Targeted modal response control of structures using inerter-based systems based on master oscillator principle

Author(s):  
Ruifu Zhang ◽  
Luqi Zhang ◽  
Chao Pan ◽  
Dario De Domenico ◽  
Qingjun Chen
Impact ◽  
2019 ◽  
Vol 2019 (10) ◽  
pp. 73-75
Author(s):  
Susumu Hara

Professor Susumu Hara is based at the Department of Aerospace Engineering, Nagoya University in Japan explains that when the Mars rover Opportunity was set to land on that planet in the first weeks of 2004, onlookers held their breath as it dropped from orbit and hurtled toward the red surface. 'Any failure in the calculations or landing systems would mean a harder than expected impact,' he highlights. 'The impacts sustained by a rover such as Opportunity can derail a mission before it even starts, damaging cargo or vital systems required to complete the mission.' Impacts occur during landing but also as the craft enters the atmosphere, when it makes sudden moves, while it is on surface or when debris strikes it. 'Therefore, a system and materials to protect a craft are vital,' outlines Hara. 'Surprisingly, the solutions to this problem are not sophisticated. In fact, most craft still employ devices resembling automobile bumpers, which absorb the energy from an impact by crumpling under the force of said impact.' Unfortunately, these cannot be reused, even during testing phases a new prototype is required after every single test run. Recent missions also employed techniques like airbags or sky cranes. While successful they too have drawbacks. 'Airbags create huge rebounds which can jostle the craft and the contents inside while sky cranes are extremely costly to develop,' Hara says. For this reason, he is dedicated to designing a new highly reliable and cost-effective shock control mechanism.


2017 ◽  
Vol 17 (03) ◽  
pp. 1750039 ◽  
Author(s):  
Kenan Yildirim ◽  
Seda G. Korpeoglu ◽  
Ismail Kucuk

Optimal boundary control for damping the vibrations in a Mindlin-type beam is considered. Wellposedness and controllability of the system are investigated. A maximum principle is introduced and optimal control function is obtained by means of maximum principle. Also, by using maximum principle, control problem is reduced to solving a system of partial differential equations including state, adjoint variables, which are subject to initial, boundary and terminal conditions. The solution of the system is obtained by using MATLAB. Numerical results are presented in table and graphical forms.


1994 ◽  
Author(s):  
Charles Zmudzinski ◽  
Chan A. Tu ◽  
Dan Botez ◽  
Luke J. Mawst ◽  
Rashit F. Nabiev ◽  
...  

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Gang Yu

In structural dynamic analysis, the blind source separation (BSS) technique has been accepted as one of the most effective ways for modal identification, in which how to extract the modal parameters using very limited sensors is a highly challenging task in this field. In this paper, we first review the drawbacks of the conventional BSS methods and then propose a novel underdetermined BSS method for addressing the modal identification with limited sensors. The proposed method is established on the clustering features of time-frequency (TF) transform of modal response signals. This study finds that the TF energy belonging to different monotone modals can cluster into distinct straight lines. Meanwhile, we provide the detailed theorem to explain the clustering features. Moreover, the TF coefficients of each modal are employed to reconstruct all monotone signals, which can benefit to individually identify the modal parameters. In experimental validations, two experimental validations demonstrate the effectiveness of the proposed method.


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