Update Regression approach and Tolerance bands power law authored by Jamie Engelhardt Simon's avatar Jamie Engelhardt Simon
...@@ -2,8 +2,9 @@ ...@@ -2,8 +2,9 @@
title: Regression approach and Tolerance bands - power law title: Regression approach and Tolerance bands - power law
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## Dependency ## Dependency
It is assumed that the data can be described by a power law, expressed as Y or X-dependent (referring to the second and first axes on a fatigue curve). It is assumed that the data can be described by a power law, expressed as Y or X-dependent (referring to the second and first axes on a fatigue curve)
```math ```math
Y = CX^m \leftrightarrow X = \left(\frac{Y}{C}\right)^{\frac{1}{m}} Y = CX^m \leftrightarrow X = \left(\frac{Y}{C}\right)^{\frac{1}{m}}
...@@ -15,7 +16,7 @@ X = CY^m \leftrightarrow Y = \left(\frac{X}{C}\right)^{\frac{1}{m}} ...@@ -15,7 +16,7 @@ X = CY^m \leftrightarrow Y = \left(\frac{X}{C}\right)^{\frac{1}{m}}
Where $m$ and $C$ are the power slope- and adjustment coefficient, respectively. Where $m$ and $C$ are the power slope- and adjustment coefficient, respectively.
## Fitting procedure ## Fitting procedure
Using the power-law as a prediction function, the model can be fitted in log10-space as follows. Using the power-law as a prediction function, the model can be fitted in log10-space as follows
```math ```math
X_{\textrm{log}} = \textrm{log10}\left(X\right), \quad Y_{\textrm{log}} = \textrm{log10}\left(Y\right) X_{\textrm{log}} = \textrm{log10}\left(X\right), \quad Y_{\textrm{log}} = \textrm{log10}\left(Y\right)
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