UK ATC 2015: A Systematic Approach to Weight Saving of Trailer Towing Systems at Jaguar Land Rover

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A Systematic Approach to Weight Saving of Trailer Towing

Systems at Land Rover

2015 UK Altair Technology Conference

Andrew Blows Technical Specialist - BCAE Strength & Durability [email protected]

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A Systematic Approach to Weight Saving of Trailer Towing Systems at Land Rover

• PALS • Parameter Diagram

• Non-Linear Material in Linear Analysis

• Systematic Approach • Critical Characteristic – Topology

• Bolted Joints

• Application of Systematic Approach

• Lessons Learnt

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• Bolted Joints


• Lessons Learnt

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Product Attribute Leadership Strategy (PALS)

Level 1 Attributes

A0: Product Efficiency A1: Safety A2: Perceived Quality A3: Accommodation & Usage A4: Vehicle HMI & Audio-Visual Performance A5: Vehicle Dynamics A6: Braking A7: Performance & Driveability A8: Vehicle NVH & Sound Quality A9: Durability & Reliability A10: Off Road & All Road Capability A11: Weight A12: Environment & Energy Management A13: Service & Ownership A14: All Weather Comfort & Vision A15: TASE A16: Security

A9: Durability & Reliability Durability vehicle life Corrosion vehicle life Retained Newness Robustness and Strength

Trailer Towing

• Trailer towing - brand DNA for Land Rover Products

• Vehicle Performance – Categories into attributes

• Product Attribute Leadership Strategy (PALS) targets are used to define and compare Land Rover’s capability against competitors

• PALS targets - maintain the high quality experience expected by our customers

A9: Durability & Reliability Durability vehicle life Corrosion vehicle life Retained Newness Robustness and Strength

Trailer Towing

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Product Attribute Leadership Strategy (PALS)

PALS

Customer Duty Cycle Targets

Requirements

Competitor Benchmarking

CAE

Physical Test Methods

Bolted Joint

Road Load Data (RLD)

Trailer Towing Optimisation

Virtual RLD

Loads & Duty Cycles

Capability Growth Projects (CGP) /

Correlation / Methods

Trailer Towing

Material Neuber

CAE / Test Correlation

2013-022 2014-204a 2014-204b

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Trailer Towing CGP – 204 b Loads Project Plan

Different Categories of Vehicles Different Trailers Different surfaces at MIRA Proving Ground

Tow bar Loads

Virtual tool set for TPJLR.00.008 Assess the existing TPJLR.00.008 Input to Body CAE for towing kit optimization project Vehicle Tow bar loads

Different trailers Different Vehicles Different road surfaces

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• Bolted Joints


• Lessons Learnt

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System

Trailer Towing CAE

Inputs Signal

Force

Ideal Function Output

Force – Deflection - Life Plastic strain < X%

Permanent deformation < Ymm Fatigue > N Repeats of Test Residual Bolt Torque > T Nm

Control Factors •Towing Capacity & Nose Load. •Loading - magnitudes & directions •Loading - Duty Cycle •Materials - Monotonic •Materials - Cyclic/Fatigue •Bolt Torque Methods •Targets - Bolt slip capacities •CAE Modelling procedure's

Noise 1 Piece-to-Piece

•Bolt Torque Tolerance •Coefficient of Friction •Material Yield Stress •Thickness variation •Welding Distortion •Residual Clamp •Assembly tolerance

Noise 2 Change Over Time

•Mig Weld size •Change to Material Yield •Residual Torque •Assembly tolerance

Noise 4 External Environment •Pre-strain •Pre-stress

Noise 5 System Interaction

Error States/Failure Modes • Excessive deformation • Fatigue • Bolt Torque Relaxation • Mass over target • Complex assembly

Noise Factors

Inner Noise (Capacity) Outer Noise (Demand)

Trailer Towing Parameter-Diagram

Noise 3 Customer Usage

•Loading magnitude •Loading directions •Loading Duty Cycle •CAE Process issues •CAE Capability Rating

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• Bolted Joints


• Lessons Learnt

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Non-Linear Material in Linear Analysis

Neuber equivalent Plastic Strains = f (Stress)

Neuber equivalent

Plastic Strains

Stre

ss

Strain

Neuber Hyperbola

Neuber

Linear Elastic FEA Stress

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• Bolted Joints


• Lessons Learnt

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Systematic Flow

Topology Opt

Targets-Displacement Stress Plastic strain Slip Capacity

Package Space

Yield Stress

Material Grade Bolt :- No / Size / Position Neuber

Linear Model

Solid Load Paths

Initial Concept Design

Critical characteristics Loads

‘Key fact holders’

Not everything can be linearized

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• Bolted Joints


• Lessons Learnt

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Topology

Concept Strategy • Optimise a bad concept Or • Optimising a good concept • Identify features that are critical to success • Explore package conflicts • Resolve to lightest design solution

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Topology

Package Design Space

Topology Optimised design

Explored Design Space find optimised designed for different Ball Joint Offset to Longitudinal • Z - Ball height • X - Offset

Z

X

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Packing Design Tool – Mass change with Ball Joint Offset

Offset from CL of Longit.

Mass

Bas

elin

e

Pro

pose

d

Provide tools to enable fundamental dimension of system to be influenced in the early design process. Offset to Longitudinal • Z - Ball height • X - Offset

% change in Mass

• Provide critical characteristics to key fact holder • More informed decision making in concept phase

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• Bolted Joints


• Lessons Learnt

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Systematic Flow

Topology Opt

Targets-Displacement Stress Plastic strain Slip Capacity Fatigue

Bolt Joint Stiffness

Design Interpretation

Package Space

Yield Stress Material Grade Bolt :- No / Size / Position

Neuber

Linear Model

Solid

Shell

Load Paths




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Torque relaxation when the bolt is first tightened

There are many potential failure modes for bolted joint.

Torque relaxation when the bolt is first tightened.

Why does this occur. ? • Compressive force in bolted joint are very large. • M14 Grade 10.9 116kN (11.6 Tonnes) • 3.5 x Fully Laden Discovery T5

3

1

Flanged Nut

1 2

3

Flanged Nut

Tension

Com

pres

sion

Com

pres

sion

Tension

Compression Compression

Compression Compression

Bolt

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Bolting Diagram Effect of External load on a Clamp Load

Load

Lev

el

E X t L E o R a N d A L

FA

Additional Bolt Load

FSA

Reduction In Joint

Load FPA

Bolt /Joint Clamp Load

Fv

Resultant Joint

Load FKR

Bolt

Joint Resultant

Bolt Load

Clamp Load Reduction from A to B

A

B

displacement

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Plate 2

Plate 1

Bolted Joint - Stiffness & Area Calculations

Plate 1

Plate 2

Washer

Washer

Flange head

B o l t Nut

Bolt dw

Nut dw

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Systematic Flow

Size / Gauge

Topology Opt

Shape / Topography

Non-Linear Model

Targets-Displacement Stress Plastic strain Slip Capacity Fatigue

Bolt Joint Stiffness

Design Interpretation

Package Space

Contact Bolt preload

Yield Stress

Non-Linear Matl

Material Grade Bolt :- No / Size / Position

Neuber

Linear Model

Solid

Shell

Shell

Mixed

Optimised Design

Design &/or

Linearization Issues

Update Linear Model

Load Paths



Strain-Life

d

esig

n fre

edom

redu

ced


Non-Linear Model

Linearization Check

Yes No

No

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• Bolted Joints


• Lessons Learnt

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Optimised Trailer Towing

For TPJLR.00.008

Optimised 22% Mass Reduction

Baseline

Improved EDT system has added a similar

weight saving

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• PALS

• Systematic FLOW overview

• Problem Understanding P-diagram • Bolted Joints • Non-Linear Material in Linear Analysis

• Critical Characteristic – Topology


• Lessons Learnt

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Lessons Learnt

Improved CAE methods, Material model, Loads & Targets Increases the capability & confidence in CAE to predict:-

• Ever more challenging engineering problems with high degree of accuracy. • Explore design opportunities & Identify design issues • Identification critical characteristics

Need to Improve Dissemination of Important critical characteristics • Provide key fact holders information in manageable form

• ‘Ball Joint offset vs. Mass’ Spreadsheet

• Greater understanding Leads to more efficient designs • Empowers Key fact holders

• Improved Data Driven Design processes • Utilised earlier – where greater design freedom & opportunities exist.

• Greater Customer satisfaction

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• Bolted Joints


• Lessons Learnt

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Thank you very much for Listening

Do you have any Questions ?

Acknowledgements:

Load - Prashant Khapane – JLR

Load - Jagan Senapathy - JLR

Optimisation - Greg Nunn - Altair Engineering

Bolted - Tim Willment – Altair Engineering

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Land Rover Discovery 3.0 SDV6 XS Category: 1900 kg+ “Still the best all-round heavy weight tow car” The Land Rover Discovery has now won the heaviest weight class seven times in eight years, making it the most successful model in the history of the Tow car awards.

Jaguar XF Sportbrake 3.0 V6 Diesel S Portfolio Category: 1700 – 1899 kg “Superb to tow with and brilliant to drive every day” Winner of it’s class for the second year

Range Rover Sport 3.0 SDV6 Autobiography Dynamic Category: 1900 kg+ Money No Object Tow Car “Superb to tow with and brilliant to drive every day” “If you have the means, this is the ultimate tow car”

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Land Rover Discovery HSE Luxury 3.0 SDV6 Judges Comments: “Effortless smooth gear changes, very comfortable” “Always in the right gear and no hunting” “Brilliant electric handbrake so held well and released when pulled away”

2015 Awards

Jaguar XF Sportbrake 3.0D V6 Portfolio Judges Comments: “Pulled like a train, lovely engine” “Effortless” “Efficient, tactile, comfortable”

Category: Over £40K 2015 TOWCAR of the Year

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Thank you very much for Listening

Do you have any Questions ?

Acknowledgements:

Load - Prashant Khapane – JLR

Load - Jagan Senapathy - JLR

Optimisation - Greg Nunn - Altair Engineering

Bolted - Tim Willment – Altair Engineering

Documents

UK ATC 2015: A Systematic Approach to Weight Saving of Trailer Towing Systems at Jaguar Land Rover