FEA of a Bycicle Frame ME 3614

8/9/2019 FEA of a Bycicle Frame ME 3614

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Finite Element Analysis: A Bicycle Frame

Heath A. FolmsbeeME 361402 / 28 / 02


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Heath FolmsbeeME 3614

02 / 26 / 02

Finite Element Analysis: A bicycle frameME 3614

Problem:

In the esi!n an en!ineerin! of "ro #cts$ the %ey is o"timi&ation as 'ell assafety( In or er that the esi!n team mi!ht accom"lish this$ one of the ste"s they nee tota%e is to loo% at the critical "oint)s* of their esi!n$ an o"timi&e the "ro #ct accor in!to that "oint or "oints( In this case 'e are !i+en a bicycle frame to analy&e$ an o"timi&e(,he frame is ma e of hi!h carbon steel$ an has a loa "lace o'n at the seat$ anhan le bars "ositions( If the eflections of the members of the frame are e-cessi+e$ or if

the critical member)s* fail$ then the frame nee s to be re esi!ne 'ith more stiffness( ,heo""osite is the case if the frame oes not eflect( In this case$ the frame 'ill be stable b#t'ill be o+er. esi!ne an therefore e-"ensi+e an or hea+y

In"#t al#es: ase 1

Hi!h arbon teel ,#bin!:Mo #l#s of Elasticity$ E$ %"si: 2 (2 - 10 6 "si )as "er correcte table E.23*

(5( )o#ter iameter*$ in: 1in,hic%ness$ in: 0(062inArea$ A$ in2: 0(1 27in 2

Moment of Inertia$ I - $ in4: 0(0201 in 4

$ Ma- istance from a-is: 0(8in

9oa in!:1(* 378lbs at )10in$ 18in$ 0in*2(* 62(8lbs( at )36in$ 18in$ 0in*

;estraints:1(* ;ear 'heel "i+ot: restraine in - an y(2(* Front 'heel "i+ot: restraine in y only(

After all of the abo+e initial con itions 'ere establishe $ the Finite element in"#t "ro!ram 'as o"ene ( ,hese +al#es 'ere entere at the a""ro"riate times an "laces anthe follo'in! o#t"#t screen 'as is"laye (


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nce this 'as com"lete the in"#t "ro!ram 'as sh#t o'n an the com"#tationalmo elin! "ro!ram 'as o"ene an then e+al#ate the bicycle esi!n in case 1( After the

com"#tational mo el 'as com"lete $ the o#t"#t "ro!ram 'as o"ene an is"laye thefollo'in! information abo#t the case 1 bi%e esi!n eformation an stress istrib#tionthro#!ho#t the frame(


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Deformation Model: Case #1


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Stress Distribution throughout the frame: Case #1

,he follo'in! are tables of is"lacements in all three artesian a-es an memberstresses res"ecti+ely(

Displacements: Case #1 )All 5is"lacements are in inches*


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Stresses in Frame Elements: Case #1 )All stresses are in "si*

Element A-ialtress

Ben in! tress at the


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#mmary: ase 1

In concl#sion$ the frame is e-tremely o+er. esi!ne $ es"ecially 'hen member 3

has a factor of safety of 74( ,here is no nee for this$ as it is a 'aste of money anmaterials$ asi e from a in! 'ei!ht to the o+erall frame( ,ho#!h none of theis"lacements are near e-cessi+e$ the front for% )element 7* is the most fle-ible$ an

'o#l be most li%ely the first to fail( ,he frame 'o#l then nee to be re esi!ne toaccommo ate this critical member an that of the o+er. esi!ne members( Also altho#!h

b#c%lin! 'as not consi ere as a factor in this esi!n analysis$ it is of eD#al ane"en in! on the sit#ation hi!her im"ortance than yiel fail#re(


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A""en i- A)Alternati+e esi!ns*


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In"#t al#es: ase 2


(5( )o#ter iameter*$ in: 1in

,hic%ness$ in: 0(038inArea$ A$ in2: 0(1061in 2

Moment of Inertia$ I - $ in4: 0(0123in 4


9oa in!:1(* 378lbs at )10in$ 18in$ 0in*3(* 62(8lbs( at )36in$ 18in$ 0in*

;estraints:3(* ;ear 'heel "i+ot: restraine in - an y(

4(* Front 'heel "i+ot: restraine in y only(After all of the initial con itions 'ere establishe $ an instit#te into the mo el$

the com"#tational mo elin! "ro!ram 'as o"ene an then e+al#ate the bicycle esi!nin case 2( After the com"#tational mo el 'as com"lete $ the o#t"#t "ro!ram 'aso"ene an is"laye the follo'in! information abo#t the case 2 bi%e esi!n

eformation an stress istrib#tion thro#!ho#t the frame(



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,he follo'in! are tables of is"lacements in all three artesian a-es an member

stresses res"ecti+ely(Displacements: Case #2 )All 5is"lacements are in inches*


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Element A-ialtress



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#mmary: ase 2

In concl#sion$ this is more on tar!et than the last frame$ 'ith the critical membersGfactor of safety ecreasin! from 6(68 to 4(03( ,ho#!h the o+erall esi!n of this frame is

more feasible an "ractical than the esi!n 1$ it still has a lon! 'ay to !o( In this case itmay be better to re esi!n each member so that they all ha+e a factor of safety that are allin the same ball"ar%(


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In"#t al#es: ase 3


(5( )o#ter iameter*$ in: 1in

,hic%ness$ in: 0(062inArea$ A$ in2: 0(1 27in 2

Moment of Inertia$ I - $ in4: 0(0201 in 4


9oa in!:1(* 378lbs2(* 62(8lbs(

;estraints:1(* ;ear 'heel "i+ot: restraine in - an y(

2(* Front 'heel "i+ot: restraine in y only(

After all of the initial con itions 'ere establishe $ an instit#te into the mo el$ thecom"#tational mo elin! "ro!ram 'as o"ene an then e+al#ate the bicycle esi!n incase 2( After the com"#tational mo el 'as com"lete $ the o#t"#t "ro!ram 'as o"ene


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an is"laye the follo'in! information abo#t the case 2 bi%e esi!n eformation anstress istrib#tion thro#!ho#t the frame(



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Element A-ialtress



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A""en i- B)Han alc#lations*

FEA of a Bycicle Frame ME 3614

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