APPENDEX-Grey Relation Analysis Using Excel...

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APPENDEX-Grey Relation Analysis Using Excel Sheet

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PAPERS EMANATED FROM THE THESIS

1. “DESIGN AND ANALYSIS OF CORRUGATED STEEL SANDWICH

STRUCTURES USING ANSYS WORKBENCH” A.Gopichand , Dr.G.Krishnaiah,

B.Mahesh Krishna, Dr.Diwakar Reddy.V, A.V.N.L.Sharma International Journal of

Engineering Research & Technology (IJERT) ISSN: 2278-0181 Vol. 1 Issue 8,

October – 2012,pp1-4

2. “DESIGN AND FABRICATION OF CORRUGATED SANDWICH PANEL USING

TAGUCHI METHOD” V.Diwakar Reddy, A. Gopichand, G. Nirupama, G.

Krishnaiah International journal of design and manufacturing technology(IJDMT)

ISSN 0976 – 6995 Volume 4, Issue 2, May - August (2013), pp. 01-13

3. “NUMERICAL SIMULATION OF STEEL SANDWICH PLATE SYSTEM (SPS)

FLOOR” A.Gopichand, Dr.G.Krishnaiah, D.Krishnaveni, Dr.Diwakar Reddy.V

International Journal of Innovative Research in Science, Engineering and

Technology ISSN: 2319-8753Vol. 2, Issue11, November 2013,pp6300-6308

4. “MODAL ANALYSIS OF A STEEL SANDWICH PLATE SYSTEM(SPS) FLOOR”

A.Gopichand, Dr.G.Krishnaiah, Dr.V.Diwakarreddy.N.V.Shankar, International

Journal of Engineering Research & Technology (IJERT), Published in Vol. 2 Issue

11, November – 2013.pp3002-3304

Design And Analysis Of Corrugated Steel Sandwich Structures Using Ansys

Workbench

1A.Gopichand ,2 Dr.G.Krishnaiah,3B.Mahesh Krishna , 4Dr.Diwakar Reddy.V, 5A.V.N.L.Sharma

1.Associate Professor, Department of Mechanical Engineering ,Swarnandhra college of Engineering and Technology,NARASAPUR,INDIA

2.Professor &HOD, Department of Mechanical Engineering Sri Venkateswara University college of Engineering,TIRUPATHI,INDIA.

3.P.G.Student, Department of Mechanical Engineering ,Swarnandhra college of Engineering and Technology,NARASAPUR,INDIA

4. Professor, Department of Mechanical Engineering Sri Venkateswara University college of Engineering, TIRUPATHI, INDIA 5.Professor &HOD, Department of Mechanical Engineering ,Swarnandhra college of Engineering and Technology,NARASAPUR,INDIA

.

Abstract A structural sandwich consists of two thin face

sheets made from stiff and strong relatively dense

material such as metal or fiber composite bonded to a

thick light weight material called core. This

construction has often used in lightweight applications

such as aircrafts, marine applications and wind turbine

blades.

In this paper the structural analysis of corrugated

sand which panel with stainless steel face sheets and

mild steel as core is done using Ansys work bench and

compressive strength is compared with experimental

value.

The model of the curved corrugated core is done in

pro/E and the effect of wave length on strengthto

weight ratio is analyzed.

1. Introduction & Literature Review Noor, Burton and Bert state that the concept of

sandwich construction dates back to Fairbairn in

England in 1849. Also in England, sandwich

construction was first used in the Mosquito night

bomber of World War II which employed plywood

sandwich construction. Feichtinger states also that

during world war II, the concept of sandwich

construction in the United States originated with the

faces made of reinforced plastic and low density core.

In 1951, Bijlaard studied sandwich optimization for the

case of a given ratio between core depth and face

thickness as well as for a given thickness[1]

Various analyses on sandwich structure are Kevin J.

Doherty investigate sandwich panels of metallic face

sheets and a pyramidal truss core subjected to panel

bending and in plane compression testing to explore the

effects of relative core density and process

parameters.[2]. Aydıncak, İlke made a design and

analysis of honeycomb structures to develop an

equivalent orthotropic material model that is substitute

for the actual honeycomb core.[3] . Jukka

Säynäjäkangas make a review in design and

manufacturing of stainless steel sandwich panels and

conclude an efficient sandwich is obtained when the

weight of the core is close to the combined weight of

the both faces[4]. Tomas Nordstrand made an analysis

on corrugated board in three-pointbending and

evaluation of the bending stiffness and the transverse

shear stiffness[5]. Pentti Kujala discussed that steel

sandwich panels that are welded by laser can save 30-

50% weight compared to conventional steel

structures[6]. Jani Romanoff presents a theory of

bending of laser welded web core sandwich panels by

considering factors that effect the total bending

response of laser welded web core sandwich plates[7].

Pentti Kujala made analysis on metallic sandwich

panels which are laser welded have excellent properties

with light weight having more applications[8]. Narayan

Pokharel determined local buckling behavior of fully

profiled sandwich panels which are based on

polyurstyrene foam and thinner and high strength

steels[9]. Pentti kujala determined ultimate strength of

all steel sandwich panels and numerical FEM analysis

and development of design formulations for these

panels.[10]

2. Corrugated sandwich structures A structural

sandwich typically consists of two thin face sheets

made from stiff and strong relatively dense material

such as metal bonded to a thick lightweight material

called core. This concept mimics an I beam, but in two

dimensions, where the face sheets support bending

loads and the core transfers shear force between the

faces in a sandwich panel under load. Face sheets used

International Journal of Engineering Research & Technology (IJERT)

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in structure are mainly in three forms flat, lightly

profiled and profiled. The face sheets of sandwich

panels provide structural stiffness and protect the core

against damage and weathering. During loading the

face sheets take compressive and tensile loads and core

transforms shear loads between the faces and provide

high bending stiffness. Sandwich structures are used in

applications requiring high stiffness to weight ratios

because for a given weight, the sandwich structures has

a much higher moment of inertia compared to solid or

I-beam structures.

Sandwich panels with top and bottom plates as well as

the core made up of steel are called steel sandwich

panels. The core structures are of different types

according to core structures the steel sandwich

structures are divided some of them are I-core, O- core

with rectangular beams, Vf/V- core with hat or

corrugated sheets as a core, web core, round O-core and

X-core with two hats as a core as shown in Fig.1.

In this paper a steel sandwich structure with curved

corrugated core made of mild steel and stainless steel

face sheets are considered.

Figure.1 Different steel sandwich structure with

various cores

3. ANSYS Workbench

ANSYS Work bench can be thought of as a software

platform or framework where you perform your

analysis (Finite Element Analysis) activities. In other

words, workbench allows you to organize all your

related analysis files and databases under same frame

work. Among other things, this means that you can use

the same material property set for all your analyses.

Some of the applications that fit into the workbench

framework are:

1. Design modeler

2. Mechanical (simulation)

3. Design Xplorer

4. AUTODYN

5. CFX Mesh

6. FE Modeler

The ANSYS Workbench platform allows users to

create new, faster processes and to efficiently interact

with other tools like CAD systems. In this platform

working on Multiphysics simulation is easy. Those

performing a structural simulation use a graphical

interface (called the ANSYS Workbench Mechanical

application) that employs a tree-like navigation

structure to define all parts of their simulation:

geometry, connections, mesh, loads, boundary

conditions and results.

By using ANSYS workbench the user can save time in

many of the tasks performed during simulation. The

bidirectional links with all major CAD systems offer a

very efficient way to update CAD geometries along

with the design parameters.

.

4. Design and Analysis of Sandwich

Structures.

Sandwich panels are modeled in PRO/E. The top and

bottom plates are modeled by using extrude command

and the core part is modeled by using sweep command.

The three parts are assembled by using assembling

command. Then the assembled part is saved in IGS

format and imported to ANSYS workbench. In ANSYS

Workbench the IGS format is Imported and geometry

will show three contact pairs. Materials properties are

given to the individual part i.e, top and bottom plates

are selected and stainless steel properties are given to

them. Now core is selected and mild steel properties are

given. now mesh the geometry as free mapped mesh

and structural analysis is done by fixing the plate at

bottom and pressure is applied at top face of the plate

as shown in fig. now by solving the structure the

deflection and von misses stress are noted. By changing

the wave length of corrugated core and same is

modeled and analyzed at a constant pressure the

variation in deflection and von misses are compared.

Compression test

Steel sandwich structure with stainless steel faces and

mild steel core are joined by welding and compression

test is conducted on Universal testing machine (UTM)

and ultimate stress and deflection are studied. The in-

plane compression testing of sandwich structure was

performed on universal testing machine (UTM)having

capacity 400KN. The samples were placed between

hardened end plates in order to protect the surface of

the machine’s platens. Load is applied uniformly and

deflection and compression strength are noted.



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Figure 8: In plane compression test

Table 1 shows the experimental results compared with

ANSYS workbench resuts

Load KN Deflection mm

Ansys workbench 13.58 0.23

UTM 15 0.25

Figure2: geometry of corrugated core

Figure 3: Von misses stress for a 3 wave core sandwich

structure

Figure 4: Total deformation for a 3 wave core sandwich

structure

Figure 5: von misses stress for a 4 wave core sandwich

structure

Figure 6: Total deformation for a 4 wave core sandwich

structure



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5. RESULTS AND DISCUSSION

Sandwic

h panel

Load

applied

(KN)

Von

misses

stresses

(MPA)

Total

deformation

(mm)

Total

weight

(N)

3 curve 13.5 521.2 0.215 161.7

4 curve 13.5 174.17 0.042 168.7

By comparing the increase in weight percentage

and increase in strength percentage the results

gives that for 4% increase of weight gives 66%

increase of strength.

Figure7: load vs deflection curve

6.CONCLUSION

The sandwich panel model in PRO/e is

efficiently imported into Ansys workbench

structural analysis is done and max stress is

observed at top face. For given length and

height of the structure increasing the number of

curved waves (3 waves to 4 waves) the strength

increases effectively. For increase of 4%

weight, the strength is increase to 66%

7. References [1] O.T. Thomson et al. (eds), sandwich structures 7;

advancing with Sandwich Structure and materials, 3-

12.

[2] Kevin J. Doherty, Aristedes Yiournas, Jordan A.

Wagner, and Yellapu Murty, “Structural Performance

of Aluminum and Stainless Steel Pyramidal Truss Core

Sandwich Panels” ,ARL-TR-4867 July 2009.

[3] Aydıncak, İlke ” investigation of design and

analyses principles of honeycomb structures”

[4] Jukka Säynäjäkangas and Tero Taulavuori,

Outokumpu Stainless Oy, Finland “A review in design

and manufacturing of stainless steel sandwich panels”

stainless steel world oktober 2004

[5] Tomas Nordstrand,” Basic Testing And Strength

Design Of Corrugated Board And Containers”

Division of Structural Mechanics, LTH, Lund

University, Box 118, SE-221 00 Lund, Sweden.

[6] Pentti kujala, Alan Klanac,” Steel Sandwich Panels

in Marine Applications” PrihvaÊeno, 2005-05-05

[7] Jani Romanoff “Bending Response of Laser-

Welded Web-Core Sandwich Plates”ISSN (printed)

1795-2239

[8] Pentti Kujala “Steel Sandwich Panels – From Basic

Research To Practical Applications” 2Vol. 16/ISSN

0784-6010 2002

[9] Narayan Pokharel and Mahen Mahendran “Finite

Element Analysis and Design of Sandwich Panels

Subject to Local Buckling Effects”

[10] Pentti kujala “ultimate strength analysis of all steel

sandwich panels”Rakenteiden Makaniikka,vol.31 Nrot

1-2,1998,s. 32-45

.



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International Journal of Design and Manufacturing Technology (IJDMT), ISSN 0976 –

6995(Print), ISSN 0976 – 7002(Online) Volume 4, Issue 2, May - August (2013), © IAEME

1

DESIGN AND FABRICATION OF CORRUGATED SANDWICH

PANEL USING TAGUCHI METHOD

V.Diwakar Reddy1, A. Gopichand

2, G. Nirupama

3, G. Krishnaiah

4

1Associate Professor,

2,3Research Scholar,

4Professor

Department of Mechanical Engineering,

Sri Venkateswara University College of Engineering, Tirupati

ABSTRACT

Open core metallic sandwich panels are novel type of structures, enabled by

innovative fabrication and topology design tools. Flexural modulus is a basic property of the

material in such fabricated open core structures welding by spot welding. In the present

work spot welded metallic panels are used to optimize the geometry. Based on the analysis,

panel structure parameters considered are Thickness of the sheet, Core height, Core shape,

Panel size and Material constituents of panel face sheet, bottom sheet and core. The

parameters are analyzed by Taguchi design of experiments by considering orthogonal array

of L36.The main aim is to optimize the panel dimensions on flexural modulus of a fabricated

metallic panel, using Finite Element Analysis. The problem is modeled in ANSYS and the

flexural modulus is evaluated in the transverse direction by three point bending test (ASTM

D790). The optimum dimensions are evaluated by Taguchi Analysis. The results show that

the proposed approach can find optimal dimensions considering both better and more robust

design.

Key Words: Taguchi, Corrugated panel, Sandwich panels, Flexural modulus

1. INTRODUCTION

The design of structures with optimal geometry includes sizing, shape and topology

optimization. Extensive research is focused on shape optimization in the process of

engineering design which has ample contribution towards cost, selection of material and time

saving. The purpose of dimensional and shape optimization is to determine the optimal shape

and dimensions of a continuum medium to maximize or minimize a given criterion such as

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ISSN 0976 – 6995 (Print)

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2

weight to volume ratio, minimization of stresses, minimum deflection etc. Researchers are

extensively adopting the computer aided optimization in solving such problems. Earlier

methods are various mathematical techniques which are complex and cumbersome. In the

past few decades a number of innovative approaches are developed and widely applied in the

design optimization such as genetic algorithms, practical swam analysis, Ant colony

algorithm and many more.

Design of experiments (DOE) has become an important methodology that maximizes

the knowledge gained for experimental data by using a smart positioning of points in the

space. The methodology provides a strong tool to design and analyze experiments; it

eliminates redundancy observations and reduces the time and resources to make experiments.

Therefore, DOE statistical techniques useful in complex physical processes, such as

determination of geometrical dimensions, Shapes, selection of material combination in many

design processes. In the present study one such technique adopted is Taguchi method. In this

method, the parameters identified for fabrication of corrugated panels are metal sheet gauge,

core height, core materials, and core shape. The effect of individual parameters under three

point bending is tested using Ansys workbench.

2. LITERATURE REVIEW

Ziad K. Awad, et al [4] presented his research aimed to develop an optimum design of

the new FRP sandwich floor panel by using Finite Element (FE) and Genetic Algorithm (GA)

method. The panel consisted of GFRP skin and Phenolic core. The problem formulation and

solution are described in detail.

James B. Min, et al [10] investigated the use of sandwich panels with solidface sheet

and metal foam core for air plane rotor blades. The face sheets and metal foam core were

made of high strength and high toughness aerospace grade precipitation hardened 17-4PH SS.

Stress analysis results showed that under combined impact, rotation and pressure loading

condition the sandwich panel resulted in lower von Mises stresses in face sheets compared to

other blade conditions. The max displacement was also found lower than the solid Ti-6Al-4V

blade.

Important and that panels is a non-polluting material. Sandwiches-panels on the

equipment which also corresponds to all norms operating in territory of the Russian

federation. Manufacturing of sandwich panels using bolted connections discussed in [11].

Detailed guidelines and numerical formulations to be used are given in [15]. The

numerical formulations are given for various conditions like for studying Linear Elastic

Response, Ultimate Strength, Fatigue analysis, vibration analysis, impact analysis. With

small changes in constants the relations proved good for the current case study. This is

proved though the comparison of analytical results and the results predicted though FEA.

Calculations are given in the next chapter. It may be noted that MathCAD 14.0 was used to

do the calculations.

Krzysztof Magnucki, et al [1] investigated pure bending and axial compression of all

steel sandwich panels. The relationship between the applied bending moment and the

deflection of the beam under four-point bending is discussed. The analytical and numerical

(FEM) calculations as well as experimental results are described and compared. Moreover,

for the axial compression, the elastic global buckling problem of the analyzed beams is

presented



3

Z. Aboura, et al [2] proposed an analytical model for assesing the behaviour of

corrugated cardboard. Computed homogeneous of linear corrugated cardboard behavior is

made use in this model. Experimental method for validating the same is described. A

parametric study is conducted studying the effect of geometrical parameters on in-plane

elastic properties. FE method used to study the relevance of homogenization method. FE

modeling is done in two ways: 1. As 3D solid model, 2. As Shell Model. Shell model is easier

and quicker to solve but the results in both the cases were comparable.

L. St-Pierre, et al [3] carried out FE simulations on corrugated sandwich panels with

top and bottom facing present and only top facing present. 3-Point being was simulated. 3-

Point being tests were performed experimentally also. Experimental and analytical

predictions are in good agreement with each other. During experimentation, it was found that

sandwich beams with front-and-back faces present collapsed by indentation whereas

structures without a back face collapsed by Brazier plastic buckling.

A lightweight sandwich panel construction with a thin-walled core provides a system

to use undervalued lingo-cellulosic based materials for production of structural and non-

structural panels is investigated by Cristopher Ray Voth [5]. Analysis of the core design is

performed to investigate the process that can be utilized for engineering design of future

sandwich panel cores. Small-diameter Ponderosa Pine wood-strands were utilized in

fabrication of a lightweight sandwich panel that has a specific bending stiffness (D, lb-in2/in)

88% stiffer than commercial OSB. The sandwich panels designed within this study utilize

60% less wood-strands and resin by weight compared to OSB panels of equivalent thickness.

A case study was performed on the wood-strand sandwich panels to determine their potential

in structural flooring as an alternative for OSB. The sandwich panel can support a 40 psf live

load and a 20 psf dead load without exceeding IBC (2006) deflection limits. Mathematical

formulation is presented. The theoretical results are verified experimentally by conducting

various tests like 3-point bending tests, Flatwise compression tests, and core shear flexure

tests. Various applications are studied practically like for flooring applications, book shelf

etc.

Haydn N. G. Wadley, et al [6] investigated the use of sandwich structures for

underwater applications. During the investigations, it was found that significant reductions in

the fluid structure interaction regulated transfer of impulse occur when sandwich panels with

thin (light) front faces are impulsively loaded in water.Combined experimental and

computational simulation approach has been used to investigate this phenomenon during the

compression of honeycomb core sandwich panels. Square cell honeycomb panels with a core

relative density of 5% have been fabricated from 304 stainless steel.

Amit Kumar Jha [7], in his thesis investigated the use of sandwich panels for

aerospace applications. In his thesis, free vibration analysis of aluminum honeycomb

structure performed. FEA Software ANSYS used to obtain the natural frequencies. Eight

nodded isoparametric shell element is used for FEA (ANSYS). A detailed parameter study

has been carried out of a simply supported sandwich panel by increasing the core depth as a

percentage of its total thickness, while maintaining a constant mass. Experimental setup used

to validate the simulation results. The results showed that the fundamental natural frequency

of the sandwich panel is 1.4 times more than that of a plain panel. The difference increases

with increase in modes. Increase in thickness of core increases natural frequency and increase

is more at higher modes. Increase in density of the core decreases the natural frequency of the

sandwich plate. Theoretically natural frequency is inversely proportional to density of the

sandwich plate hence density increase natural frequency decreases.



4

An experimental and computational study of the bending response of steel sandwich

panels with corrugated cores in both transverse and longitudinal loading orientations has been

performed by L. Valdevit, et al [8]. Panel designs were chosen on the basis of failure

mechanism maps, constructed using analytic models for failure initiation it was found that

that the analytic models provide accurate predictions when failure initiation is controlled by

yielding. However, discrepancies arise when failure initiation is governed by other

mechanisms. One difficulty is related to the sensitivity of the buckling loads to the rotational

constraints of the nodes, as well as to fabrication imperfections. The second relates to the

compressive stresses beneath the loading pattern. To address these deficiencies, existing

models for core failure have been expanded.The new results have been validated by

experimental measurements and finite element simulations.

Shawn R. McCullough [12] investigated the behavior of LASER welded corrugated

sandwich panels stiffened with concrete. The panel tested is a corrugated sandwich panel

with top and bottom steel facing separated by steel corrugation. Welding is done at both

crests and troughs. Concrete layer is placed on the top of the sheet utilizing shear connector

to ensure composite action. Structural behavior of these composites was evaluated.

Investigations showed a high increase in stiffness of the sandwich panel when concrete is

used. When 1.5” thick concrete is used, there is a 140% increase in stiffness recorded while

240% increase in stiffness is observed when 2.5” thick concrete is used. Main applications of

these sandwich panels include emergency bridge repair, building floors, fire walls etc. Beam

Theory (for narrow panels) and classical theory of orthotropic plates used for analyzing the

plates. Experimental testing used to prove the results. Results are verified for both 3-Point

and 4-Point loading.

3. FABRICATION OF CORRUGATED PANELS

The method of fabrication of panels consists of two stainless steel sheets and in

between a corrugated core is inserted and these panels are joined by means of spot welding

which is as shown in the Figure - 1 below. The geometrical specification of the panel is also

shown in the Figure.-2

Figure – 1 Panel structure of R2 Shape



5

Figure – 2 Nomenclature of the corrugated panel

Design of Experiments by Taguchi method

Taguchi method is a method that chooses the most suitable combination of the levels

of controllable factors by using S/N tables and orthogonal arrays against the factor that form

the variation in product and process. Hence, it tries to reduce the variation in product and

process. Hence, it tries to reduce the variation in product and process. Hence, it tries to reduce

the variation in product and process to least. Taguchi uses statistical performance measure

which is known as S/N ration that takes both medium and variation into consideration.

Design optimization problems in automotive industries are usually complex in formulation of

objective functions and problems have uncontrollable variations in parameters. To overcome

this issue, Taguchi method is adopted in solving the shape design optimization. The

architecture of the proposed approach is given in Figure – 3.

In this study, determination of shape of the panel and core geometry is most important

parameters in design of corrugated panels. For the analysis purpose the material selected for

face sheet is Stainless steel AISI – 304 and for core two different materials are considered

one is Mild steel and other one is parent material i.e Stainless steel. As said above for the

analysis three types of panel shapes are considered in the present case, in which two are

rectangular panels and one is square panel. The two rectangular panels are of same size but

lay of core is in transverse and longitudinal direction along the width as shown in the Figure

– 4. Along with these parameters, the other three are the corrugated shape, height of the core

and face sheet gauge. The design parameters and their levels are shown in the Table – 1.



6

Figure – 3 Design Optimization approach

Modeling in Pro-E

Finite Element Methods

Design Parameters

Material Combination

Core Shape

Face sheet Gauge

Core height

Panel shape

Design of

Experiments by

Taguchi L36

Compute Deformation, Von-Mises

Stress and Shear Stress.

Compute S/N ratios and conduct

ANOVA analysis

Optimized Design

variables

Optimum settings of

Design variables

Fabrication of Panels

using Spot welding



7

Table – 1 Parametric investigation

S.No Parameter Level – 1 Level – 2 Level – 3

1 Material Combination

(MC):

SSMS-

Face sheet x

Core

SSSS-

Face sheet x

Core

2 core shape (CS)

R-Rectangular

core

V-Shape core

3 Face sheet thickness

(FS)

20 gauge 18 gauge

4 Core height (CH) 18mm 20mm 24mm

5 Panel Shape (PS) R1-

Rectangular

panel of length

500(L)

X250(W)

R2-Rectangular

panel of length

250(L) X

500(W)

SQ-Square

panel of

350mm X

350mm

Material combination, core shape, Face sheet thickness, Core height and Panel shape

are considered as design parameters to determine their effect on the Flexural Modulus of the

Sandwich panel.

A total of 36 experiments based on Taguchi L36 mixed level orthogonal array were

carried out with mixed combinations of the input parameters which are shown in Table -2,

from this table the material combinations presented are “SSMS” & “SSSS” in which the first

two letters indicates face plates and the next two letters indicate core material (i.e., SSMS

indicates-Stainless Steel face plates & Mild steel core material; Similarly, SSSS indicates

both core and face plates are made of stainless steel). The second parameter considered is

core shape which is Rectangular (R) and Dove-tail(V) corrugated sheets as the core materials

for the panel. Gauge of the sheets were also considered as one of the parameter for the

analysis. Two gauges were considered i.e. 20 and 18. The other important parameters for

minimizing the volume fraction are the core height (20, 24 & 28 mm) and the panel shapes

are rectangular & square as explained in the previous session.

The Considered models using Taguchi method (L36) were analyzed by three point bending

test using ANSYS Work Bench. In the present analysis the model was developed by

considering the spot-welding of face-plate and core.



8

Table -2: Orthogonal Array of L36 of Taguchi

Mo

del

No

Ma

teri

al

Com

bin

ati

on

Co

re

Sh

ap

e

Fa

ce s

hee

t

Ga

ug

e

Co

re

Hei

gh

t

Pa

nel

sh

ap

e

Mo

del

No

Ma

teri

al

Com

bin

ati

on

Co

re

Sh

ap

e

Fa

ce s

hee

t

Ga

ug

e

Co

re

hei

gh

t

Pa

nel

sh

ap

e

1 SSMS R 20 20 R1 19 SSSS R 18 20 R2

2 SSMS R 20 24 R2 20 SSSS R 18 24 SQ

3 SSMS R 20 28 SQ 21 SSSS R 18 28 R1

4 SSMS R 20 20 R1 22 SSSS R 18 20 R2

5 SSMS R 20 24 R2 23 SSSS R 18 24 SQ

6 SSMS R 20 28 SQ 24 SSSS R 18 28 R1

7 SSMS R 18 20 R1 25 SSSS R 20 20 SQ

8 SSMS R 18 24 R2 26 SSSS R 20 24 R1

9 SSMS R 18 28 SQ 27 SSSS R 20 28 R2

10 SSMS V 20 20 R1 28 SSSS V 18 20 SQ

11 SSMS V 20 24 R2 29 SSSS V 18 24 R1

12 SSMS V 20 28 SQ 30 SSSS V 18 28 R2

13 SSMS V 18 20 R2 31 SSSS V 20 20 SQ

14 SSMS V 18 24 SQ 32 SSSS V 20 24 R1

15 SSMS V 18 28 R1 33 SSSS V 20 28 R2

16 SSMS V 18 20 R2 34 SSSS V 20 20 SQ

17 SSMS V 18 24 SQ 35 SSSS V 20 24 R1

18 SSMS V 18 28 R1 36 SSSS V 20 28 R2

A series of models as mentioned in table -2 were analyzed to determine the Flexural rigidity

of the panel by considering the mode of failures as Shear, Von-mises stresses and the lateral

deflection by Three Point Bending Test. A constant load of 5000N was applied in

determination of the above stresses and deflections. The goal of this analysis work was to

investigate the effects of Flexural Rigidity and observed deflection of the panel. In Taguchi

there are three categories of quality characteristics in the analysis of S/N ratio are lower the

better, Higher the better and Nominal the better. Regardless of the category of the quality

characteristic, process parameter settings with the highest S/N ratio always yield the optimum

quality with minimum variance. The category the –lower-the-better was used to calculate the

S/N ratio for all the observed parameters.

4. RESULTS:

The measured values of the Flexural-Rigidity and deflection for the models corresponding to

all the experimental runs are given Table -3.

Signal to Noise ratio: Analysis of influence of each control factor on the flexural rigidity and

deflection has been performed is so called Signal to Noise ratio response Table.

Response table of S/N ratio for Von-mises, Shear stresses and Deflections are shown in the

Tables -4, 5, 6 respectively. The influence of each control factor can be clearly presented with

the response graphs. The slope of the line which connects between the levels can clearly

show the power of the influence of each control factor.



9

Table -3: Experimental Results

Mo

del

No

Von

Mises

Stress

(MPa)

Shear

Stress

(Mpa)

Deformation

(mm)

Mo

del

No

Von

Mises

Stress

(MPa)

Shear Stress

(MPa)

Deformation

(mm)

1 137.71 75.328 0.3332 19 15.769 8.741 0.017551

2 105.69 59.709 0.22843 20 94.987 53.981 0.19447

3 137.68 77.523 0.45744 21 96.627 47.949 0.50398

4 137.71 75.328 0.33324 22 15.769 8.741 0.017551

5 105.69 59.709 0.22843 23 94.987 53.981 0.19447

6 137.68 77.523 0.45744 24 96.627 47.949 0.50398

7 137.29 75.096 0.33028 25 73.927 38.167 0.10313

8 25.394 14.164 0.094139 26 233.99 132.31 0.69529

9 68.8 38.264 0.23172 27 73.383 41.97 0.19827

10 113.26 59.884 0.39075 28 49.818 26.358 0.14367

11 49.454 27.431 0.13016 29 105.45 54.884 0.37319

12 60.302 34.228 0.14519 30 23.958 13.742 0.19047

13 22.075 11.944 0.09827 31 89.815 50.304 0.17262

14 43.272 22.846 0.13129 32 116.67 60.287 0.46334

15 89.842 46.983 0.33685 33 40.6 22.81 0.12289

16 22.075 11.944 0.09827 34 89.815 50.304 0.17262

17 43.272 22.846 0.13129 35 116.67 60.287 0.46334

18 89.842 46.983 0.33685 36 40.6 22.81 0.12289

Table-4:Response table for S/N Ratios (Smaller is better) for Von-mises stresses

Level Material

Combination

Core

Shape

Face sheet

Gauge

Core

Height Panel shape

1 -36.91 -38.24 -39.27 -35.98 -41.82

2 -36.65 -35.32 -34.29 -37.99 -31.30

3 -36.37 -37.23

Delta 0.25 2.93 4.98 2.01 10.53

Rank 5 3 2 4 1

Table-5:Response table for S/N Ratios (Smaller is better) for Shear stresses

Level Material

Combination

Core

Shape

Face sheet

Gauge

Core

Height Panel shape

1 -31.68 -33.05 -34.10 -30.63 -36.31

2 -31.37 -29.99 -28.05 -32.74 -26.26

3 -31.20 -32.00

Delta 0.32 3.06 5.15 2.11 10.05

Rank 5 3 2 4 1



10

Table-6: Response table for S/N Ratios (Smaller is better) for Deformation

Level Material

Combination

Core

Shape

Face sheet

Gauge

Core

Height Panel shape

1 13.490 13.687 12.408 16.805 7.642

2 14.350 14.153 15.433 12.665 19.124

3 12.291 14.995

Delta 0.860 0.466 3.025 4.514 11.483

Rank 4 5 3 2 1

Figure – 4: Main Effects plot for S-N Ratio

for Von-Misses stress

Figure – 5: Main Effects plot for S-N

Ratio for Shear stress

A- Material Combination

B- Core Shape

C- Face sheet Gauge

D- Core Height

E- Panel shape

Figure – 6: Main Effects plot for S-N Ratio

for Deformation



11

5. DISCUSSION

It is seen from the response Tables and according to the Rank for each control factor

that the panel shape had the strongest influence on Von-misses stresses and Shear Stresses

followed by face sheet gauge, Core Shape, Core height and least influence on Material

combination. Similarly from the response table of Deformation and according to the Rank for

each control factor that the panel shape had the strongest influence on Deformation followed

by Core height, face sheet gauge, Material combination and least influence on Core Shape.

From the Main effects plot for S/N ratio for Von-Misses Stresses Fig.4 the Von-

Misses Stresses appears to be linear increasing function for Material Combination(A), Core

Shape(B) and Face sheet Gauge (C) and variation in the levels for core height (D) and panel

shape (E).

Thus in order to reduce the von-Misses stresses under particular loading condition the

following levels has to be considered(Refer Table - 7).

Table - 7: Selected levels for the fabrication of the corrugated panel

Parameter Level

A- Material Combination SSSS-Face and core material as Stainless steel

B- Core Shape V-Dove-Tail corrugated sheet

C- Face sheet Gauge 18 gauge stainless steel

D- Core Height 20mm

E- Panel shape Rectangular

It is observed that the core height is being considered as 20mm since as height

increases the possibility of sliding failure of the panel may occur and V-Dove-Tail corrugated

sheet is considered from the analysis instead of rectangular section since the rectangular

section is taking the direct load while the Dove-Tail is taking resultant load. From the Main

effects plot for S/N ratio for Deformation Fig.6, the Deflection appears to be linear similar to

Von-Misses stresses as explained above.

5.1 Experimental Results: The corrugated Panel is fabricated for the above optimum levels

of the considered parameters and tested for Three-Point Bending. In the Analysis the

maximum load applied is 5kN and the results were drawn which are shown in Figure 7 & 8.

From the experiments, the corrugated panel has endured a maximum load of 15kN. Hence the

model is recommended up to 10kN.Fig 9 and Fig 10 shows the experimental testing of

fabricated corrugated sandwich under three point bending test.



12

Figure -7: FEA Results for Max shear stress

Figure - 8: FEA Results for Max Von-misses

stress

Figure - 9: Experimental test of three point

bending test

Figure - 10: Tested panel in three point

bending test.

.

6. CONCLUSIONS

This Study discussed an application of the Taguchi-Method for Dimensional

optimization of corrugated panel using performance measures of Three-Point Bending Test.

From this Research conclusions could be reached with a fair amount of confidence. From the

Taguchi Analysis the optimum levels decided is not modeled in L36 models. Hence for

validation of the above said result is carried out. And it is observed that the maximum shear

stress, Von-Misses stresses and deflections are 11.882Mpa,22.161 Mpa,0.09mm respectively.

From the experiments the maximum load endured by the panel is three times more than the

considered load. Finally for minimum stress induced and deflection, core and face plate are

made of stainless steel of gauge 18, core height as 20mm, core shape as Dove-tailed

corrugated sheet and the panel shape is rectangular with corrugations along the width is

considered for fabrication.



13

7. REFERENCES

[1] Krzysztof Magnucki, PawełJasion, MarcinKrus, PawełKuligowski, Leszek

Wittenbeck, Strength and Buckling of Sandwich Beams with corrugated cores,

Journal of Theoretical and Applied Mechanics,2013,51(1), pp. 15-24

[2] Z. Aboura, N. Talbi, S. Allaoui, M.L Benzeggagh, Elastic behavior of corrugated

cardboard: Experiments and Modeling, Composite Structures, 2013,63(1), pp. 53-62

[3] L. St-Pierre, N. A. Fleck, V. S. Deshpande, Sandwich Beams With Corrugated and Y-

frame Cores: Does the Back Face Contribute to the Bending Response, Journal of

Applied Mechanics, 2012,79, pp. 011002-1 - 011002-13

[4] Ziad K. Awad, ThiruAravinthan, Yan Zhuge, Cost Optimum Design of Structural

Fiber Composite Sandwich Panel for Flooring Applications, CICE 2010 - The 5th

International Conference on FRP Composites in Civil Engineering, 2010.

[5] Cristopher Ray Voth,Ligth Weight Sandwich Panels Using Small-Diameter Timber

Wood-Strands And Recycled Newsprint Cores,MS Thesis, Washington State

University,2009

[6] Haydn n. G. Wadley, Kumar P. Dharmasena, Doug T. Queheillalt, Yungchia Chen,

Philip Dudt, David Knight, Ken Kiddy, ZhenyuXue, AshkanVaziri,Dynamic

compression of square honeycomb structures during underwater impulsive

loading,Journal Of Mechanics Of Materials And Structures,2007,2(10), pp. 2025 -

2048

[7] Amit Kumar Jha,Free Vibration Analysis of Sandwich Panel,M.Tech. Thesis,

National Institute of Technology, Rourkela,2007

[8] L. Valdevit, Z. Wei, C. Mercer, F.W. Zok, A.G. Evans, Structural performance of

near-optimal sandwich panels with corrugated cores, International Journal of Solids

and Structures,2006,43(16), pp. 4888–4905

[9] Pentti KUJALA, Alan KLANAC,Steel Sandwich Panels in Marine

Applications,BrodoGradnja,2005,56 (4), pp. 305 - 314

[10] James B. Min, Louis J. Ghosn, Bradley A. Lerch, Sai V. Raj, Fredic A. Holland Jr.,

Mohan G. Hebsur,Analysis of Stainless steel sandwich panels with metal foam core

for lightweight fan blade design, 45th

AIAA/ASME/ASCE/AHS/ASC Structures,

Structural Dynamics and Materials Conference,2004

[11] COLD-FORMED CONNECTIONS,Chapter 11, Structural Connections according to

Eurocode 3 - Frequently Asked Questions, Project Continuing Education in Structural

Connections, Leonardo da Vinci Programme No. CZ/00/B/F/PP-134049, Czech

Technical University in Prague,2003, pp. 103-110

[12] Shawn R. McCullough,An Investigation of LASER welded corrugated-core sandwich

beams and plates stiffened with concrete, PhD Thesis, Rice University,2000

ISSN: 2319-8753

International Journal of Innovative Research in Science,

Engineering and Technology

(An ISO 3297: 2007 Certified Organization)

Vol. 2, Issue11, November 2013

Copyright to IJIRSET www.ijirset.com 6300

NUMERICAL SIMULATION OF STEEL

SANDWICH PLATE SYSTEM (SPS) FLOOR

1A.Gopichand,

2Dr.G.Krishnaiah,

3D.Krishnaveni,

4Dr.Diwakar Reddy.V

Research scholar, Department of Mechanical Engineering, Sri Venkateswara University college of Engineering,

Tirupathi, India1

Professor, Department of Mechanical Engineering, Annamacharya institute of Technology and Science, Tirupathi,

India2

P.G.Student, Department of Mechanical Engineering, Swarnandhra college of Engineering and Technology, Narsapur,

India3

Associate Professor, Department of Mechanical Engineering, Sri Venkateswara University college of Engineering,

Tirupathi, India4

Abstract: Steel Sandwich Plate Systems (SPS) have been used for commercial applications during the last 15 years.

Stairs & staircase landings, bulkheads and decks are the main application areas of metallic sandwich panels in cruise

ships and in other marine applications. In recent years a wide variety of applications of stainless steel sandwich panels

are used in civil and mechanical engineering as well as in other industrial sectors. These include floors of buses, walls

and floors of elevators, working platforms in industrial applications and balconies of shipyard. The sandwich structures

have potential to offer wide range of attractive design solutions. The steel sandwich structure offer high strength to

weight ratio, noise control, high stiffness etc if compared to traditional steel plate flows. In this work numerical

simulation of SPS floor with all edges clamped, subjected to uniform pressure loading is carried out in ANSYS

workbench. The SPS floor simulation results are compared with traditional steel plate of with same weight, same area

with same boundary conditions and loading.

Keywords: Sandwich panels, ANSYS Workbench, Uniform pressure load, Sandwich plate system, Numerical

simulation

I. INTRODUCTION & LITERATURE REVIEW

A. Steel Sandwich panels

Metallic Sandwich panels with top and bottom plates as well as the core made up of steel are called steel

sandwich panels. The core structures are of different types according to core structures the steel sandwich structures are

divided some of them are I-core, O- core with rectangular beams, Vf/V- core with hat or corrugated sheets as a core,

web core, round O-core and X-core with two hats as a core as shown in figure 1

ISSN: 2319-8753






Figure 1: Different steel sandwich structures with various cores

B. Application of Sandwich structures as floor

Stainless steel can be used in a variety of ways in floors. The Doltrac floor is a stainless steel floor

component with a sandwich structure. It has an upper face in 1.9 mm stainless steel sheet, and a 1.2 or 1.5 mm lower

face, spaced either by rectangular sections 50 mm high (type O), or continuous or discontinuous inverted V sections

(types V and Vf ). Figure 2 shows floor panels with inverted V sections. The components are assembled by gluing, or

by continuous or spot laser welding. These floor components provide high stiffness for low weight. Figure 4 shows the

all steel sandwich panel being used for bus floor. The use of ribbed sheets for permanent shuttering under a concrete

slab is another solution, already tested in situ. The visual quality of stainless steel provides the designer with the

possibility of leaving the metal sheet visible for ceilings thereby gaining free headroom by grouping cables and fluids

in suspended trays.

Figure 2: Stock of Doltrac floor assemblies with sandwich structure which profiles are of continuous ‘V’

ISSN: 2319-8753






Figure 3: An experimental, sandwich-panel bus floor element, in grade 1.4003, assembled using laser welding

C. Literature Review

Pentti Kujala made analysis on metallic sandwich panels which are laser welded have excellent properties

with light weight having more applications[1] Jukka Säynäjäkangas make a review in design and manufacturing of

stainless steel sandwich panels and conclude an efficient sandwich is obtained when the weight of the core is close to

the combined weight of the both faces [2]Pentti Kujala discussed that steel sandwich panels that are welded by laser

can save 30-50% weight compared to conventional steel structures [3]Romanoff & Kujala, investigated and related to

design or design optimisation of steel sandwich panels for typical steel sandwich cross sections are

studied[9].PenttiKujala, et al [11] investigated the applications of laser welded steel sandwich panels in marine

application. China Classification Society released a document standardizing the guidelines for assessment of ship

structures constructed using steel sandwich structures or other composite structures[13].

II. INTRODUCTION TO ANSYS WORKBENCH

ANSYS Workbench is a common platform for solving engineering problems. Typical tasks you can perform in

Workbench are:

• Importing models from a variety of CAD systems.

• Conditioning models for design simulations using the Design Modeler. • Performing FEA simulations using Simulation. • Optimizing designs using Design Xplorer or Design Xplorer VT.

Different processors within ANSYS Workbench are

1. Design Modeler

2. Simulation

3. DesignXplorer or DesignXplorer VT

4. AUTO DYN

5. CFX Mesh

6. FE Modeler

Basically, you will use the Design Modeler to create the geometry and the Simulation to set up the materials,

FE-mesh, loads and boundary conditions, solve the problem and analyse the results. The standard interface ANSYS

Classic (used in the first computer workshop) is still the core of ANSYS. ANSYS Workbench is a new modern

interface with more up to date functions such as, for example, the integration of CAD geometries. In this platform

working on Multiphysics simulation is easy. Those performing a structural simulation use a graphical interface (called

the ANSYS Workbench Mechanical application) that employs a tree-like navigation structure to define all parts of their

simulation: geometry, connections, mesh, loads, boundary conditions and results.

ISSN: 2319-8753






Design Modeler

Design Modeler is designed to be used as a geometry editor of existing CAD models. Design Modeler is a parametric

feature-based solid modeler designed so that you can intuitively and quickly begin drawing 2D sketches, modeling 3D

parts, or uploading 3D CAD models for engineering analysis preprocessing.

SIMULATION Use the Workbench Simulation module to define your model's environmental loading conditions,

solve the simulation, and review results in various formats depending on the type of simulation.

DesignXplorer – use this application to optimize a design using Design of Experiments (DOE) methodology.

AUTODYN – use this application to model short duration events involving large deformations or complete material

failure as well as fluid solid interaction.

CFX Mesh – use this applications to generate a mesh that is used by the CFX program.CFX performs Computational

Fluid Dynamics.

FE Modeler – use these applications to import a finite element model that was generated using the FEA program

Nastran into Workbench

III. NUMERICAL SIMULATION

A. Numerical Simulation of floor assembly.

A 3D model of sandwich floor is generated using Pro-E by assembling four sandwich panels .

Face sheets and Core Material - Stainless steel 304

Thickness of the face sheets – 18 gauge

Core shape – V

Core Height - 20 mm

Panel shape – Rectangular - 250 mm × 500 mm

The floor assembly is modelled in Pro-E and the model in igs format is imported to ANSYS Workbench as

shown in figure 4. The solid element is considered for meshing as shown in figure 5.

Figure 4 : Floor designed using optimized sandwich panels

Figure 5: Floor designed using optimized sandwich panels

ISSN: 2319-8753






All the edges of the floor are clamped and uniform pressure loading 0.01MPa, 0.02MPa, 0.03MPa, 0.04MPa, 0.05MPa

are considered for the analysis. The applied loads & boundary conditions for the sandwich panel as shown in figure 6

The Design characteristics von-mises stress, maximum shear stress and Deformation for 0.05MPa are shown in figures

7,8 ,9.

Figure 6: Applied loads & boundary conditions for the Sandwich panel

Figure 7: Von-Mises stress plot of Panel the 0.05 MPa

Figure 8: Shear stress plot of Panel for the 0.05 MPa

ISSN: 2319-8753






Figure 9: Deflection plot of panel for the 0.05 MPa

B. Numerical Simulation for Rectangular plate floor:

A 3D model of a rectangular SS plate with surface area dimensions as that of sandwich floor but with

thickness chosen such that the weight of the plate is equal to that of the sandwich floor is created in Pro/E. This plate

model is then imported into Ansys. FEA is then performed on this model to study its behavior under the same loading

and boundary conditions as that of the floor. A traditional steel plate of same weight and area, with same boundary

conditions is considered for the analysis. The Design characteristics von-mises stress, maximum shear stress and

Deformation for 0.05MPa are shown in figures 10, 11, 12.

Figure 10: Von-Mises stress plot of floor for the 0.05 MPa

Figure 11: Shear stress plot of floor for the 0.05 MPa

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