Qussay Younis Hamid

In the present work, an experimental investigation has been made of a dry sliding wear rate for aluminum, aluminum alloy (Al-Fe-V-Si), bronze, stainless steel 304 and structural steel ASTM A36, using a pin-on-disk apparatus under the effect of sliding speed and time at constant load. The materials were tested on two types of abrasive surfaces with a grit surface of 24 and 36. The applied load was equal to 2500 grams and the same load was used for all of the pins that were tested. The relative wear was indicated by the loss in length and loss in mass. The results show that the wear rate will directly proportional with sliding speed and time, and the stainless steel has less wear rate than the other materials.

Mechanical robotic arm control problems are examined in the numerical solutions for the second order system with the R.Kutta algorithms. The dynamics of a robotic arm be able to designated by a set of combined non-linear equations in the formula of coriolis, centrifugal effects and gravitational torques. This investigation attempted to minimize the error of an industrial robotic arm, which improves production systems. Results of comparisons illustrate the effectiveness of the numerical integrating algorithm based on the actual joint velocities and positions with each instant of time between the exact and numerical solutions. The obtained tables of data help to analyze the variation in the velocity and position joints at different time. The numerical results obtained by R.kutta -techniques perfectly match with the exact velocities. Depending on the relative error calculated at the obtained tables of results to reach the required motion of the mechanical robot arm.

The present research deals with preparing (11) samples of composite materials with metal matrix represented by Aluminum alloy (AA3003)cast and particulate reinforced by (SiC) having particlesvolume fractions (5,10,15 Vol.%).The alloy matrix and composite materials were prepared by stir casting method. Stir casting technique wasused to increase the homogeneity distribution of the particles in alloy matrix. Average particlesizesof (75,106,150μm) were used. The aim of this study is to investigate the relationships between ultrasonic attenuation and stirrer speed ,reinforcement contents of SiC reinforced Al-alloy (AA3003)composites .Attenuation (longitudinal and shear)were measuredusing the pulse-echo amplitude technique with normal and angle probes of (45°,60°,and70°) and frequencies of (2 and 4MHz) .The results show an increase in volume fraction of particles causes an increase in attenuation. It was also found, that the ultrasonic attenuation decreases with increasing particle size. It was observed that an increases in stirrer speed, increases in the longitudinal ultrasonic attenuation.