Table 2 - uploaded by Hani Aziz Ameen
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The main objective of this study is to find the best angle for the extrusion die by linking the die with springs having different stiffness and the die having different coefficient of friction. The Model of this study Consider the visco-plastic case for the material and the coefficient of friction between the die and the metal flow where the coeffi...
Citations
... Based upon the objective function, meta-heuristic algorithms such as simulated annealing were adopted as optimization methods for finding the optimum values of cold forward extrusion variables. Consider the visco-plastic case for the material and the coefficient of friction between the die and the metal flow where the coefficient of friction values are (0.005, 0.008, 0.015) in order to find the best die angle for the extrusion die [11]. A simple numerical approach that is based on the lubrication approximation is developed for the optimal design of a die and the predictions based on this approach are reasonably accurate as compared with those from the complete 3-D finite element simulations [12]. ...
In a typical forming limit curve (FLC), the minimum major strain where the minor value is equal to zero is located at y axes. In many forming processes, failure occurs at this region. Many studies in literature indicates that minimum major strain value is obtained about at y axis. In this study, the minimum major strain value is not determined on the y axes and it was found to be offsetted from the y axes to the right about 0.04 strain for AA 2024-T4. This value could be important for evaluations of sheet metal forming processes. In this study, the reasons for the minimum major strain of setting of the forming limit curve for AA 2024-T4 were investigated. It was found that drawbead and heat treatment were most effective parameters for this offsetting. It is observed that offsetting result from pre-strain which occur for conducted tests with using draw-bead and residual stress arising from T4 heat treatment.
ZET Tipik bir şekillendirme sınır eğrisi (ŞSE)'nde, minimum majör birim şekil değiştirme değeri, minör birim şekil değiştirme değerinin sıfır olduğu y ekseni üzerinde yer almaktadır. Birçok şekillendirme proseslerinde hasar bu bölgede meydana gelmektedir. Literatürde birçok çalışmada, ŞSE'lerde en düşük majör seviyesi hemen hemen y ekseni üzerinde elde edilmiştir. Bu çalışmada ise Al 2024-T4 alaşımı için bu değer, y ekseninden yaklaşık olarak 0,040 değerinde sağa doğru ötelenmiş olarak elde edilmiştir. Bu değer sac metal şekillendirme sonuçlarının değerlendirilmesinde önemli olabilmektedir. Bu çalışmada Al 2024-T4 sac metalin metalin minimum majör birim şekil değiştirme değerinin literatürden farklı olarak sağa ötelenmiş olarak elde edilmesinin nedenleri araştırılmıştır. Süzdürme çubuğu ve ısıl işlemin en fazla etki eden faktörler olduğu tespit edilmiştir. Ötelenmenin, süzdürme çubuğu kullanılarak yapılan testlerde oluşan ön BŞD'lerden ve T4 ısıl işlemi sonucunda meydana gelen kalıntı gerilmelerden kaynaklandığı gözlenmiştir. ABSTRACT In a typical forming limit curve (FLC), the minimum major strain where the minor value is equal to zero is located at y axes. In many forming processes, failure occurs at this region. Many studies in literature indicates that minimum major strain value is obtained about at y axis. In this study, the minimum major strain value is not determined on the y axes and it was found to be offsetted from the y axes to the right about 0.04 strain for AA 2024-T4. This value could be important for evaluations of sheet metal forming processes. In this study, the reasons for the minimum major strain of setting of the forming limit curve for AA 2024-T4 were investigated. It was found that drawbead and heat treatment were most effective parameters for this offsetting. It is observed that offsetting result from pre-strain which occur for conducted tests with using draw-bead and residual stress arising from T4 heat treatment.
