توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقاله‌های نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده می‌شوند.
۱Investigation of Thermal Effects in Sheet Metal Blanking Process
نویسنده(ها): ، ،
اطلاعات انتشار: دومین کنفرانس بین المللی و هشتمین کنفرانس ملی مهندسی ساخت و تولید، سال
تعداد صفحات: ۹
In this paper a methodology is proposed to predict the ductile damage in sheet metal blanking process using a coupled thermo mechanical finite element method. A constitutive material model combined with ductile fracture criteria was used. The effect of material softening due to heat generated during plastic work in specimen was considered in blanking simulations. To verify the validity of the proposed model several blanking simulations are performed and the results compared with those obtained from an experimental study. The interaction of fracture initiation and temperature distribution in the sheet metal during the process was studied. The effect of velocity and the clearance on the product shape was examined. It was seen at high punch speeds the viscous and thermal effects have significant effects on products quality<\div>

۲Vibration Control in Machine Tools Using Time Delay Resonator Absorber
نویسنده(ها): ، ،
اطلاعات انتشار: دومین کنفرانس بین المللی و هشتمین کنفرانس ملی مهندسی ساخت و تولید، سال
تعداد صفحات: ۸
The vibration of machine tools during machining adversely affects machining accuracy and tool life, and therefore must be minimized. This paper presents a delay resonator (DR) to minimize relative vibration between the cutting tool and workpiece during machining process. The DR is an actively tunable vibration absorber which converts a conventional passive absorber into a marginally stable resonator. This structure absorbs all the vibratory energy at its point of attachment. A strategy called ''Stability charts'' is used not only to resolve the stability question but also to find out the gain and time delay of the absorption. Results show that relative motion between cutting tool and workpiece reduced significantly.<\div>

۳Prediction of Optimum Punch–Die Clearance
نویسنده(ها): ، ،
اطلاعات انتشار: اولین کنفرانس بین المللی و هفتمین کنفرانس ملی مهندسی ساخت و تولید، سال
تعداد صفحات: ۱۱
In this paper a methodology is proposed to obtain optimum punch–die clearance values for a given sheet materials and thickness to be blanked, using the finite element technique. A combination of isotropic and kinematic hardening have been used for material model. Explicit time Integration method with the failure criteria is used for the FEM simulation of the process. The simulations results have been compared with the results of experimental data<\div>

۴An Active Noise Control Case Study: Comparison between of Robust Controller and Adaptive Fuzzy Neural Network
اطلاعات انتشار: پنجمین کنفرانس بین المللی پیشرفتهای علوم و تکنولوژی، سال
تعداد صفحات: ۸
Base on the principle of the superposition of waves, Active Noise Control (ANC) is achieved by adaptively tuning a secondary source which produces an anti–noise of equal amplitude and opposite phase with primary source. The purpose of this paper is to compare different controlling methods –Adaptive Fuzzy Neural Network controller and Robust Controller– for ANC. By the combination of fuzzy neural network with error back propagation algorithm in order to control secondary source, the acoustic attenuation in a duct is analyzed. While in the other method, a feedback active noise control based on robust analyses and control is designed. Obtained results of comparison demonstrate the robust controller successfully satisfies the desired robust performance<\div>

۵Nonlinear Dynamic Analysis of Nanoscale Beams inLiquid Electrolytes using Nonlocal Elasticity TheoryConsidering Casimir Effect
اطلاعات انتشار: سومین کنفرانس بین المللی آکوستیک و ارتعاشات، سال
تعداد صفحات: ۸
Electrostatic actuators are commonly used in gas or vacuum. As a result, there has been littleattempt to develop MEMS and NEMS actuators capable of operating in liquids. Whereasthere are several practical applications in which the N\MEMS devices have to operate in aliquid, and therefore, more effort is needed to analyze such systems. In this study, thenonlinear dynamic behaviour of electrochemically actuated nanobeams is investigated basedon a nonlinear modified continuum beam model subjected to nonlinear forces. An elasticbeam suspended horizontally over a substrate in liquid electrolyte is subjected to electric,osmotic, van der Waals, and Casimir forces. The equation of motion is derived based on thenonlocal theory of elasticity for the nonlinear Euller–Bernoulli beam theory. It should benoted that, the nonlinearity of the beam theory is due to contemplating the von Karmanstrains leading to more realistic results for some specific boundary conditions by taking thelongitudinal stretching force into account. To the best of our knowledge, dynamic analysis ofthe system considering the nonlocal theory of elasticity along with taking account of allpreviously stated nonlinear forces in the nonlinear Euller–Bernoulli beam theory is performedfor the first time. The generalized differential quadrature (GDQ) method along with theNewmark integration scheme converts the nonlinear governing equation into a system ofalgebraic equations. Then this system of equations is linearized with the assistance ofiterative Newton–Raphson method. The present research investigates the size effect on the thedynamic behaviour of the nano–beam under DC voltage using nonlocal elasticity theory. Theinteresting outcomes obtained in this study are useful in modelling and design process of electrochemically actuated micron– and submicron–scale beams.<\div>
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