The present invention relates to a computer-aided process for carrying out the structural design of a stiffened panel (9) made of a composite material, optimizing a target variable, comprising a first preparation phase (21) in which a Simulation Model (25) of the stiffened panel (9) with all the relevant information for the structural analysis thereof is obtained from a General Finite Element Model (23) and the modifiable variables and the restrictions (27) are defined, and a second simulation phase (51) in which the design variables are iteratively modified for the purpose of optimizing the target variable, taking into account in each iteration the load distribution changes resulting from the previous iteration, and verifying that the restrictive conditions and the safety margins associated to the pre-established failure modes are met using for that purpose simulation expert modules (55) of families of failure modes.