Experimental Research on the Vibration Reduction and Impact Resistance Performances of Offshore Structure Based on Magnetorheological Damper

2008 ◽  
Author(s):  
Zhongchao Deng ◽  
Dagang Zhang ◽  
Xiongliang Yao
Keyword(s):  
Vibration Reduction ◽  
Impact Resistance ◽  
Mr Damper ◽  
Magnetorheological Damper ◽  
Offshore Structure ◽  
Loading System ◽  
Vibration Experiment ◽  
Exciting Forces ◽  
The Impact ◽  
Impact Experiments

This paper presents a new kind of vibration reduction and impact resistance isolator system based on magnetorheological technique, and its experiment results. The vibration and impact experiments were designed using MTS hydraulic loading system. There were many load cases being applied in the experiment with different mass of the model, exciting forces, and controllable electricity of MR damper (Magnetorheological Damper). The experiment results indicate that this isolator system can control the vibration response very well, especially near the natural frequency of the system; and the isolator system has a good performance in the impact experiment too, the response acceleration was evidently reduced, but the characteristic of MR damper was different form its performance in vibration experiment.

scholarly journals Experimental Analysis of Power Flows in the Regenerative Vibration Reduction System with a Magnetorheological Damper

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 848
Author(s):  
Bogdan Sapiński ◽  
Paweł Orkisz ◽  
Łukasz Jastrzębski
Keyword(s):  
Experimental Data ◽  
Experimental Analysis ◽  
Vibration Reduction ◽  
Mr Damper ◽  
Magnetorheological Damper ◽  
Test Rig ◽  
Instantaneous Power ◽  
Reduction System ◽  
Inertial Energy ◽  
Regenerative Vibration

The aim of the work is to investigate power flows in the vibration reduction system equipped with a magnetorheological (MR) damper and energy regeneration. For this purpose, experiments were conducted in the test rig compound of the shaker and the vibration reduction system (electromagnetic harvester, MR damper, spring) which are attached to the sprung mass. The experimental data acquired under sine excitations enabled us to analyze instantaneous power fluxes, as well as a rate of inertial energy changes in the system.

Design and Experiment of the Magnetorheological Damper with Multiple Poles

2015 ◽  
Vol 764-765 ◽  
pp. 223-227 ◽  
Author(s):  
Yao Jung Shiao ◽  
Mei Ling Jow ◽  
Wen Hwa Kuo ◽  
Quang Anh Nguyen ◽  
Chao Wei Lai
Keyword(s):  
Mr Damper ◽  
Magnetorheological Damper ◽  
Vehicle Body ◽  
Main Function ◽  
Damping Force ◽  
Operation Conditions ◽  
Wide Range ◽  
Complete Procedure ◽  
The Impact ◽  
Multiple Poles

The main function of a suspension system is to isolate and absorb the impact from road surface to vehicle body. To provide good riding comfort, a damper with variable and wide-range damping is highly needed. This paper presents a complete procedure from design, optimization to experiment for a magnetorheological (MR) damper with multiple poles. This new designed damper is entirely different from those conventional single-pole MR dampers, effectively by extending the range of damping force. Magnetic simulation has been done in the paper to provide an optimal structure of the damper which significantly enhances the damping force while avoids magnetic saturation. The new damper was also manufactured and tested. The experimental results show that the provided damping force can be significantly increased with the increase of input current from low to high speeds. Damping force can be varied by 7.41 times. It proves that this new MR damper with high damping force can be controlled adaptively at wide range of operation conditions. It is suitable to be an adaptively variable damping source in semi-active suspension systems.

scholarly journals Real-Time Sensing Action of the Electromagnetic Vibration-Based Energy Harvester for a Magnetorheological Damper Control

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2845
Author(s):  
Bogdan Sapiński ◽  
Paweł Orkisz
Keyword(s):  
Working Conditions ◽  
Energy Harvester ◽  
Vibration Reduction ◽  
Mr Damper ◽  
The Self ◽  
Magnetorheological Damper ◽  
Test Results ◽  
Electromagnetic Vibration ◽  
Self Powered ◽  
Damper Control

This study investigated the self-sensing mechanism in the electromagnetic vibration-based energy harvester (EV-EH) prototype specially engineered for a commercial magnetorheological (MR) damper. The objective of the work is to demonstrate that the EV-EH unit with a specific self-powered feature can also be employed as a relative velocity sensor in the system. To do this, the self-sensing action of the unit was experimentally studied over the assumed range of working conditions. The analysis of the test results and the determined self-sensing function indicated that the EV-EH has a highly accurate monitoring capability. The EV-EH self-sensing and self-powered features confirm the potentials and applicability of the unit for MR damper control in a vibration reduction system with energy regeneration.

scholarly journals Impact Resistance of Concrete Structures

2015 ◽  
Vol 2015 ◽  
pp. 1-8
Author(s):  
R. Drathi
Keyword(s):  
High Pressures ◽  
Damage Model ◽  
Impact Resistance ◽  
Concrete Structures ◽  
Strain Rate Effects ◽  
Mesh Free ◽  
Mesh Free Method ◽  
The Impact ◽  
Impact Experiments ◽  
Geometric Correlation

We present simulations on the resistance of concrete structures due to impact loading. Therefore, a mesh-free method is exploited in combination with a viscous damage model that accounts for strain rate effects and high pressures that commonly occur in those events. In contrast to many other studies in the literature, we account for uncertainties in the material parameters by subjecting them to a probability distribution function. Furthermore, we also consider the geometric correlation inside the concrete and show that this geometric correlation has a minor influence on the predicted results. All numerical results are compared to the impact experiments performed by Hanchak and coworkers as well as our own impact experiments.

Effect of combined drink cans and steel fibers on the impact resistance and mechanical properties of concrete

2020 ◽  
Vol 14 (2) ◽  
pp. 6734-6742
Author(s):  
A. Syamsir ◽  
S. M. Mubin ◽  
N. M. Nor ◽  
V. Anggraini ◽  
S. Nagappan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Reinforced Concrete ◽  
Impact Resistance ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Fiber Reinforced ◽  
Indirect Tensile ◽  
The Impact

This study investigated the combine effect of 0.2 % drink cans and steel fibers with volume fractions of 0%, 0.5%, 1%, 1.5%, 2%, 2.5% and 3% to the mechanical properties and impact resistance of concrete. Hooked-end steel fiber with 30 mm and 0.75 mm length and diameter, respectively was selected for this study.  The drinks cans fiber were twisted manually in order to increase friction between fiber and concrete. The results of the experiment showed that the combination of steel fibers and drink cans fibers improved the strength performance of concrete, especially the compressive strength, flexural strength and indirect tensile strength. The results of the experiment showed that the combination of steel fibers and drink cans fibers improved the compressive strength, flexural strength and indirect tensile strength by 2.3, 7, and 2 times as compare to batch 1, respectively. Moreover, the impact resistance of fiber reinforced concrete has increase by 7 times as compared to non-fiber concretes. Moreover, the impact resistance of fiber reinforced concrete consistently gave better results as compared to non-fiber concretes. The fiber reinforced concrete turned more ductile as the dosage of fibers was increased and ductility started to decrease slightly after optimum fiber dosage was reached. It was found that concrete with combination of 2% steel and 0.2% drink cans fibers showed the highest compressive, split tensile, flexural as well as impact strength.    

scholarly journals Effect of SWCNT-Tuball Paper on the Lightning Strike Protection of CFRPs and Their Selected Mechanical Properties

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3140
Author(s):  
Kamil Dydek ◽  
Anna Boczkowska ◽  
Rafał Kozera ◽  
Paweł Durałek ◽  
Łukasz Sarniak ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Copper Foil ◽  
Impact Resistance ◽  
Mechanical Analysis ◽  
Lightning Strike ◽  
Single Wall Carbon Nanotubes ◽  
Carbon Fibre Reinforced Polymer ◽  
The Impact

The main aim of this work was the investigation of the possibility of replacing the heavy metallic meshes applied onto the composite structure in airplanes for lightning strike protection with a thin film of Tuball single-wall carbon nanotubes in the form of ultra-light, conductive paper. The Tuball paper studied contained 75 wt% or 90 wt% of carbon nanotubes and was applied on the top of carbon fibre reinforced polymer before fabrication of flat panels. First, the electrical conductivity, impact resistance and thermo-mechanical properties of modified laminates were measured and compared with the reference values. Then, flat panels with selected Tuball paper, expanded copper foil and reference panels were fabricated for lightning strike tests. The effectiveness of lightning strike protection was evaluated by using the ultrasonic phased-array technique. It was found that the introduction of Tuball paper on the laminates surface improved both the surface and the volume electrical conductivity by 8800% and 300%, respectively. The impact resistance was tested in two directions, perpendicular and parallel to the carbon fibres, and the values increased by 9.8% and 44%, respectively. The dynamic thermo-mechanical analysis showed higher stiffness and a slight increase in glass transition temperature of the modified laminates. Ultrasonic investigation after lightning strike tests showed that the effectiveness of Tuball paper is comparable to expanded copper foil.

scholarly journals Towards Sustainable Concrete Composites through Waste Valorisation of Plastic Food Trays as Low-Cost Fibrous Materials

2021 ◽  
Vol 13 (4) ◽  
pp. 2073 ◽  
Author(s):  
Hossein Mohammadhosseini ◽  
Rayed Alyousef ◽  
Mahmood Md. Tahir
Keyword(s):  
Compressive Strength ◽  
Low Cost ◽  
Impact Resistance ◽  
Food Tray ◽  
World Population ◽  
Fibrous Materials ◽  
Palm Oil Fuel Ash ◽  
Waste Plastic ◽  
Compressive Strength Of Concrete ◽  
The Impact

Recycling of waste plastics is an essential phase towards cleaner production and circular economy. Plastics in different forms, which are non-biodegradable polymers, have become an indispensable ingredient of human life. The rapid growth of the world population has led to increased demand for commodity plastics such as food packaging. Therefore, to avert environment pollution with plastic wastes, sufficient management to recycle this waste is vital. In this study, experimental investigations and statistical analysis were conducted to assess the feasibility of polypropylene type of waste plastic food tray (WPFT) as fibrous materials on the mechanical and impact resistance of concrete composites. The WPFT fibres with a length of 20 mm were used at dosages of 0–1% in two groups of concrete with 100% ordinary Portland cement (OPC) and 30% palm oil fuel ash (POFA) as partial cement replacement. The results revealed that WPFT fibres had an adverse effect on the workability and compressive strength of concrete mixes. Despite a slight reduction in compressive strength of concrete mixtures, tensile and flexural strengths significantly enhanced up to 25% with the addition of WPFT fibres. The impact resistance and energy absorption values of concrete specimens reinforced with 1% WPFT fibres were found to be about 7.5 times higher than those of plain concrete mix. The utilisation of waste plastic food trays in the production of concrete makes it low-cost and aids in decreasing waste discarding harms. The development of new construction materials using WPFT is significant to the environment and construction industry.

scholarly journals Impact resistance of steel materials to ballistic ejecta and shelter development using steel deck plates

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Hiroyuki Yamada ◽  
Kohei Tateyama ◽  
Shino Naruke ◽  
Hisashi Sasaki ◽  
Shinichi Torigata ◽  
...  
Keyword(s):  
Impact Energy ◽  
Impact Test ◽  
Impact Resistance ◽  
Protective Layer ◽  
High Strength ◽  
Steel Plates ◽  
Corrugated Plates ◽  
Shelter Construction ◽  
The Impact ◽  
Ballistic Ejecta

AbstractThe destruction caused by ballistic ejecta from the phreatic eruptions of Mt. Ontake in 2014 and Mt. Kusatsu-Shirane (Mt. Moto-Shirane) in 2018 in Japan, which resulted in numerous casualties, highlighted the need for better evacuation facilities. In response, some mountain huts were reinforced with aramid fabric to convert them into shelters. However, a number of decisions must be made when working to increase the number of shelters, which depend on the location where they are to be built. In this study, we propose a method of using high-strength steel to reinforce wooden buildings for use as shelters. More specifically, assuming that ballistic ejecta has an impact energy of 9 kJ or more, as in previous studies, we developed a method that utilizes SUS304 and SS400 unprocessed steel plates based on existing impact test data. We found that SUS304 is particularly suitable for use as a reinforcing material because it has excellent impact energy absorption characteristics due to its high ductility as well as excellent corrosion resistance. With the aim of increasing the structural strength of steel shelters, we also conducted an impact test on a shelter fabricated from SS400 deck plates (i.e., steel with improved flexural strength provided by work-hardened trapezoidal corrugated plates). The results show that the shelter could withstand impact with an energy of 13.5 kJ (2.66 kg of simulated ballistic ejecta at 101 m/s on impact). In addition, from the result of the impact test using the roof-simulating structure, it was confirmed the impact absorption energy is further increased when artificial pumice as an additional protective layer is installed on this structure. Observations of the shelter after the impact test show that there is still some allowance for deformation caused by projectile impact, which means that the proposed steel shelter holds promise, not only structurally, but also from the aspects of transportation and assembly. Hence, the usefulness of shelters that use steel was shown experimentally. However, shelter construction should be suitable for the target environment.

scholarly journals Impact Resistance of Epoxy Composites Reinforced with Amazon Guaruman Fiber: A Brief Report

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2264
Author(s):  
Raphael H. M. Reis ◽  
Fabio C. Garcia Filho ◽  
Larissa F. Nunes ◽  
Veronica S. Candido ◽  
Alisson C. R. Silva ◽  
...  
Keyword(s):  
Fiber Composite ◽  
Impact Resistance ◽  
Fiber Composites ◽  
Epoxy Composites ◽  
Impact Performance ◽  
Electron Microscopy Analysis ◽  
Ballistic Properties ◽  
Microscopy Analysis ◽  
Izod Impact ◽  
The Impact

Fibers extracted from Amazonian plants that have traditionally been used by local communities to produce simple items such as ropes, nets, and rugs, are now recognized as promising composite reinforcements. This is the case for guaruman (Ischinosiphon körn) fiber, which was recently found to present potential mechanical and ballistic properties as 30 vol% reinforcement of epoxy composites. To complement these properties, Izod impact tests are now communicated in this brief report for similar composites with up to 30 vol% of guaruman fibers. A substantial increase in impact resistance, with over than 20 times the absorbed energy for the 30 vol% guaruman fiber composite, was obtained in comparison to neat epoxy. These results were statistically validated by Weibull analysis, ANOVA, and Tukey’s test. Scanning electron microscopy analysis disclosed the mechanisms responsible for the impact performance of the guaruman fiber composites.

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