scholarly journals Vibrating barrier: a novel device for the passive control of structures under ground motion

2015 ◽  
Vol 471 (2179) ◽  
pp. 20150075 ◽  
Author(s):  
P. Cacciola ◽  
A. Tombari
Keyword(s):  
Ground Motion ◽  
Passive Control ◽  
Structural Response ◽  
Harmonic Excitation ◽  
The Novel ◽  
Closed Form Solutions ◽  
Novel Device ◽  
Adjacent Structures ◽  
Working Principle ◽  
Propagation Of Waves

A novel device, called vibrating barrier (ViBa), that aims to reduce the vibrations of adjacent structures subjected to ground motion waves is proposed. The ViBa is a structure buried in the soil and detached from surrounding buildings that is able to absorb a significant portion of the dynamic energy arising from the ground motion. The working principle exploits the dynamic interaction among vibrating structures due to the propagation of waves through the soil, namely the structure–soil–structure interaction. The underlying theoretical aspects of the novel control strategy are scrutinized along with its numerical modelling. Closed-form solutions are also derived to design the ViBa in the case of harmonic excitation. Numerical and experimental analyses are performed in order to investigate the efficiency of the device in mitigating the effects of ground motion waves on the structural response. A significant reduction in the maximum structural acceleration of 87% has been achieved experimentally.

EFFICACY OF A NOVEL DEVICE TO DETECT, ALERT AND RESOLVE NEONATAL APNEA - PILOT STUDY

2019 ◽  
Vol 9 (9) ◽  
pp. 608-613
Author(s):  
Dr. Swapna Lingaldinna,Dr. Himabindu Singh,Mona Sharma*
Keyword(s):  
Newborn Care ◽  
Standard Of Care ◽  
The Novel ◽  
Tertiary Referral ◽  
Tertiary Referral Hospital ◽  
Care Community ◽  
Novel Device ◽  
Sick Newborn ◽  
Central Apneas ◽  
Neonatal Apnea

Objective: To measure the accuracy of a novel device in detecting Bradycardia andDesaturation (B&D) events and to determine its efficacy in resolving apneas innewborns with comparison to standard monitor (which only detects B&D eventsand alerts).Design: This was a prospective observational study.Setting: Sick Newborn Care Unit of a large tertiary referral hospital in Hyderabad,India.Methods: 31 newborns were provided with a novel device, which monitored oxygensaturation and pulse rate and alarmed when values dropped below a set thresholdwhich is referred as an event, henceforth. The novel device also provided footstimulation in response to above-mentioned events. When the monitor alarmed, anurse attended to the baby to confirm whether the baby was breathing and whetherthe event had been resolved by the device. If the event had not resolved, appropriateaction as per the standard-of-care was performed.Results: The novel device “ApneBootTM” positively detected B&D events 94.03% oftimes as compared to the standard reference monitor. 56 of 67 observed B&D eventswere visually confirmed to be apneas, indicating that 83.6% of B&D eventscoincided with apneas. Of the 56 apneic events, 50 were central apneas, of which 35were resolved by the novel device, making the device’s efficacy of apnea resolution70%.Conclusion: The results of the study indicate that this novel device “ApneBootTM”is very effective in detecting and alarming B&D events, which coincides with theapnea, and resolving it by providing foot stimulation.Keywords: Novel Device, Neonatal Apnea, Low Birth Weight, Body Temperature,Kangaroo Mother Care, Community Health,

Measuring Earwax Cortisol Concentration Using a Non-Stressful Method (Preprint)

2020 ◽  
Author(s):  
Andrés Herane-Vives
Keyword(s):  
Cortisol Level ◽  
Local Stress ◽  
Extraction Methods ◽  
Cortisol Concentration ◽  
The Novel ◽  
Sampling Device ◽  
Related Factors ◽  
Novel Device ◽  
Cortisol Levels ◽  
The Right

BACKGROUND “Short-term” samples are not the most appropriate for reflecting Chronic Cortisol Concentration (CCC). Although hair is used for reflecting the systemic cortisol level over “long-term”, its use appears clinically problematic. Local stress and non-stress related factors may release a circumscribed cortisol secretion that is accumulated in hair. Non-stressful earwax extraction methods may provide a more accurate specimen to measure CCC. OBJECTIVE Correlate cortisol levels using hair, serum and earwax samples METHODS Earwax from both ears of 37 controls were extracted using a clinical procedure commonly associated with local pain. One month later, earwax from the left ear side was extracted using the same procedure, and earwax from the right ear side was comfortably extracted, using an earwax self-sampling device. Participants also provided one centimetre of hair that represented the retrospective month of cortisol output, and one serum sample that reflected the effect of systemic stressors on cortisol levels. Earwax (ECC), Hair (HCC) and Serum (SCC) Cortisol Concentration were correlated and compared. Confounders´ effect on cortisol levels were studied. RESULTS Serum showed the largest and hair the lowest cortisol concentration (p<0.01). Left-ECC was larger than Right-ECC (p=0.03). Right-ECC was the only sample unaffected by confounders (all p>0.05). Right-ECC and HCC showed the only significant association (r=0.39; p=0.03). CONCLUSIONS The self-sampling device did not represent a local stressor for the ceruminous glands. It provided the cortisol level with the least likely to be affected by confounding factors over the previous month. ECC using the novel device may constitute another accurate, but more suitable and affordable specimen for measuring CCC.

scholarly journals Effect of Frequency Characteristics of Ground Motion on Response of Tuned Mass Damper Controlled Inelastic Concrete Frame

Buildings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 74
Author(s):  
Md Motiur Rahman ◽  
Tahmina Tasnim Nahar ◽  
Dookie Kim
Keyword(s):  
Ground Motion ◽  
Structural Response ◽  
Tuned Mass Damper ◽  
Frequency Characteristics ◽  
Building Frames ◽  
Concrete Frame ◽  
Finite Element Software ◽  
Mass Damper ◽  
Lateral Displacements ◽  
Modal Mass

This paper investigates the performance of tuned mass damper (TMD) and dynamic behavior of TMD-controlled concrete structure considering the ground motion (GM) characteristics based on frequency content. The effectiveness of TMD in reducing the structural response and probability of collapse of the building frames are affected by the frequency characteristics of GMs. To attenuate the seismic vibration of the buildings, the TMD controlled building has been designed based on the modal analysis (modal frequencies and modal mass participation ratio). In this study, to investigate the performance of TMD, four different heights (i.e., 3, 5, 10, 20 stories) inelastic concrete moment-resisting frames equipped with TMDs are developed using an open-source finite element software. A series of numerical analyses have been conducted using sixty earthquakes classified into three categories corresponding to low, medium, and high-frequency characteristics of GMs. To evaluate the proposed strategy, peak lateral displacements, inter-story drift, and the probability of collapse using fragility analysis have been investigated through the structures equipped with and without TMD. The results appraise the effect of TMD and compare the seismic responses of earthquake frequency contents and the vibration control system of the inelastic building frames.

CAD AND CAE TECHNOLOGIES OF A NOVEL PLANE SIX-BAR SWAYING MACHINE

2008 ◽  
Vol 07 (01) ◽  
pp. 65-67
Author(s):  
CHANGPING ZOU ◽  
LI DU ◽  
XIANDE HUANG
Keyword(s):  
High Pressure ◽  
Kinetic Analysis ◽  
Rotational Speed ◽  
Preliminary Analysis ◽  
Unit Weight ◽  
The Novel ◽  
Parameterized Modeling ◽  
New Type ◽  
Working Principle ◽  
Key Dimensions

A new type of six-bar swaying machine was put forward, which is an ingenious combination of plane multi-bar mechanism and high pressure oil cylinder. Preliminary analysis shows that this machine has many advantages, such as the torque produced by its unit weight, its small size, its light deadweight, etc. Thus it can be applied to situations that need swaying mechanism with low rotational speed and great torque. Firstly, the mechanism composition and working principle of the swaying machine were introduced. Secondly, parameterized modeling of the mechanism was carried out by utilizing software ADAMS. Then kinematic analysis and kinetic analysis were completed by using ADAMS. Finally, key dimensions were adjusted according to kinetic analysis. These tasks are believed to be beneficial to the development of the novel transmission.

scholarly journals An approach to quantify the influence of ground motion uncertainty on elastoplastic system acceleration in incremental dynamic analysis

2017 ◽  
Vol 20 (11) ◽  
pp. 1744-1756 ◽  
Author(s):  
Peng Deng ◽  
Shiling Pei ◽  
John W. van de Lindt ◽  
Hongyan Liu ◽  
Chao Zhang
Keyword(s):  
Dynamic Analysis ◽  
Ground Motion ◽  
Earthquake Engineering ◽  
Structural Response ◽  
Incremental Dynamic Analysis ◽  
Degree Of Freedom ◽  
Maximum Acceleration ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Performance Based Earthquake Engineering

Inclusion of ground motion–induced uncertainty in structural response evaluation is an essential component for performance-based earthquake engineering. In current practice, ground motion uncertainty is often represented in performance-based earthquake engineering analysis empirically through the use of one or more ground motion suites. How to quantitatively characterize ground motion–induced structural response uncertainty propagation at different seismic hazard levels has not been thoroughly studied to date. In this study, a procedure to quantify the influence of ground motion uncertainty on elastoplastic single-degree-of-freedom acceleration responses in an incremental dynamic analysis is proposed. By modeling the shape of the incremental dynamic analysis curves, the formula to calculate uncertainty in maximum acceleration responses of linear systems and elastoplastic single-degree-of-freedom systems is constructed. This closed-form calculation provided a quantitative way to establish statistical equivalency for different ground motion suites with regard to acceleration response in these simple systems. This equivalence was validated through a numerical experiment, in which an equivalent ground motion suite for an existing ground motion suite was constructed and shown to yield statistically similar acceleration responses to that of the existing ground motion suite at all intensity levels.

A Novel Design of the Device for Measuring Draw and Plug Forces

2012 ◽  
Vol 542-543 ◽  
pp. 1029-1032
Author(s):  
Ye Hu ◽  
Zhao Jun Yang ◽  
Ming Jun Xiang ◽  
Zi Chen Qiu ◽  
Chuan Gui Yang ◽  
...  
Keyword(s):  
Data Conversion ◽  
Memory Module ◽  
Novel Device ◽  
Working Principle ◽  
Tool Shank ◽  
Novel Design

The purpose of this paper is to present a novel device for measuring draw and plug forces, which is composed chiefly of a pull stud, a top modified tool shank, a middle modified tool shank, a down modified tool shank, and an end cover. The modified tool shank structure is proposed, and the working principle of the device for measuring draw and plug forces is demonstrated. Also, the data conversion and memory module and the circuit principle are investigated.

Passive Control of Structural Vibration in Base-Isolated Shear Structures

1995 ◽  
Author(s):  
R. Hussein
Keyword(s):  
Passive Control ◽  
Structural Response ◽  
Viscous Friction ◽  
Structural Vibration ◽  
Shear Structures ◽  
Oscillating Systems ◽  
Analytic Models

Abstract This paper presents three analytic models for predictions or structural response of oscillating systems with Coulomb and viscous friction. Numeric results were obtained from the models and compared to demonstrate the effects of friction on vibration amplification.

scholarly journals A Multi-Objective Ground Motion Selection Approach Matching the Acceleration and Displacement Response Spectra

2018 ◽  
Vol 10 (12) ◽  
pp. 4659 ◽  
Author(s):  
Yabin Chen ◽  
Longjun Xu ◽  
Xingji Zhu ◽  
Hao Liu
Keyword(s):  
Ground Motion ◽  
Response Spectrum ◽  
Structural Response ◽  
Response Spectra ◽  
Computationally Efficient ◽  
Ground Motion Selection ◽  
Displacement Response ◽  
Rc Frames ◽  
Selection Approach ◽  
Displacement Response Spectra

For seismic resilience-based design (RBD), a selection of recorded time histories for dynamic structural analysis is usually required. In order to make individual structures and communities regain their target functions as promptly as possible, uncertainty of the structural response estimates is in great need of reduction. The ground motion (GM) selection based on a single target response spectrum, such as acceleration or displacement response spectrum, would bias structural response estimates leading significant uncertainty, even though response spectrum variance is taken into account. In addition, resilience of an individual structure is not governed by its own performance, but depends severely on the performance of other systems in the same community. Thus, evaluation of resilience of a community using records matching target spectrum at whole periods would be reasonable because the fundamental periods of systems in the community may be varied. This paper presents a GM selection approach based on a probabilistic framework to find an optimal set of records to match multiple target spectra, including acceleration and displacement response spectra. Two major steps are included in that framework. Generation of multiple sub-spectra from target displacement response spectrum for selecting sets of GMs was proposed as the first step. Likewise, the process as genetic algorithm (GA), evolvement of individuals previously generated, is the second step, rather than using crossover and mutation techniques. A novel technique improving the match between acceleration response spectra of samples and targets is proposed as the second evolvement step. It is proved computationally efficient for the proposed algorithm by comparing with two developed GM selection algorithms. Finally, the proposed algorithm is applied to select GM records according to seismic codes for analysis of four archetype reinforced concrete (RC) frames aiming to evaluate the influence of GM selection considering two design response spectra on structural responses. The implications of design response spectra especially the displacement response spectrum and GM selection algorithm are summarized.

On the Combined Effect of Mean Flow and Acoustic Excitation on Structural Response and Radiation

1997 ◽  
Vol 119 (3) ◽  
pp. 448-456 ◽  
Author(s):  
A. Frendi ◽  
L. Maestrello
Keyword(s):  
Mach Number ◽  
Response Spectrum ◽  
Structural Response ◽  
Harmonic Excitation ◽  
Two Dimensions ◽  
Physical Problem ◽  
Acoustic Excitation ◽  
Mean Flow ◽  
Power Spectral ◽  
The Mean

Numerical experiments in two dimensions are carried out in order to investigate the response of a typical aircraft structure to a mean flow and an acoustic excitation. Two physical problems are considered; one in which the acoustic excitation is applied on one side of the flexible structure and the mean flow is on the other side while in the second problem both the mean flow and acoustic excitation are on the same side. Subsonic and supersonic mean flows are considered together with a random and harmonic acoustic excitation. In the first physical problem and using a random acoustic excitation, the results show that at low excitation levels the response is unaffected by the mean flow Mach number. However, at high excitation levels the structural response is significantly reduced by increasing the Mach number. In particular, both the shift in the frequency response spectrum and the broadening of the peaks are reduced. In the second physical problem, the results show that the response spectrum is dominated by the lower modes (1 and 3) for the subsonic mean flow case and by the higher modes (5 and 7) in the supersonic case. When a harmonic excitation is used, it is found that in the subsonic case the power spectral density of the structural response shows a subharmonic (f/4) while in the supersonic case no subharmonic is obtained.

The Application of the Ritz Averaging Method to Determining the Response of Systems with Time Varying Stiffness to Harmonic Excitation

1980 ◽  
Vol 102 (2) ◽  
pp. 384-390 ◽  
Author(s):  
M. Benton ◽  
A. Seireg
Keyword(s):  
Linear System ◽  
Averaging Method ◽  
Approximate Solutions ◽  
Harmonic Excitation ◽  
Time Varying ◽  
Parametric Vibrations ◽  
Nonlinear Characteristics ◽  
Closed Form Solutions ◽  
Mathieu’S Equation ◽  
Stiffness Variation

Parametric vibrations occur in many mechanical systems such as gears where the stiffness variation and external excitations generally occur at integer multiples of the rotational speed. This paper describes a procedure based on the Ritz Averaging Method for developing closed form solutions for the response of such systems to harmonic excitations. Although the method is illustrated in the paper by the case of a linear system with harmonic stiffness fluctuation (defined by Mathieu’s equation) it can be readily applied to determine approximate solutions for systems with nonlinear characteristics and any periodic variations of parameters.

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