# Transcript

Narrator

The material of the tub has complicating features. This is due to the directional nature of the plies of carbon fibre set in the material matrix. In addition to this, the plies themselves can be orientated in layers, each layer direction being different

And there is a core material in the centre of the sandwich, having its own set of properties. So instead of entering just a couple of numbers, the orientations and numbers of plies have to be entered and the analysis package will determine the overall stiffness of the laminate, including the core.

Notice the use of symmetry in the model. Only half the tub was modelled. This can save a lot of time and computing resource -- not just the 50% of the missing piece.

If we double the size of a model, it is likely to increase the solver time by something like 10 times. Larger models might not even solve at all. So, using such symmetry shortcuts is a valuable saving. The only complication is the anti-symmetry boundary condition on the cut face. We’ll say a bit more about that during the next step.