Abstract. The present research aims to predict the thickness distribution of a wall of a deep drawn cup when the main parameters of deep drawing process are ...
Finite Element Simulation of Deep Drawing Parameters Effects on Cup Wall Thickness Dr. ABDUL KAREEM FLAIH HASSAN ALI HASOON ABDULHADI Mechanical Engineering Department / College of Engineering University of Basarh / Basrah / Iraq Abstract The present research aims to predict the thickness distribution of a wall of a deep drawn cup when the main parameters of deep drawing process are changed, benefiting from the using finite element method. A simplified 3D axisymmetric model which represents the deep drawing set (blank and tools) was created using a CAD software, and then imported into a finite element code ANSYS where a simulation was carried out. The model represents a cylindrical cup made of low carbon steel sheet. The sheet thickness is (0.5 mm), punch diameter equals (43 mm) and three different blank diameters (78, 82, 86) were used. Friction coefficient values of (0.05, 0.1, 0.15), blank holder force (BHF) values of (1.25, 2.5, 5, 10) kN, punch profile radius of (2, 4, 6, 8, 10, 12) mm, and die profile radius of (2, 4, 6, 8, 10, 12) mm were used in the model. The results showed that the FE model represents real deep drawing process fairly well. The cup thickness distribution values showed a good agreement with the referenced values, where the failure or success of drawing process could be predicted based on the obtained thickness results. It was observed that a high value of friction restrains material movement and resulted in producing more thinning and more punch force. High blank holder force was found to decrease the thickness of both the bottom face of the cup and the flange rim. While increasing die corner radius increases thickness and the maximum thinning occurred at the smallest die corner radius. It was found by decreasing the punch profile radius the thickness at the flat bottom of the cup and under the punch profile region were reduced.
محاكاة تأثير متغيرات السحب العميق على سمك جدار قدح باستخدام طريقة العناصر المحددة علي حسون عبداهلادي عبدالكرمي فليح حسن.د جامعة البصرة- كلية اهلندسة- قسم اهلندسة امليكانيكية العراق- البصرة
الخالصة يهدف ىذا البحث إىل ختمني توزيع السمك جلدار قدح نتج من عملية السحب العميق عند تغري العوامل األساسية لعملية السحب العميق وذلك مت أنشاء منوذج مبسط ثالثي األبعاد ومتماثل احملاور والذي ميثل منظومة عملية السحب (الصفيحة والقوالب.باالستفادة من طريقة العناصر احملددة حيث أجريت عليو حماكاهANSYS مث ادخل ذلك النموذج إىل حقيبة العناصر احملددةAutoCAD وماسك الصفيحة) باستخدام الربنامج وقطر القالب5.0 mm ميثل النموذج قدح اسطواين مصنوع من مادة الصلب الكربوين الواطئ حيث ان مسك الصفيحة يساوي.لعملية السحب 0.05, 0.1, ( قيم معامل االحتكاك البيين ىي.)78, 82, 86 mm( والصفيحة الدائرية ذات ثالثة أقطار خمتلفة34mm الذكر يساوي ) ونصف قطر حافة كل من القالب الذكر و القالب األنثى1.25, 2.5, 10.5 kN( قيم القوة املسلطة على ماسك الصفيحة ىي,) 0.15 . أن اختالف قيم كل من تلك املعامالت ىو لدراسة تأثريىا على مسك جدار القدح املتكون.)2,4,6,8,10,12 mm( كانت كالتايل 1
, وان قيمة السمك وجدت يف اتفاق معقول مع النتائج اليت قورنت معها.أظهرت النتائج ان ال نموذج املقرتح قد مثل عملية التشكيل بصورة جيدة تبني من خالل النتائج ان ىناك تأثري كبري لقيمة معامل.حيث ميكن ختمني جناح أو فشل عملية السحب اعتمادا على قيمة السمك على طول اجلدار حيث ان زيادة قيمة معامل االحتكاك تعرقل حركة املادة وبالتايل تزيد من نسبة تقليل.االحتكاك على الن تائج العددية املستحصلة من عملية احملاكاة كذلك وجد ان زيادة قوة ماسك الصفيحة تؤدي اىل تقليل مسك كل من حافة القدح املتكون وقاعدتو.السمك وتزيد قيمة القوة الالزمة للتشكيل وان زيادة نصف قطر حافة القالب االنثى يؤدي اىل زيادة مسك جدار القدح املتكون وتكون املنطقة ذات السمك االقل عند اقل نصف قطر.السفلى وكذلك املنطقة اليت تقع, ان نقصان نصف قطر حافة القالب الذكر قد ادى اىل تقليل مسك كل من الوجو السفلي للقدح.حلافة القالب االنثى .اسفل تقوس حافة القالب applied FE analysis to estimate the initial
1. Introduction Deep drawing is one of the extensively
blank shape, intermediate deform shape,
used sheet metal forming processes in the
thickness distributions and failure during
industries to have mass production of cup
multistage deep drawing operation of
usually have complicated shapes in a very
elliptic cup. Khalil (2006) [5] proposed a
short time [1]. Deng and Blesi (1999)[2]
numerical procedure for the design of deep
Proposed new theoretical models for
drawing process using FEM. A simplified
predicting the drawing fracture load of an
2D axisymmetric model of cylindrical cup
axisymmetric cup drawing. These models
of 43 mm outer diameter and 0.5 mm
take into account the influence of tri axial
thickness drawn from mild steel blanks had
stress state, anisotropy, strain hardening,
been developed. The research aimed to
bending, and tool geometry. The optimum
study the effect of some parameters which
punch profile radius is found to be between
influence the drawing process, such as
5-7 times the thickness of the sheet. Hong
friction coefficient, blank holding force,
Yao, Jian Cao (2000)[3] formulated an
punch and die corner, and to predict the
analytical model to calculate the offset of
tearing failure in drawn parts.
the simplified axisymmetric model for
2. Building of the FE model
predicting the failure height of 3D parts.
The ultimate purpose of a finite element
Simulation results demonstrate that the
analysis is to recreate mathematically the
corner stretch height is always larger than
behavior of an actual engineering system.
the side stretch height for square cup .The
In other words, the analysis must be an
accuracy of the failure height prediction
accurate mathematical model of a physical
using the 2D model with offset has been
prototype. This model comprises all the
improved. Hun and Kim (2001) [4], they
nodes, elements, material properties, real 2
constants, boundary conditions, and other
Where
features that are used to represent the
diameter,
physical system [6].
die corner radius.
2.1
the blank diameter,
is the bunch
is the cup height, and
is the
The following step includes joining the
Model Generation
existing key points with lines, Figure(3), to
A global cartesian coordinate system is
only one quarter of the geometry is
used and working plane is the x-y plane
modeled taking advantage of symmetry to
where z axis is the normal. The first step
reduce computational expense. Next is to
involved creating the key points, Figure(1),
generate a 3D model from these 2D
each point has x,y, z values defining its
entities, Figure(4).
location in space, before creating the lines that connect the key points together, the blank diameter needed for the given cup height must be calculated. The blank size for cylindrical parts with small punch radius (r
