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Research activitiesE. Nikolaidis

B. Ramaswamy

B. Dheenadayalan

A. Keerti

S. Mathew

P. Soundappan

D. Tiwary

Vibration and Reliability Lab

Friday, April 20, 2001

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Overview

1.Design under uncertainty

2. Structural dynamics

3. Knowledge-based design tools

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Design under uncertaintyNoiselevel (db)

Cost ($)

Design concept 1

Design concept 2

Design concept 3

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Profit is uncertain and depends on selection of design concept

Profit ($)

Probability density of profit

0Loss

Which design is better ?

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Goals

• Study and understand advantages and limitations of methods for modeling uncertainty (classical probability, Bayesian probability, fuzzy sets, imprecise probabilities)

• Study methods for modeling a decision-maker’s preferences and attitude toward risk

• Address issues of lack of data and high computational cost

• Develop tools for making design decisions under uncertainty by combining the above methods

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2. Structural Dynamics; Modeling and suppressing internal resonances in

vibration isolators

Front of the car

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Transmissibility of real isolator

1

Transmissibility

1

System resonance, n

Isolator Resonances

n

Actual

Ideal

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Using DVA’s to suppress internal resonances

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Global Vehicle Model

Global OptimizerGlobal design variables

Local models

Load and stiffness requirements for components

Optimal safety factor of components

Knowledge-based design tools; considering details upfront in design

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Traditional design optimization versus local/global optimization

6000

6500

7000

7500

8000

8500

9000

wei

gh

t (l

b)

nominal

no global/local

global/local

100 84 85

infeasible feasible