Figure 8 - uploaded by Mattia Serra
Content may be subject to copyright.
The cantilever beam mode shapes comparison; the first three mode shapes for the uncontrolled (NC) and the DMSC controlled system. (In order to allow the comparison, mode 1 and 3 have been ?10 amplified).
Source publication
This article presents the experimental validation of a new control technique for reducing vibration in flexible structures: Dependent modal space control. While the classic independent modal space control allows only the frequency and the damping of the controlled modes to be changed, dependent modal space control can also impose the controlled mod...
Contexts in source publication
Context 1
... Figure 8, the uncontrolled and the modified mode shapes are shown. Since the modal coordinates are unaltered, even a simple gain and/or sign modification of the mode shape would lead to sensible effects in the system response. ...
Context 2
... the modal coordinates are unaltered, even a simple gain and/or sign modification of the mode shape would lead to sensible effects in the system response. As broadly explained in Serra et al. (2013), the controlled mode shapes shown in Figure 8 are a linear combination of the first three uncontrolled modes without considering the spillover contributions coming from the others. The mode shapes for the DMSC controlled system, estimated from the experi- mental data at the measure points (accelerometers), have been represented by the green squares. ...
Citations
... These forces are generated by electro-mechanical or electrohydraulic actuators based on the feedback response from the structure, and they require a higher power source compared to the semi-active devices. Active vibration control systems are gaining increasing traction because of their flexibility and versatility (Ripamonti, Leo, and Resta 2016;Ripamonti, Orsini, and Resta 2017;Serra, Resta, and Ripamonti 2017) and (Cinquemani et al. 2016). For instance, active control systems can be simultaneously designed for different performance objectives and can be employed in a wide range of operations depending on the actuator working range (Cinitha 2014) and (Saaed et al. 2015). ...
This paper presents the results of an experimental program involving shake table testing of two full-scale reinforced concrete frame buildings. These tests were conducted to investigate the effectiveness and reliability of a newly proposed servo-hydraulic Active Mass Damper (AMD) that can be designed to enhance the target seismic performance of a building at multiple earthquake intensity levels. The two nominally identical case-study buildings were intentionally designed to exhibit a "soft story" mechanism at the first level when subject to ground shaking of sufficient intensity, but one was equipped with the newly proposed AMD, installed on the roof. The two specimens were then subject to the same loading protocol consisting of a ground shaking sequence of varying intensity, with the seismic input consisting of a selected natural ground motion.The experimental results demonstrated that the proposed AMD is extremely effective at enhancing building seismic performance. Specifically, the AMD provided peak displacement reductions in the order of 70% and was shown capable of absorbing more than 60% of the total input energy. As a consequence, the un-retrofitted structure suffered nontrivial structural and non-structural damage, while the AMD-retrofitted building remained virtually undamaged at all shaking intensities considered. ARTICLE HISTORY
... The steady state graph of posture 1 is obtained by using PolyMax method (least squares complex frequency domain method) to solve the coefficient matrix, as shown in Figure Modal confidence criterion (MAC) is used to test the correlation of modal vectors [5] [6]. The MAC value of the same modal vector to itself is infinitely close to 1, and the MAC value of two vectors of different modals (adjacent modals) should be less than 20% to meet the orthogonal requirements of modal vectors. ...
