Automation of Engineering Design Aids using Neural Networks

Siripong Malasri and Jittapong Malasri

Christian Brothers University

Kriangsiri MalasriGeorgia Tech

MAESC ’05 – May 13, 2005

Presentation Overview

• Introduction• Artificial Neural Networks• The Stress Concentration Problem• Software Development

Data preparation Network training and validation Standalone application development

• Conclusions and Future Work

Introduction

• Traditional design aids Look-up tables Graphical plots

• Shortcomings Inaccurate interpolation/extrapolation Difficult to smoothly integrate with

computer applications

Neural Networks• Have been used to recognize patterns

and project trends in data• Backpropagation model – can be trained

to generate desired input-output relationships

Stress Concentration (1)

• Objective Calculate the peak stress in a notched beam

cross-section subject to a bending moment

• Possible approaches Finite-element analysis Experimental procedures Determine a stress concentration factor

from a design aid

Stress Concentration (2)

• Stress concentration factor, C Function of the ratios a/h2 and h1/h2

• Peak stress at notch: M = bending moment applied I = cross-sectional moment of inertia c = distance from N.A.

I

McC

Software – Data Preparation• Training data obtained from a published

graphical design aid

1.0

1.2

1.4

1.6

1.8

2.0

2.2

2.4

2.6

2.8

3.0

0.00 0.05 0.10 0.15 0.20 0.25 0.30

a / h2

C

h1 / h2 = 2

h1 / h2 = 1.5

h1 / h2 = 1.1

• Inputs: a/h2 , h1/h2• Output: C• 46 training pairs,

15 calibration pairs, 15 validation pairs

Software – Network Training

• NeuroShell 2 software• Backpropagation network with 2 input neurons,

8 hidden neurons, and 1 output neuron• Excellent results from trained network

Software – Standalone Program

• Interface developed in Visual Basic

• Network code generated from NeuroShell 2

1.0

1.2

1.4

1.6

1.8

2.0

2.2

2.4

2.6

2.8

3.0

0.00 0.05 0.10 0.15 0.20 0.25 0.30

a / h2

C

h1 / h2 = 2

h1 / h2 = 1.5

h1 / h2 = 1.1

Conclusions and Future Work

• Excellent network estimates of the stress concentration factor for this particular application

• Standalone executable is portable to any Windows computer

• Future work: comprehensive stress analysis program with a variety of cross-sections