Determination of Johnson Cook Strength and Failure Parameters of EN-GJS-400 Spheroidal Graphite Cast Iron

Yıl 2024, Cilt: 40 Sayı: 2, 254 - 269, 31.08.2024

Burak Özcan , Ulvi Şeker

Öz

In this study, to investigate the mechanical behavior of EN-GJS-400 nodular cast iron material, quasi-static tensile tests were conducted at room temperature and at 300°C, 500°C, and 700°C, along with compression tests at room temperature. To examine the behavior at high deformation rates, Split Hopkinson tests were carried out at four different strain rates, reaching up to approximately 4500/s. To reveal the damage behavior of the materials, tensile tests were conducted with four different notches (R=1.25, 2.5, 5, 10mm). Microstructure experiments and spectral analyses of the materials were performed. Based on the data obtained from the experiments, Johnson-Cook (J-C) material and damage model parameters were calculated. The calculated J-C material and damage parameters were defined in the Abaqus finite element software, and virtual tensile tests were conducted and compared with the actual test data.

Anahtar Kelimeler

EN-GJS-400, Johnson-Cook, Split Hopkinson, Finite Element Analysis

EN-GJS-400 Küresel Grafitli Dökme Demir Malzemenin Johnson-Cook Malzeme ve Hasar Parametrelerinin Belirlenmesi

Öz

Bu çalışma kapsamında EN-GJS-400 küresel grafitli dökme demir malzemenin mekanik davranışlarını incelemek için oda koşullarında ve 300, 500 ve 700° derece sıcaklıklarda yarı statik çekme ve oda koşullarında basma deneyleri gerçekleştirilmiştir. Yüksek şekil değiştirme hızlarında davranışlarını incelemek için dört farklı şekil değiştirme hızında yaklaşık, maksimum 5500/s gerinim hızına kadar Split Hopkinson testleri gerçekleştirilmiştir. Malzemelerin hasar davranışlarını ortaya koyabilmek için 4 farklı çentikte (R=1.25, 2.5, 5, 10mm) çekme deneyleri gerçekleştirilmiştir. Malzemelerin mikro yapı deneyleri ve spektral analizleri gerçekleştirilmiştir. Deneylerde elde edilen veriler doğrultusunda Johnson-Cook(J-C) malzeme ve hasar model parametreleri hesaplanmıştır. Hesaplanan JC malzeme ve hasar parametreleri Abaqus sonlu elemanlar yazılımında tanımlanarak çekme testleri sanal ortamda gerçekleştirilmiş ve gerçek test verileriyle karşılaştırılmıştır.

Anahtar Kelimeler

EN-GJS-400, Johnson-Cook, Split Hopkinson, Sonlu Elemanlar Analizi

Kaynakça

• Ram, N., & Gautam, V. (2022). Evaluation of Johnson-Cook material model parameters for Si-Mo-Cr ductile cast iron. Materials Today: Proceedings, 61, 16-20.
• Hellström, P., & Olander, K. (2012). Analysis and modeling of properties of Compacted Graphite Iron on a microstructural level (Master's thesis). Chalmers University of Technology, Gothenburg, Sweden.
• Ljustina, G., Larsson, R., & Fagerström, M. (2014). A FE based machining simulation methodology accounting for cast iron microstructure. Finite Elements in Analysis and Design, 80, 1-10.
• Keser, S.(2015).CGI Malzemeye Ait Malzeme Modelinin Deneysel ve AnalitikYolla Geliştirilmesi, İstanbul Teknik Üniversitesi, Fen bilimleri Enstitüsü, İstanbul.
• Springer, H. K. (2012). Mechanical Characterization of Nodular Ductile Iron Rep (LLNL-TR-522091). Lawrence Livermore National Laboratory.
• Salomonsson, K., & Olofsson, J. (2017). Analysis of localized plastic strain in heterogeneous cast iron microstructures using 3D finite element simulations. In 4th World Congress on Integrated Computational Materials Engineering (ICME 2017) (pp. 217-225). Ypsilanti, MI, United States.
• Liu, C., Sun, D., Zhang, X., Andrieux, F., & Gersterc, T. (2024). Extension of flow behaviour and damage models for cast iron alloys with strain rate effect. Chinese Journal of Mechanical Engineering, 37(61).
• Memhard, D., Andrieux, F., Sun, D.-Z., & Häcker, R. (2011). Development and verification of a material model for prediction of containment safety of exhaust turbochargers. In 8th European LS-DYNA Users Conference 2011.
• Johnson, G.R. and Cook, W.H. (1983) A Constitutive Model and Data for Metals Subjected to Large Strains, High Strain Rates, and High Temperatures. Proceedings 7th International Symposium on Ballistics, The Hague, 19- 21 April 1983, 541-547.
• G. R. Johnson and W. H. Cook, “Fracture Characteristics of Three Metals Subjected to Various Strains, Strain Rates, Temperatures and Pressures,” Engineering Fracture Mechanics, Vol. 21, No. 1, 1985, pp. 31-48. http://dx.doi.org/10.1016/0013-7944(85)90052-9