Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : RSM

Study of Mechanical Properties of Carbon Steel Plate SA-516 Gr. 70 Welded by SAW Using V-Shape Joint Design

Samir A. Amin; Mohannad Y. Hanna; Abdulaziz S. Khider

Engineering and Technology Journal, 2020, Volume 38, Issue 2, Pages 152-165
DOI: 10.30684/etj.2021.168184

Submerged arc welding (SAW) is a fusion type welding and it is considered one of the most important welding types due to its inherent capabilities of high welding speed, high deposition rate, welding large thickness plates owing to its deep penetration characteristic and many other advantages. In this study, the goal was to investigate the effect of welding parameters, namely (welding current and welding speed) as well as the joint design on the mechanical properties (yield stress, bending force on the face of the weldment and hardness of the weld metal. Experiments were conducted employing Design of Expert (DOE) software and Response Surface Methodology (RSM) technique. The experiments were conducted by welding ASME SA-516 Gr. 70 steel plate with dimension (300 mm × 150 mm × 10 mm) depending upon the design matrix developed via the DOE. Results manifested that the optimum process parameters for maximum yield stress, maximum bending force and minimum hardness were at (425 amps) welding current and (35 cm/min) welding speed, where the arc voltage was held constant at (37 volts). The optimum values for the yield stress, bending force and hardness were (474.447 MPa, 36.997 kN and 150 HV), respectively. Finally, it was found that the predicted and experimental results of yield stress, bending force and hardness agree very well according to the ultimate error (1.05%, 1.92%, and 4.25 %), respectively.

Optimization of Hot-Dip Aluminizing Process Parameters of AISI 303 Stainless Steel Using RSM

Ahmed Naif Al-Khazraji; Samir Ali Al-Rabii; Hameed Shamkhi Al-Khazalli

Engineering and Technology Journal, 2015, Volume 33, Issue 9, Pages 2130-2145

The coating thickness is an important factor to evaluate the coating quality and determining the properties of the hot-dip aluminizing (HDA)coating. In the present work, a hot dipping pure aluminum (99%) on stainless steel (AISI 303) rods was carried out for different diameters of rods (8, 10 and 12mm) and different lengths (250 and 500 mm) at different aluminizing conditions of temperature and time. The dipping temperature was set to 700, 740, 780, 820 and 860℃ .The dipping time was set to 1, 2, 3,4 and 5 minutes. A response surface methodology (RSM) using a central composite rotatable design (CCD) for a 2³ factorial, with 5 central points and α = ±2 approach, based on the experimental data, was used to obtain the optimum modelto get the best thickness of coating and the best conditions of dipping. A 2nd polynomial model was obtained with a confiding percentage of 95%.Analysis of the experiments using RSM indicated that 807℃ and3minare optimum dipping conditions for hot-dip aluminizing process with corresponding thickness of coating layers of 134 μmto Al layer,62.9 μm to intermetallic compound (IMC) layer and 197μm to total coating layer.

Study the Effect of the Graphite Powder Mixing Electrical Discharge Machining on Creation of Surface Residual Stresses for AISI D2 Die Steel Using Design of Experiments

Ahmed Naif Al-Khazraji; Samir Ali Amin; Saad Mahmood Ali

Engineering and Technology Journal, 2015, Volume 33, Issue 6, Pages 1399-1415

This paperattempted to study the induced surface residual stressesduethe effect of Electrical discharge machining (EDM) input parameters, (the pulse current,the pulse-on time and the type of electrode).The work includedthe use of two types of electrode, the copper and graphite as well as using or without using the graphite powder mixing with the kerosene dielectric (PMEDM) for machining AISI D2 dies steel. The response surface methodology (RSM) was usedfor design the experimental work matrices. The analysis of variance (ANOVA) was used, and models were builtto predict the surface residual stresses.The obtained results showed that the minimum tensile surface residual stresses obtained when using the copper electrodeswith pulse current (22 A) and pulse on duration (40 µs) when working with kerosene dielectric alone and (8 A) with (120 µs) when working with graphite powder mixing. The results concluded that the using of graphite electrodes and kerosene dielectric alone or with powder mixing induced minimum residual stresses with pulse current (22 A) and pulse on duration (120 µs). The copper elec-trodes with kerosene dielectric and graphite powder mixing improved the induced tensile residual stresses by about (80 %) lower than when using kerosene dielectric alone and about (50%) lower than with graphite electrodes and the kerosene dielectric alone or with graphite mixing powder.

Optimum Design of Composite Laminated Plate Using Genetic Algorithm and RSM

Ammar Ali Hussein Al-filfily

Engineering and Technology Journal, 2011, Volume 29, Issue 5, Pages 1002-1020

The paper is focused on the application of the response surface method (RSM)
in structural optimization. Applications of the response surface method in the
design of composite laminated plate have been discussed. The response surface
method consists of two stages. In the first stage, the random variables is selected in
order to perform a deterministic computer simulation (finite element solution) in
the sample points. In the second stage, the approximation of the function (which
represent the buckling load) is performed in order to obtain response surfaces
using PDS module included in the ANSYS Program. This response surface is
incorporated into a genetic algorithm (GAs) for optimization of random input
variables to obtain maximum buckling load for composite laminated plate
subjected to both mechanical and thermal loading. GAs are stochastic optimization
algorithms based on natural selection and genetics. In contrast to traditional
gradient-based methods, GAs work on populations of solutions which evolve
typically over hundreds of generations. Four and five different variable
formulations are examined. It was found that for SSSS boundary condition and two
layer laminate the optimum values of buckling load for all thermal loading occur at
q1=33o, q2=59o, t1=1.23 mm and t2= 1.25 mm, also it can observe that the
significant random variable are t1 and t3 (in the case of five independent variables)
since the value of buckling load effected with t1 and t3 more than for t2.