Control on Dynamic Response of Fluid-Driven Deployable Mechanism by Application of Magnetorheological Elastomeric Materials

2011 ◽  
Vol 183-185 ◽  
pp. 2313-2317 ◽  
Author(s):  
Shi Rong Guo ◽  
Ling Yu Sun ◽  
Wei Wei Chen
Keyword(s):  
Vibration Suppression ◽  
Variable Magnetic Field ◽  
Nonlinear Material ◽  
Original Design ◽  
Dynamic Impact ◽  
Suppression Effect ◽  
Wide Range ◽  
Elastomeric Materials ◽  
Deployable Mechanism ◽  
Rotating Plate

A kind of intelligent materials named magnetorheological elastomers (MREs) is applied on the surface of a rotating plate to avoid resonance vibration and to attenuate the vibration amplitude. Under a variable magnetic field, the stiffness of structure with MREs can be changed in wide range. First, the field-induced shear modulus is numerically studied and compared with the experimental results. Then, other equivalent parameters in nonlinear material equation of MREs are determined. Finally, the vibration suppression effect is verified through numerical simulation of the dynamic impact response of rotating plate in a fluid-driven deployable mechanism subjected to impact loads. On the condition that the weight of the plate is fixed, its vibration response is suppressed in shorter time than original design.

scholarly journals A Novel Piezoelectric Ultrasonic Biological Micro-Dissection Device Based on Flexure Mechanism for Suppressing Vibration

2020 ◽  
Author(s):  
Haibo Huang ◽  
Yifan Pan ◽  
Yan Pang ◽  
Hao Shen ◽  
Xiwei Gao ◽  
...  
Keyword(s):  
Vibration Suppression ◽  
Simulation Analysis ◽  
Tissue Sample ◽  
Design Parameters ◽  
Driving Frequency ◽  
Lateral Vibration ◽  
Suppression Effect ◽  
Flexure Mechanism ◽  
Vibration Effect ◽  
Wide Range

Biological micro-dissection has a wide range of applications in the field of molecular pathology. The current laser-assisted dissection technology is expensive, and laser radiation can lead to sample contamination. As an economical and pollution-free micro-dissection method, piezoelectric ultrasonic micro-dissection has a wide application prospect. However, the performance of the current piezoelectric ultrasonic micro-dissection technology is unsatisfactory. In this paper, a novel piezoelectric ultrasonic micro-dissection device based on a flexure mechanism is proposed in order to solve the problems of low dissecting precision and excessive wear of the dissecting needle caused by the harmful lateral vibration of the current piezoelectric ultrasonic micro-dissection device. By analyzing the flexibility of flexure hinge, the type of flexure beam and the optimal design parameters are determined. Through comparing the harmonic response simulation analysis of the micro-dissection device based on a flexure mechanism and the traditional micro-dissection device without the flexure mechanism, the newly designed micro-dissection device achieves the best vibration effect when the driving frequency is 28kHz, compared with the traditional micro-dissection device, the lateral vibration suppression effect is improved by 68%. Then, based on the 3D printing technology, a prototype of a novel micro-dissection device was produced, and its performance was tested. It was found that the flexure mechanism did indeed suppress the lateral vibration of the needle tip. Finally, the experiments of 5μm thick paraffin-embedded rat liver sections were carried out, and the effects of different dissecting parameters on the dissecting effect were analyzed, and the optimal dissecting parameters were obtained. By comparing the dissecting effects of the tissue sample and the wear condition of the needle tip between the novel micro-dissection device and the traditional micro-dissection device under their optimal dissecting parameters, it is proved that the suppression of harmful lateral vibration not only significantly improves the dissecting effect, but also improves the service life and durability of the dissecting needle, which is beneficial to reduce the equipment costs.

scholarly journals Sustainable Myrcene-Based Elastomers via a Convenient Anionic Polymerization

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 838
Author(s):  
David Hermann Lamparelli ◽  
Magdalena Maria Kleybolte ◽  
Malte Winnacker ◽  
Carmine Capacchione
Keyword(s):  
Anionic Polymerization ◽  
Sodium Hydride ◽  
Reactivity Ratios ◽  
Molecular Weights ◽  
Styrene Copolymers ◽  
Wide Range ◽  
Elastomeric Materials ◽  
Complete Study ◽  
Anionic Copolymerization ◽  
Trialkylaluminum Derivatives

Soluble heterocomplexes consisting of sodium hydride in combination with trialkylaluminum derivatives have been used as anionic initiating systems at 100 °C in toluene for convenient homo-, co- and ter-polymerization of myrcene with styrene and isoprene. In this way it has been possible to obtain elastomeric materials in a wide range of compositions with interesting thermal profiles and different polymeric architectures by simply modulating the alimentation feed and the (monomers)/(initiator systems) ratio. Especially, a complete study of the myrcene-styrene copolymers (PMS) was carried out, highlighting their tapered microstructures with high molecular weights (up to 159.8 KDa) and a single glass transition temperature. For PMS copolymer reactivity ratios, rmyr = 0.12 ± 0.003 and rsty = 3.18 ± 0.65 and rmyr = 0.10 ± 0.004 and rsty = 3.32 ± 0.68 were determined according to the Kelen–Tudos (KT) and extended Kelen–Tudos (exKT) methods, respectively. Finally, this study showed an easy accessible approach for the production of various elastomers by anionic copolymerization of renewable terpenes, such as myrcene, with commodities.

Vibration Suppression of an Elastically Supported Beam With Closely Spaced Natural Frequencies

2020 ◽  
Author(s):  
Haizhou Liu ◽  
Hao Gao
Keyword(s):  
Natural Frequencies ◽  
Vibration Suppression ◽  
Fixed Point Theory ◽  
Dynamic Performance ◽  
Point Theory ◽  
Primary System ◽  
Computationally Efficient ◽  
Wide Range ◽  
Univariate Optimization ◽  
Elastically Supported

Abstract Vibration suppression of distributed parameter systems is of great interest and has a wide range of applications. The dynamic performance of a primary system can be improved by adding dynamic vibration absorbers (DVA). Although the relevant topics have been studied for decades, the trade-off between capability of suppressing multiple resonant peaks and complexity of absorbers has not been well addressed. In this paper, the vibration suppression problem of a uniform Euler-Bernoulli beam with closely spaced natural frequencies is investigated. To achieve desired vibration reduction, a two-DOF DVA is connected to the beam through a pair of a spring and a dashpot. By introducing a virtual ground spring, the parameters of the absorber are determined via extended fixed point theory. The proposed method only requires univariate optimization and is computationally efficient. Numerical examples conducted verify the viability of the proposed method and the effectiveness of a two-DOF DVA in suppressing double resonances.

Application of Reliability Analysis to Re-Qualification and Life Extension of Floating Production Unit Moorings

2016 ◽  
Author(s):  
J. Rosen ◽  
D. Johnstone ◽  
P. Sincock ◽  
A. E. Potts ◽  
D. Hourigan
Keyword(s):  
Reliability Analysis ◽  
Production Unit ◽  
Life Extension ◽  
Surface Model ◽  
Original Design ◽  
Coupled Models ◽  
Wide Range ◽  
Reliability Methods ◽  
Ocean Conditions ◽  
Failure Scenario

Life extension and asset integrity of Floating Production Unit (FPU) moorings are issues of increasing importance for operators due to changing production requirements, the requirement to extend service life, and circumstances where the met-ocean Basis of Design (BOD) has increased significantly over the life of the field. Reliability methods are gaining increasing acceptance as increased computing power allows large numbers of simulations to be undertaken using realistic fully coupled models that are validated against prior experiments. When applied to the re-qualification and life extension of FPU moorings, particularly with regard to re-qualification and life extension of in-place moorings, reliability analysis offers considerable advantages over conventional deterministic return period design. This paper details the application of a reliability approach to re-qualification and life extension of a turret-moored FPU that had design met-ocean conditions increased significantly over the life of the field. It explores key elements of reliability analysis including the probabilistic characterisation of met-ocean conditions, adequate representation of vessel dynamics and mooring loads in a Response Surface Model, and a selection of algorithms to solve for the system probability of failure. Discussion points include the advantages of the explicit identification of the most likely failure scenario versus uncertainty as to whether the worst design case has been identified, and the potential for rapid reassessment of reliability for specific design conditions (such as a degraded mooring system or a system for which degradation is ongoing). The results of this study demonstrate the significant advantages to the industry conferred by adopting reliability methods in the re-certification and life extension of existing FPU moorings. In particular, the study highlights that conventional mooring code deterministic design methods, whilst adequate for original design purposes, lack sufficient fidelity to address the multi-faceted issue of re-assessment of notionally marginal legacy systems. For a degraded existing mooring, an application of these methods can demonstrate that the level of reliability of the system is still acceptable, whereas a conventional approach may produce an over-conservative indication that the mooring is non-compliant. Applicable to a wide range of FPUs requiring re-qualification or life extension, the techniques discussed also provide pointers to more efficient and reliable mooring design for not just existing, but also for new FPUs.

The Influence of Variable-Speed Waveforms on Vibration Suppression in Time-Varying Speed Cutting

2013 ◽  
Vol 690-693 ◽  
pp. 2514-2518
Author(s):  
Juan Cong ◽  
Yun Wang ◽  
Wei Na Yu
Keyword(s):  
Wave Speed ◽  
Vibration Suppression ◽  
Sine Wave ◽  
Time Varying ◽  
Variable Speed ◽  
Suppression Effect ◽  
Speed Variation ◽  
Input And Output ◽  
System Input ◽  
Better Than

Through the research on the change of system input and output energy in time-varying speed cutting, the influence of variable-speed waveforms on vibration suppression effect in time-varying speed cutting is quantitatively analyzed in this paper. A conclusion can be drawn that sine wave speed variation is better than triangle wave speed variation in vibration suppression.

scholarly journals Finite Element Software for Rubber Products Design

2018 ◽  
Vol 3 (1) ◽  
pp. 13-20
Author(s):  
Dávid Huri
Keyword(s):  
Finite Element ◽  
Complex Analysis ◽  
Large Deformations ◽  
Material Behavior ◽  
Nonlinear Material ◽  
Material Models ◽  
Finite Element Software ◽  
Highly Nonlinear ◽  
Wide Range ◽  
Different Types

Automotive rubber products are subjected to large deformations during working conditions, they often contact with other parts and they show highly nonlinear material behavior. Using finite element software for complex analysis of rubber parts can be a good way, although it has to contain special modules. Different types of rubber materials require the curve fitting possibility and the wide range choice of the material models. It is also important to be able to describe the viscoelastic property and the hysteresis. The remeshing possibility can be a useful tool for large deformation and the working circumstances require the contact and self contact ability as well. This article compares some types of the finite element software available on the market based on the above mentioned features.

The Fairing Arrangement for Vortex Induced Vibration Suppression Effect in Soliton Current

2020 ◽  
Vol 103 (sp1) ◽  
pp. 293
Author(s):  
Xiaoliang Qi ◽  
Dagang Zhang ◽  
Haiyan Guo ◽  
Youxiao Chen
Keyword(s):  
Vibration Suppression ◽  
Vortex Induced Vibration ◽  
Suppression Effect

Materials Compatibility With Pyrolysis Biofuel

2001 ◽  
Author(s):  
D. W. Kirk ◽  
Z. R. Li ◽  
D. Fuleki ◽  
P. C. Patnaik
Keyword(s):  
Stainless Steel ◽  
Alloy Steel ◽  
Polymeric Materials ◽  
304L Stainless Steel ◽  
Chromium Alloy ◽  
Stainless Steel 316L ◽  
Diesel Fuels ◽  
Wide Range ◽  
Elastomeric Materials ◽  
Pyrolysis Oils

The conversion of biomass such as wood and wood byproducts via pyrolysis into a liquid fuel is important in maximizing the use of material resources and in providing alternative and renewable sources of energy. Pyrolysis oils (or biofuels) have good combustion characteristics but are compositionally different from conventional diesel fuels. This difference requires that materials in contact with the biofuel be tested for compatibility. Three types of biofuels were tested for compatibility with a variety of polymeric materials and metal alloys. The test temperatures were set at 80°C to represent aggressive field usage conditions. The tests were conducted using coupons, which were fully immersed in the fluid for periods up to 15 days. These tests revealed that the metals 304L stainless steel, 316L stainless steel, 430 stainless steel and 20M04 stainless steels had corrosion rates of less than 0.007 mm/y and are suitable for use with the oils tested. A non-traditional low chromium alloy steel, MASH, was also examined and was found to be highly susceptible to all fuels at the high temperature tested and corroded at rates up to 3.7 mm/y. At room temperature, the alloy showed good resistance with a corrosion rate less than <0.009 mm/y. The polymeric materials showed a wide range of properties in the oils tested. Non-elastomers such as polytetrafluoroethylene, polypropylene and high-density polyethylene in general showed little swelling or staining in the oils. The elastomeric materials were much more susceptible to swelling, weight gain and change of surface properties. The attack on elastomeric materials was quite rapid with significant volume expansion seen within 24 hours. Viton, Buna-N and EPDM had volume changes up to 100% during a 10-day test and were not considered suitable seal materials for these oils. Multiple day tests for the low alloy steel at 80°C revealed that the corrosion attack was linear in nature leaving a corrosion scale, which slowed but did not prevent further attack. Details of the material degradation will be discussed.

Mechanical Seal with Elastomeric Rotating Element. Part 2: Experimental Study

1994 ◽  
Vol 67 (1) ◽  
pp. 62-75 ◽  
Author(s):  
Michael Rivkin ◽  
Arnold Kholodenko
Keyword(s):  
Silicon Carbide ◽  
Friction Coefficient ◽  
Water Pressure ◽  
Original Data ◽  
Friction Behavior ◽  
Effective Contact ◽  
Original Length ◽  
Wide Range ◽  
Elastomeric Materials ◽  
P Type

Abstract An innovative flexible faced mechanical shaft seal using common elastomeric materials was designed and tested to determine its friction coefficient at a wide range of temperatures and speeds, its rate of heat generation, and its feasibility for use in the process industry. The new seal was constructed using an elastomeric rotating element stretched over the sleeve to at least 20 percent of its original length and an unlapped silicon carbide stationary annular ring. It was found that the main advantage of the elastomeric seal is its ability to maintain stable lubrication with a fluid film considerably thinner than that of traditional hard face seals, and consequently achieve negligible net leakage. This is particularly significant with respect to control of volatile organic carbon emissions. An experimental device was designed for precise measurement of the friction coefficient as well as the long term friction behavior of seal pairs in a wide range of liquid pressure and temperature. The original data were obtained for friction coefficient of EPDM, HNBR, FKM, and TFE/P type elastomers in contact with silicon carbide in the temperature range 15–110°C, linear speeds 0–12 m/s, water pressure 0.15–0.40 MPa, and effective contact pressure 0.8–1.2 MPa. Experiments showed that the friction coefficient constantly grows, typically from 0.05 to 0.15 at sliding speeds of 2–12 m/s, with temperature increases from 15 to 70°C. The temperature behavior of the friction coefficient above 70°C greatly depends on the elastomer. For high temperature elastomers, such as FKM, the friction coefficient may decrease slightly at 70°C; whereas, for EPDM, it continues to increase as temperature increases.

Seismic Performance of Vibration Control Device That Generates Power

2009 ◽  
Author(s):  
Taichi Matsuoka ◽  
Katsuaki Sunakoda ◽  
Kazuhiko Hiramoto ◽  
Issei Yamazaki ◽  
Akira Fukukita ◽  
...  
Keyword(s):  
Vibration Control ◽  
Earthquake Engineering ◽  
Vibration Suppression ◽  
Experimental Testing ◽  
Control Device ◽  
Shaking Table ◽  
Ball Screw ◽  
Scale Model ◽  
Small Scale ◽  
Wide Range

In a previous paper the authors proposed a semi-active vibration control device (VCD) that generates power. The device utilizes a ball screw, and has inertial and damping forces. The damping coefficient is adjusted by altering resistance at the terminal of the power generator. A small-scale VCD was manufactured for experimental testing. Frequency responses of a small-scale spring mass structure were measured in order to confirm the effects of vibration suppression within a wide range of frequencies. In this paper, as the next step, vibration tests using a benchmark structure with an installed VCD that has a 30 kN capacity are carried out at the National Center for Research on Earthquake Engineering (NCREE) in Taiwan. The benchmark structure has three stories with a 3 m height and a mass of 6 tons at each floor level for a total height and weight of 9 m and 18 tons, respectively. The VCDs are installed between adjacent floors with steel chevron braces. A simple control law that is based on a minimized Lyapunov function and employs bang-bang operation is used as a variable current controller instead of the modifying the resistance level of the VCD. Scaled earthquake motions including the Imperial Valley El Centro north-south component that is normalized to be a peak level of 0.5 m/s2, are applied to the base of the steel framed structure in the horizontal direction by a shaking table. Experimental responses of each floor for the uncontrolled and controlled cases are compared with analytical responses, and effects of vibration suppression for the large-scale model are discussed quantitatively.

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