Rotary Compression Research Articles

Numerical Modelling of a Rotary Compression Test on a Cylindrical Specimen

Numerical Modelling of a Rotary Compression Test on a Cylindrical Specimen

Rotary compression test for determination of critical value of hybrid damage criterion for railway steel EA1T

The article presents and discusses the problem of determining and characterizing the cracking limits of cross-rolled specimens. The limit values were determined in accordance with the hybrid Pater criterion. For the study, the author’s test method was used, which allows the determination of the cracking moment, formed as a result of the Mannesmann effect during the compression of specimens in the channel. In order to determine the values needed to describe the cracking criterion, it was necessary to perform laboratory tests and numerical simulations of the process of compression in the channel of discs made of EA1T steel under hot forming conditions. Experimental tests were carried out for forming processes at 950 °C, 1050 °C and 1150 °C. The tested material had a disc shape with a diameter of 40 mm and a length of 20 mm, during the pressing process the diameter of the disc was reduced to a diameter of 38 mm. The increase in forming temperature caused a significant increase in the forming path until cracking occurred. Numerical tests were carried out in the finite element calculation environment Simufact.Forming 2021. The stress and strain distributions in the specimen axis were analysed during the tests, which were then used to calculate the hybrid cracking criterion limit according to Pater. After calculations according to the Pater criterion and after statistical analysis, the cracking criterion limits were obtained.

Modified hybrid damage criterion for the cross wedge rolling process

This paper considers the problem of material fracture in the cross wedge rolling (CWR) process. A modification of the hybrid damage criterion dedicated to crack prediction in CWR was proposed. The aim of the modification was to make the limits of the new criterion independent of the implementation temperature of the calibration tests. A rotary compression test was carried out to obtain specimens in which cracking is initiated. Based on the analysis of the FE results of the rotary compression test simulation, the final version of the modified hybrid damage criterion (MHDC) was presented. Using the results of experimental tests and FE simulations, the MHDC limit values were determined. The MHDC limits for the three different temperatures were obtained at similar levels, indicating that the MHDC limits can be made independent of the rotary compression test execution temperature. The MHDC was verified on the example of the cross wedge rolling of a railway axle forging. The verification carried out confirmed the possibility of predicting cracks in CWR-rolled forgings using MHDC. The research results obtained are of an applied nature. In particular, the criterion developed can be helpful in the design of cross wedge rolling technology.

Hemostasis after transradial coronary intervention by rotary compression device with sterile gauze is associated with more adverse events: a retrospective study

Hemostasis after transradial coronary intervention by rotary compression device with sterile gauze is associated with more adverse events: a retrospective study

Effect of roller layout on biomass bales quality and baling energy consumption during rotary compression

Baling cellulosic biomass into round bales is an effective way to reduce the cost of storage and transportation. To improve the quality of bales and reduce the baling energy consumption, this paper introduces the steel roller layout parameters of the round baler into the biomass baling process. Alfalfa was used as an experimental material for five levels pitch value of roller circumferential layout baling experiments. The results showed that the introduction of chamber non-roundness (pitch value of roller circumferential layout) destroyed the formation of the entanglement high density ring cylindrical shell lamination of the outer layer of bales, which was beneficial to the compression of bales core material. When the pitch value was 30 mm, the maximum baling pressure, radial pressure transfer loss, and the baling energy consumption of baler were reduced by 30.4%, 33.4%, and 13.7%, respectively. When the pitch value was 60 mm, the relaxation ratio and radial density difference were reduced by 6.3% and 35.8%, respectively, and the radial density uniformity of alfalfa bale was increased by 32.0%. The experimental results provide a theoretical basis and technical support for the chamber structural optimization design of the round baler.

Interpolymer Complex of Chitosan and Eudragit L-100: Preparation, Characterization and Drug Release Behavior

Aims: The aim of the present investigation was to prepare interpolymer complex between Chitosan and Eudragit L100, and to evaluate its performance as a matrix for controlled release of drugs, using Diclofenac sodium as a model.
 Methodology: Interpolymer complex were prepared by combining different % chitosan solutions with different % Eudragit L100 solutions in different ratios. The formation of interpolyelectrolyte complexes (IPEC) between carbopol and Chitosan was investigated, using turbidimetry and viscosity measurement. The structure of the prepared IPEC was investigated using FTIR spectroscopy and DSC. A Rotary compression press was used to formulate matrix tablets of diclofenac sodium using polymers in physical mixture and IPECs.The amount of Diclofenac Sodium released in the dissolution medium was determined spectrophotometrically at 276 nm.
 Results: The results of the present investigation confirmed the formation of an interpolyelectrolyte complex between Chitosan and Eudragit L 100. The release of the model drug Diclofenac sodium was significantly controlled from tablets made up of the IPEC as compared with polymers alone and in combination. Release profiles were represented by a mathematical model, which indicates that the prepared system releases drug in a zero-order manner by changing the ratio of the IPEC in the tablets.
 Conclusion: Controlled release drug delivery systems designed to manipulate the drug release to achieve specific clinical objectives that are unattainable with conventional dosage forms.

Determination of the critical damage for 100Cr6 steel under hot forming conditions

In this study, the critical values of damage were determined for 100Cr6 grade steel specimens subjected to forming in the temperature range of 950–1150 °C. This was done using 8 phenomenological criteria of failure and 3 calibration tests based on uniaxial tension, torsion and rotary compression. Experiments were performed on test stands installed at the Czestochowa University of Technology and the Lublin University of Technology. The above calibration tests were modelled numerically using the commercial simulation software Simufact. Forming v. 15. The average values of temperature, strain rate and critical damage were calculated for every calibration test. Results showed a significant relationship between critical damage and forming temperature. A comparison was made between the critical damage values obtained in the torsion and tensile tests, performed at similar temperatures and strain rates. It has been found that the relationship between the critical damage values determined via torsion and uniaxial tensile testing is fairly stable for the dimensionless fracture criteria, i.e. those formulated by Oh, Oyane and Brozzo.

Prediction of ductile fracture in skew rolling processes

This paper begins with a review of the literature regarding the modelling of skew rolling processes, with a special focus on the problem of material fracture. Numerical modelling is performed to compare stresses and strains in the cross sections of bars produced by skew rolling with the use of two and three rolls. It has been found that the two-roll skew-rolled bars are more prone to the occurrence of fracture in their axial zone. It is proposed that cracking in skew rolling processes be predicted with the use of classical fracture criteria. The accuracy of crack prediction by these criteria depends on the correct determination of the critical damage. The critical damage in skew rolling processes can be determined by two tests: rotary compression of a tapered specimen (when a process is performed with two tools) or rotary compression of a disc-shaped specimen in a cavity between the tools (when a process is performed with three tools). Six fracture criteria and a new test of rotary compression of a tapered specimen are employed to investigate fracture in a two-roll skew rolling process for producing cylindrical bars made of 100Cr6 grade steel. It has been found that stress-based criteria are more suitable for modelling fracture due to their lower sensitivity to temperature variations in the axial zone of rolled bars.

A Rotary Compression Process for Producing Hollow Gear Shafts.

This paper presents selected numerical and experimental results of a study investigating the process of forming hollow stepped gear shafts from tubes by rotary compression. The objective of the study was to determine whether the rotary compression process is an effective method of producing hollow stepped gear shafts and to identify limitations of this manufacturing method. A theoretical analysis involved the numerical modeling of the proposed process by the finite element method (FEM). 3D simulations were performed using the commercial simulation software package Simufact Forming. The analysis involved examining the material flow pattern along with thermal and force parameters of the process. The FEM results were verified with experimental tests conducted under laboratory conditions. The experiments were performed on a machine specially designed for the rotary compression of hollow parts. Results demonstrate that it is difficult to form a stepped gear shaft in one operation. For this reason, such parts should be formed in two operations. The first operation involves the forming of a hollow stepped shaft by rotary compression, while in the second operation, a gear is formed on one of the steps of the shaft.

Rapid estimation of ductile crack formation in cross-wedge rolling

This study investigates the problem of predicting material cracking in cross-wedge rolling (CWR). Fifty-four cases were analyzed using the finite element method (FEM), and maximum values of the damage function were determined. Based on the results obtained from simulations, nomographs were created to allow for quick and easy determination of the maximum damage function values depending on the basic CWR parameters, mainly the forming angle, spreading angle of the wedge, and deformation ratio. The rotary compression test of a cylindrical sample was used to determine the critical damage values for the C45 grade steel formed in the temperature range 950–1150 °C. For the fracture condition to occur, it was assumed that the damage value should be higher than the critical damage value given by the damage function. This hypothesis was experimentally validated. The results of the experiments show good agreement with the numerical results of material fracture obtained with the method described in this study.

A Comparative Analysis of Forming Railway Axles in 3- and 4-Roll Rolling Mills.

The paper presents a comparative analysis of skew rolling in 3- and 4-roll CNC rolling mills. The analysis is performed using the FEM-based commercial simulation software Simufact.Forming. The formation of both solid and hollow railway axles is analyzed. Distributions of effective strain, temperature and damage criterion in rolled axles are determined, and loads and torques acting on the tools during rolling are estimated. An innovative concept of calibrating hollow axles by the rotary compression technique developed at the Lublin University of Technology is presented. Experimental tests of rolling solid axles in a 3-roll rolling mill (in a scale of 1:5) are performed, and basic force parameters of the rolling process are measured. Numerical and experimental loads and torques show a high agreement in terms of both quality and quantity.

Rotary compression as a new calibration test for prediction of a critical damage value

The article presents the problem of ductile fracture of metals and metal alloys formed in hot working conditions. The basic damage criteria used in modelling fracture as well as calibrating tests used to determine the critical damage values were discussed. A concept of a new calibrating test based on rotary compression of a disc or a cylinder was presented. Using the proposed calibrating test along with nine damage criteria the critical damage values for 50HS (1.5026) grade steel, formed in the temperature range 950 °C to 1150 °C were determined. A significant dependency of the critical damage value on temperature was observed. The stress states occurring in rotary compression and the cross-wedge rolling, skew rolling in a two-roll rolling mill and helical-wedge rolling processes were compared. On the basis of the results obtained it was advised to apply rotary compression of a cylinder samples to determine the critical damage values used in the analyses of cross- and skew rolling.

Rotary compression in tool cavity\u2014a new ductile fracture calibration test

Ductile fracture is one of the most common failure modes in hot metal forming. It can be predicted by means of so-called damage functions that describe the relation between stress, deformation and fracture initiation. A practical use of these functions requires the knowledge of the critical damage value of the material that is determined by calibration tests based on compression, tension and torsion. For the prediction to be correct, one must ensure that the modelled and real stresses are in agreement. Previous studies did not offer any effective test for determining critical values of damage under changing load conditions that occur in cross and skew rolling processes, among others. To compensate for this knowledge gap, researchers at the Lublin University of Technology have developed a new test consisting in rotary compression of a test-piece in a cavity between the tools, which is described in this paper. In the proposed test, a cylindrical test-piece is rolled over a cavity (impression) created by grooves on two mating tools. The cavity height is smaller than the test-piece diameter. At the critical value of the forming length, the state of stress induced thereby in the test-piece axis causes fracture. Knowing the critical forming length, it is possible to determine the critical value of damage by numerical modelling. The practical application of the proposed test is illustrated through the case of C45 grade steel subjected to forming in the temperature range 950–1150 °C. The analysis makes use of the normalized Cockcroft-Latham (NCL) criterion of ductile fracture.

A rotary compression test for determining the critical value of the Cockcroft–Latham criterion for R260 steel

A method for determining the critical value of the Cockcroft–Latham damage criterion is presented using the example of R260 railway steel. The determinations were performed using a rotary compression test specially developed for that purpose. The main object of the proposed test was to provide the best possible representation of the state of stress generated by cross-wedge rolling. The rotary compression test was performed in two stages: in the first stage, experimental tests were conducted to establish the moment of cracking of the specimen, and in the second stage, numerical modeling was used to determine the critical value of the Cockcroft–Latham criterion for the experimentally established cracking moment. The critical value of the Cockcroft–Latham criterion was determined under hot forming conditions.

Assessment of ductile fracture criteria with respect to their application in the modeling of cross wedge rolling

Ductile fracture is a common failure mode in cross wedge rolling (CWR) and can be predicted by analyzing material damage functions. This paper describes 10 such functions. To determine the moment of fracture, one must know the critical damage function which is calculated via calibration test. It is vital to ensure that the stress state during calibration is as close as possible to the real stress. Since there are no calibration tests dedicated to cross rolling processes, a new test has been devised, based on a rotary compression process for cylindrical samples. Using the proposed calibration test and 10 fracture criteria, the critical damage values of C45 steel deformed at 1150 °C are determined. Next, CWR tests are performed using technological parameters conducive to crack formation in the axial region of the formed step on the workpiece. Numerical and experimental results of the moment of crack initiation and its length are compared, and – as a result – 4 damage criteria that best predict material fracture are selected.

Establishment of a new hybrid fracture criterion for cross wedge rolling

This paper relates to the problem of fracture in cross wedge rolling (CWR). A FEM analysis is performed of the stresses in the axial zone of the workpiece formed by this method. Thirteen CWR cases are analyzed for different values of the forming angle, α=<15°; 35°>, spreading angle, β=<4°; 12°>, and reduction ratio, δ=<1.1; 1.9>. Numerical results demonstrate that the stresses in the CWR process are characterized by the mean stress triaxiality ηav=<0.075; 0.334> and the mean Lode angle parameter Θav<−0.905; −0.415>. Under this stress state, fracture may occur as a result of both void formation and shear fracture. A new hybrid criterion of fracture is proposed, which combines 2 well-known fracture criteria, i.e. the maximum shear stress criterion and the Oh criterion (normalized Cockcroft-Latham criterion). It should, however, be mentioned that the effect of the above criteria on the final value of the proposed hybrid criterion depends on the stress triaxiality. The critical value of the proposed fracture criterion is determined by a new calibration test based on rotary compression, in which the stress state is similar to that in parts produced by the CWR method. The critical value of the new fracture criterion is determined for the C45 grade steel in the temperature range of 950–1150 °C. Results demonstrate that increasing the forming temperature leads to an increase in the critical damage function. To verify the proposed fracture criterion, CWR tests are performed under conditions leading to fracture of the material (C45 steel). Experimental findings and numerical results obtained by the new hybrid fracture criterion show a very high agreement in terms of both quality (crack occurrence prediction) and quantity (crack length prediction).

The case of Frictional Torrefaction and the effect of reflux condensation on the operation of the Rotary Compression Unit

This work introduces the process of Frictional Torrefaction and comes as a continuation to the previous work done on Frictional Pyrolysis, which is a novel method of pyrolysis that does not utilize heat but only friction and pressure. Both processes (i.e. Frictional Torrefaction and Frictional Pyrolysis) take place in a Rotary Compression Unit without and with a reflux condenser respectively. Rotating augers are used for the development of friction and the simultaneous increase of pressure. The following types of analysis were performed: TGA, BET, CHNS and HHV. Both products have similar heating values, around 21 MJ/kg. The elemental compositions are comparable but lower hydrogen content (3.5%) was measured for Frictional Torrefaction. BET analysis showed differences on the surface areas and porous sizes of the materials. Frictional Torrefaction has higher fixed carbon (31.23% vs 28.31%), higher surface area (58.16 m2/g vs 36.88 m2/g) and higher absorbance (35 cm3/g vs 26 cm3/g).

A Theoretical and Experimental Analysis of Rotary Compression of Hollow Forgings Formed Over a Mandrel

The paper presents selected results of studies of the process of forming hollow stepped shaft forgings by rotary compression with rotary tools. The aim of the study was to determine whether rotary compression could be performed using an additional tool – a mandrel, which, when positioned in the cavity of the workpiece, could be used to shape the surface of the cavity. A theoretical analysis was based on finite element modeling using Simufact Forming software. During the simulations, distributions of deformation intensity, temperature, and the Cockroft–Latham fracture criterion were determined. Predictions were also made regarding phenomena such as slippage and deformation of forging pieces and material cracking, as potential impediments to the investigated process. Additionally, force parameters were determined during the forming of forgings. Numerical results were verified experimentally. Rotary compression tests for hollow forgings were carried out in a special forging machine designed by the present authors. The results were validated on the basis of the geometric parameters of formed forgings and the force parameters of the process. The results confirm that hollow stepped shaft forgings can be formed in the process of rotary compression using a mandrel. Forgings formed over a mandrel are characterized by greater precision and quality compared to freely formed blanks (without a mandrel).

Development and application of the compression frictional treatment method for sterilizing and valorizing organic waste

ABSTRACTConfined animal feeding operations are producing large amounts of organic waste with large fractions being mixtures of manure and sawdust. On one hand, the inhomogeneity of the material and the high water content restrict the optimal application of thermal treatment methods. On the other hand, the high concentration of bacteria in these mixed waste streams is an issue of concern. This study introduces a novel process for treating manure and woody biomass mixtures and upgrading them into valuable products. It is defined as compression frictional treatment (CFT) and takes place continuously in a rotary compression unit. Fresh poultry droppings and fresh anaerobic digester offal from a cattle feedlot were processed by means of CFT. Moisture was decreased by 52% and heating value was increased by 27% for treated poultry litter. The corresponding values were 63% moisture decrease and 25% increase for the heating value of cattle manure. On the aspect of bacteria reduction, the Escherichia coli and the Enterobacteriaceae family of bacterium were reduced by 94% and 91%, respectively.

Control and data acquisition system for rotary compressor

The rotary compressor (crimping machine) is a machine designed for making hollow forgings. The rotary compressor is a prototype device designed and built at the Technical University of Lublin. The compressor is dedicated to perform laboratory tests related to the hollow forgings of various shapes using different materials. Since the rotary compressor is an experimental device, there is no control and acquisition data system available. The article presents the concept and the capabilities of the computer control and data acquisition system supporting rotary compressing process. The main task of software system is acquisition of force and kinetic parameters related to the analysed process of the rotary forging compression. The software allows the user to declare the course of the forming forgings. This system allows current recording and analysis of four physical values: feed rate (speed of working head movement), hydraulic oil pressure at inlet and outlet of hydraulic cylinder and the torque of engine. Application functions can be divided into three groups: the configuration of the pressing process, the acquisition and analysis of data from the pressing process and the recording and presentation of stored results. The article contains a detailed description about hardware and software implementation of mentioned functions.