H 320 LA saçlarının balistik darbe etkisindeki performanslarının belirlenmesi
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Date
2004-10-06
Authors
Ali, Durmuş
Journal Title
Journal ISSN
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Publisher
Uludağ Üniversitesi
Abstract
Bu çalışmada Erdemir tarafından 7132 kalite no 'su ile üretilen soğuk şekillendirmeye uygun yüksek akma dayanımlı soğuk haddelenmiş (DİN EN 10268-99, kalite: H 320 LA) saçların balistik darbe etkisindeki performansları deneysel ve nümerik olarak incelenmiştir. Hedef olarak kullanılan plakalar 1 mm, 2 mm ve iki adet 1 mm'lik saçın birlikte kullanıldığı durum ve ısıl işlem uygulanmış 2 mm kalınlığındaki saçlardır. Mermi olarak, Makine ve Kimya Endüstrisi (MKE) Kurumu Gazi Fişek Fabrikasınca (Ankara/TÜRKİYE) üretilen Ball Powder® marka barut içeren 9 mm x 19 Parabellum fişeklerine ait mermiler kullanılmıştır. İlk aşamada merminin hedefe çarpmadan önceki hızı ve hedefi delip geçtikten sonraki hızının ölçülmesi için Dijital Mermi Hızı Ölçüm (DMHÖ) cihazı ve test düzeneğinin tasarımı ve üretimi gerçekleştirilmiştir. Farklı miktarlarda barut içeren fişekler kullanılarak 69 m/s ile 377 m/s arasındaki çeşitli mermi hızlan bu düzenek ile belirlenmiş ve cihazın hata analizleri yapılmıştır. Hedef kullanılmaksızın merminin, DMHÖ cihazının çapma ve kalıcı hız ölçüm sistemi yardımı ile hız ölçümleri ve hata analizleri gerçekleştirilmiştir. Cihazın deneysel balistik testlerde sağlıklı bir şekilde kullanılabileceği görülmüştür. Hedef malzemesi olarak kullanılan saçlardan hazırlanan çekme deneyi numunelerinin 1,33.1ü"4 s"1 (1 mm/dak), 1,33. 10"3 s"1 (10 mm/dak), 1,33. 10"2 s"1 (100mm/dak) ve 0,66.1ü"1 s"1 (500 mm/dak) gerinim hızlarındaki gerçek gerilme-gerçek birim şekil değiştirme eğrileri elde edilmiştir. Johnson-Cook Malzeme Modelinin kullanıldığı sayısal çözümlerde, simülasyonların yapılabilmesi için gerekli malzeme parametreleri; yapılan çekme testleri ve literatürdeki veriler kullanılarak elde edilmiştir. Merminin hedefe çarpma hızına bağlı olarak merminin kalıcı hızlan ve hedefteki hasar boyutlarının değişimi deneysel olarak incelenmiştir. Hedefteki hasarın değerlendirilmesinde; ön yüz deformasyon çapı, krater derinliği, delinme durumu için delik çapı tarif edilmiştir. Ayrıca metalografik yöntemler ve taramalı elektron mikroskobu ile yapılan incelemeler yardımıyla mekanik özellikler ve balistik testler ile oluşan hasarlar analiz edilmiştir.Sayısal çözümlerde 3D doğrusal olmayan açık (explicit) çözüm algoritması temeline dayanan LS-DYNA yazılımı kullanılmıştır. Kurşun çekirdek ve çekirdek üzerine kaplanmış pirinç malzemeden meydana gelen standart NATO mermisinin H 320 LA saçlarına balistik hızlarda çarpması simüle edilmiş ve deneysel balistik testlerle sürekli olarak karşılaştırmalar yapılarak elde edilen sayısal çözüm sonuçlarının deneysel sonuçlarla uyum içinde olduğu görülmüştür.
In this study, ballistic impact performances of cold rolled sheet metals, which are produced by Erdemir CO. with a brand no of 7132 that have high yield strength and appropriate for cold metal forming (DIN EN 10268-99, brand: H 320 LA), are investigated both experimentally and numerically. The specs that are used as targets have 1mm, 2 mm, and 2 pieces of 1 mm thicknesses and heat treated specs of 2 mm thicknesses respectively. The bullets used in this study are produced by Makine ve Kimya Endüstrisi (MKE) Kurumu Gazi Fişek Fabrikası (Ankara/TURKEY) and are belong to 9 mm x 19 Parabellum cartridges that contain a gunpowder with a trade mark of Ball Powder®. At the first stage, a Digital Bullet Speed Measurement (DBSM) device is developed in order to measure the speed of the bullets before hitting and after penetrating the targets. By using cartridges that contain different amounts of gunpowder, the bullet speeds are found to vary between 69 m/s and 377 m/s and error analyses are performed for the device. Without using targets and by using the impact speed and residual velocity measurement systems of the DBSM device, speed measurements and error analyses of the bullets are conducted. It is seen that the device is robust and can be used for experimental ballistic tests. Coupon tests of the materials that are used as targets are conducted and true stress-true strain curves are obtained at different strain rates,which are; 1,33. 10"4 s"1 (1 mm/min), 1,33. 10"3 s"1 (10 mm/min), 1,33. 10"2 s"1 (100 mm/min) and 0,66.10"' s"1 (500 mm/min). The required material model constants for the numerical study, where Johnson-Cook material model is used, are obtained by using these coupon tests and the data obtained from the literature. Depending on the impact speed of the bullet to the target, the residual velocity of the bullet and the dimensions of the deformation at the target are determined and investigated experimentally. During the evaluation of the deformation at the targets, diameter of the front face deformation, depth of the crater and the diameter of the hole is defined for the cases where perforation has happened. Besides, by using metallographic methods and scanning electron microscope (SEM), mechanicalIV properties and the deformations that are obtained from ballistic experiments are analyzed. LS-DYNA, which is a non-linear explicit 3D finite element code, is used for the numerical studies. The impact of the standard NATO bullets, which are made of a lead core and a brass jacket around it, into H 320 LA sheet metal specs at ballistic speeds are simulated and the results are compared with the experimental ballistic tests. The results are in good agreement with the experimentally obtained values.
In this study, ballistic impact performances of cold rolled sheet metals, which are produced by Erdemir CO. with a brand no of 7132 that have high yield strength and appropriate for cold metal forming (DIN EN 10268-99, brand: H 320 LA), are investigated both experimentally and numerically. The specs that are used as targets have 1mm, 2 mm, and 2 pieces of 1 mm thicknesses and heat treated specs of 2 mm thicknesses respectively. The bullets used in this study are produced by Makine ve Kimya Endüstrisi (MKE) Kurumu Gazi Fişek Fabrikası (Ankara/TURKEY) and are belong to 9 mm x 19 Parabellum cartridges that contain a gunpowder with a trade mark of Ball Powder®. At the first stage, a Digital Bullet Speed Measurement (DBSM) device is developed in order to measure the speed of the bullets before hitting and after penetrating the targets. By using cartridges that contain different amounts of gunpowder, the bullet speeds are found to vary between 69 m/s and 377 m/s and error analyses are performed for the device. Without using targets and by using the impact speed and residual velocity measurement systems of the DBSM device, speed measurements and error analyses of the bullets are conducted. It is seen that the device is robust and can be used for experimental ballistic tests. Coupon tests of the materials that are used as targets are conducted and true stress-true strain curves are obtained at different strain rates,which are; 1,33. 10"4 s"1 (1 mm/min), 1,33. 10"3 s"1 (10 mm/min), 1,33. 10"2 s"1 (100 mm/min) and 0,66.10"' s"1 (500 mm/min). The required material model constants for the numerical study, where Johnson-Cook material model is used, are obtained by using these coupon tests and the data obtained from the literature. Depending on the impact speed of the bullet to the target, the residual velocity of the bullet and the dimensions of the deformation at the target are determined and investigated experimentally. During the evaluation of the deformation at the targets, diameter of the front face deformation, depth of the crater and the diameter of the hole is defined for the cases where perforation has happened. Besides, by using metallographic methods and scanning electron microscope (SEM), mechanicalIV properties and the deformations that are obtained from ballistic experiments are analyzed. LS-DYNA, which is a non-linear explicit 3D finite element code, is used for the numerical studies. The impact of the standard NATO bullets, which are made of a lead core and a brass jacket around it, into H 320 LA sheet metal specs at ballistic speeds are simulated and the results are compared with the experimental ballistic tests. The results are in good agreement with the experimentally obtained values.
Description
Keywords
Balistik test, Perforasyon, Hasar analizi, Sonlu elemanlar metodu, Soğuk şekillendirme saçı, 9 mm x 19 Parabellum fişek, Mermi hızı, Barut miktarı, Ballistic test, Perforation, Damage analysis, Finite element method, Cold forming sheet metal, 9 mm x 19 Parabellum cartridge, Bullet speed, Gunpowder amount
Citation
Durmuş, A. (2004). H 320 LA saçlarının balistik darbe etkisindeki performanslarının belirlenmesi. Yayınlanmamış doktora tezi. Uludağ Üniversitesi Fen Bilimleri Enstitüsü.