Although the Chen-Ricles（CR）method and the Kolay-Ricles（KR）method have been applied to conduct pseudodynamic tests,they have both been found to have some adverse numerical properties,such as conditional stability ...Although the Chen-Ricles（CR）method and the Kolay-Ricles（KR）method have been applied to conduct pseudodynamic tests,they have both been found to have some adverse numerical properties,such as conditional stability for stiffness hardening systems and an unusual overshoot in the steady-state response of a high-frequency mode.An improved formulation for each method can be achieved by using a stability amplification factor to boost the unconditional stability range for stiffness hardening systems and a loading correction term to eliminate the unusual overshoot in the steady-state response of a high-frequency mode.The details for developing improved formulations for each method are shown in this work.展开更多
An aeroelastic optimization design methodology for air vehicle considering the uncertainties in maneuver load conditions is presented and applied to a structural design process of low-aspect-ratio wing. An aerodynamic...An aeroelastic optimization design methodology for air vehicle considering the uncertainties in maneuver load conditions is presented and applied to a structural design process of low-aspect-ratio wing. An aerodynamic load correction model is developed and used to predict the critical load conditions with the perturbations of theoretical linear aerodynamic forces and experimental aerodynamic forces from wind-tunnel test, when concerning the uncertainties in use of theoretical linear and experimental aerodynamic forces. Three objective functions of critical loads are defined. The load evaluations for three wing sections are investigated in four characteristic maneuvers, and the most critical load conditions are confirmed by using the sequential quadratic programming method. On this basis, the aeroelastic optimization design employing the genetic-gradient hybrid algorithm is conducted, in which the objective is to minimize structural mass subject to the constraints of stress, deformation and flutter speed. The resulting optimal structure is heavier than the one simply based on the theoretical linear or experimental aerodynamic forces. However, it is more robust when encountering the critical load conditions in actual flight due to the consideration of uncertainties in aerodynamic forces in the early design phase, thereby, the risk of structural redesign can be reduced.展开更多
文摘Although the Chen-Ricles（CR）method and the Kolay-Ricles（KR）method have been applied to conduct pseudodynamic tests,they have both been found to have some adverse numerical properties,such as conditional stability for stiffness hardening systems and an unusual overshoot in the steady-state response of a high-frequency mode.An improved formulation for each method can be achieved by using a stability amplification factor to boost the unconditional stability range for stiffness hardening systems and a loading correction term to eliminate the unusual overshoot in the steady-state response of a high-frequency mode.The details for developing improved formulations for each method are shown in this work.
基金supported by the National Natural Science Foundation of China (Grant Nos 10902006, 90716006)
文摘An aeroelastic optimization design methodology for air vehicle considering the uncertainties in maneuver load conditions is presented and applied to a structural design process of low-aspect-ratio wing. An aerodynamic load correction model is developed and used to predict the critical load conditions with the perturbations of theoretical linear aerodynamic forces and experimental aerodynamic forces from wind-tunnel test, when concerning the uncertainties in use of theoretical linear and experimental aerodynamic forces. Three objective functions of critical loads are defined. The load evaluations for three wing sections are investigated in four characteristic maneuvers, and the most critical load conditions are confirmed by using the sequential quadratic programming method. On this basis, the aeroelastic optimization design employing the genetic-gradient hybrid algorithm is conducted, in which the objective is to minimize structural mass subject to the constraints of stress, deformation and flutter speed. The resulting optimal structure is heavier than the one simply based on the theoretical linear or experimental aerodynamic forces. However, it is more robust when encountering the critical load conditions in actual flight due to the consideration of uncertainties in aerodynamic forces in the early design phase, thereby, the risk of structural redesign can be reduced.
