Heavy Military Land Vehicle Mass Properties Estimation Using Hoisting and Pendulum Motion Method

Mass properties such as the centre of gravity location, moments of inertia, and total mass are of great importance for vehicle stability studies and deployment. Certain parameters are required when these vehicles need to be arranged inside an aircraft for the carrier to achieve proper mass balance and stability during a flight. These parameters are also important for the design and modelling process of vehicle rollover crash studies. In this study, the mass properties of a military armoured vehicle were estimated using hoisting and pendulum method. The gross total weight, longitudinal and vertical measurements were recorded by lifting the vehicle using a mobile crane and the data were used to estimate the centre of gravity. The frequency of vehicle oscillation was measured by applying swing motion with a small angle of the vehicle as it is suspended on air. The centre of gravity and mass moment of inertia were calculated using the vector mechanics approach. The outcomes and limitations of the approach as discussed in details.

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Semi-empirical estimation and experimental method for determining inertial properties of the Unmanned Aerial System – UAS-S4 of Hydra Technologies

The Aeronautical Journal ◽

10.1017/aer.2017.105 ◽

2017 ◽

Vol 121 (1245) ◽

pp. 1648-1682 ◽

Cited By ~ 2

Author(s):

Y. Tondji ◽

R. M. Botez

Keyword(s):

Experimental Method ◽

Dynamic Models ◽

Moment Of Inertia ◽

Experimental Results ◽

Unmanned Aerial System ◽

Uniform Density ◽

Moments Of Inertia ◽

Centre Of Gravity ◽

Mass Moment ◽

Mass Moment Of Inertia

ABSTRACTThis article presents a structural analysis of the Unmanned Aerial System UAS-S4 ETHECATL. Mass, centre of gravity position and principal mass moment of inertia are numerically determined and further experimentally verified using the ‘pendulum method’. The numerical estimations are computed through Raymer and DATCOM statistical-empirical methods coupled with mechanical calculations. The mass of the UAS-S4 parts are estimated according to their sizes and the UAS-S4 class, by the means of Raymer statistical equations. The UAS-S4 is also decomposed in several simple geometrical figures which centres of gravity are individually computed, weighted and then arithmetically averaged to find the whole UAS-S4 centre of gravity. In the same way, DATCOM equations allows us to estimate the mass moments of inertia of each UAS-S4 parts that are finally sum up according to the Huygens-Steiner theorem for computing the principal moment of inertia of the whole UAS-S4. The mass of de UAS-S4 is experimentally determined with two scales. Its centre of gravity coordinates and its mass moment of inertia are found using the pendulum method. A bifilar torsion-type pendulum methodology is used for the vertical axis(14)and a simple pendulum methodology is used for the longitudinal and transversal axes(12). The test object is installed on a pendulum (simple or bifilar torsion pendulum) which is led to oscillate freely while recording the oscillation's angles and speed, by the means of three sensors (an accelerometer, a gyroscope and a magnetometer) that the calibration is also discussed. Simultaneously, nonlinear dynamic models are developed for the rotational motion of pendulums, including the effects of large-angle oscillations, aerodynamic drag, viscous damping and additional momentum of air. ‘Algorithms of minimization’ are then used to simulate and actualise the dynamic models and finally chose the model that simulated data best fit the experimentally recorded one. Pendulum parameters, such as mass moment of inertia, are lastly extracted from the chosen model. To determine the accuracy of the nonlinear dynamics approach of the pendulum method, the experimental results for an object of uniform density for which the mass moments of inertia are computed numerically from geometrical data are presented along with the experimental results obtained for the UAS-S4 ETHECATL. For the uniform density object, the experimental method gives, with respect to the numerical results, an error of 4.4% for the mass moment of inertia around theZaxis and 9.5% for the moment of inertia around theXandYaxes. In addition, the experimental results for the UAS-S4 inertial values validate the numerical calculation through DATCOM method with a relative error of 6.52% on average.

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Fire fighter dies after being ejected from a pumper in a single vehicle rollover crash - New York.

10.26616/nioshfffacef200825 ◽

2009 ◽

Keyword(s):

New York ◽

Fire Fighter ◽

Single Vehicle ◽

Vehicle Rollover ◽

Rollover Crash

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A novel semi-active actuator with tunable mass moment of inertia for noise control applications

Journal of Sound and Vibration ◽

10.1016/j.jsv.2021.116244 ◽

2021 ◽

pp. 116244

Author(s):

Stanislaw Wrona ◽

Marek Pawelczyk ◽

Li Cheng

Keyword(s):

Noise Control ◽

Moment Of Inertia ◽

Control Applications ◽

Mass Moment ◽

Mass Moment Of Inertia

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Epidemiology of West Virginia Passenger Vehicle Rollover Crash Fatalities, 2001-2018

Annals of Epidemiology ◽

10.1016/j.annepidem.2020.08.055 ◽

2020 ◽

Vol 52 ◽

pp. 114

Author(s):

Y. Tang ◽

T.M. Rudisill ◽

R. Bhandari

Keyword(s):

West Virginia ◽

Passenger Vehicle ◽

Vehicle Rollover ◽

Rollover Crash

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Modeling and validation of crankshaft speed fluctuations of a single-cylinder four-stroke diesel engine

Proceedings of the Institution of Mechanical Engineers Part D Journal of Automobile Engineering ◽

10.1177/09544070211026290 ◽

2021 ◽

pp. 095440702110262

Author(s):

Mustafa Babagiray ◽

Hamit Solmaz ◽

Duygu İpci ◽

Fatih Aksoy

Keyword(s):

Diesel Engine ◽

Dynamic Model ◽

Moment Of Inertia ◽

Mass Motion ◽

Cylinder Pressure ◽

Motion Equations ◽

Single Cylinder ◽

Mass Moment ◽

Mass Moment Of Inertia ◽

Speed Fluctuations

In this study, a dynamic model of a single-cylinder four-stroke diesel engine has been created, and the crankshaft speed fluctuations have been simulated and validated. The dynamic model of the engine consists of the motion equations of the piston, conrod, and crankshaft. Conrod motion was modeled by two translational and one angular motion equations, by considering the kinetic energy resulted from the mass moment of inertia and conrod mass. Motion equations involve in-cylinder gas pressure forces, hydrodynamic and dry friction, mass inertia moments of moving parts, starter moment, and external load moment. The In-cylinder pressure profile used in the model was obtained experimentally to increase the accuracy of the model. Pressure profiles were expressed mathematically using the Fourier series. The motion equations were solved by using the Taylor series method. The solution of the mathematical model was performed by coding in the MATLAB interface. Cyclic speed fluctuations obtained from the model were compared with experimental results and found compitable. A validated model was used to analyze the effects of in-cylinder pressure, mass moment of inertia of crankshaft and connecting rod, friction, and piston mass. In experiments for 1500, 1800, 2400, and 2700 rpm engine speeds, crankshaft speed fluctuations were observed as 12.84%, 8.04%, 5.02%, and 4.44%, respectively. In simulations performed for the same speeds, crankshaft speed fluctuations were calculated as 10.45%, 7.56%, 4.49%, and 3.65%. Besides, it was observed that the speed fluctuations decreased as the average crankshaft speed value increased. In the simulation for 157.07, 188.49, 219.91, 251.32, and 282.74 rad/s crankshaft speeds, crankshaft speed fluctuations occurred at rates of 10.45%, 7.56%, 5.84%, 4.49%, and 3.65%, respectively. The effective engine power was achieved as 5.25 kW at an average crankshaft angular speed of 219.91 rad/s. The power of friction loss in the engine was determined as 0.68 kW.

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Optimal Performance of the TLCD in Structural Pitching Vibration Control

Journal of Vibration and Control ◽

10.1177/1077546029287 ◽

2002 ◽

Vol 8 (5) ◽

pp. 619-642 ◽

Cited By ~ 5

Author(s):

S. D. Xue ◽

J. M. Ko ◽

Y. L. Xu

Keyword(s):

Numerical Optimization ◽

Sensitivity Study ◽

Optimization Approach ◽

Optimum Control ◽

Head Loss Coefficient ◽

Tuning Ratio ◽

Mass Moment ◽

Practical Design ◽

Mass Moment Of Inertia ◽

Structural Uncertainties

A detailed optimal parametric study is performed for a tuned liquid column damper (TLCD) in suppressing the pitching vibration of structures. Due to the difficulty of finding analytical solutions for the damped structure, a numerical optimization approach is proposed and applied to the system to find the optimum TLCD parameters. The variations of the optimum control parameter with system parameters are determined and discussed. Using various numerical searching data, a set of practical design formulas for the optimum tuning ratio and optimum head loss coefficient of the TLCD are then derived through regression analysis. The comparison between practical design formula and numerical optimization shows a very close agreement between the two results. The practical design formulas provide a convenient tool for designers. In order to account for the possible effects of structural uncertainties, a parametric sensitivity study on the de-tuning of optimum damper parameters is also carried out. It is found that the detuning effect is more severe for low damped structure with lower ratios of mass moment of inertia, especially for the detuning of tuning ratio.

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Research Concerning the Dynamic Model of the Conventional Sucker Rod Pumping Units

Revista de Chimie ◽

10.37358/rc.19.8.7434 ◽

2019 ◽

Vol 70 (8) ◽

pp. 2818-2821

Author(s):

Georgeta Toma

Keyword(s):

Computer Program ◽

Dynamic Model ◽

Angular Speed ◽

Management Program ◽

Programming Environment ◽

Synthesis Parameters ◽

Mass Moment ◽

Sucker Rod ◽

Mass Moment Of Inertia ◽

Pumping Units

The study of the dynamic model of the conventional sucker rod pumping units requires first determining the variation on the cinematic cycle of the synthesis parameters (the reduced moment and the reduced mass moment of inertia) and then the variation of the angular speed of the cranks, in response to the dynamic and resistant actions on the component elements that appear during operation. The paper presents the way of determining the variation on the cinematic cycle of the synthesis parameters of the dynamic model corresponding to the conventional pumping unit mechanism and of the variation of the angular speed of its cranks. The experimental records have been processed with the Total Well Management program. The simulations have been performed with a computer program developed by the author using the Maple programming environment.

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Pengaruh Variasi Radius-Dalam Rim Terhadap Pengurangan Massa dan Momen Inersia Massa Dengan Studi Kasus Benda Putar Berdiameter 10 cm

Jurnal Rekayasa Hijau ◽

10.26760/jrh.v1i1.1339 ◽

2018 ◽

Vol 1 (1) ◽

Author(s):

Eka Taufiq Firmansjah

Keyword(s):

Outer Radius ◽

Moment Of Inertia ◽

Mass Reduction ◽

Inner Radius ◽

Mass Moment ◽

Mass Moment Of Inertia ◽

Machine Elements ◽

The Moment ◽

The Masses

ABSTRAK Mesin terdiri dari sekumpulan elemen mesin yang diam dan bergerak. Elemen mesin yang bergerak dengan gerakan berputar disebut benda putar. Pada beberapa kasus seringkali diinginkan pengurangan massa dari benda putar tersebut untuk alasan ekonomis, biasanya untuk elemen mesin yag diproduksi massal. Namun pengurangan massa berakibat pada pengurangan momen inersia massa benda putar bersangkutan. Jika tuntutan perancangan tidak mempermasalahkan perubahan tersebut, maka pengurangan massa tidak menjadi masalah. Namun jika momen inersia massa tidak boleh terlalu rendah, maka harus dicari kompromi dimana pengurangan massa sebesar-besarnya namun penurunan momen inersia massa sekecil-kecilnya. Pada penelitian ini dilakukan studi kasus terhadap benda putar berjari- jari 10 cm jari-jari dalam hub 2 cm dan jari-jari luar hub 4 cm. Jumlah jari-jari ada 4 dengan lebar 1 cm dan tebal benda putar 0,5 cm. Variasi pengurangan massa dilakukan dengan memvariasikan jari-jari- dalam rim. Untuk tiap variasi, dilakukan perhitungan untuk mendapatkan jumlah massa yang dapat dikurangi dan momen inersia massa dari benda putar. Ternyata pada nilai jari-jari dalam tertentu, dapat diperoleh nilai kompromi dari permasalahan diatas. Kata kunci: benda putar, penghematan bahan, momen inersia massa. ABSTRACT Machine consists of a set of machine elements that still and moving. Machine elements that move in a circular motion called rotary object. In some cases it is often desirable reduction in the mass of the rotating object for economic reasons, usually for a mass production of machine elements. But the mass reduction results in a reduction in moment of inertia of the mass. If the demands of the design allow this decrease of moment of inertia, mass reduction is not a problem. But if the moment of inertia of the masses should not be too low, it must find a compromise in which a mass reduction profusely but the decrease in the mass moment of inertia of the smallest. In this research conducted a case study of rotating element radius of 10 cm, radius of the hub 2 cm and outer radius hub 4 cm. The number of spoke are 4 with a width of 1 cm and uniform thickness 0.5 cm all over rotating element. Variations mass reduction is done by varying the inner radius of the rim. For each variation, calculation is performed to obtain the amount of mass that can be reduced and the mass moment of inertia of the rotating object. It turned out that in the certain value of inner radius of the rim in particular, can compromise the values obtained from the above problem. Keywords: rotating element, reducing material, mass moment of inertia.

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An Improved Transfer Matrix-Direct Integration Method for Rotor Dynamics

Journal of Vibration and Acoustics ◽

10.1115/1.3269320 ◽

1986 ◽

Vol 108 (2) ◽

pp. 182-188 ◽

Cited By ~ 12

Author(s):

Jialiu Gu

Keyword(s):

Transfer Matrix ◽

Integration Method ◽

Equations Of Motion ◽

Rotor Dynamics ◽

Direct Integration ◽

Rotating System ◽

Direct Integration Method ◽

Mass Moment ◽

Mass Moment Of Inertia ◽

Matrix Iteration

A transfer matrix-direct integration combined method is proposed, which employs the transfer matrix method to derive the equations of motion of a “characteristic disk,” and uses the direct integration method to determine the critical speeds, modes and unbalance response of a rotor-bearing system, and to analyze its stability. Despite the complexity of the system, the number of governing equations is not greater than eight. For a single-spool rotating system, the number of equations is only four. A transfer matrix for a uniform shaft is derived to consider its distributed mass, moment of inertia and the effect of shearing force. An impedance matrix iteration method is proposed to consider the effect of a complicated bearing-supporting system on the rotor dynamics. Two examples are given, and the results agree satisfactorily with the experiments.

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