Design of high performance automotive brake caliper using ... - ESSS

Design of high performance automotivebrake caliper using ANSYSRafael Blumberg – AuthorNicolino 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 comparison410g 810g 680g1210g1360g10% of mass reduction

Problem Description• Loads distributionNormal force on front axis [N] 2071.29 NDeceleration [g’s] 1.6 g’sNd1 aWVehicle weight [N] 2550 NNt( a)WRatio C.G. height / wheel base 0.226Rear weight distribution 54.9 %Normal force on rear axis 478.71 N

Problem Description• Brake loadsBrake torque [Nm] 378.8 NmTdNd D4pFriction tire/road coefficientTire rolling diameter [m] 1.6 0.457 mPdLine Pressure [MPa] Td*Re BF AePiston area [mm²] 4.0 MPa 1279.41 mm²Brake factor (2 * pad/disc ) 0.8Theorical effective radius [m] 0.0925 m

Problem Description• Loads distribution

Problem Description• Loads distributionCut view to analyzethe forces

Problem Description• Loads distributionPressure = 4 MPaNormal disc forcereactionCausing bypressure

Problem Description• Loads distributionAnother cut view toanalyze the forces

Problem Description• Loads distribution Friction = 0.4Tangential discforceCausing byTorque (380 Nm)

Problem Description• Effective radius

Problem Description• Effective radiusR e

Goals• Designing the caliper to the selected position• Mass reduction• Improve rigidity• Determine effective radius

Methodology• Create the mesh184250 elements was used with 289923 nodes to mesh generation and 4 Gbof 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 discThis contact is responsible to transform pressure in torque

Methodology• Create contact regions – piston / padThis contact determine how much force is transferred to bodyand how much remains on pin

Methodology• Create contact regions – piston / bodyThis contact is important because it is the unique contact that holds thebrake disc at its position, and also, it is responsible to set caliper’s efficiencyand piston solicitation

Methodology• Double check contact regions gaps and penetrations

Methodology• Pressures, torques and supports

Methodology• Pressures, torques and supportsCylindrical support used withtangential and axial free,because at this simulation wasused fixed caliper and floatingdisc

Methodology• Pressures, torques and supportsCompression only support was selected to give a real condition at holes,although it requires more process time

Methodology• Pressures, torques and supportsThis displacement needed be used to hold the caliper on axial holes directionbecause compression only support give that freedom

Methodology• Pressures, torques and supports380 Nm moment applied, same valueas calculated at begin based onvehicle characteristics

Methodology• Pressures, torques and supports4 MPa pressure applied at every piston case, fluid lineand pistons

Methodology• Double check reaction torque at same surface that wasapplied brake torque

Methodology• Double check reaction torque at same surface that wasapplied brake torqueWas applied 380 Nm, but was obtained 338 Nm.380 ---------------- 338X ---------------- 380Torque necessary to be applied is 426 Nm in order to obtain 380 Nm as realapplied

Methodology• Double check reaction torque at same surface that wasapplied 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 precisionwithout to need a high level computer• Start simulation with thermical DOF using friction heatgeneration

THANKSProf. Dr. Roberto Bortolussi