# Stress And Strain Powerpoint

Stress And Strain Powepoint

- Created by: Thomas
- Created on: 04-11-12 09:12

## Slides in this set

### Slide 1

*

Deformation of Solids

You be able to:

(a) appreciate that deformation is caused by a pair of forces

and that, in one dimension, the deformation can be tensile or

compressive.

(b) describe the behaviour of springs and wires in terms of

load, extension, Hooke's law and the spring constant.

(c) define and use the terms elastic limit, stress, strain and

the Young modulus.

(d) describe an experiment to determine the Young modulus of

a metal in the form of a wire.

(e) distinguish between elastic and plastic deformation of a

material.

(f) deduce the strain energy in a deformed material from the

area under the force-extension graph.

(g) demonstrate knowledge of the force-extension graphs for

typical ductile, brittle and polymeric materials, including an

understanding of ultimate tensile stress.…read more

### Slide 2

Graphs

· The gradient of a stress/strain curve

will give you the Young Modulus

· The graphs look a bit odd at first

because the x and y axes have

swapped over from how they were

lower down the school…read more

### Slide 3

Stress-Strain Curves

Stress-strain graphs are really a development of force-

extension graphs, simply taking into account the factors

needed to ensure a fair test. A typical stress-strain graph

looks like this:…read more

### Slide 4

We can describe the details of the

graph as:

P is the limit of proportionality,

where the linear relationship

between stress and strain

finishes.

E is the elastic limit. Below the

elastic limit, the wire will return

to its original shape.

·Y is the yield point, where plastic deformation begins. A large

increase in strain is seen for a small increase in stress.

·UTS is the ultimate tensile stress, the maximum stress that is

applied to a wire without its snapping. It is sometimes called the

breaking stress. Notice that beyond the UTS, the force required

to snap the wire is less.

·S is the point where the wire snaps.…read more

### Slide 5

We can draw stress-strain graphs of

materials that show other properties.

Curve A shows a brittle material. This

material is also strong because there is

little strain for a high stress. The

fracture of a brittle material is sudden

and catastrophic, with little or no plastic

deformation. Brittle materials crack

under tension and the stress increases

around the cracks. Cracks propagate less

under compression.

·Curve B is a strong material which is not ductile. Steel wires

stretch very little, and break suddenly. There can be a lot of elastic

strain energy in a steel wire under tension and it will "whiplash" if it

breaks. The ends are razor sharp and such a failure is very

dangerous indeed.

·Curve C is a ductile material

·Curve D is a plastic material. Notice a very large strain for a small

stress. The material will not go back to its original length.…read more

### Slide 6

Brittle material breaks here.

Ductile material stretches

Stress / permanently beyond its elastic

Pa limit.

Release of stress.

If a material is stiff,

it produces little

strain so will have a

(0,0) steeper gradient.

Strain

Permanent Deformation.…read more

### Slide 7

### Slide 8

### Slide 9

### Slide 10

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## Similar Physics resources:

# Stress And Strain Powerpoint

Stress And Strain Powepoint

- Created by: Thomas
- Created on: 04-11-12 09:12

## Slides in this set

### Slide 1

*

Deformation of Solids

You be able to:

(a) appreciate that deformation is caused by a pair of forces

and that, in one dimension, the deformation can be tensile or

compressive.

(b) describe the behaviour of springs and wires in terms of

load, extension, Hooke's law and the spring constant.

(c) define and use the terms elastic limit, stress, strain and

the Young modulus.

(d) describe an experiment to determine the Young modulus of

a metal in the form of a wire.

(e) distinguish between elastic and plastic deformation of a

material.

(f) deduce the strain energy in a deformed material from the

area under the force-extension graph.

(g) demonstrate knowledge of the force-extension graphs for

typical ductile, brittle and polymeric materials, including an

understanding of ultimate tensile stress.…read more

### Slide 2

Graphs

· The gradient of a stress/strain curve

will give you the Young Modulus

· The graphs look a bit odd at first

because the x and y axes have

swapped over from how they were

lower down the school…read more

### Slide 3

Stress-Strain Curves

Stress-strain graphs are really a development of force-

extension graphs, simply taking into account the factors

needed to ensure a fair test. A typical stress-strain graph

looks like this:…read more

### Slide 4

We can describe the details of the

graph as:

P is the limit of proportionality,

where the linear relationship

between stress and strain

finishes.

E is the elastic limit. Below the

elastic limit, the wire will return

to its original shape.

·Y is the yield point, where plastic deformation begins. A large

increase in strain is seen for a small increase in stress.

·UTS is the ultimate tensile stress, the maximum stress that is

applied to a wire without its snapping. It is sometimes called the

breaking stress. Notice that beyond the UTS, the force required

to snap the wire is less.

·S is the point where the wire snaps.…read more

### Slide 5

We can draw stress-strain graphs of

materials that show other properties.

Curve A shows a brittle material. This

material is also strong because there is

little strain for a high stress. The

fracture of a brittle material is sudden

and catastrophic, with little or no plastic

deformation. Brittle materials crack

under tension and the stress increases

around the cracks. Cracks propagate less

under compression.

·Curve B is a strong material which is not ductile. Steel wires

stretch very little, and break suddenly. There can be a lot of elastic

strain energy in a steel wire under tension and it will "whiplash" if it

breaks. The ends are razor sharp and such a failure is very

dangerous indeed.

·Curve C is a ductile material

·Curve D is a plastic material. Notice a very large strain for a small

stress. The material will not go back to its original length.…read more

### Slide 6

Brittle material breaks here.

Ductile material stretches

Stress / permanently beyond its elastic

Pa limit.

Release of stress.

If a material is stiff,

it produces little

strain so will have a

(0,0) steeper gradient.

Strain

Permanent Deformation.…read more

### Slide 7

### Slide 8

### Slide 9

### Slide 10

## Comments

No comments have yet been made

## Similar Physics resources:

## Related discussions on The Student Room

- AQA A Psychology AS PSYA1 PSYA2 June 2013 »
- AS Psychology AQA PSYA1/2 Revision Thread 2015! »
- Edexcel 6PH01 ~ 20th May 2013 ~ AS Physics »
- The "Am I good enough for Investment Banking/Consultancy?" ... »
- The 2013 Tripos Exam Chat Thread! (Cambridge students ... »
- Open University Chat Thread »
- GOGSoc Episode VII: Game of Moans »
- TSR Med Students' Society Part VI »
- Warwick Maths Chat »
- University Transfer FAQ »

## Comments

No comments have yet been made