Author : HariKrishna ch 1
Date of Publication :7th October 2016
Abstract: The investigation of ductile fracture plays a significant role in achieving the required deformation without the failure of the specimen. Three cylindrical billets with different aspect ratios (height (h) to the diameter (d)) namely h/d=0.5, h/d=0.75 and h/d=1 were considered for the analysis. To increase the level of deformation without failure three different lubricants namely grease, molybdenum disulphide and grease were employed at the faces of the billet. A series of experiments were carried out in conjunction with the finite element modeling for different aspect ratios and different lubricants. The cylindrical billets were deformed plastically in between the two rigid dies to different strain limits. The true plastic strain at which the billet has fractured is termed as critical damage and this value was predicted using Normalized Cockroft-Latham, Cockroft-Latham, and Brozzo and Freudenthal workability criteria’s. The accuracy of the workability criteria’s with respect to the cylindrical billets of different aspect ratios was closely monitored in predicting the critical damage. An effort to improve the formability of the material enabled the effective utilization of the material and the processing conditions.
Reference :
-
- A. K. Jha and S. Kumar, ―Deformation characteristics and fracturing of sintered copper powder strips during cold forging,‖ Journal of Mechanical Working Technology,vol. 16, pp 145-164, 2013.
- X. Liang, ―Damage accumulation and fracture initiation in un cracked ductile solids subject to triaxial loading,‖ Internatioanl Journal of Solid Structures, vol. 44, pp. 5163–5181, 2007.
- C. Zheng, M. A. Jose, C Desa and FMA Pires, ―A comparison of models for ductile fracture prediction in forging processes.‖ Computational Methods in Material Science vol. 7, pp. 389 – 396, 2007.
- D.J. Kim, andB.M. Kim, ―Prediction of Deformed Configuration and Ductile Fracture for Simple Upsetting Using an Artificial Neural Network‖, International Journal of Advanced Manufacturing Technology, vol. 19, pp. 336–342, 2012
- N. Venkata Reddy, P.M. Dixit andG. L. Lal, ―Ductile fracture criteria and its prediction in axisymmetric drawing,‖ International Journal of Machine Tools and Manufacturing, vol. 40, pp. 95–111, 2012.