In the library, the elasticity property of a pole is derived from the given modulus of rupture (MOR) and section modulus.
Where MOR is related to the pole’s material (e.g. wood or metal) and
The section modulus is related to the geometric properties of a pole’s section e.g. cross-section shape
In practice, a pole’s material and cross-section shape may be different from the preset values in our library. As a result, under a given force, the physical pole will bend more or less than the simulation result using these default values.
To resolve this, the Stiffness Multiplier Widget allows you to correct the elasticity property by biaxial multipliers to user selected pole types: applying a multiplier larger than 1.0 will make the pole stiffer, vice versa. The multipliers could be either specified by a custom value or derived from real bending test results using point load force and displacement on the pole.
This is demonstrated in the following example, where the right pole has had a stiffness multiplier of 0.2 applied to it and thus bends more than the unmodified pole due to being less stiff.
For a circular pole, the stiffness multiplier is always set to 1.0 and for non-circular poles, it can only be derived from a point load on the tip of the pole and the maximum displacement on the pole
Using the widget
Open your design and click Library -> Poles.
Find the pole that needs to be corrected (ensure it is not a circular pole), find the column Stiffness Multiplier X or Stiffness Multiplier Y and click its value.
Note that if Stiffness Multiplier X and Stiffness Multiplier Y do not appear, click the ‘+’ icon at the right of a column, and find stiffness_multiplier_x or stiffness_multiplier_y.
The Stiffness Multiplier Widget will pop up. The stiffness multiplier can be specified either by a custom value or a derived value from bending test results.
This result can either be saved by using the Save button for a custom value, or if generating a derived result, Apply and Save the derived value.
The stiffness multiplier will be applied when calculating the elastic properties of the pole.
Note that the stiffness multiplier about the Y axis is derived from force and displacement in the X axis and vice versa.
