Question

Comparison between the four different materials(steel, copper,brass and Aluminum):

a. Which material has the greatest tensile strength? How did you measure that?

b.Which material has the highest yield strength?

c. Which material the greatest modulus of elasticity? How did you measure that?

d. Which material has the highest resilience? How did you measure that?

e. Which material has the highest toughness? How did you measure that?

f. Which material the stiffest one? How did you measure that?

g. Which material the most brittle one? How did you measure that?

h. Which material the most Ductile one? How did you measure that?

i. Which one of the four materials has the best mechanical properties?

Answer 1

a) Steel has the greatest tensile test.Tensile test carried out on a universal testing machine.The test process involves placing the test specimen in the testing machine and slowly extending it until it fractures.During this process, the elongation of the gauge section is recorded against the applied force. The data is manipulated so that it is not specific to the geometry of the test sample.The elongation measurement is used to calculate the engineering strain, ?, using the following equation

where ?L is the change in gauge length, L₀ is the initial gauge length, and L is the final length. The force measurement is used to calculate the engineering stress, ?, using the following equation

where F is the tensile force and A is the nominal cross-section of the specimen. so we can calucate the force F ,that is tensile strength.

b) steel has the highest yield strength.

c) steel has the highest modulus of elasticity.Modulus of Elasticity is a measurement of the rate of change of strain as a function of stress. It represents the slope of the straight-line portion of a stress-strain curve. With respect to tensile testing.

d)steel has the highest resilence.Resilience is the ability of a material to absorb energy when it is deformed elastically, and release that energy upon unloading.It is area under sress strain diagram upto elastic limit.

e)mild steel carbon has the highest toughness.It is area undes stress strain diagram upto fracuture point.

f) steel is a stiffest one. Stiffness is the rigidity of an object , the extent to which it resists deformation in response to an applied force.

g) steel is most brittle one. A material is brittle if, when subjected to stress, it breaks without significant plastic deformation.we can measure on a universal testing maachine.

h)Aluminium is the most Ductile one. Ductility is defined as the ability of a material to deform plastically before fracturing.which may be expressed as percent elongation or percent area reduction from a tensile test.

i)steel has the best mechanical properties.