This paper develops a nonlinear transient three-dimensional heat transfer finite element model and a rate independent three-dimensional deformation model, developed for the CO2 laser welding simulations in Al-6061-T6 alloy. Simulations are performed using an indirect coupled thermal-structural method for the process of welding. Temperature-dependent thermal properties of Al-6061-T6, effect of latent heat of fusion, and the convective and radiative boundary conditions are included in the model. The heat input to the model is assumed to be a Gaussian heat source. The finite element code ANSYS12, along with a few FORTRAN subroutines, are employed to obtain the numerical results. The benefit of the proposed methodology is that it offers the capability of optimizing laser welding process, and also provides a reliable estimation of the developed temperatures, as well as the thermal stress (residual stress) and strain fields reducing the experimental effort.
Two different composite materials were prepared by stir casting method of AA 6061 alloy as a matrix reinforced with two addition different ceramic materials Al2O3 and B4C of grain size 20 µm by 2.5, 5, 7.5 and10% in weight. The composite material with aluminum alloy as a matrix possesses a unique mechanical properties such as: high specific strength and hardness, low density, and high resistance to corrosion and friction wear. This composite is widely used in automotive parts space and marine applications.
Pin-on-disc technique was used to calculate the wear rate for each addition of Al2O3 and B4C particles. Rockwell hardness test and
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Communities seek to achieve the economic growth through the optimal use of resources. The human resource is considered the most important of those resources where the insurance institutions take the larger role in the protection of this resource and reducing the impact caused by dangers realization that endures. The general Iraqi insurance company is considered the leading in the field of life insurance since it was founded, and until now.
This research is based on an analyzing the relation between premiums and compensations of life insurance, for individual and the group insurance, and a reality of the
... Show MoreThis study aimed to determine obesity level of some population in Baghdad by using Bio-electrical impedance analysis (BIA) and compared with anthropometric measurements such as body mass index (BMI), waist circumference (WC) and waist-to-hip ratio (WHR). Statistical analysis results of linear correlation coefficients for obesity indicators showed that BIA correlation 0.92 was most significant and reliable for obesity measurement.
Results of BIA method for age group 20-29 years showed that 44.4% of females were healthy body while 37.8% of males suffer from increased body fat. Results of age group 30-39 year showed that 32.6 of females were in healthy body and 42% of males were obese. In case age group 40-4
... Show MoreA bolted–welded hybrid demountable shear connector for use in deconstructable steel–concrete composite buildings and bridges was proposed. The hybrid connector consisted of a partially threaded stud, which was welded on the flange of a steel section, and a machined steel tube with compatible geometry, which was bolted on the stud. Four standard pushout tests according to Eurocode 4 were carried out to assess the shear performance of the hybrid connector. The experimental results show that the initial stiffness, shear resistance, and slip capacity of the proposed connector were higher than those of traditional welded studs. The hybrid connector was a ductile connector, according to Eurocode 4, with slip capacity higher than 6 mm. A nonli
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The research objective are analyze financial leverage advantage through analyze and discuss financial leverage cost, and achieve tax advantage. study include two firms ,oil firm and industrial companies firm with limited liability.The inductive method is used for the applied part in analyzing the financial data of the companies considered in 2011-2015.The result of the study shows that the financial leverage achieve present value of the costs is Negative . The study concluded that the most important conclusions of the tax advantage of leverage is higher costs as well as achieving a low tax shield ,This study found out the results that interest payments related to pre-tax all of the loan amount and the percentage of the interest rate on b
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Abstract
Robotics manipulators with structural flexibility provide an attractive alternative to rigid robotics manipulators for many of the new and evolving applications in robotics. In certain applications their use is unavoidable. The increased complexity in modeling and control of such manipulators is offset by desirable performance enhancements in some respects. In this paperthe single- link flexible robotics manipulator was designed and implemented from Perspex and designed with 0.5 m length , 0.02 m width and with 0.004 m thickness with mass located at the tip. There are four subsystems; motion, control, accelerometer and gyro and a host computer subsystem. The work principle of single-link robotics manipul
... Show MoreThe Purpose of this study are analyze financial lease advantage through analyze and discuss financial lease cost, and achieve tax advantage to reach study objective. study include two firms ,oil firm and construction firm with limited liability. The inductive method is used for the applied part in analyzing the financial data of the companies considered in 2011-2015.The result of the study shows that the financial lease achieve present value of the costs is positive. This study found out the results that verify the hypothesis: The tax advantage of financial Leasing is characterized by decreasing cost and achieving higher tax shield. The study also found the most important recommendations of awareness of the benefits arising f
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