Towards an Automated Optimization of Laminated Composite Structures: Hierarchical Zoning Approach with Exact Blending Rules

Abstract

We present an automated methodology to optimize laminated composite structures. Our approach, inspired by bi-level optimization scheme, avoids its prime deficiencies and is based on developed computationally inexpensive stacking sequences reconstruction algorithm, which identically satisfies conventional set of blending rules. We combine it with proposed tight approximation to feasible domain of composite integral parameters and hierarchical zoning procedure to get highly efficient optimization methodology, which we test in two example applications. In both cases it is shown that blending rules compliant optimal solution remains within 10% gap from one with no rules applied.

On the Double-Double Laminate Buckling Optimum for the 18-Panel ‘Horse-Shoe’ Reference Case

“…The table focuses on the data of the second analysis step, in which all 18 panels are considered simultaneously, as it refers to the technically relevant scenario of the blended panel. One can see that the additional constraints, considered by Shvarts and Gubarev [12], lead to the highest panel mass.…”

“…The outlined procedure is hereafter applied to the 18-panel 'horse-shoe' use case, which has been intensively investigated by multiple researcher groups [4][5][6][7][8][9][10][11][12][13], which all focus on blending of conventional, non-DD laminates.…”

“…Table 2 provides an overview of the deviating aspects between the studies and outlines the related consequences. The laminate constraints considered by Shvarts and Gubarev [12], in particular the limitation to 0 • , ±45 • , 90 • plies combined with both the symmetry and the balance requirement, are close to aerospace standards, such as, for example, shown in context of CFRP frame components [22,23]. In fact, the widely used notation [% 0 • , % ±45 • , % 90 • ] represents another indicator for the relevance of the ply orientation selection.…”

“…Figure 2 shows the use case, which is explained in detail in Section 2. Multiple researcher groups [5][6][7][8][9][10][11][12][13]] use Soremekun's example as a reference and provide individual optimal stackings and corresponding minimal masses for blended panels. All those studies focus on more conventional ply orientations, with plies aligned in [0 ], and symmetric laminate architecture (even or odd symmetry).…”