Design of high performance automotive

brake caliper using ANSYS

Rafael Blumberg – Author

Nicolino Foschini Neto – Co-author

PRESENTATION TOPICS

• Formula FEI Overview;

• Problem Description;

• Goals;

• Methodology;

• Conclusion and next steps.

Formula FEI Team

• Formula SAE student competition

Problem Description

• Mass comparison

410g 810g 680g

1210g 1360g

10% of mass reduction

Problem Description

• Loads distribution

WaN

WaN

t

d

)(

1

Normal force on front axis [N]

Deceleration [g’s]

Vehicle weight [N]

Ratio C.G. height / wheel base

Rear weight distribution

Normal force on rear axis

2071.29 N

1.6 g’s

2550 N

0.226

54.9 %

478.71 N

Problem Description

• Brake loads

4

pd

d

DNT

Brake torque [Nm]

Friction tire/road coefficient

Tire rolling diameter [m]

378.8 Nm

1.6

0.457 m

ee

dd

ABFR

TP

*

Line Pressure [MPa]

Piston area [mm²]

4.0 MPa

1279.41 mm²

Brake factor (2 * pad/disc) 0.8

Theorical effective radius [m] 0.0925 m

Problem Description

• Loads distribution

Problem Description

• Loads distribution

Cut view to analyze

the forces

Problem Description

• Loads distribution Pressure = 4 MPa

Normal disc force

reaction

Causing by

pressure

Problem Description

• Loads distribution

Another cut view to

analyze the forces

Problem Description

• Loads distribution Friction = 0.4

Tangential disc

force

Causing by

Torque (380 Nm)

Problem Description

• Effective radius

Problem Description

• Effective radius

Re

Goals

• Designing the caliper to the selected position

• Mass reduction

• Improve rigidity

• Determine effective radius

Methodology

• Create the mesh

184250 elements was used with 289923 nodes to mesh generation and 4 Gb

of RAM memory was needed to solve.

Methodology

• Verifying mesh quality (aspect ratio)

Methodology

• Verifying mesh quality (aspect ratio)

Methodology

• Create contact regions

Methodology

• Create contact regions – pad / brake disc

This contact is responsible to transform pressure in torque

Methodology

• Create contact regions – piston / pad

This contact determine how much force is transferred to body

and how much remains on pin

Methodology

• Create contact regions – piston / body

This contact is important because it is the unique contact that holds the

brake disc at its position, and also, it is responsible to set caliper’s efficiency

and piston solicitation

Methodology

• Double check contact regions gaps and penetrations

Methodology

• Pressures, torques and supports

Methodology

• Pressures, torques and supports

Cylindrical support used with

tangential and axial free,

because at this simulation was

used fixed caliper and floating

disc

Methodology

• Pressures, torques and supports

Compression only support was selected to give a real condition at holes,

although it requires more process time

Methodology

• Pressures, torques and supports

This displacement needed be used to hold the caliper on axial holes direction

because compression only support give that freedom

Methodology

• Pressures, torques and supports

380 Nm moment applied, same value

as calculated at begin based on

vehicle characteristics

Methodology

• Pressures, torques and supports

4 MPa pressure applied at every piston case, fluid line

and pistons

Methodology

• Double check reaction torque at same surface that was

applied brake torque

Methodology

• Double check reaction torque at same surface that was

applied brake torque

Was applied 380 Nm, but was obtained 338 Nm.

380 ---------------- 338

X ---------------- 380

Torque necessary to be applied is 426 Nm in order to obtain 380 Nm as real

applied

Methodology

• Double check reaction torque at same surface that was

applied brake torque

Conclusion and next steps

• Results (Equivalent Stress – All bodies)

Conclusion and next steps

• Results (Equivalent Stress – All bodies)

Conclusion and next steps

• Results (Total Deformation – All bodies)

Conclusion and next steps

• Results (Equivalent Stress – Body)

Conclusion and next steps

• Results (Z deformation – Body)

Conclusion and next steps

• Results (Z deformation – Body)

Conclusion and next steps

• Results (Equivalent Stress – Pads)

Conclusion and next steps

• Results (Equivalent Stress – Piston)

Conclusion and next steps

• Results (Equivalent Stress – Pins)

Conclusion and next steps

• Results (Contact Pressure – Pad / Disc)

Conclusion and next steps

• It’s possible to analyze a brake caliper with good precision

without to need a high level computer

• Start simulation with thermical DOF using friction heat

generation

THANKS

Prof. Dr. Roberto Bortolussi