Stress and Strain

Question 1

What is the formula for Stress?

Answer 1

Question 2

What is the formula for Strain?

Answer 2

Question 3

What does this symbol represent?

Answer 3

The stress placed on an object

Question 4

What does this symbol represent?

Answer 4

The force placed on the object.

Question 5

What does this symbol represent?

Answer 5

The cross sectional area of the specimen. (m^2)

Question 6

what does a stress strain diagram look like? Where are the elastic limits, yield point, UTS and failure/ Breaking stress

Answer 6

look at the graph

Question 7

When the Material is in the Elastic zone, does the material return back to its original shape and size?

Answer 7

Yes.

Question 8

How would you identify the proportional limit?

Answer 8

The point at the end of the elastic zone, where it meets the start of the plastic zone.

Question 9

What does this symbol represent?

Answer 9

The strain placed on an object

Question 10

What does this symbol represent?

Answer 10

The extension of the object. (How much it has changed in length)

Question 11

What does this symbol represent?

Answer 11

The original length of the object.

Question 12

What does this stress strain graph represent?

Answer 12

This graph represents an object with High Strength but is brittle. Shown by a straight line that climbs high up the stress axis. Very little strain means low ductility.

This could be a material like glass

Question 13

What does this stress strain graph represent?

Answer 13

This graph represents a material with high strength yet not brittle. The curled top shows the slightly higher ductility.

This could be a material like a metal alloy.

Question 14

What does this stress strain graph represent?

Answer 14

This graph represents a material with low strength but high ductility. This is shown through the large amount of strain.

This could be a material like plastic

Question 15

What does this stress strain graph represent?

Answer 15

This graph represents a material with moderate strength and high strain indicating toughness. Toughness being measured from the area under the curve.

This could be a material like mild steel.

Question 16

There is a law called hooke’s law, what does this relate to in a graph.

Answer 16

The Linear part of the graph, in materials that contain a linear line at the beginning

Question 17

Where is the breaking point in a stress strain graph

Answer 17

at the end.

Question 18

What is Ultimate Tensile strength?

Answer 18

It means the maximum stress an object can take before it can no longer take anymore load.

Question 19

What is Proof Stress?

Answer 19

Proof stress of a material can be defined as the stress at which the material undergoes plastic deformation.

Question 20

What is Young’s Modulus?

Answer 20

A measure of the stiffness of a material. It quantifies the ability of a material to resist deformation under an applied force. It is represented by the symbol E and it’s units is in pascals.

Question 21

how can we see where the Ultimate Tensile Strength on a stress strain graph?

Answer 21

it can be seen at the highest point of the graph.

Question 22

What is a another unit for Newton meters squared. N/m^2

Answer 22

Pa. Pressure

Question 23

what is Ductility?

Answer 23

Ductility is how much plastic deformation it will undergo before fracture.

Question 24

Yield points are?

Answer 24

These points are a marked increase in strain without in an increase in stress.

Question 25

How is a material determined to be brittle?

Answer 25

if the material does not undergo plastic deformation.

plastic deformation is when a material is stretched and doesn’t go back to shape.

Question 26

What happens when a material reaches the plastic region

Answer 26

It deforms to point that it will not go back to the original shape or size.

Question 27

What happens to the material when it reaches the point of necking down on a stress strain graph?

Answer 27

The material undergoes localized deformation where the pressure is being exerted before reaching the breaking point.

Question 28

What is toughness?

Answer 28

Toughness is a measure of a material’s ability to absorb energy and deform plastically before fracturing. It represents the amount of work required to break a material. Toughness is usually measured by the area under the stress-strain curve of a material up to the point of fracture.

Question 29

What is resilience?

Answer 29

Resilience is the ability of a material to absorb and store elastic energy when deformed and then release it upon unloading. It is a measure of a material’s capacity to withstand impact or sudden loading without undergoing permanent deformation or fracture.

Question 30

What is Elastic limit

Answer 30

Elastic Limit is the maximum stress a material can withstand without undergoing permanent deformation. It is the point at which the material reaches its limit of elasticity, meaning it can return to its original shape once the applied stress is removed.

Question 31

What is work hardening on a stress strain graph?

Answer 31

The section of the graph when the material slips and dislocates, resulting in a strengthening of the material, with a decrease of ductility.

Question 32

What is uniform extension

Answer 32

That the material is stretching an even amount its length.

Question 33

What is uniform extension

Answer 33

That the material is stretching an even amount its length.