PROBLEM: Composite Optimisation

Hi,

 

I am trying to do the second phase of the composite optimisation process - the sizing part.

 

However, I get the following error : 'invalid design parameters for w.r.t' 

 

I realise that if I change my laminate properties from 'Smear' to 'Total' it works. However, I am not sure if this is correct. 

 

Also, if I add a buckling load, neither of these work.

 

Can you help me? it is urgent.

 

I have attached the FEM file with the issue

 

Best Regards,

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