Working Model - MAELabs UCSD

WM52ProductGuide.fm Page 14 Tuesday, March 2, 2004 12:04 PM
14
Figure 6-3
Dialog Provided by Flexbeam
1. Select the rectangular body within your Working Model document
which is to be modeled as a flexible beam.
2. Choose Flexbeam from the Script menu.
3. Enter the values for the structural stiffness of the beam (EI) and the
number of elements (n) with which to model the beam.
The structural stiffness can be chosen through either the highly stiff, minimally stiff,
or custom option. The highly stiff and minimally stiff options provide a specified
deflection for a load based on the weight of the beam. The highly stiff option specifies
roughly a 3% deflection, while the minimally stiff option specifies roughly a
10% deflection.
The first input quantity, the structural stiffness, is the product of E, Young’s modulus
of elasticity, and I, the area moment of inertia. I is a geometric property of the cross
section of the beam and it is given by the equation:
∫∫
I y 2 = dA
where dA is a differential element of area and y is the distance of dA from the centroid
axis (see Figure 6-4 for an example). Working Model is unable to calculate I because
it simulates in the xy plane, while the beam cross section lies on the yz plane.