Deformation of the material during cyclic expansion extrusion (CEE) is investigated using upper-bound theorem. The analytical approximation of forming loads agrees very well with the FEM results for different amounts of chamber diameter, friction factor and also for lower die angles. However, the difference between analytical and numerical solution increases at higher die angles which are expla...

An approximate numerical mthod is presented for analysis and determination of modal characteristics in straight, pretwisted non-unifom helicopter blades. The analysis considers the coupled flapwise bending (out of plane), chordwise bending (in plane), and torsion vibration of both rotating and non-rotating blades. The proposed method is based on the integral expansion of Green functions (struct...

In this paper, an upper bound approach is used to analyze the extrusion process of bimetallic rods through arbitrarily curved dies. Based on a spherical velocity field, internal, shearing and frictional power terms are calculated. The developed upper bound solution is used for calculating the extrusion force for two types of die shapes: a conical die as a linear die profile and a streamlined di...

Metal forming processes, compared with machining ones, reduce production steps and increase manufacturing speed in addition to saving raw material. In this paper, forming process of column of a steering mechanism is investigated by finite element analyses and experimental tests; and optimum die design parameters are found. Forming process parameters including die opening angle, bearing length, ...

An instrumented trimming press equipped with D2 grade steel die inserts sharp edges was used to conduct tests on DP980 sheets clearances of 10%, 20%, and 30% the sheet thickness. Trimming were conducted either or without a support pad placed under scrap piece force measured as function penetration distance upper die. The progression plastic deformation fracture processes that occurred in shear ...

The linac-driven Vacuum-Ultraviolet Free Electron Laser (VUV-FEL) at DESY, Hamburg produces short pulses of intense soft X-ray radiation. As the high gain FEL process depends strongly on a high peak current of the electron bunches, it is necessary to measure and control the bunch length. For this purpose, coherent synchrotron radiation (CSR) from a bending magnet of the bunch compressor BC2 is ...

the research was conducted in order to determine the bending stress, young’s modulus, shearing stress, and shearing energy of safflower stalk as a function of moisture content and stalk region. the bending forces were measured at different moisture contents and the bending stress and the young’s modulus were calculated from these data. for measuring the shear forces, the stalk specimens were se...