SaM - Load Cells or Pillar

Remeber:

• A Load Cell or Pillar is just a piece of material that gets deformed by a force, if we measure the deformation we can calculate the force applied or strain and vice-versa.
• However to do this calculation need to know the Young and Poisson modulus of the load cell, then we can just apply an inverse formula.
  ~ Here’s an Example:${\epsilon }_l=\frac{F}{E\cdot A}$Where:
  • ${\epsilon }_l$ : is the longitudinal strain. (defined later)
  • $F$ : is the force.
  • $E$ : is the Young modulus.
  • $A$ is the surface area.

• Here is a simple scheme for a laod cell:
  
  We define:
  • lonngitudinal strain: ${\epsilon }_l=\frac{\Delta l}{l}$.
  • transverse strain ${\epsilon }_T=\frac{\Delta w}{w}$.

• As said at the beginning we need to know the Young and/or Poisson Modulus of the load cell, so for example if we take a platinum load cell, we have that:
  • Young’s Modulus (E): $E_{Pt}\approx 168\text{GPa}$
  • Poisson’s Ratio ($\nu$): ${\nu }_{Pt}\approx 0.38$IMPORTANTE

• Also the load cell can give us a differential output:IMPORTANTE
  
  • $\nu$ is the Poisson Modulus.
  • We can take advantage of a differential output using a Differential Amplifier.

Here some other material:

• Youtube ‘What is a load cell and how does it work? Explained’

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