As more than 50% construction and demolition (CD and (ii) the deformation and permeability of RAC can be enhanced when adopting TSMA. Therefore, it demonstrates that TSMA can help to improve the durability of RAC, on top of the previously verified strength improvement, and thus opening up wider applications of RAC.

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Assessment of durability of recycled aggregate concrete produced by two-stage mixing approach

Active flutter suppression, which is a part of the group of flight vehicle technologies known as active controls, is an important contributor to the effective solution of aeroelastic instability pr...

https://arc.aiaa.org/doi/pdf/10.2514/1.C034442

Aircraft Active Flutter Suppression: State of the Art and Technology Maturation Needs

The present paper investigates the applicability of the Global Sensitivity Equation (GSE) method in the multidisciplinary synthesis of aeronautical vehicles. The GSE method provides an efficient approach for representing a large coupled system by smaller subsystems and accounts for the subsystem interactions by means of first-order behavior sensitivities. This approach was applied in an aircraft synthesis problem with performance constraints stemming from the disciplines of structures, aerodynamics, and flight mechanics. Approximation methods were considered in an attempt to reduce problem dimensionality and to improve the efficiency of the optimization process. The influence of efficient constraint representations, the choice of design variables, and design variable scaling on the conditioning of the system matrix was also investigated.

Application of global sensitivity equations in multidisciplinary aircraft synthesis

A recursive experimental design method for simultaneously optimizing both mechanical structure and control is presented in this paper. Control gains are optimally tuned for a given prototype of mechatronic system, and its mechanical structure is physically modified so that control performance can be further improved. The entire control tuning, evaluation, and structure alteration process is repeated until the desired performance goals are achieved. In each iteration, incremental design changes are determined based on a sensitivity Jacobian relating structural changes to performance improvements. The sensitivity Jacobian is updated during the recursive process using the actual data of the design changes. To estimate the Jacobian despite few data points, a pseudoinverse method and a parameter perturbation algorithm, termed singular-value excitation, are developed. The mechanical structure is modified recursively and quickly by using structure reinforcement and rapid prototyping techniques. The feasibility of mechanical structure changes is taken into account in determining the design changes. The proposed methodology is verified through simulation and applied to the design of a robot positioning system. The robot arm structure is modified with regard to stiffness and damping by using steel reinforced epoxy. PD control gains are optimized every time the structure is modified. Through the recursive procedure, an optimal combination of the arm structure and control gains is obtained.

Integrated structure/control design of mechatronic systems using a recursive experimental optimization method

Control Co-Design: An engineering game changer

: It is shown that for highly sophisticated, naturally unstable airplanes flying supersonically a joint strategy to lay out the flight control system while minimizing design loads must be adopted. The selection of control surface geometry must be performed utilizing all possibilities from overall structural optimization including aeroelastic tailoring for primary carbon fibre structures. In the proposed design philosophy the behavior of the elastic airplane structure must be introduced and optimized in the very early design stage. It is shown in the paper that the required control surface hinge moments can be reduced by optimizing mass penalties and efficiencies. Minimizing installed hydraulic power supply has also a beneficial effect on engine performance at low speed, high altitudes.

O. Sensburg

Papers

Integrated Design of Structures

Interdisciplinary design of aircraft structures for minimum weight