scholarly journals Multibody System with Elastic Connections for Dynamic Modeling of Compactor Vibratory Rollers

Symmetry ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 1617
Author(s):  
Polidor Bratu
Keyword(s):  
Multibody System ◽  
Translational Motion ◽  
Harmonic Excitation ◽  
Vibration Source ◽  
Transverse Axis ◽  
Linear Elastic ◽  
Circular Frequency ◽  
The Moment ◽  
Multi Body ◽  
Axis Passing

The dynamic model of the system of bodies with elastic connections substantiates the conceptual basis for evaluating the technological vibrations of the compactor roller as well as of the parameters of the vibrations transmitted from the vibration source to the remainder of the equipment components. In essence, the multi-body model with linear elastic connections consists of a body in vertical translational motion for vibrating roller with mass m1, a body with composed motion of vertical translation and rotation around the transverse axis passing through its weight center for the chassis of the car with mass m and the moment of mass inertia J and a body of mass m’ representing the traction tire-wheel system located on the opposite side of the vibrating roller. The study analyzes the stationary motion of the system of bodies that are in vibrational regime as a result of the harmonic excitation of the m mass body, with the force F(t)= m0rω2sinωt, generated by the inertial vibrator located inside the vibrating roller. The vibrator is characterized by the total unbalanced m0 mass in rotational motion at distance r from the axis of rotation and the angular velocity or circular frequency ω.

scholarly journals On the Effects of Structural Coupling on Piezoelectric Energy Harvesting Systems Subject to Random Base Excitation

Aerospace ◽  
2020 ◽  
Vol 7 (7) ◽  
pp. 93
Author(s):  
Hamidreza Masoumi ◽  
Hamid Moeenfard ◽  
Hamed Haddad Khodaparast ◽  
Michael I. Friswell
Keyword(s):  
Energy Harvesting ◽  
Mechanical Response ◽  
Harmonic Excitation ◽  
Point Of View ◽  
Analytical Models ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Novel Approach ◽  
Band Limited ◽  
Multi Body

The current research investigates the novel approach of coupling separate energy harvesters in order to scavenge more power from a stochastic point of view. To this end, a multi-body system composed of two cantilever harvesters with two identical piezoelectric patches is considered. The beams are interconnected through a linear spring. Assuming a stochastic band limited white noise excitation of the base, the statistical properties of the mechanical response and those of the generated voltages are derived in closed form. Moreover, analytical models are derived for the expected value of the total harvested energy. In order to maximize the expected generated power, an optimization is performed to determine the optimum physical and geometrical characteristics of the system. It is observed that by properly tuning the harvester parameters, the energy harvesting performance of the structure is remarkably improved. Furthermore, using an optimized energy harvester model, this study shows that the coupling of the beams negatively affects the scavenged power, contrary to the effect previously demonstrated for harvesters under harmonic excitation. The qualitative and quantitative knowledge resulting from this analysis can be effectively employed for the realistic design and modelling of coupled multi-body structures under stochastic excitations.

Isolation Performance Analysis of a Porous Material Vibration Isolator

2015 ◽  
Vol 741 ◽  
pp. 405-410
Author(s):  
Hua Bing Mao ◽  
Yi Zhe Huang ◽  
Tie Liang Yang
Keyword(s):  
Porous Material ◽  
Averaging Method ◽  
Piecewise Linear ◽  
Harmonic Excitation ◽  
Vibration Isolator ◽  
Plateau Phase ◽  
Vibration System ◽  
Amplitude Response ◽  
Linear Elastic ◽  
Isolation Performance

To explore the isolation mechanism and optimize the performance of the porous material in a dynamic viewpoint, a nonlinear porous material vibration isolator is modeled in this work. The stiffness of the isolator is regarded to be a piecewise linear, according to the stress–strain characteristics of porous material. Averaging method is employed to analyze the amplitude-frequency characteristics when the system excited by harmonic excitation. It is found that the vibration system represents linear, bilinear and tri-linear characteristics, when the porous material isolator works in linear-elastic phase, plateau phase and densification phase, respectively. The result shows that the amplitude response of the system in the plateau stage is much less than the linear isolator.

scholarly journals Response Analysis of Asymmetric Monostable Harvesters Driven by Color Noise and Band-Limited Noise

2021 ◽  
Vol 11 (19) ◽  
pp. 9227
Author(s):  
Shuangyan Liu ◽  
Wei Wang
Keyword(s):  
Output Power ◽  
Harmonic Excitation ◽  
Center Frequency ◽  
Response Analysis ◽  
Color Noise ◽  
Energy Harvesters ◽  
Output Performance ◽  
Response Bandwidth ◽  
Band Limited ◽  
The Moment

In this paper, we investigate the response of asymmetric potential monostable energy harvesters (MEHs) excited by color noise and band-limited noise. The motivation for this study is that environmental vibrations always have the characteristic of randomness, and it is difficult to modulate a perfectly symmetric MEH. For the excitation of exponentially correlated color noise, the moment differential equation was applied to evaluate the output performance of the asymmetric potential MEHs. Numerical and theoretical analyses were carried out to investigate the influence of noise intensity and internal system parameters on the output power of the system. Our results demonstrate that the output performance of the asymmetric MEH decreases with the increase in the correlation time, which determines the character of the color noise. On the contrary, the increase in the asymmetric degree enhances the output power of the asymmetric MEH subjected to color noise. For the band-limited noise excitation, numerical simulation is undertaken to consider the response of the asymmetric MEHs, and outcomes indicate that the frequency bandwidth and center frequency have a significant influence on the output performance. Regarding the asymmetric potential, its appearance leads the MEHs to generate higher output power at lower frequencies and this phenomenon is more obvious with the increase in the degree of asymmetry. Finally, we observed that the characteristics of the response bandwidth of asymmetric MEHs subjected to band-limited noise excitation are similar to the response under harmonic excitation.

A Comparison of Different Multibody System Approaches in the Modeling of Flexible Twist Beam Axles

2011 ◽  
Author(s):  
Tariq Z. Sinokrot ◽  
William C. Prescott ◽  
Maurizio Nembrini ◽  
Alessandro Toso
Keyword(s):  
Multibody System ◽  
Synthesis Method ◽  
Component Mode Synthesis ◽  
Elastic Theory ◽  
Mode Shapes ◽  
Flexible Body ◽  
Element Analysis ◽  
Linear Elastic ◽  
Linear Elastic Theory ◽  
Flexible Component

One of the challenging issues in the area of flexible multibody systems is the ability to properly account for the geometric nonlinear effects that are present in many applications. One common application where these effects play an important role is the dynamic modeling of twist beam axles in car suspensions. The purpose of this paper is to examine the accuracy of the results obtained using four common modeling methods used in such applications. The first method is based on a spline beam approach in which a long beam is represented using piecewise rigid bodies interconnected by beam force elements along a spline curve. The beam force elements use a simple linear beam theory in approximating the forces and torques along the beam central axis. The second approach uses the well known method of component mode synthesis that is based on the linear elastic theory. Using this method the deformation of the beam, which is modeled as one flexible body, is defined using its own vibration and static correction mode shapes. The equations of motion are, in this case, written in terms of the system’s generalized coordinates and modal participation factors. The linear elastic theory is used again in the third approach using a slightly different technique called the sub-structuring synthesis method. This method is based on dividing the flexible component into sub-structures, in which, the method of component mode synthesis is used to describe the deformation of each substructure. The fourth approach is based on a co-simulation technique that uses a Multibody System (MBS) solver and an external nonlinear Finite Element Analysis (FEA) solver. The flexibility of any body in the multibody system is, in this case, modeled in the external nonlinear FEA solver. The latter calculates the forces due to the nonlinear deformations of the flexible body in question and communicates that to the MBS solver at certain attachment points where the flexible body is attached to the rest of the multibody system. The displacements and velocities of these attachment points are calculated by the MBS solver and are communicated back to the nonlinear FEA solver to advance the simulation. The four approaches described are reviewed in this paper and a multibody system model of a car suspension system that includes a twist beam axle is presented. The model is examined four times, once using each approach. The numerical results obtained using the different methods are analyzed and compared.

A Multibody System Approach to the Wedge Damper Friction Formulation

2009 ◽  
Author(s):  
Leonardo B. Baruffaldi ◽  
Henrique B. de Arau´jo ◽  
Auteliano A. dos Santos
Keyword(s):  
Mathematical Modeling ◽  
System Approach ◽  
Multibody System ◽  
Past Century ◽  
Body Model ◽  
The Past ◽  
Frictional Damping ◽  
Friction Models ◽  
Secondary Suspension ◽  
Multi Body

Secondary suspension of railway three-piece-trucks hasn’t changed much in the past century. Despite this, its most common damping element, the friction wedge, is not yet fully understood. The frictional damping is a known source of non-linearity and non-smoothness that imposes chaotic behaviors to the system, making the mathematical modeling of such devices a difficult task. The present paper presents a multi-body model of a three-piece-truck’s secondary suspension and the results of its simulations with three types of commonly used friction models.

Numerical integration of non-linear elastic multi-body systems

1995 ◽  
Vol 38 (16) ◽  
pp. 2727-2751 ◽  
Author(s):  
O. A. Bauchau ◽  
G. Damilano ◽  
N. J. Theron
Keyword(s):  
Numerical Integration ◽  
Linear Elastic ◽  
Non Linear ◽  
Multi Body

High-Frequency Dynamic Overshoot in Linear and Nonlinear Periodic Media

2016 ◽  
Vol 12 (1) ◽  
Author(s):  
Yijing Zhang ◽  
Alexander F. Vakakis
Keyword(s):  
High Frequency ◽  
Harmonic Excitation ◽  
Strong Nonlinearity ◽  
Periodic Media ◽  
Elastic Foundations ◽  
Linear Elastic ◽  
Analytical Approximations ◽  
Linear And Nonlinear ◽  
High Frequency Harmonic ◽  
Frequency Harmonic

We study the transient responses of linear and nonlinear semi-infinite periodic media on linear elastic foundations under suddenly applied, high-frequency harmonic excitations. We show that “dynamic overshoot” phenomena are realized whereby, due to the high-rate of application of the high-frequency excitations, coherent traveling responses are propagating to the far fields of these media; and this, despite the fact that the high frequencies of the suddenly applied excitations lie well within the stop bands of these systems. For the case of a linear one-dimensional (1D) spring-mass lattice, a leading-order asymptotic approximation in the high frequency limit of the suddenly applied harmonic excitation shows that the transient dynamic overshoot is expressed in terms of the Green's function at its free end. Then, a two-dimensional (2D) strongly nonlinear granular network is considered, composed of two semi-infinite, ordered homogeneous granular lattices mounted on linear elastic foundations and coupled by weak linear coupling terms. A high-frequency harmonic excitation is applied to one of the granular lattices—designated as the “excited lattice”, with the other lattice designated as the “absorbing” one. The resulting dynamic overshoot phenomenon consists of a “pure” traveling breather, i.e., of a single propagating oscillatory wavepacket with a localized envelope, resulting from the balance of discreteness, dispersion, and strong nonlinearity. The pure breather is asymptotically studied by a complexification/averaging technique, showing nearly complete but reversible energy exchanges between the excited and absorbing lattices as the breather propagates to the far field. Verification of the analytical approximations with direct numerical simulations is performed.

Failure Analysis of Planetary Gear Shaft of Power Split Device Based on Multi-Body Dynamics

2013 ◽  
Vol 433-435 ◽  
pp. 17-20 ◽  
Author(s):  
Yan Liu ◽  
Jing Fang Ji ◽  
Long Kong ◽  
Yan Li ◽  
Ji Xin Wang
Keyword(s):  
Hybrid Electric Vehicle ◽  
Coupled Model ◽  
Planetary Gear ◽  
Threshold Function ◽  
Power Performance ◽  
Body Dynamics ◽  
Power Split ◽  
The Moment ◽  
Multi Body ◽  
And Control

Power split device (PSD) affects the power performance and control strategy of hybrid electric vehicle (HEV). In this paper, a new threshold function for wavelet denoising is used to reduce noise in test torque and rotational speed data. The dynamic simulation is carried out at the moment of planetary gear shaft (PGS) failure, after the rigid-flexible coupled model of PSD is established. According to the obtained stress of PGS, analysis of PGS fracture is verified.

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