A New Methodology for Systematic Conceptual Design

by means ofGeneralized Discrete

Representations

Research group conducted by Dr. Offer Shai

Department of Mechanics, Materials and Systems

Faculty of Engineering

Tel-Aviv University

The methodology developed in this research group offers a

mathematical apparatus enabling engineers to systematically come up with new designs by drawing them from completely different

engineering fields.In this presentation you will see this ability

through a very simple example

In this presentation you will see a demonstration of applying our design methodology for solving the

following design problem:

The force acting upon the system is alternating, while the internal spring should sustain forces of type compression only. Design the system that will satisfy this constraint.

Our approach makes possible to detect a system in completely different engineering domain – that upon transformation will yield a system satisfying given design requirements. Such a transformation is demonstrated in this presentation.

Fin

Fout

Example of transforming electrical circuit to a new mechanical device

A

B C

D

Bridge rectifier circuit

Stage 1: constructing the graph representation of the electronic circuit.

The representation is built in accordance with the structure and other properties of the engineering system.

A

B C

D

B

A

D

C

Example of transforming electrical circuit to a new mechanical device

Stage 2: Constructing a new mechanical system from the representation. The same representation can be interpreted as a representation of an

engineering system from some other engineering domain. In this example you will see how a mechanical system is constructed from the graph.

Cable

Strut

A

B C

D

B

A

D

C

Example of transforming electrical circuit to a new mechanical device

Stage 2: Constructing a new mechanical system from the representation. The same representation can be interpreted as a representation of an

engineering system from some other engineering domain. In this example you will see how a mechanical system is constructed from the graph.

Cable

Strut

As you have noticed, till now we have not used any analysis operations. We just

transformed the structure of the system from one domain to the other through the

common representation.

Since both systems are represented by the same graph representation, there should

be correspondence between their behaviors. We shall now check this hypothesis through simulation of both

systems

Verifying the correspondence in behavior between the two engineering systems.

IinFin

Fout

Iout

Behavioral mode 1:In mechanical system: Fin>0, Fout>0

In electronic circuit: Iin>0, Iout>0

Verifying the correspondence in behavior between the two engineering systems.

Iin

Iout

Fin

Fout

Behavioral mode 1:In mechanical system: Fin>0, Fout>0

In electronic circuit: Iin>0, Iout>0

Verifying the correspondence in behavior between the two engineering systems.

Iin

Iout

Fin

Fout

Behavioral mode 1:In mechanical system: Fin>0, Fout>0

In electronic circuit: Iin>0, Iout>0

Verifying the correspondence in behavior between the two engineering systems.

Iin

Iout

Fin

Fout

Behavioral mode 1:In mechanical system: Fin>0, Fout>0

In electronic circuit: Iin>0, Iout>0

Verifying the correspondence in behavior between the two engineering systems.

Fin

Behavioral mode 2:In mechanical system: Fin<0, Fout>0

In electronic circuit: Iin<0, Iout>0

Verifying the correspondence in behavior between the two engineering systems.

Fout

Iin

Iout

Iin

Iout

Fin

Fout

Behavioral mode 2:In mechanical system: Fin<0, Fout>0

In electronic circuit: Iin<0, Iout>0

Verifying the correspondence in behavior between the two engineering systems.

Fin

Fout

Behavioral mode 2:In mechanical system: Fin<0, Fout>0

In electronic circuit: Iin<0, Iout>0

Verifying the correspondence in behavior between the two engineering systems.

Iin

Iout

Fin

Fout

Behavioral mode 2:In mechanical system: Fin<0, Fout>0

In electronic circuit: Iin<0, Iout>0

Verifying the correspondence in behavior between the two engineering systems.

Iin

Iout

Verifying the correspondence in behavior between the two engineering systems.

Conclusion: in the resulting mechanical system - the force in the output element (spring) is positive (compression) no matter the direction of the

Input force. Thus the behavior is the same as in the diode bridge circuit, where the current through the output element (resistor) is always positive - no matter the

input current

The methodology developed in this research group has been applied to develop a series of

new devices. You are going to see now only a number of such

devices.

Some of the devices developed through the approach

in

in

out

1

2

3

4

A

A’

O B