Journal articles: 'Mass moment of inertia'

1

Berg, C., and J. Rayner. "The moment of inertia of bird wings and the inertial power requirement for flapping flight." Journal of Experimental Biology 198, no. 8 (January 1, 1995): 1655–64. http://dx.doi.org/10.1242/jeb.198.8.1655.

Full text

Abstract:

The agility and manoeuvrability of a flying animal and the inertial power required to flap the wings are related to the moment of inertia of the wings. The moments of inertia of the wings of 29 bird species and three bat species were determined using wing strip analysis. We also measured wing length, wing span, wing area, wing mass and body mass. A strong correlation (r2=0.997) was found between the moment of inertia and the product of wing mass and the square of wing length. Using this relationship, it was found that all birds that use their wings for underwater flight had a higher than average moment of inertia. Assuming sinusoidal wing movement, the inertial power requirement was found to be proportional to (body mass)0.799, an exponent close to literature values for both metabolic power output and minimum power required for flight. Ignoring wing retraction, a fairly approximate estimate showed that the inertial power required is 1115 % of the minimum flight power. If the kinetic energy of the wings is partly converted into aerodynamic (useful) work at stroke reversal, the power loss due to inertial effects may be smaller.

APA, Harvard, Vancouver, ISO, and other styles

2

Sun, Ling, Peng Yu, and Tong Zhang. "Measurement Method Research on Inertial Parameters of Motor Assembly." Applied Mechanics and Materials 437 (October 2013): 663–68. http://dx.doi.org/10.4028/www.scientific.net/amm.437.663.

Full text

Abstract:

Inertial parameters of the motor assembly include its mass, CM (center of mass) position, moment of inertia and product of inertia. Taking one vehicle drive motor as the research object, its mass and CM position are measured by using weight method and moment balance method respectively. Its moment of inertia and product of inertia are measured by using three-wire pendulum. On the basis of analyzing the test error, this paper proposed specific measures to reduce the test error.

APA, Harvard, Vancouver, ISO, and other styles

3

Wallach, David L. "New Theorems for Moments of Inertia." International Journal of Mechanical Engineering Education 21, no. 4 (October 1993): 355–66. http://dx.doi.org/10.1177/030641909302100406.

Full text

Abstract:

The moment of inertia of a plane lamina about any axis not in this plane can be easily calculated if the moments of inertia about two mutually perpendicular axes in the plane are known. Then one can conclude that the moments of inertia of regular polygons and polyhedra have symmetry about a line or point, respectively, about their centres of mass. Furthermore, the moment of inertia about the apex of a right pyramid with a regular polygon base is dependent only on the angle the axis makes with the altitude. From this last statement, the calculation of the centre of mass moments of inertia of polyhedra becomes very easy.

APA, Harvard, Vancouver, ISO, and other styles

4

Tondji, Y., and R. M. Botez. "Semi-empirical estimation and experimental method for determining inertial properties of the Unmanned Aerial System – UAS-S4 of Hydra Technologies." Aeronautical Journal 121, no. 1245 (October 11, 2017): 1648–82. http://dx.doi.org/10.1017/aer.2017.105.

Full text

Abstract:

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.

APA, Harvard, Vancouver, ISO, and other styles

5

THOLLESSON, MIKAEL, and ULLA M. NORBERG. "Moments of Inertia of Bat Wings and Body." Journal of Experimental Biology 158, no. 1 (July 1, 1991): 19–35. http://dx.doi.org/10.1242/jeb.158.1.19.

Full text

Abstract:

The moments of inertia of the wings about the shoulder joint and about the roll axis were estimated in eight species of bats, using strip analysis. The moment of inertia of the bat's trunk about the roll axis was estimated by assuming the body and head to be ellipsoids. The slopes of the regressions of moment of inertia of one wing about the shoulder joint (Jw) versus body mass (mtot), wing span (b) and wing area (S) were as expected for geometrically similar animals of different size. The exponent for Jwversus body mass in bats deviates from that found for birds, while the exponent for Jw versus wing span does not. A multiple regression was used to show that Jw may be estimated by: J w = 4.49 × 10−3mtot0.53b2.15S0.65. The mean value of the moment of inertia originating from the trunk is 7 % of the bat's total moment of inertia (of wings and body combined) about the roll axis. The mass of one wing (mw) was plotted against body mass for the eight bat species, which gives: m w = 0.112mtot1 11. The slope for our bats, 1.11, is similar to that obtained for birds, 1.10. Adaptations to reduce the moments of inertia may be more important for increasing a bat's flight agility (roll acceleration) than for decreasing the total mechanical power required to fly. The influences of wing moment of inertia and wing shape on manoeuvrability and agility are discussed.

APA, Harvard, Vancouver, ISO, and other styles

6

KUPRIKOV, Mikhail Yu, Lev N. RABINSKIY, and Nikita M. KUPRIKOV. "Moment-inertial representation of the Square-cube law in aircraft industry." INCAS BULLETIN 11, S (August 1, 2019): 163–64. http://dx.doi.org/10.13111/2066-8201.2019.11.s.16.

Full text

Abstract:

Flight distance depends on the dimension of the aircraft, but the designers stand against an insurmountable barrier caused by the dimension of the aircraft. In the process of analysis, alternative variants of the moment-inertial layout of fuel, engines, and commercial loads and their influence on the aircraft mass change are considered. A comparative analysis of the characteristics of the moment-inertial layouts of the main aircraft of the normal aerodynamic configuration and the aircraft made according to the flying wing scheme obtained as a result of a numerical experiment showed a clear advantage in the moment-inertia characteristics of the aircraft made according to the “Flying Wing” scheme. A number of unconditional advantages in the moment-inertial shape were revealed, such as more rational placement of the target load, fuel tanks and engines, which ensured a gain in aircraft mass up to 7-8%, only due to the rational moment-inertial layout. The moment of inertia of the aircraft depends to a fifth degree on the change in the linear type size of the aircraft.

APA, Harvard, Vancouver, ISO, and other styles

7

Podhorodeski, Ron P., and Paul Sobejko. "A Project in the Determination of the Moment of Inertia." International Journal of Mechanical Engineering Education 33, no. 4 (October 2005): 319–38. http://dx.doi.org/10.7227/ijmee.33.4.3.

Full text

Abstract:

Analysis of the forces involved in mechanical systems requires an understanding of the dynamic properties of the system's components. In this work, a project on the determination of both the location of the centre of mass and inertial properties is described. The project involves physical testing, the proposal of approximate models, and the comparison of results. The educational goal of the project is to give students and appreciation of second mass moments and the validity of assumptions that are often applied in component modelling. This work reviews relevant equations of motion and discusses techniques to determine or estimate the centre of mass and second moment of inertia. An example project problem and solutions are presented. The value of such project problems within a first course on the theory of mechanisms is discussed.

APA, Harvard, Vancouver, ISO, and other styles

8

Claret, A., and A. Gim�nez. "The moment of inertia of low mass stars." Astrophysics and Space Science 169, no. 1-2 (July 1990): 215–17. http://dx.doi.org/10.1007/bf00640716.

Full text

APA, Harvard, Vancouver, ISO, and other styles

9

Кочегаров, Aleksey Kochegarov, Беляев, Aleksandr Belyaev, Тришина, and Tatyana Trishina. "Determination of moment of inertia of the tractor." Forestry Engineering Journal 3, no. 4 (January 21, 2014): 151–55. http://dx.doi.org/10.12737/2196.

Full text

Abstract:

The substantiation of the economic efficiency of the analytical method for the determination of the moments of inertia of links and mechanisms of complex mechanical systems in comparison with the experimental method is given. Design scheme of a complex mech-anical system is proposed, which is a tractor, including its basic components: Rear Axle – Transmission – Engine – Front – Frame – Cabin. Definitions k – mass coefficient and  m – mass fraction are introduced. Position of coordinates of the center of mass of one of the nodes of the tractor – frame is defined. The proposed approach can be used to solve similar task for similar to the frame on the design of units of any mechanism.

APA, Harvard, Vancouver, ISO, and other styles

10

Lee, Hsing-Juin, Yang-Chung Lee, and Hsing-Wei Lee. "Determination of a missile polar mass moment of inertia." Journal of Spacecraft and Rockets 30, no. 6 (November 1993): 777–79. http://dx.doi.org/10.2514/3.26390.

Full text

APA, Harvard, Vancouver, ISO, and other styles

11

BELVEDERE, RICCARDO, JORGE ARMANDO RUEDA, and REMO RUFFINI. "MASS, RADIUS AND MOMENT OF INERTIA OF NEUTRON STARS." International Journal of Modern Physics E 20, supp01 (December 2011): 208–13. http://dx.doi.org/10.1142/s021830131104027x.

Full text

Abstract:

We construct the ground-state equilibrium configurations of neutron star cores. The system of equilibrium equations, taking into account quantum statistics, electro-weak, and strong interactions, is formulated within the framework of general relativity both in the rotating and non-rotating spherically symmetric case. The core is assumed to be composed of interacting degenerate neutrons, protons and electrons in beta equilibrium. The strong interaction between nucleons is mediated by the sigma-omega-rho virtual mesons. The mass-radius relation for neutron star cores is obtained for various parametrizations of the nuclear model. The equilibrium conditions are given by our recently developed theoretical framework based on the Einstein-Maxwell-Thomas-Fermi equations along with the constancy of the general relativistic Fermi energies of particles, the "Klein potentials", throughout the configuration. These equations are here solved numerically in the case of zero temperatures and for selected parameterizations of the nuclear model. We present here the new neutron star mass-radius relation.

APA, Harvard, Vancouver, ISO, and other styles

12

Øvergård, Tommy, and Erlend Østgaard. "Mass, radius, and moment of inertia for neutron stars." Canadian Journal of Physics 69, no. 1 (January 1, 1991): 8–15. http://dx.doi.org/10.1139/p91-002.

Full text

Abstract:

Using results from energy calculations of "neutron matter," we construct various equations of state. From these equations of state, together with the Tolman–Oppenheimer–Volkoff equations derived from Einstein's general theory of relativity, we calculate quantities such as pressure, mass density, mass energy density, total mass, radius, and moment of inertia for configurations described in the models. Comparison is made with calculations based on other nuclear potentials and nuclear energy calculations, and our results are in reasonable agreement with results from observational data.

APA, Harvard, Vancouver, ISO, and other styles

13

Ricardo, Bernard, and Zhe Wen Yuan. "Three-Axis Theorem in Moment of Inertia Computation." Physics Educator 02, no. 03 (September 2020): 2050012. http://dx.doi.org/10.1142/s2661339520500122.

Full text

Abstract:

A very important property in the study of rigid body dynamics, moment of inertia describes the resistance of an object to any change in its angular velocity, given a certain amount of torque. Although many novel methods have been developed to simplify its calculation, this paper presents a remarkable theorem in moment of inertia that has never been widely used, the three-axis theorem. The theorem provides an alternative way for moment of inertia computation and better visualization in integrating each infinitesimal constituent mass element of a rigid body. The key idea is to focus on the distance from this infinitesimal mass to the intersection of the three axes, instead of its distance to a certain rotational axis.

APA, Harvard, Vancouver, ISO, and other styles

14

Shadley, J. R., B. L. Wilson, and M. S. Dorney. "Unstable Self-Excitation of Torsional Vibration in AC Induction Motor Driven Rotational Systems." Journal of Vibration and Acoustics 114, no. 2 (April 1, 1992): 226–31. http://dx.doi.org/10.1115/1.2930252.

Full text

Abstract:

The most common NEMA Design Classes of AC induction motors have speed-torque characteristics that can give rise to unstable self-excitation of torsional vibration in rotational systems during start-up. A torsional vibration computational model for start-up transients has been developed as a design tool for induction motor applications. Torsional instability can occur at speeds in the positive sloping segment of the motor’s speed-torque curve and is particularly acute when the mass moment of inertia of the load device is more than two times the mass moment of inertia of the motor rotor. The computational model is compared with an exact solution method and with a laboratory test of a motor-driven inertial load. Applications of the computational model to electric submersible pump (ESP) design cases are discussed.

APA, Harvard, Vancouver, ISO, and other styles

15

White, M. W. D., and G. R. Heppler. "Vibration Modes and Frequencies of Timoshenko Beams With Attached Rigid Bodies." Journal of Applied Mechanics 62, no. 1 (March 1, 1995): 193–99. http://dx.doi.org/10.1115/1.2895902.

Full text

Abstract:

The equations of motion and boundary conditions for a free-free Timoshenko beam with rigid bodies attached at the endpoints are derived. The natural boundary conditions, for an end that has an attached rigid body, that include the effects of the body mass, first moment of mass, and moment of inertia are included. The frequency equation for a free-free Timoshenko beam with rigid bodies attached at its ends which includes all the effects mentioned above is presented and given in terms of the fundamental frequency equations for Timoshenko beams that have no attached rigid bodies. It is shown how any support / rigid-body condition may be easily obtained by inspection from the reported frequency equation. The mode shapes and the orthogonality condition, which include the contribution of the rigid-body masses, first moments, and moments of inertia, are also developed. Finally, the effect of the first moment of the attached rigid bodies is considered in an illustrative example.

APA, Harvard, Vancouver, ISO, and other styles

16

Wicke, Jason, and Genevieve A. Dumas. "Estimating Segment Inertial Parameters Using Fan-Beam DXA." Journal of Applied Biomechanics 24, no. 2 (May 2008): 180–84. http://dx.doi.org/10.1123/jab.24.2.180.

Full text

Abstract:

Body segment inertial parameters are required as input parameters when the kinetics of human motion is to be analyzed. However, owing to interindividual differences in body composition, noninvasive inertial estimates are problematic. Dual-energy x-ray absorptiometry (DXA) is a relatively new imaging approach that can provide cost- and time-effective means for estimating these parameters with minimal exposure to radiation. With the introduction of a new generation of DXA machines, utilizing a fan-beam configuration, this study examined their accuracy as well as a new interpolative data-reduction process for estimating inertial parameters. Specifically, the inertial estimates of two objects (an ultra-high molecular density plastic rod and an animal specimen) and 50 participants were obtained. Results showed that the fan-beam DXA, along with the new interpolative data-reduction process, provided highly accurate estimates (0.10–0.39%). A greater variance was observed in the center of mass location and moment of inertia estimates, likely as a result of the course end-point location (1.31 cm). However, using a midpoint interpolation of the end-point locations, errors in the estimates were greatly reduced for the center of mass location (0.64–0.92%) and moments of inertia (–0.23 to –0.48%).

APA, Harvard, Vancouver, ISO, and other styles

17

Kotb, Mahmoud, A. M. Khalaf, and F. A. Altalhi. "Structure of Superdeformed Rotational Bands in A ~ 150 Mass Region." JOURNAL OF ADVANCES IN PHYSICS 7, no. 2 (January 31, 2015): 1414–27. http://dx.doi.org/10.24297/jap.v7i2.1693.

Full text

Abstract:

The structure of superdeformed rotational bands (SDRB's) in A ~ 150 mass region are studied by using the Harris three â€“ parameter expansion and the incremental alignment. The bandhead spins Io have been determined with best fit procedure in order to obtain a minimum root mean square deviation between the calculated and the experimental dynamical moments of inertia. The kinematic moment of inertia has been calculated as a function of rotational frequency and compared to the corresponding experimental ones by assuming three spin values Io - 2 , Io , Io + 2. The transition energies and the variation of the moments of inertia as a function of rotational frequency have been calculated. The agreement between theory and experiment are excellent. The identical bands of SDRB's with Î”I = 2 staggering in 148Gd (SD6) and 149Gd (SD1) are investigated. Also the presence of Î”I = 2 staggering effect in the yrast bands of 147Eu and 150Tb has been examined.

APA, Harvard, Vancouver, ISO, and other styles

18

Ma, Shao Jun. "The Design of Two Pendulums Spherical Robot." Applied Mechanics and Materials 312 (February 2013): 741–44. http://dx.doi.org/10.4028/www.scientific.net/amm.312.741.

Full text

Abstract:

A spherical robot driven by two pendulums is designed, which is actuated by both the eccentric force and the inertial force generated by the inner drive unit when the robot is in motion. This improved drive manner improve the eccentric mass ratio greater than the robot total mass, can provide more eccentric moment and the moment of inertia, so that the robot has a higher speed of movement, Through the analysis of movement principle and design to complete the structural model and the main components of the spherical robot design.

APA, Harvard, Vancouver, ISO, and other styles

19

Koverda, Mikhail N., Eugeny N. Ofitserov, and Anna A. Koverda. "The program «Moments of inertia» for calculating the moments of inertia of the rotational motion of molecules." Butlerov Communications 57, no. 3 (March 31, 2019): 42–50. http://dx.doi.org/10.37952/roi-jbc-01/19-57-3-42.

Full text

Abstract:

The moment of inertia of the rotational motion I, as a descriptor of the spatial structure of the molecule, which determines the properties of a substance, in accordance with the works of recent years, begins to acquire significance in the study of the «structure – property» dependencies, allowing one to describe the change in the properties of compounds in homologous series and address odd homologues. The problem is that there is no universal and transparent method for calculating the moments of inertia of the rotational motion of molecules. Researchers are trying to solve this problem in various ways: presenting the molecule as its carbon chain and calculating the moments of inertia only for it, neglecting the contribution of other atoms, manually calculating the moments of inertia for small simple molecules, based on their estimated geometry, extracting intermediate results from quantum chemical calculations of the program packages like Gaussian or Gamess. We have developed a program for the exact calculation of the moments of inertia, which uses the specification of the exact geometry of the molecule in three-dimensional space using Cartesian coordinates. The program is written on Perl programming language and is available under the GNU General Public License v3.0 (free software). The program uses XYZ files as input data. The principle of the program is to iteratively calculate the inertia moments for all possible positions in the space of the axis of rotation passing through the center of mass of the calculated molecule. The minimum and maximum values of the moments of inertia obtained during the calculation correspond to two perpendicular axes of rotation of the molecule (x and z). The moment of inertia with respect to the third remaining y axis is calculated after finding the canonical equation of the straight axis perpendicular to the found x and z axes.

APA, Harvard, Vancouver, ISO, and other styles

20

Jain, P., A. Goel, and S. K. Mandal. "Moments of Inertia of SDIBs in A = 190 Mass Region using VMI Model." Journal of Scientific Research 12, no. 2 (February 1, 2020): 209–14. http://dx.doi.org/10.3329/jsr.v12i2.43867.

Full text

Abstract:

A lot of identical bands are known at present in the Normal Deformed (ND) region. In our study of the occurrence and properties of identical bands in Super-Deformed (SD) nuclei we first applied the modified Variable Moment of Inertia (VMI) model to extract the band-head spin of Super-Deformed bands. The calculated transition energies, level spins and dynamic moment of inertia are systematically examined. Then, in the framework of theoretical model several identical bands are identified. The kinematic and dynamic moment of inertia have been calculated for the six pairs of Super-Deformed Identical Bands (SDIBs) which was not reported earlier in the literature. Thus, the results are significant. In all the cases J(2) is significantly higher than J(1) over a large range of frequency.

APA, Harvard, Vancouver, ISO, and other styles

21

He, Li Zhao, Peng Yu, Tong Zhang, and Rong Guo. "Inertia Parameters Identification of Motor Assembly for Electric Vehicles Based on Modal Test Method." Applied Mechanics and Materials 470 (December 2013): 534–38. http://dx.doi.org/10.4028/www.scientific.net/amm.470.534.

Full text

Abstract:

Inertia parameters are essential for motor assembly mounting design, which mainly includes the mass, center of mass (CM) coordinates, moment of inertia and product of inertia. This paper explains the principle and methods of modal test method. One vehicle drive motor assembly is taken as the research object, its inertia parameters are identified using this modal test method. Finally test error analysis is also performed.

APA, Harvard, Vancouver, ISO, and other styles

22

Mwenegoha, Hery, Terry Moore, James Pinchin, and Mark Jabbal. "Model-Based Autonomous Navigation with Moment of Inertia Estimation for Unmanned Aerial Vehicles." Sensors 19, no. 11 (May 29, 2019): 2467. http://dx.doi.org/10.3390/s19112467.

Full text

Abstract:

The dominant navigation system for low-cost, mass-market Unmanned Aerial Vehicles (UAVs) is based on an Inertial Navigation System (INS) coupled with a Global Navigation Satellite System (GNSS). However, problems tend to arise during periods of GNSS outage where the navigation solution degrades rapidly. Therefore, this paper details a model-based integration approach for fixed wing UAVs, using the Vehicle Dynamics Model (VDM) as the main process model aided by low-cost Micro-Electro-Mechanical Systems (MEMS) inertial sensors and GNSS measurements with moment of inertia calibration using an Unscented Kalman Filter (UKF). Results show that the position error does not exceed 14.5 m in all directions after 140 s of GNSS outage. Roll and pitch errors are bounded to 0.06 degrees and the error in yaw grows slowly to 0.65 degrees after 140 s of GNSS outage. The filter is able to estimate model parameters and even the moment of inertia terms even with significant coupling between them. Pitch and yaw moment coefficient terms present significant cross coupling while roll moment terms seem to be decorrelated from all of the other terms, whilst more dynamic manoeuvres could help to improve the overall observability of the parameters.

APA, Harvard, Vancouver, ISO, and other styles

23

van Wijk, Jort M. "Added mass moment of inertia of centrifugal dredge pump impellers." Proceedings of the Institution of Civil Engineers - Maritime Engineering 167, no. 3 (September 2014): 135–43. http://dx.doi.org/10.1680/maen.14.00001.

Full text

APA, Harvard, Vancouver, ISO, and other styles

24

Breu, Cosima, and Luciano Rezzolla. "Maximum mass, moment of inertia and compactness of relativistic stars." Monthly Notices of the Royal Astronomical Society 459, no. 1 (March 14, 2016): 646–56. http://dx.doi.org/10.1093/mnras/stw575.

Full text

APA, Harvard, Vancouver, ISO, and other styles

25

Mølnvik, T., and E. Østgaard. "Calculations of mass and moment of inertia for neutron stars." Nuclear Physics A 437, no. 1 (April 1985): 239–52. http://dx.doi.org/10.1016/0375-9474(85)90235-0.

Full text

APA, Harvard, Vancouver, ISO, and other styles

26

Yoshida, N., H. Sagawa, T. Otsuka, and A. Arima. "Mass-number dependence of the moment of inertia and IBM." Physics Letters B 241, no. 4 (May 1990): 459–62. http://dx.doi.org/10.1016/0370-2693(90)91851-2.

Full text

APA, Harvard, Vancouver, ISO, and other styles

27

Said, Addasi E., and Abdullah M. Eial Awwad. "A comparative study of performance of AC and DC electric drive control systems with variable moment of inertia." Bulletin of Electrical Engineering and Informatics 10, no. 2 (April 1, 2021): 588–97. http://dx.doi.org/10.11591/eei.v10i2.2768.

Full text

Abstract:

In electric drive control systems, the main goal is to maintain the driving motor speed to meet the mechanism’s requirements. In some practical industrial applications the mechanically-coupled load to the motor shaft has a varying mass during the system operation. Therefore, the change of mass changes the value of the moment of inertia of the system. The moment of inertia impacts the system operation, particularly the transient performance. Therefore, the variation of moment of inertia on the motor shaft during its operation creates additional challenges to accomplish a high-quality speed control. The main purpose of the current work is to study the impact of the variation of moment of inertia on the performance of both AC and DC electric drive control systems and to make a comparison between them. A mathematical analysis and simulations of the control system models had been presented; one time with three-phase induction motor and another time with DC motor, both with variable moment of inertia. A simulation of both systems had been accomplished using the Simulink software in MATLAB. The simulation results of operation of these systems have been analysed in order to get useful conclusions and recommendations for the electric drive control system designer.

APA, Harvard, Vancouver, ISO, and other styles

28

Kim, Y. C., and S. Barnes. "The evolution of ‘the moment of inertia’ of stars." Proceedings of the International Astronomical Union 4, S252 (April 2008): 117–18. http://dx.doi.org/10.1017/s174392130802259x.

Full text

Abstract:

AbstractObservations of the rotation periods of cool open cluster stars display a distinctive dichotomy when plotted against stellar mass/color. Other measures of stellar activity are also known to be dependent on stellar mass and structure, especially the onset and characteristics of convection zones. One proposal for understanding the observed rotation period dichotomy suggested dependencies on the moment of inertia of either the whole star or that of only the outer convection zone (Barnes 2003).The moment of inertia of stars with the mass between 0.1Msun and 3.0Msun have been calculated using a version of Yale Stellar evolution code (aka YREC). Each star has been evolved from stellar birthline to the onset of the core He burning. For easy comparison to observations, we have calculated the isochrones of these quantities as well as the convective turnover time, of interest to the activity community.

APA, Harvard, Vancouver, ISO, and other styles

29

Lenka, Smruti Smita, Prasanta Char, and Sarmistha Banik. "Critical mass, moment of inertia and universal relations of rapidly rotating neutron stars with exotic matter." International Journal of Modern Physics D 26, no. 11 (September 19, 2017): 1750127. http://dx.doi.org/10.1142/s0218271817501279.

Full text

Abstract:

We calculate moment of inertia of neutron star with different exotic constituents such as hyperons and antikaon condensates and study its variation with mass and spin frequency. The sets of equation-of-state (EoS), generated within the framework of relativistic mean field model with density-dependent couplings are adopted for the purpose. We follow the quasi-stationary evolution of rotating stars along the constant rest mass sequences, that varies considerably with different constituents in the EoS. We also explore the universal relations associated with some of the normalized properties, such as critical mass and moment of inertia for specific EoS or as a matter of fact constituents of the dense matter. Deviations in the universal relations for moment of inertia are observed at higher compactness. This study presents important results concerning the properties of neutron stars, that could be observationally verified in the near future using Square Kilometer Array telescope.

APA, Harvard, Vancouver, ISO, and other styles

30

Li, Shi Wu, Jing Jing Tian, Zhi Fa Yang, Hai Zheng Wang, and Lin Hong Wang. "Design and Test Analysis of Precise and Fractionized Inertia System of Tire Drum Test-Bed." Advanced Materials Research 199-200 (February 2011): 137–42. http://dx.doi.org/10.4028/www.scientific.net/amr.199-200.137.

Full text

Abstract:

To analyze the relationship of brake performances and its influence factors, a kind of tire drum test-bed was designed. The gradation principle of flywheels was proposed based on the double multiplication method and an inertial system with eight steps of flywheels was put forward. The inertia-mass of tire load ranging 400 from 5000 kilograms was divided into 256 levels with the accuracy of ±10 kilograms. The dynamics simulation model was built using SOLIDWORKS and ADAMS. The program of acceleration and brake testing were schemed. The feasibility and accuracy of design methodology of test-bed inertial system were verified by the comparison analysis of simulation and road test. The accurate matching between the moment of inertia of test-bed inertial system and tire load was realized.

APA, Harvard, Vancouver, ISO, and other styles

31

Zheng, Han, Qi Dou Zhou, and Gang Ji. "Influence of Rib Strengthening on Structure Vibration and Sound Radiation of Cylindrical Shell." Applied Mechanics and Materials 226-228 (November 2012): 359–63. http://dx.doi.org/10.4028/www.scientific.net/amm.226-228.359.

Full text

Abstract:

An approach combining FEM with BEM is adopted to calculate the structural vibration and sound radiation of an underwater cylindrical shell. By using FORTRAN codes to compute the added mass and added damping matrices, DMAP codes to add them to structural mass and damping matrices, the problem of fluid-structural interaction was solved. Through comparing the mean square normal velocity level and sound radiation power level of ring-stiffened cylindrical shell with different inertia moment of stiffeners, the results can be acquired: with the moment of inertia gets bigger, the peak frequency of the frequency-response curves increases while the peak value of vibration and sound radiation decreases. The number of strengthened stiffeners has the same effect on peak frequency as the moment of inertia, but has no effect on peak value.

APA, Harvard, Vancouver, ISO, and other styles

32

Schneider, Klaus, and Ronald F. Zernicke. "Mass, center of mass, and moment of inertia estimates for infant limb segments." Journal of Biomechanics 25, no. 2 (February 1992): 145–48. http://dx.doi.org/10.1016/0021-9290(92)90271-2.

Full text

APA, Harvard, Vancouver, ISO, and other styles

33

Ke, Chen, Ai Wu, and Chen Bing. "Mechanical parameter identification of two-mass drive system based on variable forgetting factor recursive least squares method." Transactions of the Institute of Measurement and Control 41, no. 2 (April 25, 2018): 494–503. http://dx.doi.org/10.1177/0142331218765614.

Full text

Abstract:

Alternating current (AC) motor drive systems are widely used and their performances are greatly affected by motor parameters and load disturbances, so it is necessary to identify and observe their moment of inertia, the viscous friction coefficient and load torque. This paper presents an identification method combined a Luenberger observer and the variable forgetting factor recursive least squares method (FFRLSM), which does not require the torque sensor but a position encoder and can identify the moment of inertia of the drive system, the viscous friction coefficient, and the load torque, simultaneously. The Luenberger observer takes the position and the actual current to estimate speed and angular position. This information, together with variable FFRLSM is used to identify the moment of inertia, viscous friction coefficient and load torque. The identified moment of inertia of the system is substituted into the Luenberger observer model to correct the error of the system model. According to a probability density function of a normal distribution, the proposed method estimates the identification target in a short time, with stable and high identification precision. Finally, a comparison is made between the proposed algorithm and the FFRLSM. Results show that the proposed identification method achieves intended purpose and promise application values with its short consuming-time and high identification accuracy.

APA, Harvard, Vancouver, ISO, and other styles

34

Teng, Wan Qing, Zheng Yi Ren, Zhi Qiu Wang, and Bin Lv. "Using Governor Sensitivity Test Method to Analyze Moment of Inertia of Engine Generator Set." Advanced Materials Research 383-390 (November 2011): 1131–37. http://dx.doi.org/10.4028/www.scientific.net/amr.383-390.1131.

Full text

Abstract:

A new method for estimating the moment of inertia of engine generator set was proposed in this paper, which was defined as Governor Sensitivity Test Method (GSTM). In this method, the moment of inertia of engine generator set was estimated by means of measure transient speed change of engine generator set when the engine load increases suddenly. In the present, there have been some methods for estimating the moment of inertia of engine, such as, Additional Mass Method, Running Down Test Method and Accelerating- Decelerating Method Under No Load. These methods for estimating the moment of inertia of engine generator set all have shortcomings on accuracy or operability. These shortcomings have been overcome by using the GSTM method proposed in this paper. It is easy to operate, and the factors affecting estimation errors are small. In this paper, the basic principle of the GSTM method was discussed. The factors affecting estimation errors ware analyzed. An example of calculating the moment of inertia of an engine generator set using the GSTM method was presented. The result of calculating the moment of inertia of engine generator set was used to simulate the transient speed response of an engine generator set. The GSTM method was verified to be practical by comparing the results of simulation and experiment.

APA, Harvard, Vancouver, ISO, and other styles

35

Fazeli, Nima, Roman Kolbert, Russ Tedrake, and Alberto Rodriguez. "Parameter and contact force estimation of planar rigid-bodies undergoing frictional contact." International Journal of Robotics Research 36, no. 13-14 (April 1, 2017): 1437–54. http://dx.doi.org/10.1177/0278364917698749.

Full text

Abstract:

This paper addresses the identification of the inertial parameters and the contact forces associated with objects making and breaking frictional contact with the environment. Our goal is to explore under what conditions, and to what degree, the observation of physical interaction, in the form of motions and/or applied external forces, is indicative of the underlying dynamics that governs it. In this study we consider the cases of passive interaction, where an object free-falls under gravity, and active interaction, where known external perturbations act on an object at contact. We assume that both object and environment are planar and rigid, and exploit the well-known complementarity formulation for contact resolution to establish a constrained optimization-based problem to estimate inertial parameters and contact forces. We also show that when contact modes are known, or guessed, the formulation provides a closed-form relationship between inertial parameters, contact forces, and observed motions, that turns into a least squares problem. Consistent with intuition, the analysis indicates that without the application of known external forces, the identifiable set of parameters remains coupled, i.e. the ratio of mass moment of inertia to mass and the ratio of contact forces to the mass. Interestingly the analysis also shows that known external forces can lead to decoupling and identifiability of mass, mass moment of inertia, and normal and tangential contact forces. We evaluate the proposed algorithms both in simulation and with real experiments for the cases of a free falling square, ellipse, and rimless wheel interacting with the ground, as well as a disk interacting with a manipulator.

APA, Harvard, Vancouver, ISO, and other styles

36

Kotb, Mahmoud, A. M. Khalaf, and K. E. Abdelmageed. "Theoretical Determination of Level Spins of Superdeformed Bands for Nuclei in the Mass Region A = 80 â€“ 104." JOURNAL OF ADVANCES IN PHYSICS 6, no. 3 (December 20, 2014): 1251–58. http://dx.doi.org/10.24297/jap.v6i3.1765.

Full text

Abstract:

The bandhead spins of seventeen superdefomed bands in A = 80 â€“ 104 region (38Sr, 39Y, 40Zr, 41Nb,42Mo, 43Tc, 46Pd) have assigned by an indirect method. The dynamical moment of inertia J(2) as a function of rotational frequency Ñ’Ï‰ are extracted from Harris expansion and fitted to the experimental values by using a computer simulated search program. The calculated dynamic moment of inertia with the best optimized parameters are integrated to give the spins. The intrinsic aligned angular momentum (the integration constant) is assumed to be zero. The values of the spins resulting from our approach are consistent with all spin assignments of other approaches, and have been used to determine the kinematic moment of inertia J(1). The systematic variation of J (2) and J (1) with rotational frequency Ñ’Ï‰ is investigated, which turns out to be helpful in the spin prediction. Most SD bands in this mass region exhibits decreasing in J(1) and J(2) with increasing Ñ’Ï‰. The bandhead moment of inertia J0 which occur at J(2) = J (1) has been sensitive guideline parameter to spin proposition. The relationship between the Harris expansion three parameter model and the four parameter Bohr-Mottelson formula is derived.

APA, Harvard, Vancouver, ISO, and other styles

37

Zuyev, Vladimir, Sergey Krivoshapov, Ernest Rabinovich, Mihail Buravtsev, and Vitaliy Kashkanov. "Evaluation of the proposed method for inertia moments of vehicle powertrain parts measuring by acceleration and deceleration." Journal of Mechanical Engineering and Transport 12, no. 2 (February 2021): 54–60. http://dx.doi.org/10.31649/2413-4503-2020-12-2-54-60.

Full text

Abstract:

The scheme of energy transmission from the engine to the wheels of the car is considered. It is indicated that the dynamics of the vehicle when driving in low gears is significantly influenced by the value of the moment of inertia of equivalent masses. For a passenger car, when driving in first gear, the equivalent weight can increase up to 28%. In the literature, inertial masses are determined approximately. The article proposes a simple technique for assessing the moments of inertia of the main parts (wheels, transmission, engine) without disassembling the car. The essence of the method is to measure the deceleration during free run of the car with the vehicle's wheels hanging, and then without the wheels. A system of equations for the power balance of the vehicle run-out in 3rd and 4th gears of the gearbox with open clutch is compiled. When drawing up the equation, it was assumed that with the same engine speed and the same throttle opening, the engine torque would be the same. Formulas are obtained for calculating the moment of inertia of the wheels and the variable part of the transmission, according to which the inertial mass of the engine is calculated without the need to remove it from the machine. The article describes the experimental research methodology applied to the Hyundai i30 car with a working volume of 1.4 liters, manufactured in 2007. In the course of the experiment, the engine speed was measured through the OBD II connector, using the ELM 327 adapter and the ScanMaster-ELM program, the vehicle on-road speed using the Garmin eTrex 30 navigator, and the wheel revolutions were recorded on video. During the experiment, the condition of the tires Nokian Nordman SX 195/65 R15 91H was monitored, for which the residual depth of the tire tread pattern, pressure, moment of inertia were determined (by the bifilar suspension method). Based on the results of the experiment, the developed mathematical model was used to calculate the moment of inertia of the rotating parts of the Hyundai i30 in different gears. The result of the study allows you to establish the actual state of the rotating parts of the car, the knowledge of which increases the accuracy of determining the performance characteristics. The technique can be used to diagnose the conditions of transmission elements and car wheels. The technique does not require the use of complex stands and expensive devices.

APA, Harvard, Vancouver, ISO, and other styles

38

Usherwood, James R., and Tatjana Y. Hubel. "Energetically optimal running requires torques about the centre of mass." Journal of The Royal Society Interface 9, no. 73 (April 4, 2012): 2011–15. http://dx.doi.org/10.1098/rsif.2012.0145.

Full text

Abstract:

Bipedal animals experience ground reaction forces (GRFs) that pass close to the centre of mass (CoM) throughout stance, first decelerating the body, then re-accelerating it during the second half of stance. This results in fluctuations in kinetic energy, requiring mechanical work from the muscles. However, here we show analytically that, in extreme cases (with a very large body pitch moment of inertia), continuous alignment of the GRF through the CoM requires greater mechanical work than a maintained vertical force; we show numerically that GRFs passing between CoM and vertical throughout stance are energetically favourable under realistic conditions; and demonstrate that the magnitude, if not the precise form, of actual CoM-torque profiles in running is broadly consistent with simple mechanical work minimization for humans with appropriate pitch moment of inertia. While the potential energetic savings of CoM-torque support strategies are small (a few per cent) over the range of human running, their importance increases dramatically at high speeds and stance angles. Fast, compliant runners or hoppers would benefit considerably from GRFs more vertical than the zero-CoM-torque strategy, especially with bodies of high pitch moment of inertia—suggesting a novel advantage to kangaroos of their peculiar long-head/long-tail structure.

APA, Harvard, Vancouver, ISO, and other styles

39

SHEN, JIANYONG, YUN ZHANG, BIN WANG, and RU-KENG SU. "SLOWLY ROTATING PROTO STRANGE STARS IN QUARK MASS DENSITY- AND TEMPERATURE-DEPENDENT MODEL." International Journal of Modern Physics A 20, no. 32 (December 30, 2005): 7547–65. http://dx.doi.org/10.1142/s0217751x05022391.

Full text

Abstract:

Employing the Quark Mass Density- and temperature-dependent model and the Hartle's method, we have studied the slowly rotating strange star with uniform angular velocity. The mass–radius relation, the moment of inertia and the frame dragging for different frequencies are given. We found that we cannot use the strange star to solve the challenges of Stella and Vietri for the horizontal branch oscillations and the moment of inertia I45/(M/Ms)>2.3. Furthermore, we extended the Hartle's method to study the differential rotating strange star and found that the differential rotation is an effective way to get massive strange star.

APA, Harvard, Vancouver, ISO, and other styles

40

Hashimoto, Junji, Shizuo Yamamoto, and Akira Sone. "Vibration Analysis of Base-Isolated Table Installing Rotational Inertia Mass. Study on Optimization for Arrangement of Pulleys and Inertia Moment of Rotational Inertia Mass." Transactions of the Japan Society of Mechanical Engineers Series C 59, no. 559 (1993): 678–85. http://dx.doi.org/10.1299/kikaic.59.678.

Full text

APA, Harvard, Vancouver, ISO, and other styles

41

Haldeman, C. W., and M. G. Dunn. "High-Accuracy Turbine Performance Measurements in Short-Duration Facilities." Journal of Turbomachinery 120, no. 1 (January 1, 1998): 1–9. http://dx.doi.org/10.1115/1.2841382.

Full text

Abstract:

This paper describes work done in preparation for the measurement of stage efficiency in a short-duration shock-tunnel facility. Efficiency measurements in this facility require knowledge of the flow with path pressure and temperature, rotating system moment of inertia, and mass flow. This paper describes in detail and improved temperature compensation technique for the pressure transducers (Kulite) to reduce thermal drift problems, and measurements of the rotating system moment of inertia. The temperature compensation has shown that the conversion to pressure is accurate to within 0.689 kPa (0.1 psi) over the 40°C test range. The measurement of the moment of inertia is shown to be accurate to within 0.7 percent of the average value.

APA, Harvard, Vancouver, ISO, and other styles

42

Zhang, Jing Hua, Ren Huang Wang, Hong Wei Yue, and Yi Yue Li. "Feather Model and Application." Applied Mechanics and Materials 291-294 (February 2013): 2670–75. http://dx.doi.org/10.4028/www.scientific.net/amm.291-294.2670.

Full text

Abstract:

This paper establish feather piece section, volume and weight and other related mathematical calculation model and its corresponding moment of inertia computation model, then establishes a mathematic model to calculate the square of a natural feather rachis’ section by image processing and the method of least squares. Meanwhile, the formulae for calculating the volume and mass of the natural feather rachis are also provided. The results out of calculation basically accords with those out of actual measurement, which proves the feasibility of the formulae. This paper works out the formula for calculating the moment of inertia of natural feather when the arch degree is not taken into consideration, and it also puts forward a formula for calculating the moment of inertia of natural feather with an insertion angle. This paper first puts forward the feather piece model and moment of inertia calculation model, which to help badminton flight characteristics research and have practical value.

APA, Harvard, Vancouver, ISO, and other styles

43

Pasricha, M. S. Pasricha, and F. M. Hashim. "Effect of the reciprocating mass of slider-crank mechanism on torsional vibrations of diesel engine systems." ASEAN Journal on Science and Technology for Development 23, no. 1&2 (October 30, 2017): 71. http://dx.doi.org/10.29037/ajstd.94.

Full text

Abstract:

The torsional vibration phenomenon in the running gear of reciprocating engine systems isusually dealt with by considering a series of constant inertias connected by sections of massless shafting. However in reality, a slider crank mechanism is a vibrating system with varying inertia because the effective inertia of the total oscillating mass of each crank assembly varies twice per revolution of the crankshaft. Large variations in inertia torques can give rise to the phenomenonof secondary resonance in torsional vibration of modern marine diesel engines which can not be explained by conventional theory incorporating only the mean values of the varying inertias. In the past associated secondary resonances and regions of instability tended to be dismissed by most engineers as interesting but of no importance. The situation changed in recent years since there is evidence of the existence of thesecondary resonance effects which could have contributed to a number of otherwise inexplicable crankshaft failures in large slow speed marine engines. The cyclic variation of the polar moment of inertia of the reciprocating parts during each revolution causes a periodic variation of frequency and corres ponding amplitude of vibration of reciprocating engine systems. It also causes an increase in the speed range over which resonance effects are experienced and only a partial explanation of the behaviour of the systems has been worked out. It is impossible to avoid these instabilities by changes in thedesign , unless of course the variations in mass and spring constant can be made zero. In the present paper a critical appraisal of the regions of instability as determined from the equation of motion which takes into account variation of inertia is given. The motion in the form of complex waveforms is studied at different speeds of engine rotation. A comparison of theoretical results with Goldsbrough’s experimental resultsand Gregory’s analysis is included.

APA, Harvard, Vancouver, ISO, and other styles

44

Alexa, Octavian, Iulian Coropețchi, Alexandru Vasile, Ionica Oncioiu, and Lucian Ștefăniță Grigore. "Considerations for Determining the Coefficient of Inertia Masses for a Tracked Vehicle." Sensors 20, no. 19 (September 29, 2020): 5587. http://dx.doi.org/10.3390/s20195587.

Full text

Abstract:

The purpose of the article is to present a point of view on determining the mass moment of inertia coefficient of a tracked vehicle. This coefficient is very useful to be able to estimate the performance of a tracked vehicle, including slips in the converter. Determining vehicle acceleration plays an important role in assessing vehicle mobility. Additionally, during the transition from the Hydroconverter to the hydro-clutch regime, these estimations become quite difficult due to the complexity of the propulsion aggregate (engine and hydrodynamic transmission) and rolling equipment. The algorithm for determining performance is focused on estimating acceleration performance. To validate the proposed model, tests were performed to determine the equivalent reduced moments of inertia at the drive wheel (gravitational method) and the main components (three-wire pendulum method). The dynamic performances determined during the starting process are necessary for the validation of the general model for simulating the longitudinal dynamics of the vehicle. Finally, the differential and algebraic equations of the virtual model approximate more accurately the actual process of the operation of the vehicle. The virtual model, through the data obtained from the simulation process, allows for the determination, indirectly, of the variation of the mass moment of inertia coefficient and its expression of approximation.

APA, Harvard, Vancouver, ISO, and other styles

45

Littrell, Nathan B., Agnes Muszynska, and Paul Goldman. "Revisiting Rotor Rigid Body Modes: Parametric Study of Stability." International Journal of Rotating Machinery 5, no. 3 (1999): 193–201. http://dx.doi.org/10.1155/s1023621x99000172.

Full text

Abstract:

This paper presents an analytical model of a rigid rotor supported in two fluid film bearings with an emphasis on predicting the instability threshold speed. The factors contributing to the stability of the rotor are discussed and presented graphically using root locus plots. The parametric study of the stability starts from the discussion of the rotor/bearing system with “mirror symmetry”. Three basic cases are considered:(i) Rotor with relatively small gyroscopic effect (small polar moment of inertia) and relatively high transverse moment of inertia. It is found that the pivotal mode instability exists, but the lateral mode controls stability. (ii) Highly gyroscopic rotor (relatively large polar moment of inertia) with also relatively low transverse moment of inertia. It is found that the pivotal mode is infinitely stable and the lateral mode controls stability. (iii) Highly gyroscopic rotor with relatively high transverse moment of inertia. It is found that the pivotal mode exists and controls stability. The lateral mode always exists.Both asymmetry in rotor geometry (location of center of mass with respect to the bearings) and fluid bearing parameters (stiffness, damping) are considered. It is shown that, for a given bearing asymmetry parameter, the maximum stability is achieved when the geometric asymmetry parameter is of equal value. The recommendations on the optimal design from the stability standpoint are given.

APA, Harvard, Vancouver, ISO, and other styles

46

Risby, M. S., Khalis Suhaimi, Tan Kean Sheng, Arif Syafiq M. S., and Mohd Hafizi N. "Heavy Military Land Vehicle Mass Properties Estimation Using Hoisting and Pendulum Motion Method." Defence Science Journal 69, no. 6 (December 13, 2019): 550–56. http://dx.doi.org/10.14429/dsj.69.13478.

Full text

Abstract:

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.

APA, Harvard, Vancouver, ISO, and other styles

47

Zhang, Li Jun, and Rui Wang. "Key Factors Effect on Vehicle Braking Performance Based on Nonlinear 3DOF Vehicle Dynamic Model." Key Engineering Materials 439-440 (June 2010): 950–55. http://dx.doi.org/10.4028/www.scientific.net/kem.439-440.950.

Full text

Abstract:

3DOF nonlinear braking dynamic model considering tire-road adhesion characteristics was established, and non-dimensional equations were gained from the above mathematic models by using braking torque coefficient, front and rear axle equivalent inertia coefficients and braking force distribution coefficient. Based on the numerical calculation in Matlab-Simulink software, the effect of key factors, (including vehicle mass and vehicle gravity center position variation, frontal and rear braking force distribution coefficient, and frontal and rear axle inertial variation caused by driven mode) on vehicle braking performance, such as braking distance and wheel lockup status, was investigated and summarized. Several 3D visualizations of the simulation results show that variation of vehicle center of gravity, vehicle mass, braking moment distribution, wheel equivalent inertia due to driveline, can cause quite complex effect. It can be assumed that the gained results in this study can help to improve vehicle braking performance and enhance braking stability.

APA, Harvard, Vancouver, ISO, and other styles

48

Ibrahim, Peter, Mustafa Arafa, and Yasser Anis. "An Electromagnetic Vibration Energy Harvester with a Tunable Mass Moment of Inertia." Sensors 21, no. 16 (August 20, 2021): 5611. http://dx.doi.org/10.3390/s21165611.

Full text

Abstract:

This paper presents a vibration-based electromagnetic energy harvester whose resonance frequency can be adjusted to match that of the excitation. Frequency adjustment is attained by controlling a rotatable arm, with tuning masses, at the tip of a cantilever-type energy harvester, thereby changing the effective mass moment of inertia of the system. The rotatable arm is mounted on a servomotor that is autonomously controlled through a microcontroller and a photo sensor to keep the device at resonance for maximum power generation. A mathematical model is developed to predict the system response for different design parameters and to estimate the generated power. The system is investigated analytically by a distributed-parameter model to study the natural frequency variation and dynamic response. The analytical model is verified experimentally where the frequency is tuned from 8 to 10.25 Hz. A parametric study is performed to study the effect of each parameter on the system behavior.

APA, Harvard, Vancouver, ISO, and other styles

49

Eke, F. O., and T. C. Mao. "On the Dynamics of Variable Mass Systems." International Journal of Mechanical Engineering Education 30, no. 2 (April 2002): 123–37. http://dx.doi.org/10.7227/ijmee.30.2.4.

Full text

Abstract:

This paper accomplishes two things. It presents a derivation of the equations of motion of variable mass systems. The method presented here is based on Kane's formalism, and is complete, efficient, and mathematically rigorous—avoiding heuristics and many other pitfalls of previous attempts at such derivation. The paper also presents a detailed discussion of the meaning and importance of the various terms of the equations of motion, and the circumstances under which each term can be neglected. It is found that certain judiciously simplified versions of the equations of motion are adequate for most studies. The most important forces contributed by mass variability appear to be the thrust vector and the Coriolis force. The jet damping moment and the moment due to inertia variation are the dominant moments due to mass variability. The study ends with specific equations that are recommended for use in the study of the dynamics of variable mass systems. These equations capture all the important features of the motion of variable mass systems, while remaining simple enough to permit tractable analyses of the behaviour of such systems.

APA, Harvard, Vancouver, ISO, and other styles

50

Zhang, Aihua, Jianfei Ni, and Hamid Reza Karimi. "Reaction Wheel Installation Deviation Compensation for Overactuated Spacecraft with Finite-Time Attitude Control." Mathematical Problems in Engineering 2013 (2013): 1–10. http://dx.doi.org/10.1155/2013/268904.

Full text

Abstract:

A novel attitude tracking control scheme is presented for overactuated spacecraft to address the attitude stabilization problem in presence of reaction wheel installation deviation, external disturbance and uncertain mass of moment inertia. An adaptive sliding mode control technique is proposed to track the uncertainty. A Lyapunov-based analysis shows that the compensation control law can guarantee that the desired attitude trajectories are followed in finite-time. The key feature of the proposed control strategy is that it globally asymptotically stabilizes the system, even in the presence of reaction wheel installation deviation, external disturbances, and uncertain mass of moment inertia. The attitude track performance using the proposed finite-time compensation control is evaluated through a numerical example.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Mass moment of inertia'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles