Environmental variables in the cost function of RBDO

Hi UQ community,

First of all, I’d like to thank UQLab developers for such an useful toolbox.

As stated in the title, I have some doubts regarding the cost function in the RBDO.

Particularly, I’m facing the RBDO of a laminated composite plate. The limit state function involves the failure due to buckling of the structure, and the cost function is the structural weight of the plate.

The variables involved are:

Two fibre orientations, the thickness of the laminae and the fibre volume fraction (which affects the longitudinal, transverse and shear moduli, Poisson’s ratios and density of the material). Its input definition is available in the enclosed image.


The four mentioned variables affect the limit state function, whilst the cost function is influenced by the thickness and fibre volume fraction. However, I am considering the latter as an environmental variable since it is affected by the manufacturing processes.

May you have any suggestion on how to solve this issue? Or should I be treating fibre volume fraction as a design variable?

Thank you for your comments,