When your school/university reject it because it is impossible to fabricate, I think the answer is quite obvious, ain't it? Simulation is your closest approach if you seriously want to do it.

The strength of nanotube come largely from the architecture and configuration of the structure. What you can do, is to scale-up the model, using suitable material and measurable strength, flexibility, with matching property (which is properly scale) to appropriately describe your scale-up model. Then formulate the factor of the strength of your model against actual nanotube, you may need to quote from journal etc.

Do a simulation model of the original nanotube and scale up model, to verify that your emperical formula is within the tolerance.

You will also need to construct a scale model of a common molecular structure/model as your reference model when you do your testing/experiment.