ansys ncode design life - user groups 2011
TRANSCRIPT
© 2011 ANSYS, Inc. 8/29/111
ANSYS nCode DesignLife™
for 13.0 ANSYS® Workbench™
Jeff MentleyHBM-nCode
© 2011 ANSYS, Inc. 8/29/112
Agenda
IntroductionWhat is Fatigue and Why is it importantApproaches for FatigueANSYS nCode DesignLife overviewWhat is new for ANSYS 13.0 DesignLife SP1Questions
© 2011 ANSYS, Inc. 8/29/113
ANSYS® nCode DesignLife™
Integrated within ANSYS Workbench 13 to provide a leading solution for advanced fatigue analysis.
© 2011 ANSYS, Inc. 8/29/114
What is Fatigue?Fatigue is:
Fai lure under a repeat ed or ot herw ise var y ing load w hic h never reac hes a level suf f i c ient t o c ause fa i lu re in a s ing le appl ic at ion.
T he in i t iat ion and g row t h of a c rac k , or g row t h o f a pre-ex is t ing defec t , unt i l it reac hes a c r i t ic a l s ize.
The progressive and localized structural damage that occurs when a material is subjected to cyclic loading.
Strain
Str
ess
Time
Str
ess
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Slide 5
Early Failures
1808 Trevithick's “Catch-me-who-can”
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Slide 6
Present Day Fatigue Failure
– Hit br idge p i l lar - 100 k i l led
– Ear ly w heel des ign c aused v ib rat ions
– New w heel des ign– Based upon st ree t c ar des ign– Not t es t ed at h igh speed
before ser v ic e– Com plet e prot ot ypes never
t es t ed– Crash f ind ings
– Caused by c rac k in w heel– Dynam ic , repet i t ive forc es
had not been ac c ount ed for in des ign
– Design lac ked an adequat e m arg in o f safe t y
1999 – ICE high-speed trail derailed at Eschede, Germany
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Why is it Important ?
Why do we need to do Fatigue Analysis?• “...Between 80 - 90% of all structural failures
occur through a fatigue mechanism…”• “...The estimated annual cost of fracture and
fatigue to the US was 4.4% of GDP…”
“The Economic Effects of
Fracture in the United States,” National
Bureau of Standards, U.S. Department of
Commerce, Gaithersburg, MD, Special
Publication 647-2, 1983.
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Fatigue Analysis Process
Fatigue is a statistical, not deterministic, phenomenon.
• Stress-life• Strain-life• Crack growth
Life
Loading Environment
Geometry
Material Properties
Post-processing optimization
Fatigue Analysis
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Fatigue Analysis: Stress-Life (SN)
SN is also known as “High Cycle Fatigue” or “Nominal Stress Approach”
Elastic stress history used to determine life
May be applied to either material or component
Used extensively for welded joints and non-metallics
Suitable for lives greater than 1e4 cycles
Well established, Familiar, Large amount of material data available, Simple loadings can be analyzed as a hand calc.
Wöhler circa 1850
104 105 106Cycles, N
Str
ess
, ce
ntn
ers
/zo
ll2
400
200
600
800
Smooth shoulder
Sharp shoulder
© 2011 ANSYS, Inc. 8/29/1110
EN is also known as “Low Cycle Fatigue”, “Crack Initiation” or “Local Strain Approach”
Elasto-plastic strain history used to determine life
Local plasticity can be estimated from fully elastic FE analysis or computed directly in ANSYS
Suitable for low and high cycle fatigue
Cycle counting and plasticity corrections difficult to do by hand.
Fatigue Analysis: Strain-Life (EN)
ε
N
Plastic (Low CycleFatigue Line)
Elastic (High CycleFatigue Line)
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Fatigue Analysis: Crack Growth
Crack growth known as crack propagation, or fracture mechanics
Predicts cycle by cycle crack growth
Used in aerospace Damage Tolerance analysis
Determine impact of known or suspected flaws
Crack
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Materials
Stresses
Loads
Mechanical
Engineering Data
DesignLife
ANSYS® nCode DesignLife
ANSYS™ Workbench®
© 2011 ANSYS, Inc. 8/29/1113
ANSYS® nCode DesignLife™
– nCode OEM Par t nersh ip– nCode Des ignLi fe
– Advanc ed Fat igue Analys is
– Proc ess Or ient at ion– Ease o f Use
– Wor k benc h In t eg rat ion– DesignLi fe Syst em s– Design Param et ers– Mat er ia l l ibrar y
© 2011 ANSYS, Inc. 8/29/1114
ANSYS® nCode DesignLife™ - FeaturesStreamlining the Virtual
Engineering Process
– Powerful Fatigue Analysis Technology
– Integrated Reporting and Process Encapsulation
– Fast, Expandable, and Scalable
© 2011 ANSYS, Inc. 8/29/1115
ANSYS® nCode DesignLife™ - Features
Intuitive and easy to use software for per for m ing fat igue anal ys is o f f in i t e e lem ent m odels .
Efficiently analyze large f in i t e e lem ent m odels and c om plet e usage sc hedules.
Wide range of fatigue analysis capabilities inc lud ing s t ress-l i fe , s t ra in-l i fe , m ul t i -ax ia l, w eld analys is, v i r t ua l shaker t ab le , and m ore.
Single environment for bot h Test and CAE dat a.
Ex t ens ive material database
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ANSYS® nCode DesignLife™ - Capabilities
–St ra in-L i fe (aut om at ed m ul t i -ax ia l c or rec t ions)–St ress-L i fe (s ing le , m ul t i -c ur ve, Haigh d iag ram s)–Crac k Grow t h (LEFM)–Seam w elds and spot w elds–High t em perat ure fat igue–Vibrat ion fat igue (shaker s im ulat ion)–Vir t ual St ra in gage–Com plet e dut y c yc les / f l ight spec t r um s–Mult ip le r uns in a s ing le ana lys is–Mult i -proc essor enabled for fast resul t s
Fin i t e Elem ent resu l t s suppor t ed– St at ic (l inear
super pos i t ion)– Trans ient – Modal– Frequenc y Response– Linear & Non-l inear
Fin i t e Elem ent so lvers suppor t ed
– ANSYS– Abaqus– Nast ran– LS-Dyna
ANSYS nCode DesignLife has an extensive scope of fatigue capabilities…
© 2011 ANSYS, Inc. 8/29/1117
ANSYS® nCode DesignLife™ - Benefits
– Perfor m v i r t ua l durabi l i t y assessm ent up f ront t o reduc e re l ianc e on physic a l t es t and avoid c ost l y des ign and t ool ing c hanges
– Perfor m sm ar t er and qu ic k er phys ic a l t est s by s im ulat ing f i r s t
– Design durabi l i t y in t o your produc t s and reduc e w ar rant y c la im s
– St andar dize analys is proc esses t o im prove c onsis t enc y and qual i t y
– Aut om at e proc esses t o bet t er ut i l i ze engineers ’ t im e and w or k load
– Assess m ore design opt ions, c onsider m ore real is t ic load ing c ondi t ions and m ore c onf ident l y reduc e c ost and w e ight
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ANSYS® 13 nCode DesignLife™ SP1
– Support for Named Selections– New state engine to manage DesignLife system
updates– DesignLife processes saved with results– FKM mean stress with multicurve SN– Material map import deactivate– Seam weld enhancements– BS7608 and Eurocode 3 weld analysis
© 2011 ANSYS, Inc. 8/29/1119
Questions
ANSYS ® nCode DesignLife™
© 2011 ANSYS, Inc. 8/29/1120
Thank you!
Jeff Mentley
HBM - nCode
Tel: +1.248.945.4368
Ray Browell
ANSYS, Inc.
Tel: +1.724.514.3070 [email protected]
ANSYS ® nCode DesignLife™