Tensile Test

Were the data taken while unloading consistent with those taken while loading? Explain.

What was the strain when the specimen was totally unloaded at the end of the experiment? Is this

what you expected? Explain.

What happens on the interatomic level both the direction parallel to and perpendicular to the

direction of loading when a material experiences elastic deformation?

Based on macroscopic properties. why is Poisson's ratio always positive?

Use your values of the elastic modulus and Poisson's ratio $($experimental values$)$ to calculate the

fractional change in volume experienced by the gage section of your specimen on being stressed from

zero to the maximum applied stress.

Show that the circumferential strain measured by a transverse gage on a round bar is the same as the

radial strain. Explain why this is consistent with our definition of Poisson's ratio equal to the ratio of

perpendicular strain to parallel strain.

The strain indicators read in units of microstrain $(10-6).$ If a strain gage with a resistance of $120$

ohms is used and the gage factor is $2\mathrm{.}175,$ what resistance change corresponds to a strain of $250$

$(250$ x $10-6)?$

Describe a$.$ situation or project in which you would want to measure strain. Would strain gages be

needed. or can you think of another way to measure strain? Clearly explain.

Cantilever Beam

Is the measured strain dependent on the distance from the load? Explain $($HINT: Referencing your

strain values along the length of the beam can help here$).$

Is the measured strain dependent on the position across the width of the beam? $($Is the strain

significantly different if measured at the edges $($sides$)$ v$.$ the middle of the top of the beam?$)$ Explain.

How do the strains measured on the top and bottom of the beam correspond to each other? Explain.

What is the strain on the unconstrained end of the beam when only the intermediate load is applied?

Is this what you expected? Explain.

Explain superposition of strains. Why is superposition important? Judging from your experimental

data would you say that it is a useful tool? $($Attach your completed tables$)$

Describe a real system that uses a cantilever beam as a component Which part of the beam

experiences the most deformation? Explain. What is done to compensate? Why?