scholarly journals Mathematical Modeling of Cardiovascular System Dynamics Using a Lumped Parameter Method

2004 ◽  
Vol 54 (6) ◽  
pp. 545-553 ◽  
Author(s):  
Eun Bo Shim ◽  
Jong Youb Sah ◽  
Chan Hyun Youn
Keyword(s):  
Mathematical Modeling ◽  
System Dynamics ◽  
Cardiovascular System ◽  
Parameter Method ◽  
Lumped Parameter ◽  
Lumped Parameter Method

scholarly journals Simulation of the Cardiovascular Mechanical System Based on Pressure-Flow Model Rest Condition

2020 ◽  
Vol 5 (7) ◽  
pp. 104-115
Author(s):  
Dimas Primasatya ◽  
Erry Rimawan ◽  
Hendi Herlambang ◽  
Horas Canman S
Keyword(s):  
Cardiovascular System ◽  
Flow Model ◽  
Physiological State ◽  
Left Ventricular ◽  
Ventricular Pressure ◽  
Parameter Method ◽  
Pressure Flow ◽  
Lumped Parameter ◽  
Rest Condition ◽  
Lumped Parameter Method

Non-invasive measurement method has made rapid developments in the field of biomedical engineering. One of research is impedance cardiography (ICG), which provide information of pulsation basic. By knowing this kind of measurement technique, it will assist inspection of the patient's physiological condition with cardiovascular system. This research is aimed to determine the mechanical characteristics of the cardiovascular system in the human body such as a wave graph of pressure, flow, and volume, based on pressure–flow model in rest condition, and analyze the simulation results by implementing state of the physiology cardiovascular disease. To obtain the wave chart that is modeled by the cardiovascular system using a lumped parameter method, formulate the differential equations of the pressure–flow dynamics equation for an incompressible fluid in a segment of a cylindrical elastic tube and simulate the model using the Simulink toolboxes from Matlab R2008b. The simulation with lumped parameter method resulted wave graphics of pressure, flow, and volume of physiological state a person in rest condition, the left ventricular pressure is 120 mmHg , right ventricular pressure is 30 mmHg , left ventricular outflow is 800 mL / sec and volume in the left ventricle is 160 mL . By implementing the simulation have been developed on the physiological state of cardiovascular disease, hypertension occurs when the arteries resistance R3i = 0.61 mmHg × s mL with the pressure of the left ventricle is 145 mmHg. For coronary heart condition, ventricular pressure decreased until 82 mmHg in the value of the coronary arteries resistance is R3o = 0.852 mmHg × s mL. This research assumed heart haves the character of passive because there is no feedback signal that can compensate if the pressure in the systemic circulation is reduced. The research can be concluded that the graph from simulation shows the results are not much different from the reference chart, this results indicates that the equation and the simulation was able to reflect on the human circulatory physiological circumstances. A little different of a graphic simulation result due to differences in the parameters and assumptions used.

An improved lumped parameter method for calculating static characteristics of multi-recess hydrostatic journal bearings

2019 ◽  
Vol 234 (2) ◽  
pp. 301-310
Author(s):  
Yongtao Zhang ◽  
Shijie Yu ◽  
Changhou Lu ◽  
Haixia Zhao ◽  
Peng Liang
Keyword(s):  
Total Pressure ◽  
Control Volume ◽  
Journal Bearings ◽  
Parameter Method ◽  
Static Characteristics ◽  
Application Range ◽  
Continuity Equations ◽  
Pressure Distributions ◽  
Lumped Parameter ◽  
Lumped Parameter Method

This paper proposes an improved lumped parameter method for calculating the static characteristics of multi-recess hydrostatic journal bearings. The improved lumped parameter method can estimate the total pressure distribution in the circumferential direction by introducing control volume in the middle of each inter-recess land, and utilizing the flow continuity equations for each recess and each control volume with the assumption that the pressure distributions are parabolic on the inter-recess land. Then the recess pressure and the fluid film force can be calculated. The calculation accuracy of the improved lumped parameter method and the traditional lumped parameter method is comparatively discussed under different eccentricity ratios and wrap angles of the recess. The results show that the improved lumped parameter method has higher calculation accuracy and wider application range.

scholarly journals Analysis and Application of Screens for Acoustic Impedance in a Speaker Box with a Passive Radiator to Decrease Standing-Wave Influence

2020 ◽  
Vol 10 (3) ◽  
pp. 866
Author(s):  
Yuan-Wu Jiang ◽  
Dan-Ping Xu ◽  
Zhi-Xiong Jiang ◽  
Jun-Hyung Kim ◽  
Ki-Hong Park ◽  
...  
Keyword(s):  
Standing Wave ◽  
Acoustic Resonance ◽  
Experimental Result ◽  
Parameter Method ◽  
Analysis Tool ◽  
Analysis Method ◽  
The Finite Element Method ◽  
Lumped Parameter ◽  
Acoustic Domain ◽  
Lumped Parameter Method

Micro speakers are playing an increasingly important role with the development of multimedia devices. This study applies the lumped-parameter method, which uses an equivalent circuit to model the electromagnetic and mechanical domains. The acoustic domain is modeled using the finite element method. Based on the analysis tool, the use of a screen is analyzed, and the screen is designed to depress the acoustic resonance in the sound-pressure-level curve and improve the performance. The samples are fabricated, and the experiment verifies the analysis method. The experimental result shows that the peak and dip due to the standing wave are cancelled, and the frequency response is smooth when the screen is used.

A Simple Shear and Torsion-Free Beam Model for Multibody Dynamics

2017 ◽  
Vol 12 (5) ◽  
Author(s):  
Juan Carlos García Orden ◽  
Javier Cuenca Queipo
Keyword(s):  
Computer Animation ◽  
Axial Stiffness ◽  
Parameter Method ◽  
Beam Model ◽  
Nonlinear Dynamical ◽  
Lumped Parameter ◽  
Proposed Model ◽  
Space Mechanisms ◽  
Lumped Parameter Method ◽  
Free Beam

This paper describes a very simple beam model, amenable to be used in multibody applications, for cases where the effects of torsion and shear are negligible. This is the case of slender rods connecting different parts of many space mechanisms, models useful in polymer physics, computer animation, etc. The proposed new model follows a lumped parameter method that leads to a rotation-free formulation. Axial stiffness is represented by a standard nonlinear truss model, while bending is modeled with a force potential. Several numerical experiments are carried out in order to assess accuracy, which is usually the main drawback of this type of approach. Results reveal a remarkable accuracy in nonlinear dynamical problems, suggesting that the proposed model is a valid alternative to more sophisticated approaches.

scholarly journals Analysis and Design of Helmholtz Protector to Improve High-Frequency Response of Insert Earphone

2019 ◽  
Vol 9 (12) ◽  
pp. 2541 ◽  
Author(s):  
Yuan-Wu Jiang ◽  
Dan-Ping Xu ◽  
Zhi-Xiong Jiang ◽  
Jun-Hyung Kim ◽  
Sang-Moon Hwang
Keyword(s):  
Frequency Response ◽  
High Frequency ◽  
Experimental Result ◽  
Parameter Method ◽  
Analysis Tool ◽  
Analysis Method ◽  
Analysis And Design ◽  
High Frequency Response ◽  
Lumped Parameter ◽  
Lumped Parameter Method

With the development of multimedia devices, earphones are playing an increasingly important role. This article applies the lumped parameter method using an equivalent circuit to model the electromagnetic, mechanical, and acoustic domains of earphones. Then, parameters are determined according to the dimensions and material properties of earphone parts. On the basis of the analysis tool and determined parameters, a Helmholtz protector is analyzed and designed to improve the high-frequency response. Samples are fabricated, and the experiment verifies the analysis method. The experimental result shows that the peaks at 7 k and 10 k are decreased at 8.05 dB and 7.89 dB. The root means square value of SPL deviation compared with target curve decreased from 9.77 to 4.39. High-frequency response is improved by using the Helmholtz protector.

The Bending Vibration Analysis on the Main Drive Axis of CNC Spiral Bevel Gear Milling Machine

2013 ◽  
Vol 655-657 ◽  
pp. 1296-1299
Author(s):  
Li Juan Yu ◽  
Zhao Jun Yang ◽  
Fu You Liu
Keyword(s):  
Drive Shaft ◽  
Resonance Problem ◽  
Parameter Method ◽  
Force Model ◽  
Lumped Mass ◽  
Mass Model ◽  
Bending Vibration ◽  
Lumped Parameter ◽  
Lumped Mass Model ◽  
Lumped Parameter Method

Gear machine tool main drive shaft to avoid resonance problem is studied.The force of the drive shaft is analyzed, and the vibration form of the drive shaft is confirmed. Using the lumped parameter method to simplify the main drive shaft, the lumped mass model and the force model were been obtained. When bending vibrating, the natural frequency of the main drive shaft is calculated using the transfer matrix method. The calculated critical speed is 43755r/min, which far outweighs the motor rated speed .It means that the drive shaft under normal work won't be resonance, which accords with the request of production.

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