Load Cells in Bending
Some load cells are constructed to express output with respect to bending stress. When constructed with a full bridge it is common that two strain gages will be positioned for tension and two strain gages will be positioned for compression. These strain gages are frequently mounted on the outer walls of the load cell where the bending stress is greatest. The stress at the gages may be determined using the equation below.
σ = Stress (psi, Pa)
M = Moment (in-lb,mm-N)
c = Distance from lateral neutral axis to gage (in, mm)
I = Area moment of inertia (in 4, mm 4) |
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Load Cells in Shear
Some load cells are constructed to express output with respect to shear stress. When constructed with a full bridge it is common that two strain gages will be positioned for tension and two gages will be positioned for compression. The gages are frequently mounted in pockets on the neutral axis of the load cell where shear stress is greatest. The stress at the gages may be determined using the equation below.
τ = Shear Stress at Point of Interest (psi, Pa)
V = Shear (Lb, N)
A = Cross Sectional Area Between Point of Interest & Outer Wall (in 2, mm 2)
y = Distance from Neutral Axis to Centroid of A (in, mm)
I = Area Moment of Inertia (in 4, mm 4)
T = Width of Beam at Point of Interest (in, mm) |
