No abstract

The presented study has the aim of finding out the relationships between input variables and process parameters that describe mathematical models, also to estimate the impact of independent parameters on the Heat Affected Zone (HAZ). In the presented paper, A2-Tool Steel material is the utilized workpiece material, whereas copper is the electrode material. RSM, which is the abbreviation of Response Surface Methodology, is used for identifying the impact of controllable parameters; such controllable effects consist of pulse current, pulse on time, and pulse off time on HAZ. It has been noticed that the model has been developed by RSM adequacy is suitable since the coefficient related to the determination is considered closest to one for HAZ, whereas the highest percentage of error between experimental and predicted data is (-13.829%). From ANOVA, the pulse current has the most significant factor affected by HAZ with 67.219% contribution.

The values of Many parameters which involve in the design of fluid film journal bearings mainly depend on the bearing applied load when using the conventional design method to design the journal bearings, in this study, as well as applied bearing load, the dynamic response and critical speed have been used to calculate the dimensions of journal bearings. In the field of rotating machine, especially a heavy-duty rotating machines, the critical speed and response are the main parameters that specify bearing dimensions. The bearing aspect ratio (bearing length to bore diameter) and bearing clearance have been determined based on rotor maximum critical speed and minimum response displacement. The analytical solution of rotor Eq. of motion was verified by numerical solution via using ANSYS Mechanical APDL 18.0 and by comparing the numerical solution with the preceding study. The final study results clearly showed that the bearing aspect ratio has little effect on the critical speed, but it has a high effect on the dynamic response also the bearing clearance has little effect on the critical speed and considerable effect on the dynamic response. The study showed that the more accurate values of bearing aspect ratio to make the response of rotor as low as possible are about 0.65 - 1 and bearing percent clearance is about 0.15 - 0.2 for different rotor dimensions.