Design Optimization and Robust Design for Fatigue

Jeff Mentley HBM nCode Sumeet Parashar Esteco

Agenda

HBM nCode Intro Esteco Intro nCode DesignLife Overview modeFRONTIER Overview Robust Design Example Multi-Objective Design Optimization of a Connecting Rod Questions

From Physical Measurement to Virtual Testing

Projects Sensors

Services DAQ Hardware

Calibration DAQ Software Analysis & Data Processing

Simulation and Prediction

nCode DesignLife Overview

HBM-nCode Analysis and Simulation

nCode Product RangeData Processing System for Engineers Streamlining the Virtual Fatigue Engineering Process Web-based Processing for Engineering Data

Complex analysis to report, simply done Graphical, interactive & powerful analysis World leading fatigue analysis capabilities

Powerful fatigue analysis technology Integrated reporting and process encapsulation Fast, expandable, and scalable

Search, query and reporting data through secure web access. Analyze, trend and understand using configurable processing.

nCode DesignLifeTM Streamlining the Virtual Fatigue Engineering Process Intuitive and easy to use software for performing fatigue analysis of finite element 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. Plus Python enables new or proprietary fatigue methods to be added. Single environment for both Test and CAE data. Enables automation of complete analysis processes and reporting.

nCode DesignLifeTM - Capabilities Stress-Life (single, multi-curve, Haigh diagrams) Strain-Life (automated multi-axial corrections) Multi-axial safety factor (Dang Van) Seam welds and spot welds High temperature fatigue Vibration fatigue (shaker simulation) Multiple runs in a single analysis Complete duty cycles / flight spectrums Multi-threaded enabled for fast results Finite Element results supported4

Static (linear superposition) 4 Transient 4 Modal 4 Frequency Response 4 Linear & Non-linear

Major FE codes supported4

ANSYS 4 ABAQUS 4 NASTRAN 4 LS-Dyna

nCode DesignLifeTM User Interface

Running DesignLife in Batch

Flowproc (1) runs DesignLife process in batch Inputs4 DesignLife

flow 4 Flowproc script Specifies input data ( replaces drag and drop ) Modify glyph properties ( change property values saved in flow ) Only exposed properties of CAE Analysis glyphs

Outputs4 Files

with overwrite set to Yes

(1) Flowproc is not available under Hyperworks Licensing

nCode DesignLifeTM Summary

Predict Up-front durability assessment

Process Capture knowledge and integrate CAE & test

Productivity DesignLife can handle fatigue analysis with relative ease, and thisis down to the companys long standing expertise in this area. MCAD Magazine

Spend more time where it counts

modeFRONTIER Overview

Robust Design Example

Robust Design Example

Analysis tools: ANSYS WB for stress analyses nCode DesignLife for fatigue analysis Loading Fatigue Strength Surface Roughness

Robust Design

ANSYS Workbench Housing Model

Model Description Aluminum Pressure Loading Constrained at Mating surface Mounting screws

DesignLife Process

Statistical Fatigue Analysis

Material Properties Surface Finish Surface Treatment PASS FAIL Temperature Loads Notches Internal Stresses

stress

strength

Confidence of Survivalt = f (2Nf ) b 10 zse + f (2Nf ) c 10 zsp E

z : number of standard deviations from the mean se & sp : standard error of log(e) & log(p) respectively

Total strain amplitude

nominal life line :90% life line :

t =t =

f (2Nf ) b + f (2Nf ) c E

i.e. z = 0

50% 90%

f (2Nf ) b 10 1.28se + f (2Nf ) c 10 1.28sp E i.e. z = 1.28

Number of SDs from mean -3 -2 -1 090% 50%

% Certainty of survival 99.9 nominal life-line 97.7 90% confidence life-line 84 50

Reversals to failure

DesignLife Process

StrainLife Analysis Exposed properties load scale factor certainty of survival surface roughness Constant load provider 0 to 5 MPa 2nd Pass worst node Output CSV file

Running DesignLife using Flowproc

DOS Command to run flowproc: C:\nCode\GlyphWorks51\bin\flowproc /flow=cover_doe_notrans.flo /script=flowproc.script /verbose=yes cover_doe_notrans.flo flowproc.script DesignLife process file script file

Example script file

modeFRONTIER Workflow

modeFRONTIER Workflow

modeFRONTIER Workflow

modeFRONTIER Workflow

modeFRONTIER Workflow

modeFRONTIER Workflow

Robust Design Sensitivity Analysis

Student Chart for Sensitivity Analysis

Robust Design Life Distribution

Multi-Objective Design Optimization of a Connecting Rod

Multi-Objective Design Optimization of a Connecting Rod

Analysis tools: ANSYS WB for stress analyses of two working conditions: firing and return nCode DesignLife for fatigue analysis Minimize mass Minimize maximum stress Maximize fatigue life Maximum stress < 100 MP Fatigue life > 1e9

Objectives:

Constraints:

Design Variables

Design variables:1. Thickness scale (of center portion) (0.1~1.0) 2. Thickness (5 ~30 mm) 3. Upper fillet (1~100 mm) 4. Lower fillet (1~150 mm) 5. Upper width (3~10 mm) 6. Lower width (3~10 mm)

ANSYS Workbench Model

Firing Loadcase Return Loadcase 25 kN compressive 2500 N tensile load load Bearing supports Journal Pin

DesignLife Flow

Stress Life TimeStep load provider Firing Return 2nd Pass worst node Output CSV file

modeFRONTIER Workflow

NSGA-II more suitable for - Multiple objectives - Robust & global convergence - Better constraints handling - Discrete & continuous variables

modeFRONTIER Workflow

Sensitivity Analysis - Student Chart

Correlation analysis - Scatter Matrix

Feasible vs. Unfeasible

Pareto Froniter

Pareto Froniter

modeFRONTIER Workflow (3 Objectives)

Sensitivity analysis - Overall Student Chart

Tradeoff analysis - Bubble Chart

Tradeoff analysis - Parallel Coordinates

Each design represented as connected poly-line

Tradeoff analysis - Parallel Coordinates

Filter only Pareto designs

Tradeoff analysis - Parallel Coordinates

Filter based on designers preference

Summary

DesignLife allows virtual fatigue life predictions from FE results Batch operation of DesignLife allows its use by 3rd party optimization programs such as modeFRONTIER Combining DesignLIfe with modeFRONTIER allows4 Robust

Design 4 Shape optimization based on fatigue results

Jeffrey Mentley

Questions?

HBM - nCode 26555 Evergreen Road, Ste. 700 Southfield, MI 48076

(248) 945-4368 phone (248) 225-6844 cell jeff.mentley@hbm.com www.hbm.com/ncode