Parametric Analysis in Tug-of-War Based on Ideal Biomechanical Model

2012 ◽  
Vol 192 ◽  
pp. 207-210
Author(s):  
Bing Zhang
Keyword(s):  
Simple Model ◽  
Parametric Analysis ◽  
Biomechanical Model ◽  
Mechanical Analysis ◽  
Maximum Energy ◽  
Maximum Pressure ◽  
Force Analysis ◽  
Maximum Friction

This paper, in perspective of biomechanics, analyzes tug-of-war, on condition of maximum friction and stable rope, and achieves the sequence which can exert maximum energy. The key to exert maximum energy is to achieve maximum friction. Firstly, build an ideal and simple model, with mechanical analysis, and get that point. Secondly, analyze the maximum pressure and conduct force analysis of rope, with a conclusion that if the sequence is arrayed from short to tall and only when the heights are the same, the athletes with greater weight should stand behind.

Computational modelling and analysis of haemodynamics in a simple model of aortic stenosis

2018 ◽  
Vol 851 ◽  
pp. 23-49 ◽  
Author(s):  
Chi Zhu ◽  
Jung-Hee Seo ◽  
Rajat Mittal
Keyword(s):  
Simple Model ◽  
Aortic Stenosis ◽  
Secondary Flow ◽  
Pressure Fluctuation ◽  
Computational Modelling ◽  
Maximum Pressure ◽  
Cardiac Auscultation ◽  
Curved Pipe ◽  
Free Jet ◽  
Wall Pressure Fluctuation

In a study motivated by considerations associated with heart murmurs and cardiac auscultation, numerical simulations are used to analyse the haemodynamics in a simple model of an aorta with an aortic stenosis. The aorta is modelled as a curved pipe with a$180^{\circ }$turn, and three different stenoses with area reductions of 50 %, 62.5 % and 75 % are examined. A uniform steady inlet velocity with a Reynolds number of 2000 is used for all of the cases and direct numerical simulation is employed to resolve the dynamics of the flow. The poststenotic flow is dominated by the jet that originates from the stenosis as well as the secondary flow induced by the curvature, and both contribute significantly to the flow turbulence. On the anterior surface of the modelled aorta, the location with maximum pressure fluctuation, which may be considered as the source location for the murmurs, is found to be located around$60^{\circ }$along the aortic arch, and this location is relatively insensitive to the severity of the stenosis. For all three cases, this high-intensity wall pressure fluctuation includes contributions from both the jet and the secondary flow. Spectral analysis shows that for all three stenoses, the Strouhal number of the vortex shedding of the jet shear layer is close to 0.93, which is higher than the shedding frequency of a corresponding free jet or a jet confined in a straight pipe. This frequency also appears in the pressure spectra at the location postulated as the source of the murmurs, in the form of a ‘break frequency.’ The implications of these findings for cardiac auscultation-based diagnosis of aortic stenosis are also discussed.

The Force Analysis on the Shaft of Electric Vehicle Based on Unigraphics

2012 ◽  
Vol 507 ◽  
pp. 242-245
Author(s):  
Tao Fen Wang
Keyword(s):  
Electric Vehicle ◽  
Mechanical Analysis ◽  
Force Characteristic ◽  
Analysis Method ◽  
Force Analysis ◽  
Design Quality ◽  
Analysis Process ◽  
Electric Shaft ◽  
3D Software ◽  
Force Data

Although the mechanical analysis on electric shaft is a complex and trival analysis process, the analysis method of using UG makes the force analysis of electric shaft single, rapid, accurate, and we realized the graphical level and improve the design efficiency and design quality. Through establishing a mathematical model, this paper analyzed the force characteristic of shaft according to the mathematical model.Then analyzed the force of connecting in rod automobile engine by using 3D software Unigraphics (UG).Fianlly we get the force data, whch provides theoretical basis and technical support for the axis force research of electric vehicle.

Numerical Simulation Analysis of Centrifugal Pump Floating Ring Seal

2011 ◽  
Vol 317-319 ◽  
pp. 2148-2151
Author(s):  
Jian Yong Han ◽  
Guo Jing Chen
Keyword(s):  
Numerical Simulation ◽  
High Pressure ◽  
Centrifugal Pump ◽  
Simulation Analysis ◽  
Maximum Pressure ◽  
Force Analysis ◽  
Sealing Ring ◽  
Fluent Software ◽  
Ring Seal ◽  
Liquid Flows

According to the studying on the force analysis of floating ring of centrifugal pump, the paper think that floating ring stress will change with the change of centrifugal pump’ s condition. Using fluent software, the floating ring seal was simulated and analyzed. Results show that the liquid force acted on the floating ring is nonuniform and asymmetrical as wedging effect, and that section maximum pressure is not lies in the smallest clearance place, but in the wedge area where liquid flows to the minimum clearance, because the effect of Leak resistance is better in high pressure than low pressure. The leakage decreases and liquid resistance increases with the increases of RPM. The leakage increases with the increases of differential pressure in sealing ring sides and eccentricity. Pressure distribution within the seal clearance is not uniform with the increases of eccentricity.

THORAX INJURY CRITERIA ASSESSMENT THROUGH NON-LETHAL IMPACT USING AN ENHANCED BIOMECHANICAL MODEL

2017 ◽  
Vol 17 (07) ◽  
pp. 1740027 ◽  
Author(s):  
MICHÈLE BODO ◽  
ANTHONY BRACQ ◽  
REMI DELILLE ◽  
CHRISTOPHE MARECHAL ◽  
SÉBASTIEN ROTH
Keyword(s):  
Lung Injury ◽  
Injury Risk ◽  
Soft Tissues ◽  
Biomechanical Model ◽  
Local Stress ◽  
The Body ◽  
Constitutive Law ◽  
Maximum Pressure ◽  
Fe Model ◽  
Injury Criteria

Ballistic injury refers to the interaction of a projectile and the human body, resulting in penetration or blunt trauma. In order to consider both consequences, a hydrodynamic elastoplastic constitutive law was implemented in a numerical FE model of the human torso to simulate soft tissues behavior and to evaluate their injury risk. This law, derived from 20% ballistic gelatin, was proven to be very efficient and biofidelic for penetrating ballistic simulation in soft tissues at very high velocity. In this study, the ability of the hydrodynamic law to simulate blunt ballistic trauma is evaluated by the replication of Bir et al.’s (2004) experiments, which is a reference test of the literature for nonpenetrating ballistic impact. Lung injury criteria were also investigated through the Bir et al.’s experiments numerical replication. Human responses were evaluated in terms of mechanical parameters, which can be global (acceleration of the body, viscous criteria and impact force) or local (stress, pressure and displacement). Output results were found to be in experimental corridors developed by Bir et al., and the maximum pressure combined with the duration of the peak of pressure in the lungs seems to be a good predictor for lung injury.

Simple model for the parametric analysis of grid amplifiers

2009 ◽  
Vol 3 (5) ◽  
pp. 877
Author(s):  
I. Russo ◽  
L. Boccia ◽  
G. Amendola ◽  
G. Di Massa ◽  
P.S. Hall
Keyword(s):  
Simple Model ◽  
Parametric Analysis ◽  
Grid Amplifiers

scholarly journals Experimental and numerical study on the thrust of a water-retaining curtain

2017 ◽  
Vol 20 (2) ◽  
pp. 316-331 ◽  
Author(s):  
Wei He ◽  
Jijian Lian ◽  
Fang Liu ◽  
Chao Ma ◽  
Shunqi Pan
Keyword(s):  
Pressure Difference ◽  
Numerical Study ◽  
Experimental Tests ◽  
Maximum Pressure ◽  
Arc Length ◽  
Practical Application ◽  
Force Analysis ◽  
Height Ratio ◽  
Maximum Value ◽  
Inflow Condition

Abstract A water-retaining curtain (WRC) has become a useful facility in selective withdrawal and sedimentation control, but the force analysis of a curved curtain is still lacking. Based on flume experimental tests and numerical simulations, this paper analyzes the variation laws of pressure difference and thrust of WRC. The results show that under the uniform inflow condition, the distribution of pressure difference on the WRC is relatively even, and the maximum value is located at the upper part of the curtain. When arc length–height ratio increases, the location of maximum pressure difference gets lower. In addition, the variation law of thrust of WRC conforms to the classical resistance equation. The drag coefficient is found to fit a power function of the water-retaining ratio, a second-degree polynomial function of arc length–height ratio, and linear function of inclination ratio. The results also yield a simplified forecasting formula of thrust of WRC which is proposed and verified using flume simulations and a real reservoir model test. The newly developed formula systematically considers the water-retaining height, arc length and inclination degree, providing a rapid and accurate algorithm to predict the thrust, and lays a theoretical foundation for practical application.

The Prediction of Startup Test With Load Rejection and Parametric Study of SBPCS for Lungmen Nuclear Power Plant

2010 ◽  
Author(s):  
Chiung-Wen Tsai ◽  
Chunkuan Shih ◽  
Hao-Tzu Lin ◽  
Jong-Rong Wang ◽  
Yng-Ruey Yuan ◽  
...  
Keyword(s):  
Time Constant ◽  
Parametric Analysis ◽  
Nuclear Power ◽  
Test Procedure ◽  
Pressure Rise ◽  
Pressure Control ◽  
Lag Time ◽  
Maximum Pressure ◽  
Pressure Regulator ◽  
Time Constants

A Lungmen RETRAN-3D model has been constructed to predict the transient behaviors for startup test, furthermore verify the acceptance criteria specified in the documents of startup test procedure. This study focuses on the prediction of the startup test with Load Rejection (LR) with bypass and the parametric analysis of lead-lag time constants in pressure regulator. For the analysis of LR with bypass, the major mitigation functions, i.e., Selected Control Rods Run-In (SCRRI) and turbine bypass function, are simulated to examine whether scram is initiated during the transient or not. The analytic results show the reactor is brought to a steady state without scram. The neutron flux in the final state is around 34%, and the pressure regulator sensed maximum pressure rise is limited to a maximum of 3kPa. The result also shows that the 110% steam bypass capacity is capable to mitigate the power increase caused by the positive reactivity insertion as a result of pressure-wave-induced void collapse. For the parametric analysis of lead-lag time constants in pressure regulator, the time domain response of Steam Bypass and Pressure Control System (SBPCS) is demonstrated by a step change of pressure setpoint and different combinations of lead-lag time constants defined in pressure regulator. The results show that the responses, i.e., response time and overshooting, are minimized when the lag time constant is between 4 to 6 seconds and the lead time constant is 50% to 70% of lag time constant. The analysis result of SBPCS provides the trend as a reference for the adjustment of lead-lag time constants during the future Lungmen startup test.

Energy harvesting by flow-induced flutter in a simple model of an inverted piezoelectric flag

2016 ◽  
Vol 790 ◽  
pp. 582-606 ◽  
Author(s):  
Kourosh Shoele ◽  
Rajat Mittal
Keyword(s):  
Simple Model ◽  
Energy Harvesting ◽  
Scaling Law ◽  
Reynolds Numbers ◽  
Maximum Energy ◽  
Vibrational States ◽  
Electric Interaction ◽  
Inclination Angles ◽  
Simple Scaling ◽  
Large Amplitude Vibrations

Two-dimensional numerical simulations are used to study the coupled fluid–structure–electric interaction of a simple model of an inverted piezoelectric flag, and to investigate the dynamics of the flow–structure interaction of this configuration as well as its energy harvesting performance. In particular, the dynamic response of the inverted flag as well as the associated flow patterns are examined for a range of inertia, bending stiffness and Reynolds numbers, and categorized into distinct vibrational states based on the symmetry of the motion as well as the amplitude. Simulations indicate that large-amplitude vibrations can be achieved over a large range of parameters and there is also evidence of lock-on between the flag flutter and the intrinsic wake shedding phenomenon. The initial inclination of the flag to the prevailing flow is found to significantly affect the flutter performance for inclination angles exceeding $15^{\circ }$. The state with large symmetric flutter is identified as being most promising for energy harvesting, and the effect of piezoelectric material parameters on the energy harvesting performance of this flutter state is examined in detail. The maximum energy efficiency of the flags is found to be approximately $7\,\%$, and the maximum occurs when there is a match between the time scales of flutter and the intrinsic time scale of the piezoelectric circuit. The simulations are used to examine a simple scaling law that could be used to predict the energy harvesting performance of such devices.

scholarly journals A Parametric Analysis of Femoral Stem Impaction

2021 ◽  
Author(s):  
Nicholas E Bishop ◽  
Phil Wright ◽  
Martin Preutenborbeck
Keyword(s):  
Simple Model ◽  
Parametric Analysis ◽  
Soft Tissues ◽  
Femoral Stem ◽  
Stress Waves ◽  
Energy Component ◽  
Material Stiffness ◽  
Component Design ◽  
Basic Understanding ◽  
Mass Increase

Abstract BackgroundPress-fitted implants are implanted by impaction to ensure adequate seating, but without overloading the components, the surgeon, or the patient. To understand this interrelationship a uniaxial discretised model of the hammer/introducer/implant/bone/soft-tissues was developed. A parametric analysis of applied energy, component materials and geometry, and interaction between implant-bone and bone-soft-tissue was performed, with implant seating and component stresses as outcome variables. ResultsTo reduce stresses without compromising seating, the following outcomes were observed: Less energy per hit with more hits / Increase hammer mass / Decrease introducer mass / Increase implant-bone resistance (eg stem roughness). Material stiffness and patient mechanics were found to be less important.ConclusionsThis simple model provides a basic understanding of how stress waves travel through the impacted system, and an understanding of their relevance to component design.

EM of rapidly solidified permanent magnets

1992 ◽  
Vol 50 (1) ◽  
pp. 198-199
Author(s):  
Raja K. Mishra
Keyword(s):  
Melt Spinning ◽  
Permanent Magnets ◽  
Dark Field Image ◽  
Dark Field ◽  
Maximum Energy ◽  
Quench Rate ◽  
Maximum Energy Product ◽  
Energy Product ◽  
Annular Dark Field ◽  
Rapidly Solidified

The discovery of a new class of permanent magnets based on Nd2Fe14B phase in the last decade has led to intense research and development efforts aimed at commercial exploitation of the new alloy. The material can be prepared either by rapid solidification or by powder metallurgy techniques and the resulting microstructures are very different. This paper details the microstructure of Nd-Fe-B magnets produced by melt-spinning.In melt spinning, quench rate can be varied easily by changing the rate of rotation of the quench wheel. There is an optimum quench rate when the material shows maximum magnetic hardening. For faster or slower quench rates, both coercivity and maximum energy product of the material fall off. These results can be directly related to the changes in the microstructure of the melt-spun ribbon as a function of quench rate. Figure 1 shows the microstructure of (a) an overquenched and (b) an optimally quenched ribbon. In Fig. 1(a), the material is nearly amorphous, with small nuclei of Nd2Fe14B grains visible and in Fig. 1(b) the microstructure consists of equiaxed Nd2Fe14B grains surrounded by a thin noncrystalline Nd-rich phase. Fig. 1(c) shows an annular dark field image of the intergranular phase. Nd enrichment in this phase is shown in the EDX spectra in Fig. 2.

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