Automated Stability Analysis of a Vehicle in Combined Pitch and Roll

2002 ◽  
Author(s):  
James K. Sprague ◽  
Shyi-Ping Liu
Keyword(s):  
Stability Analysis ◽  
Rigid Body ◽  
Contact Forces ◽  
Design Parameters ◽  
Spherical Coordinates ◽  
Stability Boundaries ◽  
Overturning Stability ◽  
Heading Angle ◽  
The Stability ◽  
Six Degree Of Freedom

This paper presents a rigid body modeling approach using ADAMS™ for an overturning stability analysis of a vehicle stopped at an arbitrary heading angle on a steep grade. The vehicle is modeled as a six-degree-of-freedom rigid body with multiple contact forces acting on the ground. A gravity vector bounded by sets of spherical coordinates is applied to the vehicle to represent the physics of a vehicle stopped on a grade with any arbitrary combination of pitch and roll angles. A design of experiments study is performed to locate the overturning stability boundaries within given levels of design parameters. Results are output using two effective graphical means of depicting the stability regions and magnitude of contact forces.

Stability Analysis of High-Speed Railway Vehicle Based on Multibody Dynamics Analysis

2013 ◽  
Vol 392 ◽  
pp. 156-160
Author(s):  
Ju Seok Kang
Keyword(s):  
Stability Analysis ◽  
Multibody Dynamics ◽  
High Speed ◽  
Equations Of Motion ◽  
Contact Forces ◽  
Design Parameters ◽  
Railway Vehicle ◽  
Dynamics Analysis ◽  
Contact Points ◽  
The Stability

Multibody dynamics analysis is advantageous in that it uses real dimensions and design parameters. In this study, the stability analysis of a railway vehicle based on multibody dynamics analysis is presented. The equations for the contact points and contact forces between the wheel and the rail are derived using a wheelset model. The dynamics equations of the wheelset are combined with the dynamics equations of the other parts of the railway vehicle, which are obtained by general multibody dynamics analysis. The equations of motion of the railway vehicle are linearized by using the perturbation method. The eigenvalues of these linear dynamics equations are calculated and the critical speed is found.

scholarly journals On the Stability Analysis of a Coupled Rigid Body

2018 ◽  
Vol 09 (03) ◽  
pp. 210-222
Author(s):  
Olaniyi S. Maliki ◽  
Victor O. Anozie
Keyword(s):  
Stability Analysis ◽  
Rigid Body ◽  
The Stability

Linear Stability Analysis of a Waveboard Multibody Model With a Minimal Set of Equations

2021 ◽  
Author(s):  
A. G. Agúndez ◽  
D. García-Vallejo ◽  
E. Freire ◽  
A. M. Mikkola
Keyword(s):  
Stability Analysis ◽  
Multibody System ◽  
Equations Of Motion ◽  
Nonholonomic Constraints ◽  
Design Parameters ◽  
Multibody Model ◽  
Aspect Ratios ◽  
Holonomic And Nonholonomic Constraints ◽  
The Stability ◽  
Nonlinear Equations Of Motion

Abstract In this paper, the stability of a waveboard, the skateboard consisting in two articulated platforms, coupled by a torsion bar and supported of two caster wheels, is analysed. The waveboard presents an interesting propelling mechanism, since the rider can achieve a forward motion by means of an oscillatory lateral motion of the platforms. The system is described using a multibody model with holonomic and nonholonomic constraints. To perform the stability analysis, the nonlinear equations of motion are linearized with respect to the forward upright motion with constant speed. The linearization is carried out resorting to a novel numerical linearization procedure, recently validated with a well-acknowledged bicycle benchmark, which allows the maximum possible reduction of the linearized equations of motion of multibody systems with holonomic and nonholonomic constraints. The approach allows the expression of the Jacobian matrix in terms of the main design parameters of the multibody system under study. This paper illustrates the use of this linearization approach with a complex multibody system as the waveboard. Furthermore, a sensitivity analysis of the eigenvalues considering different scenarios is performed, and the influence of the forward speed, the casters’ inclination angle and the tori aspect ratios of the toroidal wheels on the stability of the system is analysed.

Non-linear stability analysis of floating ring bearings using Hopf bifurcation theory

2011 ◽  
Vol 225 (12) ◽  
pp. 2804-2818 ◽  
Author(s):  
A Amamou ◽  
M Chouchane
Keyword(s):  
Stability Analysis ◽  
Hopf Bifurcation ◽  
Linear Stability ◽  
Linear Stability Analysis ◽  
Limit Cycles ◽  
Critical Speed ◽  
Design Parameters ◽  
Stable Limit ◽  
Non Linear ◽  
The Stability

Floating ring bearings are used to support and guide rotors in several high-speed rotating machinery applications. They are usually credited for lower heat generation and higher vibration suppressing ability. Similar to conventional hydrodynamic bearings, floating ring bearings may exhibit unstable behaviour above a certain stability critical speed. Linear stability analysis is usually applied to predict the stability threshold speed. Non-linear stability analysis, however, is needed to predict the presence and the size of stable limit cycles above the stability threshold speed or unstable limit cycles below the stability critical speed. The prediction of limit cycles is an important step in bearing stability analysis. In this article, a non-linear dynamic model is derived and used to investigate the stability of a perfectly balanced symmetric rigid rotor supported by two identical floating ring bearings near the critical stability boundaries. The fluid film hydrodynamic reactions of the floating ring bearings are modelled by applying the short bearing theory and the half Sommerfeld solution. Hopf bifurcation theory is then utilized to determine the existence and the approximate size of stable and unstable limit cycles in the neighbourhood of the stability critical speed depending on the bearing design parameters. Numerical integration of the non-linear equations of motion is then carried out in order to compare the trajectories obtained by numerical integration to those obtained analytically using Hopf bifurcation analysis. Stability boundary curves for typical bearing design parameters have been decomposed into boundaries with supercritical stable limit cycles and boundaries with subcritical unstable limit cycles. The shape and size of the limit cycles for selected bearing parameters are presented using both analytical and numerical approaches. This article shows that floating ring stability boundaries may exhibit either stable supercritical limit cycles or unstable subcritical limit cycles predictable by Hopf bifurcation.

The Stability Analysis on Reservoir Bank Slope of Granite Stained Subgrade

2011 ◽  
Vol 250-253 ◽  
pp. 1711-1716
Author(s):  
Li Chao Wang ◽  
Ping Gen Zhou
Keyword(s):  
Stability Analysis ◽  
Rigid Body ◽  
Limit Equilibrium ◽  
Limit Equilibrium Method ◽  
Dynamic Compaction ◽  
Sliding Surface ◽  
Bank Slope ◽  
The Stability ◽  
Safety Operation ◽  
Reservoir Bank Slope

The limit equilibrium method for rigid body is used to analyze the stability of subgrade reservoir bank slope of granite stained. The sliding of subgrade reservoir bank slope reinforced by dynamic compaction along the interface will not be happened. In the most unfavorable conditions , the sliding surface will be formed inside the stained subgrade, which threatened to the safety operation of the expressway.

Hydrodynamic Memory Effect on Stability, Bifurcation, and Chaos of Two-Point Mooring Systems

1997 ◽  
Vol 41 (01) ◽  
pp. 26-44
Author(s):  
Jin-Sug Chung ◽  
Michael M. Bernitsas
Keyword(s):  
Memory Effect ◽  
Design Parameters ◽  
Wave Loads ◽  
Mooring Lines ◽  
Stability Boundaries ◽  
The Stability ◽  
Systems With Memory ◽  
Hydrodynamic Wave ◽  
Nonlinear Elastic ◽  
With Memory

The stability properties of two-point mooring systems governed by their slow horizontal motions are studied theoretically. The often-neglected memory effect due to hydrodynamic wave loads change—in some cases critically—the stability boundaries in the system design space. The third-order maneuvering equations and a nonlinear elastic spring model are used to describe the dynamics of the moored vessel and the mooring lines, respectively. The resulting model accurately represents a two-point mooring system and can be used for stability analysis in the sense of Lyapunov. The stability charts of mooring systems with memory effects exhibit considerable differences from systems without memory in local regions of bifurcation diagrams. Further, the pattern of these changes of stability boundaries varies with the hydrodynamic properties of the moored vessel and/or the environmental conditions. The findings of this study suggest that the number of influencing design parameters can be much more than the present stability theory of dynamical systems can handle. They prove, however, that neglecting the memory effect may result in selecting unsafe configurations of two-point mooring systems.

Stability Analysis of a Flexible Rotor Supported by Plain Circular Bearings with Micropolar Fluid

2014 ◽  
Vol 592-594 ◽  
pp. 1381-1385
Author(s):  
Pankaj Bhatia ◽  
Jaideep Gupta
Keyword(s):  
Stability Analysis ◽  
Micropolar Fluid ◽  
Hydrodynamic Lubrication ◽  
Tangential Direction ◽  
Design Parameters ◽  
Flexible Rotor ◽  
Basic Principles ◽  
Operating Variables ◽  
The Stability ◽  
Micropolar Lubrication

This paper describes the stability analysis of a flexible rotor supported by two horizontal identical plain circular bearings lubricated with Non-Newtonian fluid as micropolar fluid. The basic principles of hydrodynamic lubrication are also discussed here to study the dynamics of rotor bearing system. The mechanisms of hydrodynamic film generation and the effects of operating variables such as velocity, load, design parameters etc., on the performance of such films are outlined. The effects in hydrodynamic lubrication of rotor system using Non-Newtonian lubricant found some undesirable vibrations, undergoes periodic and quasi-periodic motion is described and their influence on bearing performance assessed. The numerical solution of modified Reynolds equation under micropolar lubrication with the usual lubrication assumptions is considered which yield the pressure distribution to find the couple of resulting forces in radial as well as in tangential direction.

Dynamic Behaviour and Stability Analysis of Multibody Haptic Systems

2012 ◽  
Author(s):  
Sara Shayan-Amin ◽  
László L. Kovács ◽  
József Kövecses
Keyword(s):  
Dynamic Model ◽  
Force Feedback ◽  
Joint Model ◽  
Simplified Model ◽  
Design Parameters ◽  
Experimental Investigations ◽  
Stability Boundaries ◽  
Flexible Joint ◽  
Haptic Devices ◽  
The Stability

To investigate the effects of mechanical design parameters on the performance of force feedback haptic devices, a representative dynamic model of the system is required. In this paper, the experimental investigations conducted on a 2DoF haptic device revealed that flexibility associated with the joints reduced the stable domain of operation considerably. Therefore, dynamic model of the investigated mechanism including the joint flexibility and physical damping is considered. The stability boundaries achieved by using the proposed flexible joint model is in good agreement with experimental results. A simplified model of the system is then developed employing a decomposition proposed in [1]. It is shown that the stability limits obtained by this simplified model give a slightly conservative but close estimate to the stability boundaries of the higher DoF flexible joint model. Such a simplified and experimentally validated model can be used for impedance-type haptic devices. The developed model makes it possible to investigate the effect of different mechanical parameters on the performance of multibody haptic systems.

A Stability Algorithm for the General Milling Process: Contribution to Machine Tool Chatter Research—7

1968 ◽  
Vol 90 (2) ◽  
pp. 330-334 ◽  
Author(s):  
R. Sridhar ◽  
R. E. Hohn ◽  
G. W. Long
Keyword(s):  
Stability Analysis ◽  
Milling Process ◽  
Stability Boundaries ◽  
Machine Tool Chatter ◽  
Milling Operation ◽  
Cutting Operation ◽  
Differential Difference Equation ◽  
Linear Differential ◽  
The Stability

In this paper, a method of stability analysis for the general milling process is given. The milling operation is described by a linear differential-difference equation with periodic coefficients. An algorithm which can be used in conjunction with the digital computer is developed as a means of analytically determining the stability of this equation. This algorithm will permit the determination of the stability boundaries in the space of controllable parameters associated with a cutting operation and allows more realistic models for milling to be studied than have been attempted up to the present time. The technique is used to predict the stability in an example of a milling operation.

scholarly journals A Method for Parametric Analysis of Stability Boundaries for Nonlinear Periodic Vibrations of Structures With Contact Interfaces

2018 ◽  
Author(s):  
E. P. Petrov
Keyword(s):  
Parametric Analysis ◽  
Large Scale ◽  
Contact Stiffness ◽  
Stability Loss ◽  
Forced Response ◽  
Scale Model ◽  
Design Parameters ◽  
Stability Boundaries ◽  
Analysis Of Stability ◽  
The Stability

A method for parametric analysis of the stability loss boundary has been developed for periodic regimes of nonlinear forced vibrations for a first time. The method allows parametric frequency-domain calculations of the stability loss together with the vibration amplitudes and design parameter values corresponding to the stability boundaries. The tracing algorithm is applied to obtain the trajectories of stability loss points as functions of design parameters. The parametric stability loss is formulated for cases when: (i) the design parameters characterise the properties of nonlinear contact interfaces (e.g. gap, contact stiffness, friction coefficient, etc.) and (ii) the design parameters describe linear components of the analysed structure (e.g. parameters of geometric shape, material, natural frequencies, modal damping etc.) and (iii) these parameters describe the excitation loads (e.g. their level, distribution or frequency). An approach allowing the multiparametric analysis of stability boundaries is proposed. The method uses the multiharmonic representation of the periodic forced response and aimed at the analysis of realistic gas-turbine structures comprising thousands and millions degrees of freedom. The method can be used for the effective search of isolated branches of the nonlinear solutions and examples of detection and search of the isolated branches are given: for relatively small and for large-scale finite element models. The efficiency of the method for calculation of the stability boundaries and for the search of isolated branches is demonstrated on simple systems and on a large-scale model of a turbine blade.

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