Tensile Strength and Testing

Question 1

What is stress and how can we calculate it?

Answer 1

Stress is the internal resistance of a material to an externally applied load. We can calculate stress by taking a load and dividing it by the cross sectional area of the material.

Question 2

What are the 2 ways to decrease stress?

Answer 2

1) Increase the cross sectional area
2) Decrease the load

Question 3

What material properties can be determined from a tensile test?

Answer 3

1) Yield strength
2) Ductility
3) Toughness
4) Stiffness
5) Ultimate Tensile Strength

Question 4

What is strain?

Answer 4

Amount of stretching/deformation that occurs due to an applied load

Question 5

When is the yield point reached?

Answer 5

Stress at which the material shows an increase in strain without an increase in stress

Question 6

What is ultimate tensile strength?

Answer 6

Maximum stress that a material can develop while maintaining its original cross sectional area

Question 7

What is elastic deformation?

Answer 7

Strain that is recoverable upon removing the stress

Question 8

What is plastic deformation?

Answer 8

Strain that is not recoverable upon removing the stress

Question 9

What is ductility?

Answer 9

A property which enables the material to undergo a permanent deformation without failure

Question 10

A material is put through a tensile test and does not show a distinct yield stress on the graph. What can be done to determine the yield strength of that material?

Answer 10

If no distinct yield is shown 0.2% offset is used based on the modulus of Elasticity

Question 11

What are the 2 ways ductility can be measured?

Answer 11

1) % Elongation: (Lf - Lo)/Lo * 100%
2) % Reduction of Area: (Af - Ao)/Ao * 100%