How to measure normal stress?

by chusifer
Tags: measure, normal, stress
chusifer is offline
Oct23-04, 04:34 PM
P: 7 engineering professor just gave us this crazy hw problem. he wants use to design a tool to measure the normal stress in a biological tissue. now it doesnt have to be extremely detailed in any way, but...we dont even know how normal stress is measured. the problem asks for it to measure 1000 dyn/cm^2 up to 1,000,000 dyn/cm^2. now...this is obviously impossible, and he said that. he just wants us to think about the design.

so my question does a tool measure normal stress?
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photon_mass is offline
Oct23-04, 05:12 PM
P: 29
isn't that the question you're supposed to answer?
enigma is offline
Oct23-04, 05:28 PM
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P: 1,817
Measure the force. Measure the area. Divide the two.

chusifer is offline
Oct23-04, 06:36 PM
P: 7

How to measure normal stress?

well im suppose some type of tool specific to a certain condition dealing with the body. im not really asking the specifics, im more just asking how does any a scale, measure the normal stress?
photon_mass is offline
Oct23-04, 07:01 PM
P: 29
like how enigma said.
skin on a body is stretched. every seen before and after pictures of a very fat person before and after lipo? skin is stretched over the body. because it is stretched it subject to a restoring force. this is proportional to the amount your skin is stretched(clearly). how would you find out how much the skin is stretched on your body when it is still on your body?
Pyrrhus is offline
Oct23-04, 07:17 PM
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P: 2,280
Well Stress is defined as

[tex] \sigma = E \delta D [/tex]

where E is the modulus of elasticity of the body, and D is the deformation.

[tex] \sigma = \frac{F}{A} [/tex]

Do like enigma said.

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