Damper force Characteristics of a Separated Dual-chamber Single-rod Type Damper utilizing an Elastomer Particle Assemblage in the Case of both Chambers Containing Particles

2020 ◽  
pp. 1-27
Author(s):  
Atsushi Toyouchi ◽  
Yasushi Ido ◽  
Yuhiro Iwamoto ◽  
Makoto Hanai
Keyword(s):  
Friction Force ◽  
Vibration Frequency ◽  
Compressive Force ◽  
Packing Fraction ◽  
Dual Chamber ◽  
Hard Particles ◽  
Large Hysteresis ◽  
Particle Dampers ◽  
Force Characteristics ◽  
Good Agreement

Abstract Particle dampers that use soft/hard particles are attracting attention as a solution to problems such as oil leakage of oil dampers and the temperature dependence of their characteristics. Particle dampers effectively attenuate vibration using the friction and inelastic normal collisions generated between particles or between particles and walls. Here, the effects of the packing fraction of particles, the vibration frequency, and hardness of the material on the damper force characteristics of a separated dual-chamber single-rod type damper with elastomer particle assemblages were investigated experimentally. The maximal damper force and its hysteresis increased with the packing fraction, the vibration frequency, and the Young's modulus of the particle material. Numerical simulations using the discrete element method were performed to confirm the behavior of the elastomer particles when they were packed in both chambers. The compressive force distribution and velocity vector diagram of particles in the simulations showed that friction and compression between particles due to particle movement, friction between particles and the chamber walls, and the viscosity of the elastomer particles caused a large hysteresis in the damper force. The maximum damper force is affected by the viscoelastic component force and the friction force in the same proportion, and the hysteresis is dominated by the friction force. The simulation results were confirmed to be in good agreement, both qualitatively and quantitatively, with the experimentally measured damper force characteristics.

scholarly journals Influence of Frequency on the Resolution of Magnetostrictive Bio-Inspired Whisker Sensors

2018 ◽  
Vol 2018 ◽  
pp. 1-7
Author(s):  
Ran Zhao ◽  
Bo-wen Wang ◽  
Quan-guo Lu ◽  
Jian-wu Yan ◽  
Xiao-cui Yuan
Keyword(s):  
Vibration Frequency ◽  
Dynamic Testing ◽  
Theoretical Calculations ◽  
Beam Theory ◽  
Experimental System ◽  
Flow Sensors ◽  
Maximum Resolution ◽  
Sensing Model ◽  
Euler Bernoulli Beam ◽  
Good Agreement

Magnetostrictive biomimetic whiskers have been used as tactile and flow sensors. Compared to other types of whiskers, such whiskers have the advantage of being able to perform static and dynamic measurements. For dynamic measurement, the whisker’s resolution changes with varying vibration frequency; however, the mechanism for this influence has not been studied yet. Thus, the aim of this study is to investigate the resolution–frequency correlation. First, the structure and operation principle of the whisker were analyzed. Then, the Euler–Bernoulli beam theory was employed to establish the sensing model of the magnetostrictive whisker. Finally, the mapping relationship between sensor resolution and frequency was obtained. The eigenfrequency analysis was implemented by FEM to obtain the frequency response of the whisker. A vibration experimental system was built for dynamic testing. The experimental results were in good agreement with the theoretical calculations. Furthermore, it was noted that the resolution was positively correlated with frequency, and the maximum resolution was attained at the natural frequency (two peak values appeared at the first-order and second-order eigenfrequencies). Our research reveals the manner in which a whisker sensor’s resolution is affected by the vibration frequency. The theoretical model can be used to predict the resolution of magnetostrictive whisker sensors.

Simulating Dynamic Activities Using a Five-Axis Knee Simulator

2005 ◽  
Vol 127 (1) ◽  
pp. 123-133 ◽  
Author(s):  
Lorin P. Maletsky ◽  
Ben M. Hillberry
Keyword(s):  
Sagittal Plane ◽  
Compressive Force ◽  
Knee Prostheses ◽  
Plane Model ◽  
Knee Simulator ◽  
Specific Loading ◽  
Total Knee ◽  
Five Axis ◽  
Cadaveric Knee ◽  
Good Agreement

This work describes the design and capabilities of the Purdue Knee Simulator: Mark II and a sagittal-plane model of the machine. This five-axis simulator was designed and constructed to simulate dynamic loading activities on either cadaveric knee specimens or total knee prostheses mounted on fixtures. The purpose of the machine was to provide a consistent, realistic loading of the knee joint, allowing the kinematics and specific loading of the structures of the knee to be determined based on condition, articular geometry, and simulated activity. The sagittal-plane model of the knee simulator was developed both to predict the loading at the knee from arbitrary inputs and to generate the necessary inputs required to duplicate specified joint loading. Measured tibio-femoral compressive force and quadriceps tension were shown to be in good agreement with the predicted loads from the model. A controlled moment about the ankle-flexion axis was also shown to change the loading on the quadriceps.

Experimental Characterization of a T-Shaped Programmable Multistable Mechanism

2018 ◽  
Vol 140 (9) ◽  
Author(s):  
Mohamed Zanaty ◽  
Simon Henein
Keyword(s):  
Numerical Simulations ◽  
Reaction Force ◽  
Experimental Measurements ◽  
Experimental Characterization ◽  
Stable States ◽  
Stability Behavior ◽  
The Stability ◽  
Force Characteristics ◽  
Good Agreement

Programmable multistable mechanisms (PMM) exhibit a modifiable stability behavior in which the number of stable states, stiffness, and reaction force characteristics are controlled via their programming inputs. In this paper, we present experimental characterization for the concept of stability programing introduced in our previous work (Zanaty et al., 2018, “Programmable Multistable Mechanisms: Synthesis and Modeling,” ASME J. Mech. Des., 140(4), p. 042301.) A prototype of the T-combined axially loaded double parallelogram mechanisms (DPM) with rectangular hinges is manufactured using electrodischarge machining (EDM). An analytical model based on Euler–Bernoulli equations of the T-mechanism is derived from which the stability behavior is extracted. Numerical simulations and experimental measurements are conducted on programming the mechanism as monostable, bistable, tristable, and quadrastable, and show good agreement with our analytical derivations within 10%.

Dry Friction Effect on the Work of Viscous Torsion Damper

2016 ◽  
Vol 817 ◽  
pp. 13-18
Author(s):  
Celina Jagiełowicz-Ryznar
Keyword(s):  
Friction Coefficient ◽  
Free Vibration ◽  
Friction Force ◽  
Vibration Frequency ◽  
Forced Vibration ◽  
Dry Friction ◽  
Viscous Damper ◽  
The Real ◽  
Free Vibration Frequency ◽  
Marine Engines

The results of crankshaft forced vibration calculations, including the dry friction force which can be formed in the viscous damper bearing sliding, were presented. This problem concerns the big dampers used in the marine engines. The friction force influence is presented using the function {sign}. Low values of friction coefficient, corresponding to the conditions similar to the real ones, were assumed. In the range of tested value, it was found that the vibration increases linearly, and system free vibration frequency doesn’t change practically.

scholarly journals Hysteretic restoring force characteristics of unbounded prestressed concrete framed structure under earthquake load

1989 ◽  
Vol 22 (2) ◽  
pp. 112-121
Author(s):  
M. Nishiyama ◽  
H. Mugurama ◽  
F. Watanabe
Keyword(s):  
Prestressed Concrete ◽  
Analytical Method ◽  
Concrete Beam ◽  
Concrete Columns ◽  
Restoring Force ◽  
Bond Slip ◽  
Earthquake Load ◽  
Reversed Cyclic ◽  
Force Characteristics ◽  
Good Agreement

An analytical method, by which hysteretic restoring force characteristics of unbonded prestressed concrete framed structure can be statically pursued on the basis of material properties, is presented. The bond-slip relationship between concrete and prestressing tendon is taken into account, and thus the method covers unbonded members and bonded members. For verifying the propriety of the analytical method, the experiment is carried out on a portal frame with an unbonded prestressed concrete beam of 4.2 m in length and reinforced concrete columns of 1 m in height. High intensity reversed cyclic lateral loading is applied. The experimental results show a good agreement with the analytical ones in terms of load-deflection relation and the fluctuation of the tendon stress at anchorage end.

scholarly journals Experimental and Numerical Analysis of Torque Properties of Rotary Elastomer Particle Damper considering the Effect of Gap and No Gap between Rotor and Body of the Damper

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Allah Rakhio ◽  
Yasushi Ido ◽  
Yuhiro Iwamoto ◽  
Atsushi Toyouchi
Keyword(s):  
Rotational Speed ◽  
Packing Fraction ◽  
Vital Role ◽  
Simulation Approach ◽  
Analysis Method ◽  
Gap Model ◽  
Element Analysis ◽  
Metallic Particles ◽  
Simulation Results ◽  
Particle Dampers

Particle dampers are devices used to control the vibration of mechanical systems. In this research, prototypes of rotary elastomer particle dampers are experimentally tested considering gap and no gap between shaft and cylinder. There is a gap between the rotor and cylinder in the gap model; particles can move from one chamber to another. There is no space for the particles to move from one chamber to another in the no-gap model. Elastomer particles are soft, and they have different behavior from hard (metallic) particles. Experiments on rotary elastomer particle dampers considering the gap between rotor and cylinder helped investigate the effects of the change in packing fraction, rotational speed, size of elastomers, and the gap between the rotor and the damper body. A numerical simulation approach based on the discrete element analysis method is used to perform a quantitative and qualitative analysis of the rotary elastomer particle damper. The simulation results are in great agreement with the experiment results. It is observed that packing fraction, rotational speed, size of elastomer particles, and the gap between rotor and cylinder play a vital role in producing higher damper torque.

On the Inclusion of Sliding Kinematical Effects on the Biodynamical Modeling of Symmetrical Lifting Activities

2009 ◽  
Author(s):  
Mohammed M. Hassan ◽  
E. M. Bakr ◽  
A. A. Hegazy
Keyword(s):  
Present Model ◽  
Compressive Force ◽  
Dynamic Responses ◽  
Normal Range ◽  
Body Postures ◽  
Symmetric Lifting ◽  
Angular Velocities ◽  
Severe Back Pain ◽  
Vast Range ◽  
Good Agreement

In this paper, A new biodynamical model was developed with the objective of analyzing the dynamic responses of the human back during the exertion of symmetric lifting activities. More emphasis was placed on the study of the lumbosacral disc located between the fifth lumbar and first sacral vertebrae (L5/S1). The present model accounts for the sliding components of velocity and acceleration as well as the Coriolis acceleration in the kinematical equations of the human back. The inclusion of those terms has enabled a more accurate computation of the generated sliding effect of the flexible disc as well as the change in its height and width which normally occurs during the gross body rotation of the back. This has turned to have a significant effect on the resulting compressive force applied at the L5/S1 region. A computer model was developed in this study to automate the biodynamical simulation processes for workers of different genders and for a vast range of body postures. Results indicated that the inclusion of the sliding components of velocity and acceleration do actually have a significant effect on the whole range of lifting activities in which an angular velocity exceeding 24 degree/sec is employed. Results obtained in this paper were compared with the experimental and computational (simulated) results of recent relevant publications. The comparison shows that there are good agreements between the results for angular velocities exceeding 24 degree/second, which is known as the normal range of operation in lifting activities. Results obtained in this paper were in good agreement with NIOSH action and maximum limits which make it reliable for use as a guideline to help workers in industry to avoid hostile lifting activities and bring to attention an early warning to avoid engaging industrial labors with postures leading to severe back pain problems.

Theoretical Model of Plastic Hysteresis in Spherical Contact Under Combined Normal and Tangential Loading

2008 ◽  
Author(s):  
Yuri Kligerman ◽  
Izhak Etsion
Keyword(s):  
Theoretical Model ◽  
Stress State ◽  
Friction Force ◽  
Contact Area ◽  
Contact Condition ◽  
Experimental Results ◽  
Tangential Displacement ◽  
Elastic Plastic ◽  
Plastic Sphere ◽  
Good Agreement

The behavior of an elastic-plastic contact between a deformable sphere and a rigid flat under combined constant normal and reciprocating tangential loading is investigated in the present work. The theoretical model is based on the assumptions of full stick contact condition and two kinds of the sphere material hardening. Hysteretic change of friction force versus tangential displacement during reciprocating tangential loading is investigated along with the study of the change of the contact area and stress state in the elastic-plastic sphere. Good agreement between theoretical and experimental results is obtained.

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