Modelling of variable friction in cold forging

In metal forming operations, the friction between die and workpiece is a complex phenomenon and has a strong influence on the metal forming parameters and the product quality This study aims to investigate the effect of friction in cold forging operations using different friction models. In the analyses, the forging operations are simulated using the Coulomb and constant friction models, and the results are compared with the simulation results obtained by using the variable friction models developed by Wanheim-Bay (general friction model) and Levanov, which are integrated into the program. Cylinder upsetting and bolt head forging are numerically simulated and the cylinder upsetting results are compared with the experimental data. The results showed that depending on the workpiece geometry and the contact pressure, the coefficient of friction may change significantly during the process and the constant coefficient of friction may not simulate the actual friction condition in the cold forging process.


Investigating the mechanical properties of single walled carbon nanotube reinforced epoxy composite through finite element modelling
Zuberi, Muhammad Jibran Shahzad; Esat, Volkan (2015-03-15)
Varying experimental results on the mechanical properties of carbon nanotube reinforced polymer composites (CNTRPs) have been reported due to the complexities associated with the characterization of material properties in nano-scale. Insight into the issues associated with CNTRPs may be brought through computational techniques time- and cost-effectively. In this study, finite element models are generated in which single walled carbon nanotube models are embedded into the epoxy resin. For modelling interface...
TEKKAYA, AE; SEN, A (1992-12-01)
The rigid-plastic finite element analysis of metal forming processes is known to be much more efficient and stable than the elastic-plastic one. This efficiency results from the absence of kinematical nonlinearities in the formulation. Contact algorithms used in rigid-plastic models must agree with this fact, otherwise the efficiency can be damaged seriously.
Akhmet, Marat (2016-01-01)
In this paper, mechanical models with Newton's Law of impacts are studied. One of the most interesting properties in some of these models is chattering. This phenomenon is understood as the appearance of an infinite number of impacts occurring in a finite time. Conclusion on the presence of chattering is made exclusively by examination of the right hand side of impact models for the first time. Criteria for the sets of initial data which always lead to chattering are established. The Moon-Holmes model is su...
Analysis of forging for three different alloy steels
Civelekoğlu, Barış; Darendeliler, Haluk; Gökler, Mustafa İlhan; Department of Mechanical Engineering (2003)
Forging is a manufacturing process which is preferred among the others in that, the final product shows more enhanced properties. The properties of the final product are directly related with the material used in the forging process. Main parameters such as forging temperature, number of stages, preform design, dimensions of the billet, etc. may be affected by the forging material. Alloys are one of the main areas of interest in the forging industry. The use of alloy steels may bring superior properties, es...
Computational Methods for Inclined Cracks in Orthotropic Functionally Graded Materials Under Thermal Stresses
Dağ, Serkan; TOPAL, SERRA (2013-10-03)
This article sets forth two different computational methods developed to evaluate fracture parameters for inclined cracks lying in orthotropic functionally graded materials, that are under the effect of thermal stresses. The first method is based on the J(k)-integral, whereas the second entails the use of the J(1)-integral and the asymptotic displacement fields. The procedures introduced are implemented by means of the finite element method and integrated into a general purpose finite element analysis softw...
Citation Formats
O. N. Cora, M. Akkök, and H. Darendeliler, “Modelling of variable friction in cold forging,” PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART J-JOURNAL OF ENGINEERING TRIBOLOGY, pp. 899–908, 2008, Accessed: 00, 2020. [Online]. Available: