The Presentation 18-09-2015

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PROJECT PRESENTATION

TITLE:

THE ANALYSIS OF

CYLINDRICAL GRAIN

SILOS BY FINITE

ELEMENT METHOD

STUDENT NAME:

SHAYO, Noela S.

REGISTRATION NO.:

2011-04-0222

PROJECT SUPER!ISOR:

DR. HENRY M. "I#ELU

UNI!ERSITY O$ DAR ES SALAAM

COLLEGE O$ ENGINEERING ANDTECHNOLOGY

STRUCTURAL AND CONSTRUCTIONENGINEERING DEPARTMENT

SD4%%: $INAL PROJECT II

2014&1'

PRESENTATION DATE: 1-0%-201'


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INTRODUCTIONSilo is a storage facility for bulk materials such as food products,

sawdust, cement, coal and whatnot ranging from a few tonnes to

hundreds or thousands of tonnes.

It is derived from a Greek word:siros, meaning corn pit, also fromthe atin wordsilus, which means cellar

A(ea) o* a++lao/: agriculture, mining and manufacturing

industries for the storage of grain, fluids, cement and platinum ores


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D**e(e/ *o() a/ )a+e) o* )lo)


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!aterials used for construction can be concrete "staves#, steel "panels#,

wood "staves# and$or cast concrete.

%ifferent types of silos are widely used depending on cost variation,

durability, and air tightness tradeoffs. &he three main types are: o3e( )lo,

bunker silo and bag silos.

Grain silo is a cylindrical tower silo used for storing grains"mai'e, soya

beans, wheat..#

Structural analysis of silos is governed mainly by the two approaches:

Classical approach andFinite Element approach.


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INTRODUCTION$INISHED

&he classical methods are available for simple structural members sub(ect

to specific loadings such as a)ially loaded bars, prismatic beams in a stateof pure bending, and circular shafts sub(ect to torsion.

*inite element approach appro)imates the structure as an assembly of

elements or components with various forms of connections between themand uses appro)imate solutions of differential e+uations as the basis for

structural analysis.

egardless of approach, the formulation is based on the same three

fundamental relations: e+uilibrium, constitutive, and compatibility. &he

solutions are appro)imate when any of these relations are only

appro)imately satisfied, or only an appro)imation of reality.


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PROLEM STATEMENT

Structural analysis is the basis of design of any structure. It is

important to select an appropriate approach for analysis in order to

prevent unnecessary failures.

&ower Grain silos are one of many sensitive structures that threaten

both human and the surrounding once they fail due to insufficient

)(55(al a/al6)), design and$or construction, poor operation and

maintenance- hence there rise a need to establish and practise a

more accurate approach for its analysis.


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OJECTI!E

To 7alae e 5)e o* $/e Elee/ A/al6)) eo a) a/ale(/a7e a++(oa o e a/al6)) o* 8(a/ )lo)

nalysis of grain silos by the classical methods is possible e)cept that

it tends to be cumbersome and may fail to account for some factors dueto the comple)ity of the structure. *actors such as openings in silos

used as connection to other silos "grain elevators#, temperature/induced

stresses are usually difficult to analyse with classical methods.


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SCOPE

&his pro(ect is based on the finite element analysis of a 6l/(al-

)a+e, *(ee-)a//8 o3e( 8(a/ )lo that isae o* o/(ee.

nalysis focusing on the cylindrical part of the silo, i.e. 0)cludingthe hopper. nd stresses that are e)erted by the grain only on the wall

of the storage structure, namely hoop stresses.


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METHODOLOGYMETHODOLOGY

iterature review on grain silos, the classical approach of analysis ofsilos and *inite element method of analysis.

Step by step analysis of a supposed grain silo by the 1lassical

pproach and *inite element analysis method.

1omparison of results obtained by the two methods.

1onclusion and remarks.


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2*' 3 4-"56 7 d56# 7 89%dh 3 56 7 gdh

1onsider the e+uilibrium of forces on a differential element


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Stress normal to the wall, 5w3 5v;


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THE $INITE ELEMENT ANALYSIS APPROACH

&his is a numerical techni+ue for gaining an appro)imate answer to a

problem by representing the ob(ect by finite elements A rather like a

childs ego model. 0ach these building elements is connected toad(acent elements at nodes.

&his approach has three main stages: build the model, solve the

model, and display the results.

&he model built in a finite element analysis program represents the

ob(ect plus all forces, constraints and materials.

Elee/ 6+e) )eleo/ depends on the type structure and the

thickness. 1an be plane elements, general solid elements,

a)isymmetric solid element, plate elements, and shell elements.


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&he physics of the situation is built into each element through a

variational principle to minimi'e energy.

&hus the finite element analysis problem is to find the nodal

displacement u")# which minimi'es the energy 6"u")##, yet satisfies

the boundary constraints for u")#.

6"u")## is called a functional and u")# a function.

1omputer programs incorporates this principle in carrying out

analysis.


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CASE STUDY


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COMPUTATION Y THE CLASSICAL APPROACH

nalysis done at mid/height, ' 3 Bm

Te )a 7e(al +(e))5(e, P!:

56 3

3 @C,D4D.D@ ?$m@

Sa o(9o/al +(e))5(e, P#/e(/al +(e))5(e;:

5E 3


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Hoo+ )(e)), /:

n 3 "5E;r# 3 [email protected];"@/4.#

3 @,B4.BD ?$m

3

3 4H,BB@.?$m@ J &his result is compared with the one

obtained via *inite 0lement nalysis

!ethod.


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ANALYSIS Y THE $INITE ELEMENT METHOD

Analysis is carried using LISA 8.O software which isprogrammed under Finite element principles of analysis.


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Elee/ )elee: Shell four sided

linear element. &his is suitable since

the case study is a relatively thin

curved structure.

D)(e)ao/: &he +uadrant is

divided into C vertical elements and

@ hori'ontal elements making a

total of K elements.


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o5/a(6 o/o/)

Pla/e Noe D)+laee/ Noe Roao/

LM )34 rot'34- roty34

LN y34 rot'34- rot)34

NM"bottom# '34 /


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Loa/8

Inward pressure is applied on the mid/plane of the shell elements faces at their

respective depths as shown.

Loae oel

S&No. De+, 9 ; P(e))5(e, P3 N-2;

1 9.!" 1#$#%.1

$ 8.1$" 1"1"#.8

#.8!" 18%."

& ".#$" 1$$".8

" &.!" 1%18.#

# .1$" 8%1.#

! 1.8!" "$&$.&

8 %.#$" 191%.!


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Ooop stress obtained after solving the model is 4H,D44.H ?$m@. !ore

elements are introduced so as to obtain a yet closer value to the analytical

computed value 4H,BB@.?$m@.

S5a(6 o* (e)5l) 3 (e)+e o /5


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COMPARISON O$ RESULTS

Pe(e/a8e **e(e/e

3 " #;44

3 4.4CP


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CONCLUSION

&he finite model was successfully developed which

was in very good agreement with classical analysis

It is valid to use *inite 0lement !ethod as an

approach in the analysis of stresses in grain silos.

It is advisable to use finite element modelling which is

faster and accurate other than doing e)perimental test

which is very e)pensive.


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RE$ERENCES AND CITATIONS

Q333.e5.e5&)o(a&2011e(8.+*,&he *armerRs &ower: &he %evelopment of the &ower Silo oran

erg.

QEikipedia, the free encyclopedia,https://en.wikipedia.org/wiki/Silo.QEN 1%%=-4-1, "@44H#, "0nglish#: 0urocode D: %esign of steel structures / 5art F/: SilosQ+:&&333.3)e8ee>.o(8&3a-)-a-8(a/-)lo.QLa+>o, A/(9e?@ P(5)el, Jola/a A., "Tctober @44F#, Structural analysis of 1 circular grouped silos

under patch actions, cademic Uournal.QA/(9e? La+>o, KK, 1omputational model of silo shell with grain and wall structure interaction,

%epartment of 1ivil 0ngineering, &echnical Vniversity of ialystok, 5oland.

QYa/ 58e, "@44H#, ecture B / 5late and Shell 0lements and D% 5roblems, 1I60 D4 Structuralnalysis and 1omputer pplications.QR. RUSINE", J. BU"ASU", @44F, Influence of moisture content on pressure ratio of rape seeds,

Institute of grophysics, 5olish cademy of Sciences, ublin, 5oland, 0S. G. 0?G., B4, @44F "#:

/F.QJ. Ho(a a/ R. R5)/e>, @44@, 5ressure ratio of cereal grains determined in a unia)ial compression

test, Institute of grophysics, 5olish cademy of Sciences, Int. grophysics, , @D/@C.Q"a(l Jao


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The Presentation 18-09-2015