Use of Casting Stress Simulation for Fatigue Simulation
E
C
A
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Pouring Of Cast Irons A Complex p Production Process Convection
Flow Heat Transport
Segregation
Cooling
Chemical Composition
Gases
Machining Metallurgy
Solidification Stresses
Heat Treatment
Distortion
Content How MAGMA supports you in the development of castings: ¬ Optimized component development through
integration of process simulation ¬ Substitution into cast components - tools to define optimal component design
Optimized Component Development Object es Objectives ¬ Reducing development time and costs through
improved virtual component design ¬ Reliable assessment of fatigue life considering local
material behavior ¬ Exploitation of full material potential
¬ Scrap p reduction through g early y integration g of
process simulation ¬ Castable designs ¬ Early identification of potential problems
¬ Robust quality / Improved reliability
Integrated CAE process - Simultaneous optimization p - Zero prototyping
Reso ources
The Integrated CAE Process for Castings
Simultaneous optimization (component + process) Prototypes
Resources
Integrated CAE procedure
Verification Trial Time
Prototypes II Component optimization P t t Prototypes I
P Process optimization ti i ti Trial
Simulation Time
Conventional development process - Hardware based - Sequential optimization
MAGMAmesh Finite Volume Mesh ¬ The MAGMASOFT®
mesh (Finite Volume Mesh)is shown in the pictures.
MAGMASOFT® - Temperature Result
¬ The temperature distribution
from MAGMASOFT® at the end of solidification is shown.
MAGMAlink Input-Result Selection ¬The input and output formats are selected
in the marked window.
¬The results to be mapped
are selected in this window.
MAGMAlink – Input and Output Format Variables ¬
The INPUT formats available are:
¬
The OUTPUT formats available are:
¬ ABAQUS
¬ ABAQUS
¬ UNIVERSAL
¬ IDEAS
¬ PATRAN
¬ PATRAN
¬ ANSYS ¬ PERMAS ¬ PAMCRASH ¬ RADIOSS ¬ STL ¬ CT-DATA
¬ ANSYS ¬ PERMAS ¬ PAMCRASH ¬ RADIOSS ¬ HYPERVIEW
Finite element mesh ¬ The Finite Element Mesh
is shown in the pictures.
Mapped Results - Temperature ¬The MAGMASOFT® results
(temperature distribution at the end of solidification) are mapped onto the FEM mesh.
Benefits of MAGMAlink – #1 ¬ Improved Communication = Better Quality ¬ Sharing results with casting designers in their language ¬ Providing the designers with valuable information for
developing high performance, superior quality castings
Benefits of MAGMAlink – #2 ¬ Provide a Premium Service with Little Extra Effort ¬ Competitive edge in developing stronger, better performing
castings ¬ Minimal effort is required by the simulation engineer to
provide this information p
Examples ¬ Impact of residual stresses on the safety factors for
engine design ¬ Impact of casting processes on life time of chassis components ¬ Impact of local component properties on the crash behavior of structural components
Residual Stresses in Crankcases
max 130 MPa max.
C
min. -150 150 MPa
2
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Impact of Residual Stresses on Fatigue Life
FSF = 1.3 13
With t residual Without id l stresses t
FSF = 0.8 08
With residual id l stresses t
Considering Thermal Residual Stresses caused by Design es g ¬ Residual stresses can be harmful or useful! ¬ Residual stresses are a pre-load that need to be
integrated into durability calculation ¬ Integrating information from process simulation
into FE-Analysis y allows an optimized p design g (higher performance, less weight)
Impact of Casting Processes on Life Time o C Chassis ass s Co Component po e t for
Prototype Sand casting : max. 13,200 load cycles
Series Permanent mold casting : max 43,300 max. 43 300 load cycles
Integration into Crash Simulation: Porosities for a B-Pillar
Courtesy of AUDI AG
Optimized Crash Simulation by Integration of oca p properties ope t es local Experiment
Simulation
Courtesy of AUDI AG
Summary of Advantages ¬ Replacement of physical with virtual trials ¬ Lower design and planning costs ¬ Significantly lower development time ¬ Optimized machining parameters ¬ Improved process stability ¬ Higher production capacity
Development of Residual Stresses in a Cylinder Head due to T6-Heat T6 Heat Treatment
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Description of the Manufacturing Process
Residual stresses during Heat Treatment ¬ Solution Treatment (T
At solution treatment temperatures all residual stresses caused by the casting process are relaxed due to creep. ¬ Quenching
Due to inhomogeneous cooling, residual stresses develop. ¬ Artificial Ageing (160°C – 200°C)
Residual stresses are relaxed due to creep. The level of relaxation is about 30%, depending on ageing temperature and time.
Typical positioning of cylinder heads during T6 Heat Treatment Process
Quenching Basket
Definition of local, temperature dependent eat Transfer a s e Coe Coefficients c e ts ((HTC) C) Heat Q
HTC outside
HTC
HTC inside
HTC-1
HTC-2
Surface temperature
HTC-4 HTC-3
Temperature distribution during quenching
Temperature distribution after 20s in a slice
T=310°C T=120 C T=120°C
High temperature differences during quenching will ill result lt iin hi high h residual id l stresses t
Stress development during Quenching
Relaxation of residual stresses due to artificial a t c a age ageing g
Influence of machining process on residual st esses stresses
Critical areas in cylinder heads
Validation of residual stress prediction 150 125 100 75
M Messung
50 25 0 -150
-125
-100
-75
-50
-25
0
25
50
75
100
-25 -50 -75
Cylinder Head 1 Cylinder y Head 2
-100
Simulation fits well -125 with measurements. The typical band width is-150about +/- 25 MPa and is within the scatterSimulation off the measurements.
125
150
Influence of residual stresses on HCF-Safety acto s Factors
Without Residual Stresses
Including Residual Stresses
Transfer of residual stresses on the FEes for o fatigue at gue life e prediction p ed ct o mesh >100 MPa
Exhaust
Compression
EX
Froont End
-100 MPa
0 MPa
+100 MPa
Intake
Water Side View
IN
Tension
>100 MPa
>100 MPa
Gas Side View
High-Cycle-Fatigue Safety Factors
HCF-Crack Initiation
EX
Exhaust Port
Durable
3.0
Fronnt End
Fronnt End
5.0
1.0
IN
Critical
Critical !
Water Side View
Tangential Intake
Contact Info Christof Heisser President MAGMA Foundry Technologies, Inc. 10 N. Martingale Road, Suite 425 Schaumburg, IL 60173 www.magmasoft.com
[email protected] 847-969-1001 Direct: 847-252-1650