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

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 ablows@jaguarlandrover.com 1

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 3

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 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 Trailer towing - brand DNA for Land Rover Products 5

Product Attribute Leadership Strategy (PALS) PALS Requirements Competitor Benchmarking Customer Duty Cycle Road Load Data (RLD) Targets Physical Test Methods Loads & Duty Cycles Capability Growth Projects (CGP) / Correlation / Methods CAE Material Neuber Bolted Joint CAE / Test Correlation Trailer Towing Optimisation Virtual RLD Trailer Towing 2013-022 2014-204a 2014-204b 6

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 7

Trailer Towing Parameter-Diagram Inner Noise (Capacity) Outer Noise (Demand) 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 3 Customer Usage Loading magnitude Loading directions Loading Duty Cycle CAE Process issues CAE Capability Rating Noise 4 External Environment Pre-strain Pre-stress Noise 5 System Interaction Noise Factors Inputs Signal Force System Trailer Towing CAE 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 Ideal Function Output Force Deflection - Life Plastic strain < X% Permanent deformation < Ymm Fatigue > N Repeats of Test Residual Bolt Torque > T Nm Error States/Failure Modes Excessive deformation Fatigue Bolt Torque Relaxation Mass over target Complex assembly 9

Non-Linear Material in Linear Analysis Neuber equivalent Plastic Strains = f (Stress) Stress Neuber Hyperbola Linear Elastic FEA Stress Neuber equivalent Plastic Strains Strain Neuber 11

Systematic Flow Package Space Initial Concept Design Load Paths Critical characteristics Linear Model Topology Opt Solid Targets- Displacement Stress Plastic strain Slip Capacity Loads Key fact holders Yield Stress Material Grade Bolt :- No / Size / Position Neuber Not everything can be linearized 13

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 15

Topology Package Design Space Explored Design Space find optimised designed for different Ball Joint Offset to Longitudinal Z - Ball height X - Offset Topology Optimised design Z X 16

Packing Design Tool Mass change with Ball Joint Offset Provide tools to enable fundamental dimension of system to be influenced in the early design process. Offset to Longitudinal Z - Ball height Mass X - Offset % change in Mass Baseline Proposed Provide critical characteristics to key fact holder More informed decision making in concept phase Offset from CL of Longit. 17

Systematic Flow Package Space Initial Concept Design Load Paths Critical characteristics Linear Model Topology Opt Design Interpretation Solid Shell Targets- Displacement Stress Plastic strain Slip Capacity Fatigue Loads Material Grade Bolt :- No / Size / Position Bolt Joint Stiffness Yield Stress Neuber Not everything can be linearized 19

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.? Flanged Nut Compressive force in bolted joint are very large. M14 Grade 10.9 116kN (11.6 Tonnes) 3.5 x Fully Laden Discovery T5 Flanged Nut 1 2 3 Compression T e n s i o n Compression Bolt 3 Compression 1 Compression T e n s i o n Compression Compression 20

Bolting Diagram Effect of External load on a Clamp Load Joint Load Level Bolt /Joint Clamp Load Fv Bolt A B Additional Bolt Load F SA Reduction In Joint Load F PA E X t L E o R a N d A L F A Resultant Bolt Load Resultant Joint Load F KR Clamp Load Reduction from A to B displacement 21

Bolted Joint - Stiffness & Area Calculations Plate 1 Plate 2 Plate 1 Plate 2 Washer Washer Bolt dw Flange head B o l t Nut Nut dw 23

Systematic Flow Package Space Initial Concept Design Load Paths Material Grade Bolt :- No / Size / Position Linearization Check Yes No Design &/or Linearization Issues Critical characteristics No Non-Linear Model Linear Model Topology Opt Design Interpretation Bolt Joint Stiffness Size / Gauge Shape / Topography Non-Linear Model Solid Shell Shell Mixed design freedom reduced Targets- Displacement Stress Plastic strain Slip Capacity Fatigue Loads Yield Stress Strain-Life Neuber Non-Linear Matl Contact Bolt preload Update Linear Model Not everything can be linearized Optimised Design 24

Optimised Trailer Towing Baseline Optimised 22% Mass Reduction Improved EDT system has added a similar weight saving For TPJLR.00.008 26

A Systematic Approach to Weight Saving of Trailer Towing Systems at Land Rover PALS Systematic FLOW overview Problem Understanding P-diagram Bolted Joints Non-Linear Material in Linear Analysis Critical Characteristic Topology Application of Systematic Approach Lessons Learnt 27

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 28

A Systematic Approach to Weight Saving of Trailer Towing Systems at Land Rover 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 30

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. 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 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 31

2015 Awards 2015 TOWCAR of the Year Category: Over 40K 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 Jaguar XF Sportbrake 3.0D V6 Portfolio Judges Comments: Pulled like a train, lovely engine Effortless Efficient, tactile, comfortable 32