WOLFRAM|DEMONSTRATIONS PROJECT

Estimating Cohesion and Tensile Strength of Compacted Powders

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normal and shear stress scales
σ: -5. to 10. and τ: 0. to 10.
Warren-Spring equation parameters
C
2.
T
1.5
n
1.5
YLC points
number of points
3
4
5
6
7
8
σ
1
8.
τ
1
7.
σ
2
8.
τ
2
6.7
σ
3
6.
τ
3
6.
σ
4
6.
τ
4
5.7
σ
5
4.
τ
5
5.
σ
6
4.
τ
6
4.5
σ
7
2.
τ
7
3.8
σ
8
2.
τ
8
3.2
Warren-Spring equation rounded parameters
C = 2.00
T = 1.50
n = 1.50
MSE = 0.0359
The flowability of a cohesive powder is determined by shearing specimens compacted and tested under various compressive loads. The resulting family of yield shear stress versus the compressive normal stress relationships, known as the yield loci curves (YLCs), is used to calculate the principal stresses from which the flow function of the powder is constructed.
Individual YLCs have been frequently described by the Warren–Spring equation, whose parameters are cohesion
C
, tensile strength
T
and curvature index
n
. These three parameters can be estimated using Mathematica's Manipulate function by matching three or more experimental shear stress-normal stress data points with a YLC generated using the Warren–Spring equation as a model.