Physical modeling and finite element analysis of friction encountered in large deformation processes (original) (raw)
Related papers
Determination of friction coefficient encountered in large deformation processes
Tribology International, 2002
A new technique, namely, the open-die backward extrusion test technique, was developed as an alternative method to the ring compression test in order to quantitatively evaluate the coefficient of friction, m, at the die/workpiece interface. This technique relates the percentage deformation in height of the specimen to the percentage increase in extruded height of the specimen. In this study, the open-die backward extrusion tests (ODBET) were simulated for different aspect ratios, (H/D), and different die geometries, (d/D), by utilizing an elastic-plastic finite element code (ANSYS) in order to obtain the friction calibration curves (FCCs). The results indicated that the extruded height is related to the friction conditions at the die/workpiece interface. Therefore, ODBET can be used to generate FCCs to determine the coefficient of friction at the die/workpiece interface in large deformation processes.
ESDA 1996: Composite …, 1996
The main objective of this research was to investigate whether generalized friction calibration curves, as recommended in the literature for use with ring compression tests, are applicable to all types of materials and test conditions. Specifically, the effects of material properties, strain-rate sensitivity, and "barreling" on the behavior of friction calibration curves were investigated. To this end, a series of ring compression tests were conducted in order to determine the magnitude of the friction coefficient, m, as well as the corresponding calibration curves for two types of modeling materials, white and black Plasticine. The experiments were first conducted using the Physical Modeling Technique (PMT) and then simulated via an elastic-plastic finite element code (ABAQUS). In contrast to the results available in the literature, where the same friction calibration curves are recommended for all types of materials and test conditions, the results of this investigation showed that friction calibration curves are indeed affected by the material properties and test conditions and every material possesses its own distinctive friction calibration curve.
EXPERIMENTAL AND SIMULATION DETERMINATION OF FRICTION COEFFICIENT BY USING THE RING COMPRESSION TEST
EXPERIMENTAL AND SIMULATION DETERMINATION OF FRICTION COEFFICIENT BY USING THE RING COMPRESSION TEST, 2018
One of the main problems in the plastic deformation of materials is the determination of the coefficient of friction as well as the subsequent application of the simulation for comparative analysis. However forecasting process and matching between simulation and experimental data is still a problem. Causes of this are factors such as roughness, mechanical properties of the material, chemical composition, etc. which strongly influence the behavior of the material in the simulation of the process. In this study, an approach is proposed to determine the changeable coefficient of friction in the deformation process experimentally, taking into account implicitly the influence of surface roughness on the friction curves. For the comparative analysis between experiment and simulation of the process, the experimental data for objective assessment was introduced. Nevertheless, there are differences between experiment and simulation, which is most evident in high loads, using lubricants differing from more than 12 units for graphite lubricant, with more than 6 units with oil and with dry friction with 8 units.
Proceedings of the 1994 ASME European Joint …, 1994
The main objective of this research was to investigate whether generalized friction calibration curves, as recommended in the literature for use with ring compression tests, are applicable to all types of materials and test conditions. Specifically, the effects of material properties, strain-rate sensitivity, and "barreling" on the behavior of friction calibration curves were investigated. To this end, a series of ring compression tests were conducted in order to determine the magnitude of the friction coefficient, m, as well as the corresponding calibration curves for two types of modeling materials, white and black Plasticine. The experiments were first conducted using the Physical Modeling Technique (PMT) and then simulated via an elastic-plastic finite element code (ABAQUS). In contrast to the results available in the literature, where the same friction calibration curves are recommended for all types of materials and test conditions, the results of this investigation showed that friction calibration curves are indeed affected by the material properties and test conditions and every material possesses its own distinctive friction calibration curve.
On the measurement of friction coefficient utilizing the ring compression test
Tribology International, 1999
The main objective of this research was to investigate whether generalized friction calibration curves, as recommended in the literature for use with ring compression tests, are applicable to all types of materials and test conditions. Specifically, the effects of material properties, strain-rate sensitivity, and "barreling" on the behavior of friction calibration curves were investigated. To this end, a series of ring compression tests were conducted in order to determine the magnitude of the friction coefficient, m, as well as the corresponding calibration curves for two types of modeling materials, white and black Plasticine. The experiments were first conducted using the Physical Modeling Technique (PMT) and then simulated via an elastic-plastic finite element code (ABAQUS). In contrast to the results available in the literature, where the same friction calibration curves are recommended for all types of materials and test conditions, the results of this investigation showed that friction calibration curves are indeed affected by the material properties and test conditions and every material possesses its own distinctive friction calibration curve.
Determination of Friction Coefficient by Employing the Ring Compression Test
The main objective of this research was to investigate the effect of material properties, strain-rate sensitivity, and barreling on the behavior of friction calibration curves. The compression tests were conducted to obtain the necessary material properties for the finite element analysis. A series of ring compression tests were then conducted in order to determine the magnitude of the friction coefficient, . The experiments were first conducted for the modeling materials, namely, white and black plasticine and later on, for aluminum, copper, bronze, and brass. The experiments were then simulated via an elasticplastic finite element code (ABAQUS). Contrary to the results available in the literature, where the same friction calibration curves are recommended for all types of materials and test conditions, the results of this investigation showed that friction calibration curves are indeed affected by the material properties and test conditions.
International Journal of Engineering and Technical Research (IJETR)
The objective of this work is to obtain the friction factor & coefficient of friction by compressing a small cylindrical Ring under dry and lubricated condition. Friction is very sensitive to the forming process (like forging, drawing, Extrusion, etc.). In this experiment a standard size of cylindrical ring of dimension outer diameter 42 mm, inner diameter 21 mm and height of 14 mm is examined under compressive load. This standard dimension is in the ration of 6:3:2 (Outer Diameter: Inner Diameter: Height) which was defined by the MALE & COCKCRAFT in their experiment. This standard dimension is widely accepted. Aluminum alloy (AA-6101) rod was used for making ring of standard dimension by using Lath machine. These Rings are compressed on Universal Testing Machine under dry condition, servo 2T Diesel oil, Allyl isothiocyanate and Grease. Deformation took place under the influence of load and contact friction in the lateral and longitudinal direction. By substituting the value of change in the inner diameter and chance in the height in the formula given by Male and Depierre, Avitzur, we calculate the friction factor and friction coefficient. Load applied to deform the specimen, is insensitive to friction condition.
Determination of friction factor by ring compression testing and FE analysis
Computer methods in materials science, 2015
The goal of this study was to examine performance of various lubricants for aluminium alloy AA5083. Conventional ring compression tests were conducted at 200 °C. Samples were compressed to 50% of the initial height with a constant ram velocity 0.5 mm/s using a servo-controlled hydraulic press. The optimization procedure was implemented in self-developed software to identify friction factors from experiments. The application launches remotely finite element (FE) simulations of ring compression with a changing friction factor until a difference between experiment and numerical prediction of the internal diameter of the sample is smaller than 0.5%. FE simulations were run using Forge3 commercial software. The obtained friction factor quantitatively describes performance of a lubricant and can be used as an input parameter in FE simulation of other processes. It was shown that application of calcium aluminate conversion coating as pre-lubrication surface treatment reduced friction facto...
Friction studies at different normal pressures with alternative ring-compression tests
Journal of Materials Processing Technology, 1998
In the present paper, experimental investigations and theoretical analyses of friction are carried out with alternative ring-compression tests applying three different ring geometries, namely a concave-, rectangular- and convex-shaped ring cross-section, resulting in three different normal pressures, at low, medium and high level. Aluminum alloy AA6082 was used in the experiments, in both annealed and work-hardened conditions. Two different lubricants were applied in the experiments, i.e. soap and molybdenum disulphide, both in connection with an aluminate conversion coating. In order to directly study the influence of friction whilst avoiding any coinciding influence of the strain hardening, a friction model with a constant absolute value was applied in finite-element method (FEM) simulations for calibration of the friction. Calibration curves with the friction constant A as a parameter were obtained using FEM analysis and verified by the experimental results. The influence of strain hardening and pressure level on friction and metal flow are discussed.
An alternative ring-test geometry for the evaluation of friction under low normal pressure
Journal of Materials Processing Technology, 1998
Quantitative evaluation of the tribological conditions at the tool–workpiece interface in metal forming is usually accomplished by the ring-compression test. The popularity of the test can be attributed to its practical convenience including the fact that friction can be judged from deformation alone. Due to the geometrical design of the conventional ring-test, the interface stresses will, however, always be greater than the flow stress of the material, thereby impeding quantification of friction, and evaluation of the behaviour of lubricants, for processes where interface stresses below the flow stress of the material occur. This paper presents a new complementary ring-test geometry, which allows the characterisation of friction under low pressure conditions. Finite-element analysis in conjunction with metal experiments applying both the conventional and the modified geometry for different lubricants provides the validation for the general feasibility of the proposed test geometry.