The Evergreen Group is as comfortable in the air as it is on the sea, and its prominence in international transport is growing steadily in these realms. After establishing Evergreen Marine and making it into one of th...The Evergreen Group is as comfortable in the air as it is on the sea, and its prominence in international transport is growing steadily in these realms. After establishing Evergreen Marine and making it into one of the world's premier ocean carriers with just 20 years of service, the company took to the skies in 1989 by forming EVA Air. It focused on quality service and safety, and built EVA to become Taiwan's leading independent airline. Today, EVA Air carries passengers and cargo to all corners of the globe.展开更多
EVA Mr has developed rapidly over the last 17 years. Now it is ranked one of the top 50 airlines in the World. In preparation for the chartered flights of the Mid-autumn festival, EVA Air has been approved to operate ...EVA Mr has developed rapidly over the last 17 years. Now it is ranked one of the top 50 airlines in the World. In preparation for the chartered flights of the Mid-autumn festival, EVA Air has been approved to operate 2 flights to any of the four cities (which includes Beijing, Shanghai-Pudong, Guangzhou and Xiamen) and has decided to operate both of their flights to Shanghai. China's Foreign Trade exclusively interviewed Cho, Po-yue, Chief Representative of EVA Air's China's Mainland office. He gave us a detailed description of his company's development.展开更多
A linearization method and an engineering approach for the geometric nonlinear aeroelastic stability analysis of the very flexi- ble aircraft with high-aspect-ratio wings are established based on the little dynamic pe...A linearization method and an engineering approach for the geometric nonlinear aeroelastic stability analysis of the very flexi- ble aircraft with high-aspect-ratio wings are established based on the little dynamic perturbation assumption.The engineering practicability of the method is validated by a complex example.For a high-altitude long-endurance unmanned aircraft,the nonlinear static deformations under straight flight and the gust loads are calculated.At the corresponding nonlinear equilibrium state,the complete aircraft is linearized dynamically and the vibration modes are calculated considering the large deformation effects.Then the unsteady aerodynamics are calculated by the double lattice method.Finally,the aeroelastic stability of the complete aircraft is analyzed.The results are compared with the traditional linear calculation.The work shows that the geometric nonlinearity induced by the large structural deformation leads to the motion coupling of the wing chordwise bending and the torsion,which changes the mode frequencies and mode shapes.This factors change the aeroelastic coupling relationship of the flexible modes leading to the decrease of the flutter speed.The traditional linear method would give not only an imprecise flutter speed but also a possible dramatic mistake on the stability.Hence,for a high-altitude long-endurance unmanned aircraft with high-aspect-ratio wings,or a similar very flexible aircraft,the geometric nonlinear aeroelastic analysis should be a necessary job in engineering practice.展开更多
文摘The Evergreen Group is as comfortable in the air as it is on the sea, and its prominence in international transport is growing steadily in these realms. After establishing Evergreen Marine and making it into one of the world's premier ocean carriers with just 20 years of service, the company took to the skies in 1989 by forming EVA Air. It focused on quality service and safety, and built EVA to become Taiwan's leading independent airline. Today, EVA Air carries passengers and cargo to all corners of the globe.
文摘EVA Mr has developed rapidly over the last 17 years. Now it is ranked one of the top 50 airlines in the World. In preparation for the chartered flights of the Mid-autumn festival, EVA Air has been approved to operate 2 flights to any of the four cities (which includes Beijing, Shanghai-Pudong, Guangzhou and Xiamen) and has decided to operate both of their flights to Shanghai. China's Foreign Trade exclusively interviewed Cho, Po-yue, Chief Representative of EVA Air's China's Mainland office. He gave us a detailed description of his company's development.
基金supported by the National Natural Science Foundation of China(Grant Nos.90716006,10902006)the Research Fund for the Doctoral Program of Higher Education of China(Grant No.20091102110015)
文摘A linearization method and an engineering approach for the geometric nonlinear aeroelastic stability analysis of the very flexi- ble aircraft with high-aspect-ratio wings are established based on the little dynamic perturbation assumption.The engineering practicability of the method is validated by a complex example.For a high-altitude long-endurance unmanned aircraft,the nonlinear static deformations under straight flight and the gust loads are calculated.At the corresponding nonlinear equilibrium state,the complete aircraft is linearized dynamically and the vibration modes are calculated considering the large deformation effects.Then the unsteady aerodynamics are calculated by the double lattice method.Finally,the aeroelastic stability of the complete aircraft is analyzed.The results are compared with the traditional linear calculation.The work shows that the geometric nonlinearity induced by the large structural deformation leads to the motion coupling of the wing chordwise bending and the torsion,which changes the mode frequencies and mode shapes.This factors change the aeroelastic coupling relationship of the flexible modes leading to the decrease of the flutter speed.The traditional linear method would give not only an imprecise flutter speed but also a possible dramatic mistake on the stability.Hence,for a high-altitude long-endurance unmanned aircraft with high-aspect-ratio wings,or a similar very flexible aircraft,the geometric nonlinear aeroelastic analysis should be a necessary job in engineering practice.
