Lecture 34: Designing Hybrid Materials

Jayant Jain Assistant Professor,

Department of Applied Mechanics, IIT Delhi, Hauz Khas, 110016

So far we have looked into the materials available to us: Materials selection including shape and process, complex problems, simple problems

As an engineer, think of creating materials: Improving material can help you only a bit but Creating material can help you a lot Gives more options, there is no limit to that

This is where the idea of hybrid materials comes

Significant areas in property map is empty: holes in materials property space

Extending Materials Property Space

Zero expansion material

What are hybrid materials?? Hybrid materials combine the properties of two (or more) monolithic materials, or of one material and space. They include fibrous and particulate composites, foams and lattices, sandwiches, and almost all natural materials.

Hybrid Materials: Man made materials

After combining materials think of hybrid as a material in its ownthink about their effective properties and then plotting them on the chart

What are going to be key ingredients of the hybrid design??

Special requirements on this front then think of creating these materials

Function will help in deciding the configuration

Our task would be is to make hybrid materials also eligible for selection In other words we should be able to estimate their effective properties and plot them on the chart

What might we hope to achieve??

Where would you end up depends on: Ingredients of hybrid design

A: Zinc coated steel,

B: fiber reinforced composites: rule of mixture

C: gains are less spectacular, particulate

composites

D: Fire sprinkler: metal-wax system

Hybrid Design

If the design requirements are

exceptionally demanding, no single

material may be found that can meet

them all:

Identify and

separate the

conflicting

requirements

Example

Materials for long-span power cables

The objectives are to minimize the electrical resistance, but at the same time to maximize the strength since this allows the greatest span

All materials lie above broken Trade-off line