Stress-Aware Optimal Placement of Actuators for High Precision Quality Management in Composite Aircraft Assembly

Better quality management in manufacturing systems usually means preventing defects, reducing carbon emissions, and making systems greener. Modeling stress-induced processes is challenging and extremely critical in the quality management of advanced manufacturing systems. While residual stresses may be beneficial in some situations, in composite aircraft assembly, high residual stresses and extreme deformations are crucial and must be accounted for to prevent future catastrophic failures. Currently, conventional approaches to the optimal placement of actuators on composite structures are non-optimal, require ten actuators heuristically, and do not consider residual stresses. To overcome these limitations, we propose a
Stress-Aware Optimal Actuator Placement framework
. We provide theoretical investigations that demonstrate the convergence to global optimum, computational complexity, and mean prediction error of the proposed optimization algorithm. The stress-aware optimal actuator placement framework is able to achieve significant reductions of at least 39.3% in mean root mean squared deviations (RMSD) and 52% in maximum forces (MF), and only requires eight actuators on average while satisfying the safety threshold of residual stresses.
Note to Practitioners
—In aerospace manufacturing, about 80% of defects are associated with the assembly process. Defects may result in large errors and waste, high energy costs, low product quality, or even endanger human lives. The actuator placement usually significantly impacts the final quality of the assembled airplanes. Existing actuator placement strategies are not sufficient for composite aircraft assembly due to the complex nonlinear properties, ultra-high precision requirement, and residual stress requirement. The proposed method can improve the dimensional quality by optimizing actuator placement, as well as lower the residual stress and ensure the safety of products. Although our optimization framework was applied to the placement of actuators on composite fuselages, it could also be applied to the engineering design of other actuating systems in which both dimensional quality and stresses are sensitive. The proposed approach can reduce carbon emissions by preventing defects and improving quality management, ultimately aiming at zero-defect green manufacturing.