STRUCTeam and Ruster Sports Optimisation of the New Dimond ...

S T R U C Te a m a n d R u s t e r S p o r t s O p t i m i s a t i o n o f t h e

N e w D i m o n d B i k e F r a m e

Frederic Louarn

Principal engineer

STRUCTeam Ltd

© Copyright STRUCTeam Ltd

Under legal protection by 1886 International Copyright Act and Berne Convention

NOT to be modified, reused, copied or distributed in any way without permission of STRUCTeam Ltd

STRUC Team Introduct ion

19/07/2018 Slide: 2

Independent Composites Solution Provider

We help our clients to:

¤ Make better decisions

¤ Reduce costs

¤ Improve efficiency

¤ Select and develop appropriate technologies for their composite

business

Over 200 successful projects across all markets sectors


D i m o n d b i ke p ro j e c t I n t ro d u c t i o n

10/23/2018Slide: 3


This project was carried out for Ruster

Sport’s new Dimond triathlon bike design - https://www.dimondbikes.com -

with a twofold objective.

STL to provide Ruster Sport with

an understanding of complex load

paths within the critical chainstay

crotch area and to make basic

recommendations in terms of

reinforcement

STL to validate the final

laminate specification by

using appropriate safety

margins for composite

structures.

https://www.dimondbikes.com/

S t r u c t u ra l D e s i g n Wo r k f l o w

10/23/2018Slide: 4


STRUCTeam's approach consisted of

developing design load cases to be

implemented in a global beam finite

element model of the bike.

Chainstay loads were extracted from

this global model and applied to a local

shell finite element sub-model of the

frame chainstay, enabling detailed

analysis of load paths as well as

strength analysis within the critical

crotch area.

Composide FESpace

Ansys ACP

Recommendations vs

reinforcement weight

and fibre orientations

Strength

validation

Ruster Sports provided

design inputs in terms

of frame geometry and

initial laminates

Manufacturing

loop

10/23/2018Slide: 5

Global beam finite element model of the bike


G l o b a l B i ke F E A

10/23/2018Slide: 6

Beam Finite Element Model developed in CompoSIDE FESpace

Envelope static load cases based on EN standards and published data:

1. EN 14781 (Race bikes)

2. EN 14766 (Mountain bikes),

3. Development of experimental methods for fatigue testing of composite racing bicycle frames, S.

Styns, MSc Thesis,

4. Bicycle Frame Optimization by Means of an advanced Gradient method Algorithm, L. Maestreli,

A. Falsini.



7

Loads and boundary conditions for static load case example

Ux=Uy=Uz=0

@ contact

between aft tire

and road

Ux=Uy=0

@ front dropouts

Pedal force

Fy=-1.19 kN

Fx= -0.16 kN

chain force

reaction @

cog

Handle bar

forces

chain force

Fz=2.7 kN

Fy=-0.13 kN


8

Predicted displacements for static load case example

Frame response dominated by

transverse bending in way of

chainstay

Chainstay crotch critical

loads components:

- axial force on chain

side

- transverse BM

Reactions Rx, Ry, Rz used

as inputs for shell FEA

10/23/2018Slide: 9

Local shell finite element model of the frame

chainstay


L o c a l C h a i n s t ay F E A

10/23/2018Slide: 10


Finite Element Mesh

16692 1st order laminated shell elements

“shell 181”

Refined mesh: 0.3-

0.5mm edge sizing

beam elements

around bottom

bracket penetrations

(steel ring)

Accurate geometrical

features in way of crotch

area


10/23/2018Slide: 11


Laminates are simplified initially in terms of

fibre orientation and thickness VS accurate

final laminate thicknesses and fibre directions

used for validation

Contour plot of final Laminate thicknesses in ANSYS ACP


10/23/2018Slide: 12


Loads and boundary conditions example

Ux=Ux=Uz=0 around downtube perimeter

Rx, Ry and Rz from framework model


10/23/2018Slide: 13


Understanding load paths to make recommendations vs laminate fibre directions


10/23/2018Slide: 14


Principal strain predictions to make recommendations vs reinforcement weights


10/23/2018Slide: 15


Predicting strains and strength minimum reserve factors (“RF”) for final validation (after manufacturing loop)…vs ultimate static strength…and vs fatigue limit state.

10/23/2018Slide: 16

Conclusions


C o n c l u s i o n s

10/23/2018Slide: 17

This presentation is intended to illustrate how

structural design inputs from STRUCTeam Ltd

have helped Ruster Sports to deliver the Dimond

bike frame.

Whereas the focus herewith has been on

structural design aspects, the importance of the

collaboration between the two parties has also

been highlighted as being key to a successful

project:

➢ from manufacturing inputs,

➢ to prototyping and testing,

➢ Leading to series production


"Collaborating with Structeam on this project was a huge success for us. Their

analysis gave us a huge leg up in the development process. Using their work to

guide our initial layup design, and then being able to validate that and get

feedback from them has resulted in a great product. The resulting part has

seen zero issues, with 100s of frames in the field for 2 years and hundreds of

thousands of miles of use."

Matt Cymanski

Chief Engineer

Rüster Sports | Dimond Bikes

http://www.rustersports.com/

http://www.dimondbikes.com/

Thank you for your attention

Frederic Louarn

[email protected]

STRUCTeam

www.structeam-ltd.com

+44 (0)1983 240534

© Copyright STRUCTeam Ltd Slide: 18

STRUCTeam and Ruster Sports Optimisation of the New Dimond ...

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