The LifeCycle of a Bumper System

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The Life-Cycle of a Bumper System

• Øyvind Johnsen Ryen
• Erik Nes, Trond Furu, Bjørn Holmedal, Jesper
  Friis, Ole Runar Myhr, Øystein Grong

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Bumper system
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The life-cycle of a bumper system
Casting-Homogenisation-Extrusion
Solution heat treatment quenching
Forming (bending)
Ageing
Use
Crash
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Ageing treatment of Al-Mg-Si (AA6xxx)
solution heat treat. 540C/15min
ageing 185C
forming
peak aged T6
overaged T7
underaged T6x
Precipitation sequence sss ? GP-zones ? b ? b
? b (Mg2Si)
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Ageing cont.
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Solution heat treatment quenching

• Alloying elements (Mg, Si) supersaturated solid
  solution
• 6082 1.5 MgSi
• AlMg3 3.2 Mg
• Combined effect of Mg and Si
• Dynamic precipitation/ clustering

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Forming
Non-uniform deformation along bumper beam
(e0-10)
FEM ee(x,y,z)
Dislocation density (r) varies
Work hardening model (Alflow) Calculates rr(e)
for a given alloy composition (solute)
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Forming Alflow calculation
6082 W10
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Ageing
Dislocation density (r) varies
Nucleation and diffusion influenced
Peak lower and earlier
Precipitation model (NaMo) Input Alloy comp, T,
time, r (from Alflow) Output r, f, ss, Rp0.2
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Ageing NaMo calculation
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Crash

• Large deformations
• Not only Rp0.2 that is important
• Work hardening, energy absorption, ductility

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Crash Alflow calculations
Work hardening model (Alflow) Input r, f, ss,
Rp0.2 (from NaMo) Output ss(strain, strain
rate)