Basrah Journal for Engineering Sciences

This paper explains a new control structure based on the artificial immune system, Fuzzy and fractional order PID control schemes. In this paper immune feedback control system, Fuzzy logic and fractional order control schemes will be combined and optimized using clonal selection algorithm. Fuzzy-immune fractional order PID Control schemes will be used as a new controller for path tracking of the robot manipulator. The performance of the proposed control scheme is compared with fuzzy-immune PID control schemes. The parameters of fractional PID and conventional PID controllers are optimized using Clonal Selection Algorithm (CSA). Simulation results state that optimal Fuzzy-immune fractional PID is better than optimal fuzzy-immune PID Control schemes for path tracking problem under the same condition. All control schemes were tested using SIMULINK under MATLAB2014a.

In the present paper the natural convection in a square cavity utilizing Cu-water nanofluid is examined numerically. The cavity is exposed to cooling air stream with free stream temperature (T∞) from left wall and its right and bottom walls kept with cold and hot temperatures (TC) and (TH) respectively, while the cavity top wall considered as adiabatic. The nanofluid flow inside the cavity is assumed to be laminar and obeying to Boussinesq approximation. The governing equations are solved by finite volume method using ANSYS FLUENT code. The results are accomplished with a range of nanofluid volume fraction =0–0.16, Rayleigh number Ra=103–105 and free stream Reynolds number Re∞=103–104. The effects of these variables are displayed on the stream function (), isotherms () contours and average Nusselt number (Nuavg). The results show the heat transfer rate augmented with increasing , Ra and Re∞. Also, the increment in both  and Ra increases the circulation inside the cavity while increasing Re∞ produces secondary vortices and reduces circulation at the main vortex of the cavity. The results of local Nusselt number (Nu) and isotherms () are compared with other studies and show good agreement with maximum error values 14.28% and 3.2% respectively.

The main objective of the present paper is to study the vibration behavior of cantilever beam with a bolted joint of different lap’s type (i.e. Single lap, Double lap) for free and forced vibration. The effects of various parameters such as beam configuration, preload, harmonic force magnitude and harmonic force positions on natural frequency, mode shape, and amplitude have been investigated. The experimental work carried out during this study included material selection, chemical composition test, tension test, preparation configurations of beam, free and forced vibration tests at per- torques range (6-60N.m) and at rotational speeds range (300-900RPM). Numerically, a general purpose finite element method (ANSYS Ver.16.1 package) has been used. The results show that the natural frequencies of single lap (1Bolt, 2Bolt) bolted beams were roughly equal to those of intact beam. But, in double lap bolted beam were slightly lower than those of intact beam with same profile. Moreover, as preload or pre-torque on the bolt increases, the natural frequency becomes constant for all types of beam configuration. For forced vibration, the vibration amplitude is largely dependent on magnitude and position of harmonic force. The validation results present a good agreement with numerical results as the largest margin of error is about (5%).

The precise control of internal pressure and axial feeding loading paths important influences the final tube quality. In this research the impact of loading path of the tube hydroforming process and final part requirements ( i.e. thickness specification and shape conformation) were studied numerically. Small bulge shape tube hydroforming parts were utilized in the finite element analyses to get several guidelines on the effect of the relation between the internal pressure and axial compressive feeding programs. Two dimension model of bulge shape tube (50 mm) bulge width has been developed from cylindrical tube with thickness (2mm) of the copper and (60 mm) outer diameter. A commercial available finite element program code (ANSYS 11), is used to perform the numerical simulation of the tube hydroforming operation. The results demonstrate that, the loading path has very important influenced on the thickness distribution over the tube and capability attained the target shape of the required product.