Publication: Ekstrüzyon ile imal edilmiş ısıl işlem uygulanmış alüminyum alaşımlardan AA2024’ün kademelendirme formunun geri yaylanma hesaplarının sayısal ve deneysel yolla belirlenmesi
Abstract
EKSTRÜZYON İLE İMAL EDİLMİŞ ISIL İŞLEM UYGULANMIŞ ALÜMİNYUM ALAŞIMLARDAN AA2024’ÜN KADEMELENDİRME FORMUNUN GERİ YAYLANMA HESAPLARININ SAYISAL VE DENEYSEL YOLLA BELİRLENMESİ Bu çalışmada ekstrüzyon yöntemi ile imal edilmiş olan alüminyum alaşımlardan 2024-T3 ve 7075-T6’ya kalıp ile kademe formu verilirken oluşan geri yaylanma miktarları deneysel ve sonlu elemanlar yöntemi ile araştırılmıştır. Öncelikle uçak parçalarındaki kademe formu standartları incelenmiş ve genellikle tercih edilen kademe oranları belirlenmiştir. Kademe oranı uzunluğun derinliğe oranı ile hesaplanmaktadır. Uzunluğunun derinliğe oranı 3, 5 ve 6 olan kademe formlarının çokça kullanıldığı görülmüştür. Çalışmamda havacılık standartlarına uygun, kademe oranı 3, 5 ve 6 olan ekstrüzyon uçak parçası tasarlanıp bu parçalara kademe formu vermek için uygun kalıp tasarımları yapılmıştır. Belirlenen değişkenler ile parçalara kademe formu verilmiş ve ölçümleri yapılmıştır. Elde edilen sonuçlar sonlu elemanlar analizi ile karşılaştırılmış ve verilerin kontrolü sağlanmıştır. Sonlu elemanlar yöntemi için Pam-stamp analiz kullanılarak ekstrüzyon yöntemi ile imal edilmiş olan parçalar için analiz modellemesi sağlanmıştır. Sonuçlar incelendiğinde bazı geri yaylanma değerlerinin ölçü toleranslarının dışında kaldığı görülmüştür. AA7075-T6’daki geri yaylanmanın AA2024-T3’e göre daha fazla olduğu belirlenmiştir. Ayrıca kalınlık arttıkça ve kademe oranı büyüdükçe geri yaylanmanın arttığı tespit edilmiştir. Kademe formu verilirken soğuk şekillendirme yönteminde sıcak şekillendirme yöntemine göre daha fazla geri yaylanma olduğu görülmüştür. Bu çalışma sayesinde geri yaylanma değerleri ile ilgili veriler kullanılarak ve Pam-stamp analiz programında çözümleme yaparak geri yaylanma değerleri önceden tahmin edilmiştir. Bu tezin sonucunda kalıbı tekrar işleme maliyeti düşürülmüş, kalıp hurda miktarı ve uçak parçası hurda miktarları azaltılmıştır. v
NUMERICAL AND EXPERIMENTAL DETERMINATION OF THE SPRING BACK CALCULATION JOGGLE FORM OF AA2024 ALUMINUM ALLOY TO APPLIED HEAT TREATMENT PRODUCED BY EXTRUSION In this study, the springback values that occur while the aluminum alloys 2024-T3 and 7075-T6 which are produced by the extrusion method while given the joggle form with the mold were investigated by experimental and finite element method. First of all, joggle form parts were researched standards in aircraft and joggle ratios were determined generally preferred. The joggle ratio is calculated by the ratio of length to depth. It has been seen that joggle forms with a length to depth ratio of 3, 5 and 6 are used widely. In my study, extruded aircraft part was designed with joggle ratio of 3, 5 and 6 in accordance aviation standards and conforming mold designs were made to give joggle form to these parts. Joggle form was given the parts with the predetermined variables and they measured. The obtained results were compared with the finite element analysis and the data were checked. For the finite element method, analysis modeling was made for the parts manufactured by the extrusion method with the Pam-stamp analysis program. When the results were inspected, some springback values were out of tolerances. The springback in AA7075-T6 was higher than in AA2024-T3 according this study. In addition, it was determined that the springback increased as the thickness increased and the joggle ratio increased. There was more springback in the cold forming method than in the hot forming method. Thanks to this study, the springback values were predicted by using the data results and analyzing in the Pam-stamp analysis program. As a result of this thesis, the cost of reworking the mold was reduced, the amount of mold scrap and aircraft of part scraps were reduced
NUMERICAL AND EXPERIMENTAL DETERMINATION OF THE SPRING BACK CALCULATION JOGGLE FORM OF AA2024 ALUMINUM ALLOY TO APPLIED HEAT TREATMENT PRODUCED BY EXTRUSION In this study, the springback values that occur while the aluminum alloys 2024-T3 and 7075-T6 which are produced by the extrusion method while given the joggle form with the mold were investigated by experimental and finite element method. First of all, joggle form parts were researched standards in aircraft and joggle ratios were determined generally preferred. The joggle ratio is calculated by the ratio of length to depth. It has been seen that joggle forms with a length to depth ratio of 3, 5 and 6 are used widely. In my study, extruded aircraft part was designed with joggle ratio of 3, 5 and 6 in accordance aviation standards and conforming mold designs were made to give joggle form to these parts. Joggle form was given the parts with the predetermined variables and they measured. The obtained results were compared with the finite element analysis and the data were checked. For the finite element method, analysis modeling was made for the parts manufactured by the extrusion method with the Pam-stamp analysis program. When the results were inspected, some springback values were out of tolerances. The springback in AA7075-T6 was higher than in AA2024-T3 according this study. In addition, it was determined that the springback increased as the thickness increased and the joggle ratio increased. There was more springback in the cold forming method than in the hot forming method. Thanks to this study, the springback values were predicted by using the data results and analyzing in the Pam-stamp analysis program. As a result of this thesis, the cost of reworking the mold was reduced, the amount of mold scrap and aircraft of part scraps were reduced