Based on nonlinear precise integration method, two new numerical integration methods of pseudo-dynamic test of structures are presented. One is explicit predict-correct, four order accuracy and multistep method avoidi...
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ISBN:
(纸本)9783038351658
Based on nonlinear precise integration method, two new numerical integration methods of pseudo-dynamic test of structures are presented. One is explicit predict-correct, four order accuracy and multistep method avoiding calculating the inversion of the state matrix. The other is implicit predict-correct, four order accuracy and multistep method that need calculate the inversion of the state matrix. Since their accuracies are superior to the central difference method by enlarging time step and their stabilities are better, the structural systems of multi-degree of freedom could be well tested and the testing work would be largely reduced. Finally, a pseudo-dynamic test of combined tube structure has been executed with the explicit multi-step method.
To perform autonomous unpowered approach to designated landing interface,a three-dimensional trajectory generation method for compound UAV is presented.A reference profile by piecing together three flight segments is ...
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ISBN:
(纸本)9781479946983
To perform autonomous unpowered approach to designated landing interface,a three-dimensional trajectory generation method for compound UAV is presented.A reference profile by piecing together three flight segments is adopted in the trajectory generation *** predict-correct method,the algorithm adjusts three parameters'values of the trajectory and propagates the trajectory to match the landing interface *** the usually used optimization method,the method is able to generate reference profiles quickly,which indicates its ability for onboard *** results from different scenarios are presented in order to validate the effectiveness of the method.
In the view of the fault of bistable response appeared in the disk-rod-fastening rotor, the peculiar structure of this kind rotor was taken into account in this paper. By considering the influence of contact effect of...
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ISBN:
(纸本)9783037850374
In the view of the fault of bistable response appeared in the disk-rod-fastening rotor, the peculiar structure of this kind rotor was taken into account in this paper. By considering the influence of contact effect of discontinuous interfaces on the rotor stiffness, the tie-rod and the contact surface between the wheel disks were equated to a bending resistance spring with nonlinear stiffness. Then the equation of motion of the disk-rod-fastening rotor was put forward according to this simplification. The vibration characteristics of rotor was calculated by the harmonic balance method that combined with the predict-correct and homotopy arithmetic. The bistable response behaviors recurred in this simplified model was much closer to the measured results in flying. The study showed that the nonlinear factor of stiffness, resulted from the contact effect of discontinuous interfaces, was the main reason which led to the appearance of bistable response in the disk-rod-fastening rotor.
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