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1
Analiza numeryczna walcowania skośnego stopniowanych wałków ze stopów metali nieżelaznych
100%
Lis K. , Pater Z.
Rudy i Metale Nieżelazne Recykling
|
2019
|
tom R. 64, nr 1
21--25
PL
W artykule opisano przykłady kształtowania stopniowanych wałków ze stopu tytanu w gatunku TiAl6V4 oraz stopu magnezu w gatunku AZ31 metodą walcowania skośnego. Stopniowane wałki kształtowano za pomocą trzech rolek stożkowych obracających się z jednakową prędkością w tą samą stronę, które miały możliwość jednoczesnego zsuwania lub rozsuwania się w celu redukcji przekroju poprzecznego odkuwki. Na podstawie wykonanych obliczeń numerycznych uzyskano: rozkłady intensywności odkształcenia, temperatury, kryterium zniszczenia według Cockrofta-Lathama oraz rozkłady sił i momentów walcowania.
EN
he paper describes a skew rolling process for production of stepped shafts made of titanium alloy TiAl6V4 and AZ31 magnesium alloy. The parts are formed by three tapered rolls that are rotated at identical speed in the same direction. The rolls can simultaneously converge or diverge in order to reduce the cross section of the workpiece. The numerical analysis provided information about the distributions of effective strains, temperatures, Cockroft-Latham damage criterion as well as the variations in the loads and torques.
2
Content available Determination of Critical Damage Function Values of CW008A Copper and S355 Steel in Tensile and Torsion Tests
80%
Walczuk-Gągała P. , Pater Z. , Wójcik Ł. , Lis K.
Advances in Science and Technology. Research Journal
|
2023
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tom Vol. 17, no 2
173--180
EN
The article describes the problem of material fracture in metal forming processes. It describes and compares the values of damage functions obtained in classical tensile and torsion tests of two materials, i.e. CW008A copper and S355 steel under cold forming conditions. The presented research methodology includes experimental tests and numerical simulation carried out using Simufact.Forming v.15 software. The damage values were analysed according to various criteria, including the growth and coalescence of micro cracks (Rice&Tracey, Oyane, Argon), the initiation and development of ductile cracking in forming processes (Freudenthal, Cockroft-Latham, Brozzo, Oh) and using extended phenomenological models based on the history of stress triaxiality (Ayada) or the mean and equivalent stress (Zhan). The conducted tests showed that the values of the damage function depend on: the calibration test, the material grade and the geometry of the specimen.
3
Content available Numerical Analysis of the Cross-Wedge of a Hollow Rail Axle
80%
Pater Z. , Lis K. , Walczuk-Gągała P.
Advances in Science and Technology. Research Journal
|
2020
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tom Vol. 14, no 1
145--153
EN
The article presents an innovative method of manufacturing hollow rail axles using three combined wedge rolls. The proposed solution was evaluated using numerical simulation. Two cases of forming, differing in the wall thickness of the billet, were analysed. The geometry of the formed axles, distributions of the effective strain, temperature and damage function were presented. Moreover, the changes to the forces and torques acting on each roll were presented.
4
Content available Preliminary analysis of a rotary compression test
80%
Pater Z. , Walczuk P. , Lis K. , Wójcik Ł.
Advances in Science and Technology. Research Journal
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2018
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tom Vol. 12, no 2
77--82
EN
The paper addresses the problem of material fracture in cross rolling processes. A new test based on rotary compression for determining limit values of the damage function after the Cockroft-Latham criterion is proposed. A FEM analysis is performed to determine the stress and strain states in a workpiece subjected to this test. The numerical results demonstrate that the axial region of the workpiece is characterized by the presence of alternating tensile and compressive stresses conducive to fracture. The distribution of the Cockroft-Latham integral in the axial region of the workpiece is determined.
5
Content available remote Forming of rail car axles in a CNC skew rolling mill
80%
Pater Z. , Tomczak J. , Lis K. , Shu X.
Archives of Civil and Mechanical Engineering
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2020
|
tom Vol. 20, no. 3
78--90
EN
This study relates to an innovative method for forming rail car axles by skew rolling in a CNC 3-roll mill. The rolling mill was constructed at the Lublin University of Technology. The use of this machine makes it possible to produce elongated axisymmetric parts that are up to 55 mm in diameter and up to 1000 mm in length. Experimental rolling tests are performed (in 1:5 scale) using this machine. Two types of axles are analysed: one manufactured in accordance with North American standards (AAR Class E) and one manufactured in compliance with European standards (BA302). Diameters of produced axles have a dimensional accuracy of ± 0.4 mm. Produced axles are free from internal cracks, and their surface defects (shallow helical grooves) can easily be removed by machining. The major shortcoming of the proposed method is the presence of chucking allowance. To eliminate this allowance, it is proposed that the forming process should be performed in two operations: rolling extrusion and skew rolling. Results of a numerical analysis were performed using the Simufact.Forming program confirms that rail car axles can be formed by the proposed method.
6
Content available Prediction of Waviness Values in Skew Rolling Using Machine Learning Methods
70%
Lis K. , Pater Z. , Tomczak J. , Bulzak T. A. , Kusiak T.
Advances in Science and Technology. Research Journal
|
2023
|
tom Vol. 17, no 5
350--359
EN
Skew rolling with three rolls is used for producing axisymmetric parts. In this method, the tools are spaced every 120° on the circumference of the workpiece. They are also set askew relative to the rolling axis. Cross sectional reduction is made effective by moving the tapered rolls closer to or away from the center line of the workpiece. Experiments were conducted with variable initial conditions of the rolling process to examine surface topography of rolled parts. Obtained experimental results were then analyzed using machine learning methods in order to determine the most effective regression model with the highest coefficient of determination R2 for waviness prediction.
7
Content available remote Design and technological capabilities of a CNC skew rolling mill
61%
Tomczak J. , Pater Z. , Bulzak T. , Lis K. , Kusiak T. , Sumorek A. , Buczaj M.
Archives of Civil and Mechanical Engineering
|
2021
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tom Vol. 21, no. 2
524--540
EN
Results of a study investigating a skew rolling process for elongated axisymmetric parts are presented. Despite the fact that the skew rolling technique for producing such parts was developed and implemented in the mid-twentieth century, there are no studies on this problem. The first part of this paper presents the results of FEM modelling of skew rolling stepped axles and shafts (solid and hollow). The FEM analysis was performed using the MSC Simufact Forming software. The numerical simulation involved the determination of metal flow patterns, the analysis of thermal parameters of the material during rolling, and the prediction of cracking by the Cockcroft-Latham ductile fracture criterion. Force parameters of rolling solid and hollow parts were also determined. The aim of the FEM analysis was to determine initial design assumptions and parameters for the development of the skew rolling mill. Later on in the paper, a design solution of a CNC skew rolling mill for rolling parts based on their envelope profile is proposed. FEM strength test results of a mill stand, obtained with MSC. NASTRAN, are presented. Finally, the performance test results of the constructed rolling mill are presented. The experiments involved rolling real stepped shafts that were modelled numerically. Obtained results show that the proposed skew rolling method has considerable potential. The designed and constructed rolling mill can be used to perform the rolling process according to the proposed method, with the tool and material kinematics being controlled based on the set parameters of a workpiece envelope.
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