2012 HWPA Automotive Webinar Series Fatigue Analysis with DesignLife
2012 HWPA
Automotive
Webinar Series
Fatigue Analysis
with DesignLife
Agenda
• Why do we need to do fatigue analysis?
• nCode product range
• Introduction to DesignLife
• What’s new in nCode 8
• Demonstration of DesignLife
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.
nCode Product Range
• Complex analysis to report, simply done
• Graphical, interactive & powerful analysis
• World leading fatigue analysis capabilities
• Enables collaboration, manages data, and automates standardized analysis
• Search, query and reporting through secure web access.
• Data to information to decisions
• Fatigue analysis technology for FEA
• Process encapsulation
• Fast, configurable, and scalable
Data Processing System for Durability
Streamlining the CAE Durability
Process
Maximizing ROI on Test and
Durability
4
Introduction to DesignLife
6
Virtual Fatigue Analysis with DesignLife
• Intuitive and powerful graphical interface to perform fatigue analysis on FE models
• Efficiently analyze large finite element models and complete usage schedules
• Wide range of fatigue analysis capabilities including stress-life, strain-life, multi-axial, weld analysis, virtual shaker table, and more
• Highly configurable for the expert user
• Single environment for both Test and CAE data
• Enables automation of complete analysis processes and reporting
7
Inputs
Fatigue Analysis Process
Geometry
Loading
Environment
Material Properties
Fatigue Analysis Fatigue Results
• Stress Life
• Strain Life
• Crack Growth
• Etc
8
User Interface
Available Data Workspace Glyph Palette Toolbars
9
DesignLife Glyph Palette
• Below is a list of notable pre-configured analysis glyphs that can be found on the DesignLife Glyph Palette
SN CAE Fatigue
EN CAE Fatigue
Spot Weld CAE Fatigue
Seam Weld CAE Fatigue
Virtual Strain Gage
Vibration CAE Fatigue
10
Saving a Process
• Save Process saves all the glyphs, pipes, and properties
The process is saved as an .flo file
• Save Process With Data also saves the inputs and results that flow through the process
The process is saved as an .fdb file
• Package Process And Data also saves the process and data into a portable package
The process and all data are saved as a .zip file
11
Getting Help
• Context-sensitive Help on Property is available by right-clicking on any property
• The Manuals menu gives access to pdf documents such as
Contents
Glyph Reference
Theory Guide
Worked Examples
What’s new in nCode 8
Thermo-Mechanical Fatigue
• Components in high temperature operating environments such as engine pistons and exhaust systems can suffer from complex failure modes.
High temperature fatigue methods:
• Chaboche method is a stress-life
approach that uses stresses from
FE and either a constant or cycle-
by-cycle temperature correction.
• ChabocheTransient method
accounts for temperature by
normalizing the stress history prior
to cycle counting.
Creep analysis methods:
• Larson-Miller uses a master creep
curve (paired X-Y curve or
polynomial function) to calculate
damage per time increment of
applied load.
• Chaboche creep is a non-linear
damage summation approach that
uses a set of creep curves, where
each curve is for a specific
temperature.
Short Fiber Composite
• An SN approach is used for the analysis of anisotropic materials such as glass fiber filled thermoplastics
• The stress tensor for each layer and section integration point through the thickness is read from FE results
• The material orientation tensor describing the “fiber share” at each calculation point is provided by a manufacturing simulation mapped to the FE model
• Requires standard materials data of two or more SN curves for differing fiber orientations, to calculate an appropriate SN curve for each calculation point and orientation
Image courtesy e-Xstream engineering
Adhesive Bond
• DesignLife uses a fracture mechanics based method
Linear shells are used on the sheets with regular and congruent meshes on the flanges of ~10 mm
Beam elements represent the adhesive bond and Grid Point Forces are used to determine line forces and moments at the edge of the glued flange
Sheets and bond elements are grouped in sets
• Calculations of the strain energy release rate (the equivalent J-integral) are made at the edge of the adhesive to give a safety factor
Performance Improvements
• Analysis
EN with AbsMaxPrincipal combination method.
Loading is duty cycle with 91 events, 135 channels with 80% PeakValley compression resulting in 16,356 data point per channel
6,000 nodes analyzed
• Computer Hardware
2 x quad-core 2GHz, 4GB RAM
Windows7 64-bit
• DesignLife 8.0 fatigue analysis engines are up to twice as fast as previous releases through code and compiler optimization.
• Base DesignLife also now uses 2-threads without access to additional thread licenses, so giving a FOUR TIMES faster analysis of base product 8.0 over version 7.0.
Times are for analysis run only and do not include FE translation time.
Demonstration of DesignLife
Agenda
• Why do we need to do fatigue analysis?
• nCode product range
• Introduction to DesignLife
• What’s new in nCode 8
• Demonstration of DesignLife
Thank you
www.hbm.com/ncode
HBM, Inc. (HBM-nCode)
Travelers Tower 1
26555 Evergreen Rd, Ste.
700
Southfield, MI 48076
Tel: (248) 350 8300
Toll free: (877) 737 4242