Keywords : strain path


INFLUENCE OF THE FORMING PROCESSES ON THE RATE OF CORROSION OF GALVANIZED HIGH STRENGTH LOW ALLOY STEEL SHEETS

Dr. F. M. Abdulla; A. M. Ali; H. A. Ibrahim

Al-Rafidain Engineering Journal (AREJ), 2010, Volume 18, Issue 6, Pages 95-104
DOI: 10.33899/rengj.2010.34930

ABSTRACT:
The effect of deformation on the corrosion of galvanized high strength low alloy steel sheet is studied. Specimens in the uniaxial, plain and biaxial strains were stretched by a hemispherical punch to three different punch heights for each path of strain. After each deformation, The deformed specimens together with a fourth non deformed specimen were subjected to a corrosive medium for the same sequential times. To determine the effect of corrosion, all the specimens were weighted before and after each corrosion stage and the hardness was also measured It was found that corrosion in the deformed specimens was higher than in the non-deformed ones. Also it was found that corrosion increased by moving from the uniaxial to the biaxial strain passing through the plain strain path and by increasing the punch heights. The results were verified by the hardness measurement.

KEYWORDS: galvanized HSLA steel, corrosion, deformation, strain path

Numerical Study Of The Effect Of Some Forming Paramiters In Hemispherical Punch Stretching

W.J. Ali; A. Alsaati; F. M.Alkaissy

Al-Rafidain Engineering Journal (AREJ), 2007, Volume 15, Issue 2, Pages 71-84
DOI: 10.33899/rengj.2007.44958

ABSTRACT
In this work a finite element simulation is used for the hemispherical punch stretching test. The effect of strain hardening exponent, the original thickness of the sheet metal and the coefficient of friction between the punch and the blank on the formability of sheet metal are investigated. The results of this simulation are used to derive an empirical formula combining the simultaneous effect of the three parameters on the final thickness of the sheet. This formula is used to derive a numerical criterion which can be used in a separate finite element program for predicting the initiation and the position of localized necking. The effect of the three parameters on the level of the forming limit diagram is also investigated. An emphasis is put on the relation between the coefficient of friction and the strain path.

Keywords : Localized necking, empirical formula, strain path

FRICTION TECHNIQUE FOR DETERMINING FORMING LIMIT CURVES

A. Alsaati; W. J.Ali; F. M.Alkaissy

Al-Rafidain Engineering Journal (AREJ), 2006, Volume 14, Issue 4, Pages 11-23
DOI: 10.33899/rengj.2006.45352

A new method for establishing the Forming Limit curve (FLC) in sheet metal forming is introduced in this work. The method is based on varying the strain path by changing the coefficient of friction between the punch and the blank.
Three finite element simulations are used for the hemispherical punch stretching test. One simulation is for the positive minor strain side and two are for the negative minor strain side of the FLC. Relations between the major and the minor strains are deduced from the results of these simulations. These relations are used to draw the FLC.
The curves obtained were compared with experimental results and found to have a good agreement with them.

KEYWORDS strain path, forming limit curve


ABSTRACT
A new method for establishing the Forming Limit curve (FLC) in sheet metal forming is introduced in this work. The method is based on varying the strain path by changing the coefficient of friction between the punch and the blank.
Three finite element simulations are used for the hemispherical punch stretching test. One simulation is for the positive minor strain side and two are for the negative minor strain side of the FLC. Relations between the major and the minor strains are deduced from the results of these simulations. These relations are used to draw the FLC.
The curves obtained were compared with experimental results and found to have a good agreement with them.

KEYWORDS strain path, forming limit curve