An integrated testing and
model based design
approach for semi-trailer
weight reduction
J. Pauwelussen, J.Visscher, M. Merts, K. Kural
HAN University, Arnhem, The Netherlands
Outline
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Mo#va#on Project strategy First results Upscaling the project: FORWARD: Fuel Op#mised trailer Referring to Well Assessed Realis#c Design loads HAN Automotive Research:
Some projects on heavy vehicles
Hybrid design
Hydrogen truck
Roll-over monitoring
stability
Guidance control
Problem statement
•  20 % of CO2 emission due to road transport •  2000 – 2020: Freight transport will grow with 20 % •  1985 – 2006: GHG has grown with 35 % •  Transport efficiency and constraints: –  Produc#vity –  Capacity –  Fuel consump#on  aiming for lower vehicle weight Present problem areas
•  Realis#c design loads are not clear –  vehicle, payload –  condi#ons of use: road, manoeuvre,… •  Large safety margin due to conserva#ve loading •  Large #me pressure if trailer breaks down •  Design: zooming in to cri#cal spots –  not regarding global structural behaviour •  new materials  unconven#onal design There is a need for:
more tes#ng larger variety in vehicles design prac#ces analysis/development tools, that fit in the exis#ng design process •  These tools must be efficient •
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–  #me –  money •  representa#ve loading Project approach
Practical conditions of use
Experiments
Model
king-pin forces
tyre forces
updated design
overall response
detailed response
estimated fatigue
First step, three trailers
A: box-trailer
B: trailer with a belt unloading system
C: flexi-trailer
Loading & instrumentation
Part of prac#cal use (> 3 weeks) •  Cornering •  Braking •  Road disturbances •  90 degrees drive away Instrumentation
Lateral, forward speed
Yawrate
ABS signals Accelerations, x, y, z
Axle accel.(2),
displac.(4)
Air pressures
+ brake pressures
+ steering wheel
cornering
Fy
speed
body slip
angle
yaw rate
Faxle
Fkingpin
mass, position CoG
lateral acceleration
Fkingpin, sum of axle forces
lateral axle force
yaw rate
body slip angle
load transfer
axle slip angles
separate wheel side forces
Vertical loading
air pressure
displacement
accelerations
stationary air spring forces
axle loads
filter
spring forces
damper forces
hinge forces
(vertical, quasi-stationary)
spring forces
damper forces
axle acceleration
hinge forces (dynamic)
Real life test
Cornering,results
ay(g)
Air pressures (bar)
Axle torque (kNm)
axle
King pin
Side force (kN)
Wheel side force (kN)
Bump overpass
az axle (g)
Dynamic axle
loads (kN)
az chassis (g)
Fx kingpin (kN)
Fz kingpin (kN)
Braking,results
damper springforce (kN)
ax axle (g)
Axle springforce (kN)
Dynamic axle
loads (kN)
Fx kingpin (kN)
Fz kingpin (kN)
Critical accelerations/hr
Frequency (Nr/hr)
Frequency (Nr/hr)
Acceleration ax
Acceleration az
order of magnitude
•  Total brake force: 30 – 40 kN •  x-­‐force at king-­‐pin: 60 – 100 kN •  z-­‐force at king-­‐pin: 130 – 150 kN (sta#onary: order 100 kN) •  Cornering force all axles: 45 – 60 kN •  Cornering force king-­‐pin: order 30 kN •  Torque around trailer axles: 15 – 20 kNm •  dynamic az axle can be > 10 g (peak) with low az king-­‐pin (depending on elas#city neck) FORWARD
•  HAN University of Applied Sciences •  11 trailer manufacturers and suppliers (steering systems, suspension) –  7 different trailer ‘families’ •  Dutch Chassis and Body Work Associa#on FOCWA •  Delg University •  Light-­‐weigth structures (company) Improvements
•  Dynamic interac#on with payload •  More extensive measurements: –  ver#cal accelera#on at king-­‐pin –  GPS based systems –  trailer and tractor •  field-­‐tests and valida#on tests •  extended model environment •  efficient test instrumenta#on –  vehicle state es#ma#on Principle
Measurement data set King-­‐pin Forces Tyre Forces •  Mul#body vehicle model –  Modularity (different axles, dimensions, cargo, suspension, containers…) –  Accuracy –  Emphasis on kinema#cs of suspension •  Advanced Tyre models 3/17/10
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Next Goal
•  avoid user to do complex modeling •  easy to compile model of your interest •  provide sufficiently accurate input for FEM 3/17/10
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MATLAB/Graphical User
Interface (GUI)
•  user friendly environment •  complete model genera#on supported by User’s Guide Step 1: type of cargo Step 2: truck parameters Step 3: trailer parameters Step 4: suspension characteris#cs Step 5: automa#c model genera#on 3/17/10
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Validation procedure
MEASURED DATA
steering angles
wheel veloci6es wheel ver6cal displ.
MULTIBODY VEHICLE MODEL
yaw rate velocity body accelera6ons
...
wheel load
yaw rate velocity body accelera6ons
wheel load
…
Scope
3/17/10
Validation Testing Program
Test •  Steady state cornering •  Straight braking •  Bump overpass •  General handling Goals •  Obtain lateral tyre proper#es •  Longitudinal tyre proper#es, height CoG •  Suspension proper#es •  Overall handling FEM analysis
Conclusions
•  First: bridge gap between test-­‐data and light-­‐weight design •  ‘launching’ manufacturers •  results are considered of added value •  Extended scope  FORWARD •  Manufacturers involved  fit with prac#cal design prac#ces