How is normal stress measured in biological tissues?

AI Thread Summary
Normal stress in biological tissues is measured by calculating the force applied to the tissue divided by the area over which it is applied, expressed as σ = F/A. For practical applications, such as designing a tool to measure stress in skin, one must consider the tissue's elasticity and deformation, represented by the equation σ = EδD, where E is the modulus of elasticity and D is the deformation. The challenge lies in creating a device that can accurately assess these parameters in real-time conditions, such as skin stretching during weight changes. The discussion emphasizes the need for innovative design while acknowledging the complexity of measuring stress in biological materials. Understanding these principles is crucial for developing effective measurement tools.
chusifer
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ok...my engineering professor just gave us this crazy homework problem. he wants use to design a tool to measure the normal stress in a biological tissue. now it doesn't have to be extremely detailed in any way, but...we don't 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 is...how does a tool measure normal stress?
 
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isn't that the question you're supposed to answer?
 
Measure the force. Measure the area. Divide the two.
 
well I am suppose to...design some type of tool specific to a certain condition dealing with the body. I am not really asking the specifics, I am more just asking how does any device...like a scale, measure the normal stress?
 
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?
 
Well Stress is defined as

\sigma = E \delta D

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

Also
\sigma = \frac{F}{A}

Do like enigma said.
 
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