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Flexible roll forming process is an advanced manufacturing process, for producing complex and lightweight profiles with variable cross-section. One of the major observed defects in this process is the flange wrinkling of the profiles, which has limited its development especially for the automotive industry. In this paper, the deformation mechanics of the flexible roll forming process is revisited, and the methodology for predicting the onset of wrinkling, which had previously been developed based on the wrinkling limit curve in the space of effective strain versus stress triaxiality, is improved. Then, a new criterion based on the wrinkling limit curve is proposed to predict the possibility of wrinkling in finite element analys
In this study, three ductile fracture criteria were used to investigate the fracture in U-bending of AA6061-T6 aluminum alloy sheets. Considering the importance of the calibration procedure, three different tension tests including the uniaxial, plane strain, and notched tensions were conducted based on the stress state analysis. The Ayada, Rice-Tracey, and normalized Cockroft-Latham fracture criteria were calibrated through a hybrid experimental-numerical method to determine their critical damage values. Fracture envelopes (i.e., the locus of fracture strains) were constructed for the investigated fracture criteria based on the results of various tension tests in their calibration procedure. The calibrated fracture criteria were implemented
In this study, the modified Mohr-Coulomb (MMC) ductile fracture criterion was employed to investigate the ductile fracture during the roll forming process of the AA6061-T6 aluminum alloy. To this aim, the MMC fracture criterion was calibrated based on the tension tests and was integrated into the commercial finite element (FE) Abaqus/Explicit using an appropriate user subroutine. The experimental procedures were designed based on two distinct forming strategies, namely single-stage and multi-stage roll forming processes. The results indicate that the calibrated fracture model based on tension tests is capable to predict the fracture initiation in the single-stage roll forming process at an error rate of 4.47%. Meanwhile, the numerically pre
The present study evaluates the fracture behavior of the AA6061-T6 aluminum alloy during the roll forming process using ductile fracture criteria. Three criteria including Ayada, Rice-Tracey, and normalized Cockroft-Latham were utilized to develop an accurate fracture model for predicting fracture onset during the roll forming process. To this end, the fracture criteria were calibrated using uniaxial, plane-strain, and notched tension tests. The model was developed by integrating the calibrated fracture criteria into the numerical analysis (commercial finite element code Abaqus/Explicit) through an appropriate user subroutine. Based on the results, the damage weighting function and calibration procedures had a significant effect on the accu
In this paper, the effects of the joint type on the driven-out bead of the roll-formed pipes, welded by high-frequency induction welding process are studied. The main goal is to predict and reduce the volume of the bead driven out in the weld seam. Moreover, it aims to move the semi-solid bead during welding to the outer diameter of the pipe. This study has two prior aims: to produce a defect-free joint and to improve the mechanical and metallurgical properties. In order to optimize the weld joint, various joint types have been investigated by experimental tests and simulation. Lastly, destructive tests were used to determine if the desired mechanical properties of the weld joint were obtained. The metallurgical properties and the derivatio
In this study the radial-forwad-backward extrusion of axially joint cup shaped AM60 magnesium alloy part is investigatd. In the experimental tests, the cylindrical AM60 alloy samples were prepaed and pressed by a punch into the die cavity. In the next step, the initial and extruded samples were investigated in terms of microstructural evolution and mechanical poperties variation. The microscopic observations showed the significant grain refinement of AM60 is occurred at the end of extrusion proessingwhere the fine grains in size of ~7μm are obtained from the initial value of ~75μm. Also, the Vickers microhardness is increased to 88Hv from the initial value of 56 Hv. The obtained results of uni-axial tensile tests showed the increase in yi
In this paper, determination of the fracture onset by the ductile fracture criteria was studied and the effect of damage function, calibration method, and calibration tests were investigated on the fracture prediction accuracy. Based on the stress state analysis, three different tension tests including the uniaxial, plane strain, and notched tension tests were conducted to determine the critical value of the ductile fracture criteria. In order to investigate the fracture behavior of AA6061-T6 aluminum alloy sheets, The Ayada, Rice-Tracey, and normalized Cockroft-Latham phenomenological ductile fracture criteria were calibrated through a hybrid experimental-numerical method. The finite element (FE) method were used to simulate the process an
Exact estimates of the power required in manufacturing processes prevent machines from being designed with capacities that are several times greater than those required. Owing to the high energy consumption in the manufacture of tubes and profiles, in this study and considering the effects of some input parameters (including the bend angle increment at each stand, internal distance between the stands, strip thickness, channel flange width, and corner radius) in the production of a symmetrical channel section, the energy consumption and required torque were investigated and optimized using the full factorial method. The results showed that an increase in the bend angle increment at each stand increases the required torque and ch
In this paper, the uniaxial loading–unloading–reloading (LUR) tensile test was conducted to determine the elastic modulus depending on the plastic pre-strain. To obtain the material parameters and parameter of Yoshida-Uemori’s kinematic hardening models, tension–compression experiments were carried out. The experimental results of the cyclic loading tests together with the numerically predicted response of the plastic behavior were utilized to determine the parameters using the Ls-opt optimization tool. The springback phenomenon is a critical issue in industrial sheet metal forming processes, which could affect the quality of the product. Therefore, it is necessary to represent a method to predict the springback. To achieve this aim
Aluminum alloys are considered a lot in the automotive and aerospace industry because of their high strength to weight ratio. In this manuscript, the gas forming process of aluminum AA6063 tubes at high temperatures up to 500 C is investigated, through experimental and numerical tests. Therefore, an experimental setup is prepared and so, tube specimens are formed in a die with square cross section. Finite element simulation of the hot gas forming process is carried out to investigate the effects of process parameters including time period of forming process, temperature, and loading path. Uniaxial tensile tests under various temperatures and strain rates is performed, in order to obtain flow stress curves of the material. Corner radius and
In this paper, the modified Mohr-Coulomb (MMC) ductile fracture criterion was adopted to analyze the fracture behavior of the AA6061-T6 aluminum alloy sheet during the U-bending process. Appropriate calibration procedures were employed using various tension tests. A finite element (FE) model was built using the commercial FE code Abaqus/Explicit incorporating the calibrated MMC fracture criterion. It was found that the MMC criterion calibrated by the uniaxial, plane strain, notched, and modified in-plane shear tension tests can predict the onset of fracture in the U-bending process with reasonable accuracy. The error of the predicted fracture displacement was about 2% as compared to experiments. Due to the dependency of the fracture predict
Jamming is defined as sudden and unwanted immobilization of workpiece during its loading/unloading into the fixture. Investigation of workpiece jamming in fixture and prediction of its occurrence during fixture design process may induce to modification of the fixturing plan, reduction of the fixture fabrication costs and decreasing of the jamming-related consequences. The present study focuses on the numerical investigation of workpiece jamming in fixture using block and palm case study and comparison of its results to the theoretical predictions. For this purpose, numerical analysis of block and palm case study is conducted using Adams? software. Results of numerical analysis represent that jamming is occurred for block by traveling of dis
Todays, since using metallic nanoparticles has been developed in various industries, achieving new methods to produce them is considered as an important issue. Comparing to other nanoparticle production methods, the dielectric discharge process has been emphasized due to its low cost and environmental compatibility. In this study, the ultrasonic-assisted electrical discharge process is designed and manufactured in order to produce copper nanoparticles in di-ionized fluid. The different machining parameters effect, as current intensity, pulse on/off time, and the ultrasonic vibrations on the produced particle size, material removal rate, suspensive particle stability in the fluid, and the particle abundance percentage is investigated. Charac
Metal foams are a new category of materials that in the last decade have been introduced thanks to their good physical and mechanical properties such as high stiffness and low density. Metal foam sheets cannot be formed or bent using the conventional mechanical forming processes because of their low ductility. To overcome this difficulty, a thermal approach was followed in this study, namely, the laser forming process was used to achieve higher bending angles in aluminum closed-cell foam sheets by using the irradiation of a CO2 laser beam on the surface of the sheets to produce a temperature gradient across the sheet thickness. The effect of the process parameters, including the laser power, scan velocity, beam diameter, and nu
In the 3D laser forming process, developing an appropriate laser scan pattern for producing specimens with high quality and uniformity is critical. This study presents certain principles for developing scan paths. Seven scan path parameters are considered, including: (1) combined linear or curved path; (2) type of combined linear path; (3) order of scan sequences; (4) the position of the start point in each scan; (5) continuous or discontinuous scan path; (6) direction of scan path; and (7) angular arrangement of combined linear scan paths. Regarding these path parameters, ten combined linear scan patterns are presented. Numerical simulations show continuous hexagonal, scan pattern, scanning from outer to inner path, is the optimized. In ad
The cold roll forming is a continuous metal forming process to produce a large variety of profiles. A major product of the cold roll forming is wide profiles whose application is expanding in the construction of houses, bridges, airports, sports arenas, etc. The edge wrinkling is one of the common defects in the cold roll forming of the wide profiles. The edge wrinkling leads to several problems, such as decrease of dimensional tolerances, abrasion of forming rolls due to contact with the wrinkled edge, non-uniform distribution of forming through the production line, and unsuitable energy consumption. In this paper, the mechanics of edge wrinkling in the cold roll forming of the wide profile is investigated, and the effect of t