Exercises - Lesson 9

Exercises

Exercise 1:

a) Using a single one-dimensional beam element with cubic displacement interpolation (e.g. ANSYS Beam188 element), re-perform the analysis for the tip-loaded cantilever beam in the tutorial. What do you notice? How do these one-dimensional FEA predictions for tip deflection and normal stress at the wall compare with those values predicted by the full three-dimensional model?

b)  Refine the mesh over the entire span of the I-Beam mesh in (a). How does the mesh refinement affect the FEA predictions for the tip deflection and normal stress at the wall? What conclusion might you draw from this exercise?

Exercise 2:

Recall in the tutorial that the tip load was distributed over the web of the beam only. Why might this specific choice for the loading have been chosen?

Exercise 3:

Re-perform the three-dimensional analysis in the tutorial using the following two prescriptions for the tip loading:

a) a distributed line load along the neutral axis (effectively a point tip load).

b) a uniformly distributed shear stress applied on the full area of the cross-section, i.e. including the I-Beam flanges.

In each case, what are the effects on the predictions for tip deflection and normal stress at the wall?