SEMINAR REPORT ON

“APPLICATION OF MAGNETORHEOLOGICAL FLUID

IN HYDROFORMING ”

Seminar End Semester Evaluation

Submitted By

SHAILESH PATEL140080709012

M.E. (MACHINE DESIGN)

DEPARTMANT OF MECHINACAL ENGINEERINGBIRLA VISHWAKARMA MAHAVIDYALAYA

VALLABH VIDYANAGAR-388120, GUJARAT, INDIAOCTOBER 2015

I

OCTOBER 2015

CERTIFICATE

This is to certify that the Seminar entitled, “APPLICATION OF

MAGNETORHEOLOGICAL FLUID IN HYDROFORMING”being submitted by

SHAILESH PATEL (140080709012)to the Birla Vishwakarma Mahavidyalaya,

VallabhVidyanagar in Mechanical Engineering Department is a Bonafide record of

research work carried out.

The results presented in this report have not been submitted, in part or full time

course, to any other University for the award of any Degree or Diploma.

Examiner’s Signature

II

INDEX

Abstract 1

Introduction 2

Magnetorheological fluids 8

Application of MR fluid in Hydroformin 12

Conclution 16

Rreferences 17

III

ABSTRACT

Viscosity has a great effect on the formability of sheet metal in viscous

pressure forming.

A new flexible-die forming method for sheet metal using magneto

rheological (MR) fluids, magneto rheological pressure forming (MRPF), is

proposed, which enables the viscosity of flexible-die medium adjustable by

changing the magnetic fields during the forming process.

Experimental results show that MR fluids can be used effectively as a

flexible-die medium to form the parts and its rheological behavior can be

adjusted during bulging process. Variation of MR fluid’s rheological

behavior can lead to different forming pressure load paths and have an effect

on sheet metal formability

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INTRODUCTION:

Automobile has become one of the largest consumer products, which is

influencing the human social lives. Low cost, high quality and High

productivity are the common targets in all manufacturing industries in

a customer based market structure. Automobile and other industries

dealing with sheet metal products seek for economical production

methods to reduce the manufacturing cost with increased quality.

A special type of die forming using a high pressure Hydraulic fluid to

press room temperature working material into a die Hydroforming –

the manufacture of hollow bodies with complex geometries by means

of fluid pressure has been shown to offer an interesting technical and

economic potential to sheet metal manufacturers.

Hydroforming process is divided into two main groups. sheet

hydroforming and tube hydroforming.

1. Tube hydroforming

Tubular hydroforming is used to form pre-fabricated sheet metal tubes into

structural members.

2. Sheet hydroforming

Sheet hydroforming is used to form pre-fabricated sheet metal into structural

members.

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TUBE HYDROFORMING

In this is a method, which is employed to for Tubular components of

different shapes. The process sequence is described below.

Tube sections or performs cut to the appropriate length are placed in the die.

The tube is then sealed at the ends by hydraulic pistons and filled

with ,hydraulic fluid. The pistons apply an axial compressive load on the

tube. The fluid is then pressurized so that the material expands

circumferentially to take the internal shape of the die.

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Low pressure hydroforming simply re-shapes tubes, producing a very

good shape, but is not as useful if better cross-section definition is

required.(less than 350 MPa)

High-pressure hydroforming totally changes the tube shape and alters

the length to circumference ratio by up to 50%. It gives very good

tolerance control, being a highly robust process.(greater than 350 MPa)

A basic difference is drawn between hydroformed components which

permit the following process conditions, in particular based on part

geometry and friction:

– continuous expansion and compression or

– only partial expansion and compression or

– only calibration

Used when a complex shape is needed

A section of cold-rolled steel tubing is placed in a closed die set

A pressurized fluid is introduced into the ends of the tube

SHEET HYDROFORMING

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This process uses hydrostatic pressure to form a sheet rather than the

mechanical forming with a punch against a die. Here the punch forms the

sheet against a hydraulic fluid chamber. The penetration of the punch into

the chamber causes a counter pressure.

• Sheet hydroforming is classified into two types Sheet HydroForming with

Punch (SHF-P) and Sheet HydroForming with Die (SHF-D).

The penetration of the punch into the chamber causes counter – pressure

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which presses the sheet the against the punch All the methods, which

influence metal flow in deep drawing like, draw beads, blank shape, lock

beads and optimization of the blank holder pressure can be used for this

process.

Greater draw depths can be obtained. Parts with tapered ,shaped walls can be

drawn in one operation unlike conventional multistage deep drawing

followed by mechanical stretch forming.

WARM HYDROFORMING

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There have been continuous demands for the use of lightweight materials to

reduce lightweight materials to reduce fuel consumption. A 10% weight

reduction in an average automotive body could improve the fuel efficiency

by 6-8%. Aluminium alloys and magnesium alloys offer a great potential for

weight reduction in vehicle construction due to their high strength to weight

ratio.

Warm Hydroforming operating temperature is below recrystallization

temperature, ranging from 0.2 to 0.5 times the recrystallization temperature.

The use of temperature opens up the possibility of increasing the ductility

and associated forming capability of the material along with reducing the

yield point and forming pressures and forces required

MAGNETO RHEOLOGICAL FLUIDS

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Magnetorheological (MR) fluids are materials that respond to an applied

magnetic field with a change in rheological behavior. Typically, this change

is manifested by the development of a yield stress that monotonically

increases with applied field.

Interest in magnetorheological fluids derives from their ability to provide

simple, quiet, rapid-response interfaces between electronic controls and

mechanical systems. That magnetorheological fluids have the potential to

radically change the way electromechanical devices are designed and

operated has long been recognized.

Magnetorheological (MR) fluids are smart and controllable materials, even

though at the first glance they do not look so impressive. They are a non

colloidal mixture of ferromagnetic particles randomly dispersed in oil or

water , plus some surfactants useful to avoid the settling of the suspended

particles. The overall aspect is like a greasy quite heavy mud, since MR

fluids density is more than three times the density of water.

• In the absence of external field MR fluid behave like Newtonian fluid, but

when stimulus is applied, the viscosity and plasticity of MR fluid dramatic

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change. These changes are repeatedly reversible and rapid (last a few

milliseconds)

Rheological Properties

The rheological properties of controllable fluids depend on concentration

and density of particles, particle size and shape distribution, properties of the

carrier fluid, additional additives, applied field, temperature, and other

factors.

The magnetorheological effect of the four MR fluids was measured on a

custom rheometer using a 46 mm diameter parallel plate geometry set at a 1

mm gap. In the parallel plate geometry, shear rate varies linearly across the

fluid sample with the maximum shear rate occurring at the outer radius. The

rheometer is capable of applying greater than 1 Tesla through the fluid

sample

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Figure 2 shows the shear stress in the MR fluids as a function of flux density

at a maximum shear rate of 26 s-1. At such a low shear rate, this shear stress

data is approximately equivalent to the fluid yield stress as defined in Eq.

(1). At low flux densities, the fluid stress can be seen to exhibit a power law

behavior. The approximate power law index of 1.75 lies in the range of low

to intermediate field behavior predicted by contemporary models of

magnetorheology.

There are basically three

components in an MR fluid:

A. Base fluid :: The base fluid is an inert or non magnetic carrier fluid in which

the metal particles are suspended. The base fluid should have natural lubrication

and damping features. For better implementation of MRF technology the base

fluid should have a low viscosity and it should not vary with temperature.

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B. Metal particles :: For proper utilization of this technology we need such type

of particles which can magnetized easily and quickly therefore we use metal

particles. Metal particles used in the MR- technology are very small. Size of the

particle is approximate of the order of 1μm to 7μm [1]. Commonly used metal

particles are carbonyl iron, powder iron and iron cobalt alloys.

C. Additives :: It is necessary to add certain additives to MR fluid for

controlling its properties. These additives include stabilizers and surfactants [7].

Surfactants serve to decrease the rate of settling of the metal particles. While the

functions of additives are to control the viscosity of the fluid, maintain friction

between the metal particles and to reduce the rate of thickening of the fluid due

to long term use of the fluid thus additives also increase the life of the

MR fluid

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MR FLUID IN HYDROFORMING

Related studies showed that viscosity has a great effect on the

formability of sheet metal in viscous pressure forming. However, the

viscosity of viscous medium keeps constant in VPF.

New flexible-die forming method for sheet metal using

magnetorheological (MR) fluids, magnetorheological pressure forming

(MRPF), is proposed, which enables the viscosity of flexible-die

medium adjustable by changing the magnetic fields during the forming

process. Squeezing tests of MR fluid show that its rheological behavior

can be changed greatly under different magnetic fields.

The sealing limit is one important limitation of the process window of

sheet metal hydroforming.

Avoiding these leakages by using special active fluid media like

magnetorheological fluids can strongly increase the robustness of the

forming process.

The aim of this fluids used isa combined forming and sealing medium

for forming processes and wether the selective application of magnetic

fields in the flange area leads to a decrease of leakage rates.

The method of magnetorheological pressure bulging process proposed

in this paper is schematically illustrated in Fig. 1. The distinct

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difference between this method and VPF or hydroforming is the

utilization of MR fluid as a flexible-die medium, which can change its

viscosity under different magnetic fields.

To ensure the sufficient change of MR fluid’ rheological behavior, a

coil is applied to generate a uniform magnetic field.

Different electric currents are applied to the coil to generate different

magnetic fields. Then a camera is used to record the change of MR

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fluid’s rheological behavior. Fig. shows the surface morphology of MR

fluid under different magnetic fields.

When there is no magnetic field, the MR fluid is shown in Fig. (a). It’s

similar with the silicone oil. When the magnetic flux density is 0.180T

and 0.318T, we can see obviously from Fig. (b) and Fig. (c) that the

medium becomes thick and sticky. When the magnetic flux density

reaches 0.412T, peak phenomenon of MR fluid can be easily observed.

It shows clearly that MR fluid’s rheological behavior can change

greatly under the current experimental device.

Bulging specimen obtain under different conditions piston strokes S

and magnetic flux density B) are shown in Fig. 15. As most of the

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specimens burst when the piston stroke reaches 12.0 mm, new tests are

conducted with a stroke of 11.0 mm, which is below the fracture limit

of the sheet metal

A specimen obtained with a stroke of 11.0 mm and magnetic flux density of

0.180T is shown in Fig.15(b). All the specimens with a stroke of 12.0 mm

burst except for the condition when magnetic flux density is 0.412T. So

additional tests under a magnetic flux density of 0.412T are conducted,

which is to obtain the corresponding piston strokes when the specimens

burst. The obtained average piston stroke is 12.5 mm and the maximum

difference is not greater than 0.4 mm.

The average dome heights of bulging specimens of various conditions are

shown in table 4. For each condition, at least four specimens are tested.

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The maximum difference of the dome heights is not greater than 0.89 mm

for each condition. The minimum value is 0.14 mm when the piston stroke

is 8.0 mm and no field is applied. Then two specimens which dome heights

are most close to the average value are chosen for strain measurement.

CONCLUTION This technology is very useful in those places where controlled fluid with

varying viscosity is required.

MRF technology are fast response , simple interface between electrical input

and mechanical output and intelligent controllability.

The main drawback of MRF technology is that the MR fluid becomes thick

after prolonged use and needs to be replaced, also due to presence of high

density metal particles, the weight of MRF products is high.

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REFERENCES TUBE HYDROFORMING PROCESS: A REFERENCE GUIDE : A.

ALASWAD , K.Y. BENYOUNIS, A.G. OLABI :MATERIALS AND

DESIGN 33 (2012) 328–339

DEVELOPMENTS IN SHEET HYDROFORMING FOR COMPLEX

INDUSTRIAL PARTS :M. BAKHSHI-JOOYBARI, A. GORJI AND M.

ELYASI

PATENT: US 2012/0153531 A1 FORMING PROCESSES USING

MAGNETORHEOLOGICAL FLUID TOOLING: PUB. DATE: JUN. 21,

2012

MECHANICS OF THE HYDROFORMING AND TUBULAR

HYDROFORMING PROCESS : JOHN ALEXIS ,

RUTHUPAVAN ,G.CHANDRAMOHAN

RESEARCH ON SHEET-METAL FLEXIBLE-DIE FORMING USING

MAGNETO RHEOLOGICAL FLUID : WANG ZHONG-JIN WANG

PENG-YI SONG HUI :JOURNAL OF MATERIALS PROCESSING

TECHNOLOGY(2014)

MR-FLUID TECHNOLOGY AND ITS APPLICATION- A REVIEW :

DEEPAK BARANWAL, DR. T.S. DESHMUKH :INTERNATIONAL

JOURNAL OF EMERGING TECHNOLOGY AND ADVANCED

ENGINEERING[2012]

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