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The slab method can rapidly predict the rolling force and torque in metal forming processes and a large amount of CPU time can be saved. Up to now, the work hardening effect has not been considered in the slab analysis for forging process of double-layer clad sheet. Evaluation of considering or eliminating the work hardening effect on material behavior in the slab analysis of three layer clad sheet forging process and investigating the subsequent effects on the process outputs are novel subjects considered in this paper. The pressure distribution as well as the forging force is investigated for both conditions. In addition, three layer clad sheet forging process is entirely simulated using ABAQUS/Explicit software. The results show that considering the work hardening effect on material behavior will result into having higher stresses and forces in the process. Moreover, the results of considering the work hardening effect have better agreements with those from simulation. Finally, some experiments were performed on forging process of two layer Al/Cu clad sheet to evaluate the bonding quality of sheets. Therefore, forging process can be used for producing multi-layer clad sheets in various industries. [ABSTRACT FROM AUTHOR]

In this paper, with the aim of providing a new test pattern for empirical prediction of FLD of 304 stainless steel tube, first, numerical investigation of hydro-bulging process with various load paths and die geometries has been performed on strain path and plastic instability. Study on geometry of dies has been performed by varying die corner radius (R) and bulging length (W). Here, effect of axial feeding on strain ratio (β) has been studied. In this condition, by increasing W. strain ratio (β) tends to avalue of zero, a situation that is independent of boundary condition. By increasing die corner (R) in free loading condition, reduction of p occurs and the strain path approaches to plane strain state; while in loading with axial feeding condition, increasing of R has negligible effect on strain path and ratio. In loading with axial feeding condition, increase in axial feeding strain ratio (β) is reduced drastically. From the simulated tests, number of 10 tests with distributed loading path on strain diagram was selected for empirical study. Meshed tubes are loaded controllably until tearing and the FLCs were drawn using strains obtained near tearing locations. [ABSTRACT FROM AUTHOR]

In recent years, rubber pad forming process has conferred many advantages, such as high flexibility, good surface quality and lower manufacturing costs. RPF has been widely used in automotive, aerospace and military industries. In the present research, numerical and experimental analysis of free bulging 304 stainless steel seamed tube, using a polyurethane elastic pad has been studied. First, 3D simulation of seamed tube bulging using the finite element ABAQUS/Explicit 6.12 software by several frictional conditions has been performed. An incompressible hyperelastic pad has been modeled by Mooney-Rivlin constitutive equation and the elastic-plastic behavior as a more progressive ductile damage criterion FLD for steel tube were assumed. In the experimental activity, compression test of rubber was carried out according to ASTM D575-91 standard and compressive stress-strain curve and the Mooney-Rivlin constants were determined. Forming of meshed tubes by using elastic pad with different lubricating systems has been conducted up to onset of bursting in the seam weld and longitudinal, hoop and thickness strains were measured. Results showed that friction, especially between rubber and tube plays the main role in controlling wrinkles, increasing the bulge depth, reducing the forming load and friction dissipation energy of the process. Also, it was observed that the intact parts without any wrinkles were formed using nylon lubricant between tube and rubber and drawing oil between tubes and die. [ABSTRACT FROM AUTHOR]

When two bodies slide on each other, friction is created. By superposing ultrasonic oscillation to one of the bodies, the friction force is reduced. This phenomenon is widely used in metal forming and metal cutting. For the production and transmission of ultrasonic vibrations to a target it is necessary to use an ultrasonic system, the components of which are a generator, a transducer and a horn. Horn constitutes an important part of the Ultrasonic systems. The main task of the horn is to transmit the ultrasonic vibrations and amplify the ultrasonic vibration amplitude at the output. In this study, an Aluminum horn was designed in cylindrical-conical-cylindrical shape geometry and analyzed by the finite-element method(FEM), and manufactured using the Abaqus software. The resonance frequency obtained in Abaqus was equal to 19976 Hz. The resonance frequency obtained from the generator was equal to 19920 Hz. Hence very good agreement exists between the experimental result and the FEM simulation. The difference between the finite element simulation results and the experimental ones is less than one percent. Moreover, a horn--workpiece assembly for applying the ultrasonic sliding friction was designed and manufactured. Then the fixture and the tool holder clamp were designed for the vibrating tool so that it can be installed on a milling machine and the friction force measurement is possible while the ultrasonic vibrations are applied. [ABSTRACT FROM AUTHOR]