Wasit Journal of Engineering Sciences

Numerical simulation plays an indispensable role in the modern manufacturing process, especially in production operation and metal forming by using different of forming Dies Because it give perfect product design to improving quality and performance and reduce the time and cost .Because of the most of forming operation include contact option between the product surface (contact surface) and Die surface (Target surface) then the determination of the contact surface nature and material behavior ( uniform linear ) or ( not uniform nonlinear) that very effect on the carryout of forming process with required product .To improving simulation accuracy, approximations of linear behavior have become less acceptable, while it is possible to perform nonlinear analysis and design more often while minimizing approximations, the nonlinear analysis capabilities in general-purpose programs such as ANSYS Mechanical.The significance of the research is into linear simulation analysis and its limitation and development to nonlinear simulation where interest with the development manufacturing processes that including change in the geometry , properties and material behavior through forming ,the search give an example of Case study with Cylindrical rolling contact that very important for wide application to manufacturing processes such as drawing ,Rolling ,Forging , Extrusion, Bending and other .The structural nonlinearities can be classified as geometric nonlinearity, material nonlinearity, and contact or boundary nonlinearity Numerical results indicate the success of ANSYS contact technologies in solving very large scale engineering problems especially large deformation frictional contact problems with the new surface based contact elements have many advantages over the node based contact elements .

In this research, a scientific study has been proceeded to illustrate the impact of adding methanol – alcohol of 10% and 20% by volume of gasoline without lead with (81) octane number on performance and noise emitted from single cylinder - internal combustion engine work by ignition with compression ratio of (9.5:1), where the previous studies that have been proceeded were on compression ratio ranged about (5:1 – 8:1). Consequences showed that; the addition of 10% methanol can increase the break power about (22%) while the addition of 20% methanol reduces the break power about (8%) after a comparison with the performance of engine without addition. For the fuel consumption, the study showed that the rate of consumption increases (1.8%), (30%) with addition of 10% and 20% methanol consecutively after a comparison with the performance of engine without addition. Also, the consequences showed that reduing of the OASPL about (3.3%) with use the addition of 10% methanol while addition of 20% methanol causes increasing in OASPL about (1.2%) after a comparison with the performance of engine without addition. Also the experiments have been preceded with three stages to illustrate the impact of the sonic isolator (crok isolator 2.5cm thickness, and glass isolator 4mm thickness) a space of air 2.5 cm thickness separat between them. The first stage included proceede the experimente without isolator, second stage by using crok isolator and the third by using two isolators (crok &glass), the consequences was showed reducing of OASPL about 5dB with crok iso. and 8 dB with using two isolators .

This paper is concerned with the study of the kinematic and kinetic analysis of a slider crank linkage using D\'Alembert\'s principle. The links of the considered mechanism are assumed to be rigid. The analytical solution to observe the motion (displacement, velocity, and acceleration), reactions at each joint, torque required to drive the mechanism and the shaking force have been computed by a computer program written in MATLAB language over one complete revolution of the crank shaft. The results are compared with a finite element simulation carried out by using ANSYS Workbench software and are found to be in good agreement. A graphical method (relative velocity and acceleration method) has been also applied for two phases of the crank shaft (q2 = 10° and 130°). The results obtained from this method (graphical) are compared with those obtained from analytical and numerical method and are found very acceptable. To make the analysis linear the friction force on the joints and sliding interface are neglected. All results, in this work, are obtained when the crank shaft turns at a uniform angular velocity (w2 = 188.5 rad/s) and time dependent gas pressure force on the slider crown.

This paper presents a subspace method of spot centroiding algorithm for locating the centers of laser spots. It focuses on how to find the position of the activated pixel which is the position of the imaged spot on the detector of the camera using Gaussian Approximation method (GAM), Center of Mass (COM) method and Blais and Rioux algorithm. The traditional subspace methods based on either singular value decomposition (SVD) or eigen decomposition (ED) to estimate the signal or noise subspace, these decomposition methods tend to be computationally intensive. In order to improve the algorithm of spot position determination, a proposed subspace analysis is used to determine spot position without eigen decomposition. Therefore, a method of fast subspace decomposition using Lanczos algorithm is presented and compared with other methods. A simulated example is provided to evaluate the proposed method and the simulation results shows that the proposed algorithm has the advantages of reduction the computational load and superior estimation performance.

The present work is a numerical investigation of the effect of laminar natural convection flow of nano fluid taking Cu nano particles and the water as based fluid on a vertical cylinder in presence of magnetohydrodynamics. The governing equations which used are continuity, momentum and energy equations. These equations are transformed to dimensionless equations using vorticity-stream function method and the resulting nonlinear system of partial differential equations are then solved numerically using finite difference approximation. A thermal boundary condition of a constant wall temperature is considered. A computer program was built to calculate the rate of heat transfer in terms of average Nusselt number, velocity distribution as well as temperature distribution for magnetohydrodynamics range of and the volume fraction . Numerical solution have been considered for a fluid Prandtl number fixed at (Pr = 6.2), Rayleigh number . The results show that Nu increase with increasing Ral and M and increased with the particle volume fraction up to φ = 0.15 then decreased due to viscosity and agglomeration effect. The effect of Rayleigh number and magnetohydrodynamics on the rate of heat transfer is concluded by a correlation equation.