Applications of ANSYS AUTODYN

61 Pages·2006·14.01 MB·English

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EONve Srveimewin aArU TODYN simulations Simulating Transient Herta RICHTER
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Effects of Pulsed Beams
PPaaggee 11 [email protected]
Overview
• Material Failure & Simulation of
Transient Effects
• Examples from CERN
– n-TOF
– ISOLDE
• Simulating with ANSYS AUTODYN
• Using ANSYS AUTODYN @
CERN
– Liquid targets (Hg, Pb)
– Solid targets (Cu, Pb, Ta, W)
EN Seminar Simulating Transient Herta RICHTER
July 3rd, 2009 CERN, EN/STI/RBS
Effects of Pulsed Beams
Page 2 [email protected]
Motivation
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EN Seminar Simulating Transient Herta RICHTER
July 3rd, 2009 CERN, EN/STI/RBS
Effects of Pulsed Beams
Page 3 [email protected]
What Causes Material Failure?
(schematic) Short term effects
~ ns – 10 µs
Shock wave
High stress
→ spall/cavitation
→ Fracture
(
h
a i
g
n (ductile or brittle)
h
e
l
m y
)
o d
n y
e n
High energy deposition
h a
p m

c i
→ Melting & Vaporization c
i
t
a p
t h
s
e
) n
i
s o
a Static Touching Cyclic stress m
u
q e
( n
stress surfaces → Fatigue a
(@ elevated → Wear
temperatures)
→ Creep
Long term effects
EN Seminar Simulating Transient Herta RICHTER
July 3rd, 2009 CERN, EN/STI/RBS
Effects of Pulsed Beams
Page 4 [email protected]
Simulation Parameters
schematic Failure
Initial
EOS
model
Volume V conditions
Density ρ Stress σ
Pressure P
Heat
transfer
Temperature T
Energy e
Boundary
Strain ε
conditions
…
Conservation of mass,
.
Strain rate ε
momentum & energy Strength
model
… and of course static as well as dynamic phenomena
EN Seminar Simulating Transient Herta RICHTER
July 3rd, 2009 CERN, EN/STI/RBS
Effects of Pulsed Beams
Page 5 [email protected]
Reality Is A “Little” Different
• Static vs. Dynamic:
– Implicit code for quasi-static simulations
– Explicit code for highly dynamic simulations
(explicit time integration)
• EOS, strength & failure models:
– Simulation can only be as accurate as the
models fed into it
• Discretization of simulated body
• Solving of governing equations numerically
with different solution techniques (solvers)
EN Seminar Simulating Transient Herta RICHTER
July 3rd, 2009 CERN, EN/STI/RBS
Effects of Pulsed Beams
Page 6 [email protected]
The Equation of State (EOS)
Pressure-volume Pressure-volume-temperature
wide-range multi-phase copper EOS (by Lomonosov et. al.)
Laser and Particle Beams (2007), 25, 639–647
“Spall fracture” by Tarabay Antoun et. al (Springer, 2003)
DOI: 10.1017/S0263034607000766
Shock Hugoniots, isotherms, isobars, isentropes, polymorphic
transformations, melting region, evaporating region with the critical
point, solid, liquid & gaseous phase, liquid & gas coexistence,
(dense) Plasma, ionization, crystallization, …
EN Seminar Simulating Transient Herta RICHTER
July 3rd, 2009 CERN, EN/STI/RBS
Effects of Pulsed Beams
Page 7 [email protected]
The Strength & Failure Models
Strength models: Transition elastic-plastic (yield criterion)
Failure models: Criterion for onset of fracture & cavitation
Both are dependent on:
– Degree of strain (work – Crystalline structures
hardening)
– Unloading/loading path
– Strain rate
– Damage
– Energy/temperature
– Porosity
– Pressure
– Isotropy
– Grain size
– Impurity
– …
EN Seminar Simulating Transient Herta RICHTER
July 3rd, 2009 CERN, EN/STI/RBS
Effects of Pulsed Beams
Page 8 [email protected]
Examples from CERN
EN Seminar Simulating Transient Herta RICHTER
July 3rd, 2009 CERN, EN/STI/RBS
Effects of Pulsed Beams
Page 9 [email protected]
Beam Intercepting Devices
• Targets
≤ 7 TeV/c
• Absorbers/Stoppers
• Collimators
• Scrapers
• Aperture limiters
2.12 GeV/c
• Masks
• …
20 GeV/c
Short pulses and high
energy deposition
EN Seminar Simulating Transient Herta RICHTER
July 3rd, 2009 CERN, EN/STI/RBS
Effects of Pulsed Beams
Page 10 [email protected]