The Periodic Impact Responses of Human-Body in a Vehicle Traveling on the Rough Terrain

2002 ◽  
Author(s):  
Ke Yu ◽  
Albert C. J. Luo
Keyword(s):  
Linear Model ◽  
Human Body ◽  
Rotational Motion ◽  
Large Mass ◽  
Rough Terrain ◽  
Lumped Mass ◽  
The Stability ◽  
Vehicle Chassis ◽  
Specific Number ◽  
Impact Motion

The human-body in a vehicle traveling on the rough terrain is modeled through the lumped mass approach and its periodic impact motions and stability are investigated through a linear model of vehicle and passenger systems. The linear model assumes the motion response of vehicle is very small compared to passenger’s rotational motion since the vehicle chassis has a very large mass and moment of inertia. The period-1 impact motion for two impacts respectively on two walls for a specific number of periods is predicted analytically and numerically. The stability and bifurcation of such a period-1 impact motion are developed analytically. The phase planes of the periodic impact motions are illustrated for a better understanding of the human-body impacting motion in the vehicle.

Open discussion

1982 ◽  
Vol 99 ◽  
pp. 605-613
Author(s):  
P. S. Conti
Keyword(s):  
Buenos Aires ◽  
Large Mass ◽  
List Type ◽  
Common Phenomenon ◽  
Open Discussion ◽  
The Stability ◽  
Ring Nebulae

Conti: One of the main conclusions of the Wolf-Rayet symposium in Buenos Aires was that Wolf-Rayet stars are evolutionary products of massive objects. Some questions:–Do hot helium-rich stars, that are not Wolf-Rayet stars, exist?–What about the stability of helium rich stars of large mass? We know a helium rich star of ∼40 MO. Has the stability something to do with the wind?–Ring nebulae and bubbles : this seems to be a much more common phenomenon than we thought of some years age.–What is the origin of the subtypes? This is important to find a possible matching of scenarios to subtypes.

scholarly journals Wormhole Solutions in Symmetric Teleparallel Gravity with Noncommutative Geometry

Symmetry ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1260
Author(s):  
Zinnat Hassan ◽  
Ghulam Mustafa ◽  
Pradyumn Kumar Sahoo
Keyword(s):  
Linear Model ◽  
Noncommutative Geometry ◽  
Teleparallel Gravity ◽  
Exponential Model ◽  
Model Parameter ◽  
Exponential Models ◽  
Feasible Solutions ◽  
The Stability ◽  
Tov Equation

This article describes the study of wormhole solutions in f(Q) gravity with noncommutative geometry. Here, we considered two different f(Q) models—a linear model f(Q)=αQ and an exponential model f(Q)=Q−α1−e−Q, where Q is the non-metricity and α is the model parameter. In addition, we discussed the existence of wormhole solutions with the help of the Gaussian and Lorentzian distributions of these linear and exponential models. We investigated the feasible solutions and graphically analyzed the different properties of these models by taking appropriate values for the parameter. Moreover, we used the Tolman–Oppenheimer–Volkov (TOV) equation to check the stability of the wormhole solutions that we obtained. Hence, we found that the wormhole solutions obtained with our models are physically capable and stable.

scholarly journals Study of Corrosion Resistance and Degradation Mechanisms in LiTiO2-Li2TiO3 Ceramic

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 753
Author(s):  
Dmitriy Shlimas ◽  
Artem L. Kozlovskiy ◽  
Maxim Zdorovets
Keyword(s):  
Degradation Mechanism ◽  
Diffraction Method ◽  
Large Mass ◽  
Time Frame ◽  
X Ray Diffraction ◽  
Acidic Media ◽  
X Ray ◽  
Mass Losses ◽  
The Stability ◽  
Thermal Sintering

The interest in lithium-containing ceramics is due to their huge potential as blanket materials for thermonuclear reactors for the accumulation of tritium. However, an important factor in their use is the preservation of the stability of their strength and structural properties when under the influence of external factors that determine the time frame of their operation. This paper presents the results of a study that investigated the influence of the LiTiO2 phase on the increasing resistance to degradation and corrosion of Li2TiO3 ceramic when exposed to aggressive acidic media. Using the X-ray diffraction method, it was found that an increase in the concentration of LiClO4·3H2O during synthesis leads to the formation of a cubic LiTiO2 phase in the structure as a result of thermal sintering of the samples. During corrosion tests, it was found that the presence of the LiTiO2 phase leads to a decrease in the degradation rate in acidic media by 20–70%, depending on the concentration of the phase. At the same time, and in contrast to the samples of Li2TiO3 ceramics, for which the mechanisms of degradation during a long stay in aggressive media are accompanied by large mass losses, for the samples containing the LiTiO2 phase, the main degradation mechanism is pitting corrosion with the formation of pitting inclusions.

REVIEW ON THEORETICAL STUDIES OF SUPERHEAVY NUCLEI

2006 ◽  
Vol 15 (07) ◽  
pp. 1587-1599 ◽  
Author(s):  
ZHONGZHOU REN ◽  
DINGHAN CHEN ◽  
CHANG XU
Keyword(s):  
Ground State ◽  
Large Mass ◽  
Mass Region ◽  
Superheavy Nuclei ◽  
Theoretical Studies ◽  
Shape Coexistence ◽  
Good Test ◽  
Α Decay ◽  
The Stability ◽  
Theoretical Results

Superheavy elements have provided a good test of the validity of both nuclear structure models and nuclear decay models in a large mass region. We firstly review the recent progress on theoretical studies of superheavy nuclei. Emphasis is placed on the structure and decay of superheavy nuclei. Then theoretical results of odd-odd nuclei with Z = 109 - 115 are presented and discussed. It is clearly demonstrated that there is shape coexistence for the ground state of many superheavy nuclei from different models and many superheavy nuclei are deformed. In some cases superdeformation can become the ground state of superheavy nuclei and it is important for future studies of superheavy nuclei. This can lead to the existence of low-energy isomers in the superheavy region and it plays an important role for the stability of superheavy nuclei. As α-decay and spontaneous fission plays a crucial role for identifications of new elements, we also review some typical models of α-decay half-lives and spontaneous fissions half-lives. Some new views on superheavy nuclei are presented.

A Study of Noise Impact on the Stability of Electrostatic MEMS

2020 ◽  
Vol 15 (11) ◽  
Author(s):  
Yan Qiao ◽  
Wei Xu ◽  
Hongxia Zhang ◽  
Qin Guo ◽  
Eihab Abdel-Rahman
Keyword(s):  
Noise Intensity ◽  
Initial Conditions ◽  
Basins Of Attraction ◽  
Low Noise ◽  
Intensity Level ◽  
Lumped Mass ◽  
Mass Model ◽  
Restoring Force ◽  
Electrostatic Mems ◽  
The Stability

Abstract Noise-induced motions are a significant source of uncertainty in the response of micro-electromechanical systems (MEMS). This is particularly the case for electrostatic MEMS where electrical and mechanical sources contribute to noise and can result in sudden and drastic loss of stability. This paper investigates the effects of noise processes on the stability of electrostatic MEMS via a lumped-mass model that accounts for uncertainty in mass, mechanical restoring force, bias voltage, and AC voltage amplitude. We evaluated the stationary probability density function (PDF) of the resonator response and its basins of attraction in the presence noise and compared them to that those obtained under deterministic excitations only. We found that the presence of noise was most significant in the vicinity of resonance. Even low noise intensity levels caused stochastic jumps between co-existing orbits away from bifurcation points. Moderate noise intensity levels were found to destroy the basins of attraction of the larger orbits. Higher noise intensity levels were found to destroy the basins of attraction of smaller orbits, dominate the dynamic response, and occasionally lead to pull-in. The probabilities of pull-in of the resonator under different noise intensity level are calculated, which are sensitive to the initial conditions.

Evaluation of Human Body Dynamical Behaviour During Handling Maneuvers and Crash Test Simulations Using Multi-Body Codes

2006 ◽  
Author(s):  
Francesco Braghin ◽  
Paolo Pennacchi ◽  
Edoardo Sabbioni
Keyword(s):  
Rigid Body ◽  
Human Body ◽  
Dynamical Behaviour ◽  
Crash Test ◽  
Frontal Crash ◽  
Race Car ◽  
Body Dynamics ◽  
Multi Body ◽  
Vehicle Chassis ◽  
Crash Tests

The dynamic behavior of the human body during race car maneuvers and frontal crash tests is analyzed in this paper. Both the vehicle and the human body have been modeled using the multi-body approach. Two commercial codes, BRG LifeMOD Biomechanics Modeler®, for the simulation of the human body dynamics, and MSC ADAMS/Car® for the modeling of the vehicle behavior, have been used for the purpose. Due to the impossibility of co-simulating, at first the accelerations on the driver’s chassis are determined using the vehicle’s multibody code and approximating the driver as a rigid body. Then, the calculated accelerations are applied to the vehicle chassis in the biomechanics code to assess the accelerations in various significant points on the driver.

scholarly journals New criterion for the stability of a human body in floodwaters

2014 ◽  
Vol 52 (1) ◽  
pp. 93-104 ◽  
Author(s):  
Junqiang Xia ◽  
Roger A. Falconer ◽  
Yejiang Wang ◽  
Xuanwei Xiao
Keyword(s):  
Human Body ◽  
The Stability ◽  
New Criterion

Development of a Model to Represent an Aluminum Springboard in Diving

1989 ◽  
Vol 5 (3) ◽  
pp. 297-307 ◽  
Author(s):  
Eric J. Sprigings ◽  
Denise S. Stilling ◽  
L. Glen Watson
Keyword(s):  
Finite Element ◽  
Effective Mass ◽  
Linear Model ◽  
Simulation Studies ◽  
Characteristic Parameters ◽  
Lumped Mass ◽  
Interaction Forces ◽  
Finite Element Approach ◽  
Element Approach ◽  
Stiffness And Damping

The purpose of this study was to develop a springboard model that could be used to predict, in future diving simulation studies, the vertical interaction forces between a diver’s feet and the board during the time of board depression and recoil. To achieve this, the characteristic parameters (effective mass, stiffness, and damping) for a Duraflex springboard were first examined using a finite element approach. The finite element results indicated that a linear model, consisting of a lumped mass and spring, could be used to simulate the actual dynamic behavior of a springboard system. The effects of damping on the board’s motion were found to be negligible and could safely be ignored. The values for the model’s parameters (board stiffness and effective board mass) were determined empirically and are reported in this paper.

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