Showing 3 results for Hashemi
E. Masoumi Khalil Abad, A. Ghazanfari, R. Hashemi,
Volume 3, Issue 4 (12-2013)
Abstract
In this study, an extended stress-based forming limit diagram (FLD) for prediction of necking based on the
Marciniak and Kucznski (M-K) model is represented and applied in tube hydroforming. The bulge forming
of a straight tube is simulated by finite element method and verified with published experimental data. This
adaptive simulation technique is based on the ability to detect the onset and growth of defects (e.g., bursting
and wrinkling) and to promptly readjust the loading paths. Thus, a suitable load path is determined by
applying Adaptive Simulation Method in ANSYS Parametric Design Language (APDL).
Eng. Seyyed Ali Akbar Hashemi Milani, Dr. Reza Tavangar, Dr. Maziyar Azadbeh, Eng. Ibrahim Kahinpoor, Eng. Hossein Sadeghi-Nasab,
Volume 10, Issue 4 (12-2020)
Abstract
Drying temperature of the flux at normal atmosphere has a crucial role in brazing quality in automotive aluminum-based heat exchangers. Over the course of this research, NOCOLOK® flux consists of two phases of K2AlF5.H2O and KAlF4 with melting point around 580 °C was used. A flux slurry was applied on the base metal, and dried at 220, 300 and 380 °C in air. Mechanical assessment revealed that when flux dried at 300 °C, the joint withstands maximum shear stress of 44 MPa with complete bonding. At 220 °C and 380 °C, joint shear stresses are 34 MPa, 30 MPa respectively. 380 °C dry-off temperature under nitrogen gas improved shear strength to 39 MPa. Taking dry-off temperature as 300 °C the amount of defective heat exchangers was reduced from 6% to 2% on a daily basis.
Majid Fallah Tafti, Ramin Hashemi, Mohammad Sedighi,
Volume 12, Issue 2 (6-2022)
Abstract
This paper aims to examine the influences of heat treatment on forming limit diagrams and mechanical properties of aluminum alloy AA6061 sheets with thicknesses of 1.5 mm. The uniaxial tensile and the micro-hardness tests are employed to specify the mechanical properties and their variations. The Nakazima test is performed to characterize the strain forming limits of this aluminum alloy. Comparison between the results of micro-hardness and forming limit diagrams indicates that by increasing the temperature up to the peaked ageing temperature, the strength of the alloy is increased, but the forming limits are decreased, and after the peaked aged in over the aged state, the strength is decreased and the forming limits are increased. The peaked-aging is touched in this specific alloy after 4 hours heat treatment at 180 oC.
