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