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A numerical method was developed to study vortex-induced vibration (VIV) on free-spanning marine pipelines. The numerical method uses a partitioned fluid-structure interaction solver with implicit coupling. The method was applied to a baseline model of cross flow around a circular cylinder with structure deformation. Further studies would include the effects of sea flow sediment deposition and scour.
This paper presents a slightly different concept of energy harvesting method as compared to the conventional energy harvesters. The new energy harvester of interest is known as Hybrid Energy Harvester (HEH). It comprises of the Piezoelectric and Magnetostrictive/Electromagnetic transducers integrated into a system. Theoretically, the hybrid energy harvester device developed is targeted to expand the...
Harvesting energy from mechanical vibrations to provide power in remote areas where there is no lines of electricity has attracted a great research interest. Linear vibration energy harvesters (VEH) are not able to scavenge energy over broadband of frequencies. The performance of the linear harvesters can be improved using the concept of nonlinearity using magnets which has been extensively studied...
Recently, the fire-rescue ladder is towards to the direction of faster operation, lighter, extended length and larger outreach. The lightweight of the fire-rescue ladder and the limited stiffness of the ladder structure directly lead to different bending vibration problems in different modes. In this paper, the fire-rescue ladder is modeled as segmented Euler-Bemoulli beam with gravity and tip mass...
Signal source localization and separation are key tasks for many applications. In this paper, a new deterministic method is proposed for estimating the 3D location and separating multiple acoustic or vibration sources, simultaneously active. The method is based on TDOA measurements obtained via crosscorrelation. Then, with the information from the estimated locations, source separation is achieved...
Vibrotactile stimulation to the gluteal or back regions through seats is a promising approach to deliver supplemental information to humans. Designing a method to achieve pleasant vibrotactile stimuli was addressed in this study, as such stimuli tend to result in unpleasant experiences for users. In particular, we investigated the properties of continual vibrotactile stimulation to the gluteal region...
This paper presents a vibration control design to the string-tip-mass system by using a non-symmetric peak-detector mechanism. Previously, this peak-detector system was used as an easy algorithm to mitigate vibration on a real flexible structure. Moreover, its mathematical representation is simple and it just has two parameters to tune. Following this former experience, we adequate this strategy to...
Patients with neurodegenerative disorder suffers from performing their daily tasks resulting in a reduced community ambulation. Tremor is suggested to be reduced by mechanical means using passive vibration controller. Human hand is modeled in the horizontal plane to describe the flexion-extension motion at the shoulder, elbow and wrist joints. Tremor is modeled as sinusoidal function driven at two...
This paper presented a numerical simulation of an electrochemical seismometer, which provided an effective approach to study its transfer functions. The fluid-solid coupling model was firstly used in this paper to establish the link between the external vibrations and the internal velocities of the liquid inertial mass of the electrochemical seismometer. Some key parameters in the numerical simulation...
This paper proposes a sensorless chatter detection method for a ball screw drive system used in milling, by introducing the mechanical energy factor (MEF). The MEF is an indicator for detecting self-excited chatter, based on the power factor theory used in electric systems, and monitors the phase difference between dynamic cutting force and displacement. By monitoring the MEF, the self-excited chatter...
In underground low-pressure gas pipelines, a leak may result in a complication more dangerous and difficult to detect, known as the water ingress problem. Groundwater enters the gas pipeline through a crack, and eventually blocks the gas flow. Vibration sensors are used to detect the water ingress problem. The sensor output indicates a marked increase in the occurrence of spikes from the vibration...
The paper presents a mathematical model of a piston compressor which is a part of an oxygen gas generator. Taking into account the structural parameters of the compressor, as well as the suction and pressurization valves, such model allows one to obtain the dynamics of the pressure amplitude under the compressor's piston with the vibration velocity and vibration acceleration that are transmitted in...
In this work Integral Force Feedback and Multiple Positive position Feedback techniques are evaluated in active vibration suppression of a flexible beam. Integral Force Feedback (IFF) and Multiple Positive Position Feedback (MPPF) are independently applied as the controlling inputs to a PZT patch actuator attached to the flexible beam. Finite Element and modal models of the flexible beam are then...
Fault detection and diagnosis is a research area that has a significant impact due to commercial and industrial implications. The study presented in this paper is based on the idea that mathematical models can be assigned to any processes so, in this context, we have started from the assumption that the fault monitoring and detection in industrial processes could be made using frequency model of the...
In order to further improve the riding comfort of trackless rubber tire vehicle, to ensure the safety of coal mine underground transportation, a quarter vehicle of the dynamics equation was established for two-degree of freedom suspension system. And the underground road roughness value of the input signal was calculated. Then based on the Simulink module of MATLAB software, the mathematical simulation...
Study of electron transport in nanopillar transistor at 300K shows that elastic vibration is an intrinsic behavior of the device. The frequency observed in the drain-source current is found to agree with the charging frequency. Given a quantum dot of size 10×10×9nm3, the maximum displacement is estimated to be 0.3nm. Once the displacement diminishes to zero, single-electron tunnel becomes the dominating...
The paper is dedicated to a direct sensitivity analysis of a generic piezoelectric energy harvester working in a fluid flow. The aim of the analysis is to obtain a better knowledge about such kind of devices. The energy harvester has a beam-type structure which incorporates a piezo-active material. Under the action of the fluid flow induced forces the structure performs random vibrations. Due to the...
This article discusses the issues related to diagnosing the vibrational activity of marine engines. The authors introduce the method of assessment developed by them marine engine vibroactivity, generated by the gas dynamics and mechanical factors. This method of vibrational diagnostics can be effectively used to solve the problem of ensuring the operational status of marine engines both at the design...
The paper considers the problem of change detection and diagnosis (CDD) in vibration analysis, from the point of view of challenges and solutions. In this framework, Matlab Toolbox VIBROTOOL is presented, implementing functions for change detection and diagnosis in vibration engineering. Compared to other toolboxes in the same domain, Matlab VIBROTOOL Toolbox promotes blind source separation and advanced...
According to rotary vibration at the end of the concrete pump truck boom, analysis of the boom rotary vibration mechanism is carried out. Rigid-flexible coupling dynamics model and vibration control co-simulation model of the boom system are established. The analysis of the dynamic model solution shows that the simulation rotation vibration displacement curves at the end of the boom are coincided...
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