3 DOF Lumped Mass Tracked Vehicle Model

2015 ◽  
Vol 799-800 ◽  
pp. 803-807
Author(s):  
Mehmet Nuri Özdemir ◽  
Varlık Kılıç
Keyword(s):  
Degrees Of Freedom ◽  
Equivalent Stiffness ◽  
Vehicle Model ◽  
Lumped Mass ◽  
Tracked Vehicle ◽  
Matlab Simulink ◽  
System Parameters ◽  
Equivalent Damping ◽  
Equivalent Mass

A 3 DOF lumped mass tracked vehicle model was constructed in Matlab Simulink Environment and used for positioning the vehicle on gradients and missile firing operations. Pitch center, roll center and system parameters such as equivalent stiffness values, equivalent damping values and equivalent mass/inertias of 3 DOF model were obtained from 32+ degrees of freedom tracked vehicle model by simulations. Moments in pitch and roll directions were applied to the vehicle to find the pitch and roll centers. A range of step forces in bounce direction and a range of step moments in pitch and roll directions were applied to the vehicle and responses in the related directions of 32+ degrees of freedom model were used to determine the system parameters of 3-DOF model. Finally attitude of the vehicle on the gradients and missile firing scenario were simulated with both models and the results showed that 3 DOF model reasonably predicts the behavior of the tracked vehicle.

Influence of Equivalence Dynamic Parameters Variation About Behavior Structure of Milling Machine Tools

2007 ◽  
Author(s):  
Petru A. Pop
Keyword(s):  
Machine Tools ◽  
Experimental Tests ◽  
Dynamic Structure ◽  
Original Method ◽  
Milling Process ◽  
Milling Machine ◽  
Dynamic Parameters ◽  
Equivalent Stiffness ◽  
Equivalent Damping ◽  
Equivalent Mass

This paper has presented a study about behavior structure at universal precision milling machine for tool-shop by the variation of machine’s Equivalence Dynamic Parameters (EDP). These parameters of milling machine: equivalent mass – m [kg], equivalent damping constant – c [N/ms−1], equivalent stiffness – k [N/m], have been determined by experimental tests and from calculations, obtaining a exactly range values for each parts. All these had been calculated in function of eigenvalues of milling machine-ωn, which had been determined by experimental tests and mathematical model of dynamic milling process. For that, has been created an original program “Study mck”, which is used by SIMULINK program from MATLAB R14.v7.01 system. Then were executed 11 simulation tests, which were done by certain combinations of m, c, k values and cutting forces parameters, recorded approximately 300 diagrams. The results were significant has determined the chatter frequency very close to eigenvalues of machine by an original method, which had confirmed the experimental measures and analytical calculus and certain solution for improving the dynamic structure of milling machine by its equivalent dynamic parameters.

The Role of Air Damping in Synthesized Damping of Litchi Tree Vibration

2013 ◽  
Vol 295-298 ◽  
pp. 2041-2044
Author(s):  
Tian Hu Liu ◽  
Yu Xiang Luo
Keyword(s):  
Damping Ratio ◽  
Mass Range ◽  
Equivalent Stiffness ◽  
Trunk Length ◽  
Equivalent Damping ◽  
Air Damping ◽  
Air Resistance ◽  
Equivalent Mass ◽  
Canopy Size

In order to analyze the role of air damping in synthesized damping of litchi tree vibration, the fruit tree was simplified into a cantilever firstly. Then, according to equations of equivalent stiffness, equivalent damping, and equivalent mass, the damping ratio of air resistance was analyzed. The results showed that such damping ratio increases with the height of canopy center and the canopy size, and decreases with canopy mass and trunk radius. Within normal trunk radius, trunk length, canopy size, and canopy mass range, the damping ratio of air resistance is much smaller than 1.

scholarly journals Numerical Analysis for Dynamic Instability of Electrodynamic Maglev Systems

1995 ◽  
Vol 2 (4) ◽  
pp. 339-349 ◽  
Author(s):  
Y. Cai ◽  
S.S. Chen
Keyword(s):  
Degrees Of Freedom ◽  
Magnetic Force ◽  
Numerical Solutions ◽  
Dynamic Instability ◽  
Theoretical Models ◽  
Coupled Vibration ◽  
Vehicle Model ◽  
System Parameters ◽  
Maglev Vehicle ◽  
Force Data

Suspension instabilities in an electrodynamic maglev system with three- and five-degrees-of-freedom DOF vehicles traveling on a double L-shaped set of guideway conductors were investigated with various experimentally measured magnetic force data incorporated into theoretical models. Divergence and flutter were obtained from both analytical and numerical solutions for coupled vibration of the three-DOF maglev vehicle model. Instabilities of five direction motion (heave, slip, roll, pitch, and yaw) were observed for the five-DOF vehicle model. The results demonstrate that system parameters such as system damping, vehicle geometry, and coupling effects among five different motions play very important roles in the occurrence of dynamic instabilities of maglev vehicles.

scholarly journals Analytical Study on the Cornering Behavior of an Articulated Tracked Vehicle

Machines ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 38
Author(s):  
Antonio Tota ◽  
Enrico Galvagno ◽  
Mauro Velardocchia
Keyword(s):  
Mathematical Model ◽  
Degrees Of Freedom ◽  
Analytical Study ◽  
Proportional Integral Derivative ◽  
Vehicle Model ◽  
Tracked Vehicle ◽  
Tracked Vehicles ◽  
Side Slope ◽  
Skid Steering ◽  
And Control

Articulated tracked vehicles have been traditionally studied and appreciated for the extreme maneuverability and mobility flexibility in terms of grade and side slope capabilities. The articulation joint represents an attractive and advantageous solution, if compared to the traditional skid steering operation, by avoiding any trust adjustment between the outside and inside tracks. This paper focuses on the analysis and control of an articulated tracked vehicle characterized by two units connected through a mechanical multiaxial joint that is hydraulically actuated to allow the articulated steering operation. A realistic eight degrees of freedom mathematical model is introduced to include the main nonlinearities involved in the articulated steering behavior. A linearized vehicle model is further proposed to analytically characterize the cornering steady-state and transient behaviors for small lateral accelerations. Finally, a hitch angle controller is designed by proposing a torque-based and a speed-based Proportional Integral Derivative (PID) logics. The controller is also verified by simulating maneuvers typically adopted for handling analysis.

Experimental study on the dynamic properties of the dual-chamber solid and liquid mixture vibration isolator

2018 ◽  
Vol 24 (22) ◽  
pp. 5302-5311 ◽  
Author(s):  
FS Li ◽  
Q Chen ◽  
JH Zhou
Keyword(s):  
Liquid Mixture ◽  
Dynamic Properties ◽  
Liquid Column ◽  
Test Results ◽  
Equivalent Stiffness ◽  
Dual Chamber ◽  
Equivalent Damping ◽  
Fluid Damping ◽  
Equivalent Mass ◽  
Stiffness And Damping

The dual-chamber solid and liquid mixture (SALiM) isolator exhibits multiple stiffness and damping properties with various parameters. As a passive isolation device, the dual-chamber SALiM isolator can also obtain a variable stiffness property by substituting the valve with an active throttle device. Before that, the dynamic properties of the isolator need to be further investigated. Sine sweep tests under different valve openings were implemented to analyze the frequency response characteristics of the system. Two hydro pressure sensors were added into the two chambers to record the pressure signals, with which the equivalent stiffness, equivalent damping, fluid damping, and equivalent mass of the liquid column were identified. Based on the test results, numerical and theoretical analysis, the dynamic properties of the isolator including the influence of the fluid damping and inertia mass on the equivalent stiffness, the relation between the isolator's equivalent damping and the fluid damping, the fluid capacity of the linking tube, and the equivalent mass of the liquid column were analyzed in depth. Conclusions about stiffness and damping obtained from the test results correspond well with those from the theoretical analysis, but the identification results of the equivalent mass, which show that the negative correlation of equivalent mass of the liquid column with its response amplitude seems controversial. An assumption is proposed to explain the abnormal characteristics of the liquid column. However, the exact model of the inertia track needs further exploration and verification.

Adaptive Control of a Sliding Seat Using Magnetorheological Energy Absorbers

2010 ◽  
Author(s):  
Min Mao ◽  
Norman M. Wereley ◽  
Alan L. Browne
Keyword(s):  
Adaptive Control ◽  
Degrees Of Freedom ◽  
Adaptive Controller ◽  
Degree Of Freedom ◽  
Lumped Mass ◽  
Adaptive Controllers ◽  
Bingham Number ◽  
Control Objective ◽  
Payload Mass ◽  
Energy Absorbers

Feasibility of a sliding seat utilizing adaptive control of a magnetorheological (MR) energy absorber (MREA) to minimize loads imparted to a payload mass in a ground vehicle for frontal impact speeds as high as 7 m/s (15.7 mph) is investigated. The crash pulse for a given impact speed was assumed to be a rectangular deceleration pulse having a prescribed magnitude and duration. The adaptive control objective is to bring the payload (occupant plus seat) mass to a stop using the available stroke, while simultaneously accommodating changes in impact velocity and occupant mass ranging from a 5th percentile female to a 95th percentile male. The payload is first treated as a single-degree-of-freedom (SDOF) rigid lumped mass, and two adaptive control algorithms are developed: (1) constant Bingham number control, and (2) constant force control. To explore the effects of occupant compliance on adaptive controller performance, a multi-degree-of-freedom (MDOF) lumped mass biodynamic occupant model was integrated with the seat mass. The same controllers were used for both the SDOF and MDOF cases based on SDOF controller analysis because the biodynamic degrees of freedom are neither controllable nor observable. The designed adaptive controllers successfully controlled load-stroke profiles to bring payload mass to rest in the available stroke and reduced payload decelerations. Analysis showed extensive coupling between the seat structures and occupant biodynamic response, although minor adjustments to the control gains enabled full use of the available stroke.

Finite Element Analysis of 2-D Structures by New Strain Based Triangular Element

2018 ◽  
Vol 35 (3) ◽  
pp. 305-313 ◽  
Author(s):  
C. Rebiai
Keyword(s):  
Dynamic Analysis ◽  
Degrees Of Freedom ◽  
Numerical Solutions ◽  
Time Integration ◽  
Triangular Element ◽  
Membrane Element ◽  
Lumped Mass ◽  
Element Analysis ◽  
Benchmark Tests ◽  
Three Degrees Of Freedom

ABSTRACTIn this investigation, a new simple triangular strain based membrane element with drilling rotation for 2-D structures analysis is proposed. This new numerical model can be used for linear and dynamic analysis. The triangular element is named SBTE and it has three nodes with three degrees of freedom at each node. The displacements field of this element is based on the assumed functions for the various strains satisfying the compatibility equations. This developed element passed both patch and benchmark tests in the case of bending and shear problems. For the dynamic analysis, lumped mass with implicit/explicit time integration are employed. The obtained numerical results using the developed element converge toward the analytical and numerical solutions in both analyses.

Vertical vibration modelling and vibration response analysis of Chinese high-speed train passengers at different locations of a high-speed train

2020 ◽  
Vol 235 (1) ◽  
pp. 35-46 ◽  
Author(s):  
Chun-jun Chen ◽  
Chao Fang ◽  
Guo-qing Qu ◽  
Zhi-ying He
Keyword(s):  
High Speed ◽  
Degrees Of Freedom ◽  
Vibration Signal ◽  
Vertical Vibration ◽  
Response Analysis ◽  
High Speed Train ◽  
Vehicle Model ◽  
Internal Organs ◽  
Damping Coefficients ◽  
Track Irregularity

To study the vibration of a passenger's head and internal organs at different locations of a high-speed train, a 9-degrees-of-freedom (DOF) model of seated passengers is proposed in this paper, and its parameters of the damping coefficients and stiffnesses are identified. Next, the response of the head and internal organs is simulated by applying the vibrational stimulation generated by a 27-DOF vehicle model under track irregularity. Moreover, by applying the measured vibration signal, the following conclusions can be drawn: (1) the weakest response is detected at the centre of the compartment of the wagon, and a stronger response is detected at the centre of the bogie, with the rolling motion having a greater effect 1 m away from the centre of the bogie; (2) the response of the human internal organs is stronger than that of the head under stimulation with a lower frequency of less than 3 Hz, and a similar conclusion can be drawn in the range of 5 to 8 Hz. However, if the frequency is in the range between 8 and 15 Hz, the situation is entirely different. The responses of both the head and internal organs are reduced at frequencies over 20 Hz; (3) from the real application, it can be inferred that the greatest response can be detected at approximately 3 Hz for internal organs and at 8 Hz or higher for the head.

Motorcycle Analytical Modeling Including Tire–Wheel Nonuniformities for Ride Comfort Analysis

2017 ◽  
Vol 45 (2) ◽  
pp. 101-120 ◽  
Author(s):  
Matheus de B. Vallim ◽  
José M. C. Dos Santos ◽  
Argemiro L. A. Costa
Keyword(s):  
Degrees Of Freedom ◽  
Analytical Modeling ◽  
Ride Comfort ◽  
Experimental Tests ◽  
Rotational Frequency ◽  
Analytical Models ◽  
Vertical Force ◽  
Lumped Mass ◽  
Multi Body ◽  
4 Degrees Of Freedom

ABSTRACT The transmission of vibrations in motorcycles and their perception by the passengers are fundamental in comfort analysis. Tire nonuniformities can generate self-excitations at the rotational frequency of the wheel and contribute to the ride vibration environment. In this work a multi-body motorcycle model is built to evaluate the ride comfort with respect to tire nonuniformities. The aim is to obtain a multi–degrees-of-freedom dynamic model that includes both the contributions of the motorcycle and tire–wheel assembly structures. This representation allows the tire nonuniformities to predict the vertical force variations on the motorcycle and can be used through a root mean square acceleration evaluation for ride comfort analysis. The motorcycle model proposed is a 10-degrees-of-freedom system, where each tire–wheel is a 4-degrees-of-freedom model. The tire–wheel assemblies include two types of nonuniformities: lumped mass imbalance and radial run-out. Simulations of analytical models are compared with experimental tests.

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