Multiple Impacts and Multiple-Compression Process in the Dynamics of Granular Chains

2019 ◽  
Vol 14 (12) ◽  
Author(s):  
Yajie Feng ◽  
Wenting Kang ◽  
Daolin Ma ◽  
Caishan Liu
Keyword(s):  
Wave Propagation ◽  
Contact Point ◽  
High Amplitude ◽  
Multiple Impacts ◽  
Compression Process ◽  
Pulse Profile ◽  
High Frequency Oscillations ◽  
Granular Chains ◽  
Multiple Compression ◽  
Single Contact Point

Abstract In this paper, we study the dynamics of one-dimensional chains composed of elastoplastic beads. Three uniform chains, which were experimentally studied in the existing literature, are taken as benchmark examples for manifesting wave propagation induced by multiple impacts between particles and by multiple-compression process in a single contact point. We perform simulations using an elastoplastic contact model developed recently for the binary contact of a sphere. Numerical results show good agreement with the experimental observations, including the profile and amplitude of the incident and reflected solitary waves, the travel time of the wave propagation, and the high-frequency oscillations residing in the high-amplitude stress wave. Our simulations also show that the multiple-compression process of the contact between particles is responsible for the oscillations residing in the pulse profile.

scholarly journals Elastic–Plastic Wave Propagation in Uniform and Periodic Granular Chains

2015 ◽  
Vol 82 (8) ◽  
Author(s):  
Hayden A. Burgoyne ◽  
Chiara Daraio
Keyword(s):  
Wave Propagation ◽  
Hopkinson Bar ◽  
High Amplitude ◽  
Pulse Velocity ◽  
Stress Waves ◽  
Laser Vibrometer ◽  
Particle Properties ◽  
Elastic Plastic ◽  
Rate Dependent ◽  
Granular Chains

We investigate the properties of high-amplitude stress waves propagating through chains of elastic–plastic particles using experiments and simulations. We model the system after impact using discrete element method (DEM) with strain-rate dependent contact interactions. Experiments are performed on a Hopkinson bar coupled with a laser vibrometer. The bar excites chains of 50 identical particles and dimer chains of two alternating materials. After investigating how the speed of the initial stress wave varies with particle properties and loading amplitude, we provide an upper bound for the leading pulse velocity that can be used to design materials with tailored wave propagation.

High-amplitude elastic solitary wave propagation in 1-D granular chains with preconditioned beads: Experiments and theoretical analysis

2014 ◽  
Vol 72 ◽  
pp. 161-173 ◽  
Author(s):  
Erheng Wang ◽  
Mohith Manjunath ◽  
Amnaya P. Awasthi ◽  
Raj Kumar Pal ◽  
Philippe H. Geubelle ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Theoretical Analysis ◽  
Solitary Wave ◽  
High Amplitude ◽  
Granular Chains

scholarly journals Non-reciprocal wave propagation in modulated elastic metamaterials

2017 ◽  
Vol 473 (2202) ◽  
pp. 20170188 ◽  
Author(s):  
H. Nassar ◽  
H. Chen ◽  
A. N. Norris ◽  
M. R. Haberman ◽  
G. L. Huang
Keyword(s):  
Wave Propagation ◽  
Elastic Wave ◽  
Effective Mass ◽  
Mass Operator ◽  
High Amplitude ◽  
Coupled Mode Theory ◽  
Coupled Mode ◽  
Transient Regimes ◽  
Elastic Metamaterials ◽  
Large Frequency

Time-reversal symmetry for elastic wave propagation breaks down in a resonant mass-in-mass lattice whose inner-stiffness is weakly modulated in space and in time in a wave-like fashion. Specifically, one-way wave transmission, conversion and amplification as well as unidirectional wave blocking are demonstrated analytically through an asymptotic analysis based on coupled mode theory and numerically thanks to a series of simulations in harmonic and transient regimes. High-amplitude modulations are then explored in the homogenization limit where a non-standard effective mass operator is recovered and shown to take negative values over unusually large frequency bands. These modulated metamaterials, which exhibit either non-reciprocal behaviours or non-standard effective mass operators, offer promise for applications in the field of elastic wave control in general and in one-way conversion/amplification in particular.

High-amplitude and high-frequency oscillations of temperature and current in SOI structure

1999 ◽  
Vol 48 (1-4) ◽  
pp. 343-346
Author(s):  
V.N. Dobrovolsky ◽  
L.V. Ishchuk ◽  
G.K. Ninidze ◽  
M. Balucani ◽  
A. Ferrari
Keyword(s):  
High Frequency ◽  
High Amplitude ◽  
High Frequency Oscillations

Analysis and Computation of Two Body Impact in Three Dimensions

2017 ◽  
Vol 12 (4) ◽  
Author(s):  
Yan-Bin Jia ◽  
Feifei Wang
Keyword(s):  
Closed Form ◽  
Contact Point ◽  
Positive Definiteness ◽  
Rigid Bodies ◽  
Three Dimensions ◽  
Sliding Velocity ◽  
Form Analysis ◽  
Coulomb’S Friction ◽  
The Matrix ◽  
Single Contact Point

A formal impulse-based analysis is presented for the collision of two rigid bodies at single contact point under Coulomb's friction in three dimensions (3D). The tangential impulse at the contact is known to be linear in the sliding velocity whose trajectory, parametrized with the normal impulse and referred to as the hodograph, is governed by a generally nonintegrable ordinary differential equation (ODE). Evolution of the hodograph is bounded by rays in several invariant directions of sliding in the contact plane. Exact lower and upper bounds are derived for the number of such invariant directions, utilizing the established positive definiteness of the matrix defining the governing ODE. If the hodograph reaches the origin, it either terminates (i.e., the contact sticks) or continues in a new direction (i.e., the contact resumes sliding) whose existence and uniqueness, only assumed in the literature, are proven. Closed-form integration of the ODE becomes possible as soon as the sliding velocity turns zero or takes on an invariant direction. Assuming Stronge's energy-based restitution, a complete algorithm is described to combine fast numerical integration (NI) with a case-by-case closed-form analysis. A number of solved collision instances are presented. It remains open whether the modeled impact process will always terminate under Coulomb's friction and Stronge's (or Poisson's) restitution hypothesis.

Selective loss of high-frequency oscillations in phrenic and hypoglossal activity in the decerebrate rat during gasping

2006 ◽  
Vol 291 (5) ◽  
pp. R1414-R1429 ◽  
Author(s):  
Vitaliy Marchenko ◽  
Robert F. Rogers
Keyword(s):  
Power Distribution ◽  
High Frequency ◽  
Spectral Characteristics ◽  
Low Frequency ◽  
High Amplitude ◽  
Medial Branch ◽  
Adult Rats ◽  
Time Frequency ◽  
High Frequency Oscillations ◽  
Nerve Recordings

Respiratory motor outputs contain medium-(MFO) and high-frequency oscillations (HFO) that are much faster than the fundamental breathing rhythm. However, the associated changes in power spectral characteristics of the major respiratory outputs in unanesthetized animals during the transition from normal eupneic breathing to hypoxic gasping have not been well characterized. Experiments were performed on nine unanesthetized, chemo- and barodenervated, decerebrate adult rats, in which asphyxia elicited hyperpnea, followed by apnea and gasping. A gated fast Fourier transform (FFT) analysis and a novel time-frequency representation (TFR) analysis were developed and applied to whole phrenic and to medial branch hypoglossal nerve recordings. Our results revealed one MFO and one HFO peak in the phrenic output during eupnea, where HFO was prominent in the first two-thirds of the burst and MFO was prominent in the latter two-thirds of the burst. The hypoglossal activity contained broadband power distribution with several distinct peaks. During gasping, two high-amplitude MFO peaks were present in phrenic activity, and this state was characterized by a conspicuous loss in HFO power. Hypoglossal activity showed a significant reduction in power and a shift in its distribution toward lower frequencies during gasping. TFR analysis of phrenic activity revealed the increasing importance of an initial low-frequency “start-up” burst that grew in relative intensity as hypoxic conditions persisted. Significant changes in MFO and HFO rhythm generation during the transition from eupnea to gasping presumably reflect a reconfiguration of the respiratory network and/or alterations in signal processing by the circuitry associated with the two motor pools.

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