analysis therefore forms part of the overall properties had been used. In this case, the boundary conditions qualification process. The stiffened and honeycomb panels are applied in such a way to determine the mode shapes and the being considered in this document form the outer box structure resonance frequencies. Furthermore, the stress values had been of the satellite. These panels consist of the space-facing facet determined with respect to the applied static and dynamic (SFF), solar panels including solar cells and earth facing facet loading cases. They had been compared with the allowable (EFF). All these panels are key parts of the satellite's structure stress values of the materials. In this paper the complete finite and are critical to mission safety. The separation panel is element analyses procedures are described and the results of particularly highly loaded, since it supports the battery pack, the analyses are presented. According to the computed results, reaction wheels, gyro module, magnetorquer rods and sun some conclusions are drawn in order to guide experimental sensors. The separation panel also supports the solar panel qualification tests. assembly. The solar panels are also of critical importance, their integrity maintaining the required power supply to operate the satellite's electronic systems. As being different from the SFF