In the present study, the effects of process and geometrical parameters on the maximum temperature of tool have been investigated. Simulation of mild steel machining process in different cutting depths, speed of rotation (SOR), feeding rates, and different rake angles was performed. To verify the simulation, numerical results were compared with experimental results. Based on the results, it was found that by increasing the speed of rotation at a constant cutting depth and a constant feed rate, the maximum temperature of the process experiences a significant increase. By increasing the depth of the cut, the geometric location of the workpiece maximum temperature was transmitted to the edge of the tool and surface changes occurred, which it was accompanied with increment in the depth of the cut. The tool with the rake angle of -10° and the depth of cutting of 2 mm had the highest recorded temperature due to the lack of sufficient space for removing chips from the work surface. پرونده مقاله

In this paper, analytical and finite element solutions of mechanical buckling of a thick Functionally Graded (FG) plate have been investigated. Boundary conditions have been assumed as simply supported at all edges and three different loadings have been applied. In analytical section the procedure of developing the critical buckling force by third order shear theory has been presented and then the stability Equations have been reduced from 5 to 2. In continue, the problem has been solved using numerical simulation by ABAQUS. To validate the FEM, results have been compared and validated with analytical solution. The results show that the bi-axial compression loading case with the loading ratio of R to one and R to zero are the most possible and most unlikely case in buckling occurrence, respectively. پرونده مقاله

Friction stir welding (FSW) is a solid state bonding process in which the parts are joined together at the temperature below the melting point. In present study, a modified model was developed based on the partial sticking/sliding assumption in the tool-workpiece interface and the dependence of the thermal energy equations on the temperature-dependent yield stress to determine heat generation in FSW process that is independent from coefficient of friction. So to eliminate the dependence of the final equations on the coefficient of friction, an equation was used which the coefficient of friction was expressed as a function of workpiece yield stress. To validate the model, the FSW process was simulated by the finite element package ABAQUS and two subroutines of DFLUX and USDFLD and then the simulation results were compared with the experimental ones. The results showed that the modified model is appropriately capable of predicting the temperature and the residual stresses in the different zones of welded section. پرونده مقاله

پنل های ساندویچی دارای قابلیت و توان بالا در زمینه جذب انرژی و مستهلک سازی انرژی جنبشی حاصل از برخورد در مواجهه با موج های انفجاری می باشند. در پژوهش حاضر تاثیر جهت گیری هسته لانه زنبوری پنل ساندویچی نسبت به صفحات جانبی و راستای بارگذاری بر قابلیت جذب و مستهلک سازی انرژی ناشی از برخورد کابین آسانسور با پنل ساندویچی تعبیه شده در چاله آسانسور مورد بررسی قرار گرفته است. از شش زاویه 30, 20, 10, 5, 0 و 45 درجه بدین منظور استفاده گردید. مشاهده شد که با افزایش میزان زاویه جهت گیری هسته پنل نسبت به راستای ضربه میزان سختی پنل دچار افت خواهد شد و این افت با افزایش بیشتر زاویه جهت گیری هسته به صورت شدید تری اتفاق خواهد افتاد. با افزایش میزان زاویه هسته لانه زنبوری از حد بهینه، سازه به دلیل کرنش پلاستیک بزرگ فشردگی و مچالگی را تجربه خواهد نمود که این امر موجب افزایش شدید سختی پنل می گردد و پنل به دلیل عدم تراکم پذیری همانند یک جسم صلب عمل می نماید و قابلیت مستهلک سازی انرژی آن به شدت دچار کاهش می گردد. پرونده مقاله