Optimization of dynamically sensitive parameters of Linke Hofmann Busch coach considering suspended equipment using design of experiment

2019 ◽  
Vol 25 (12) ◽  
pp. 1793-1811 ◽  
Author(s):  
S.D. Singh ◽  
Rakesh Mathur ◽  
R.K. Srivastava
Keyword(s):  
Sensitivity Analysis ◽  
Design Of Experiment ◽  
High Speed ◽  
Degrees Of Freedom ◽  
Research Work ◽  
Comfort Level ◽  
Design Parameters ◽  
Response Analysis ◽  
Frequency Range ◽  
Response Level

The high speed coach running on irregular track is always accompanied by inferior comfort for the passengers. The optimal design of coach parameters improving comfort level can be achieved through response analysis. The present study is concerned with the optimization of Linke Hofmann Busch rail coach design parameters to augment comfort level. The coach body and bogie frame under four degrees of freedom are modeled with the finite element method to obtain dynamic parameters of the coach, that is, eigenvalues and eigenvectors. The sensitivity analysis based on partial derivatives against frequency response function displacement with respect to various design parameters is conducted, and most influential coach parameters are optimized through computer experimentation using central composite design and response surface methodology of design of experiment (DOE). Using modal parameters obtained as above and Indian Rail Road power spectral density of track irregularities, both vertical and lateral responses are determined at vicinity to the center mass of coach body in a 0.1– 40 Hz frequency range of interest. Results conclude that peak vertical responses occur in 0 – 10 Hz, whereas peak lateral responses fall at still lower frequency representing long wavelength irregularities of track that causes discomfort to vehicle riders. Findings of the research work embodied herein reveal that the left end bio toilet tank mass has least effect on response. Also, these findings suggest scope for further attainment in comfort level by computer experimentation for combinations of three coach design parameters (wheel base, equivalent primary, and secondary suspension stiffness) on minimizing the response level without altering the basic design of the coach model. The present paper represents a significant move forward on the dynamic analysis of coach body considering suspended equipment, sensitivity analysis through mathematical approach rather than step parametric variation, and its optimization through DOE, which have not been addressed earlier. The outcome of the paper may help rail coach designers to modify coach design parameters for better comfort level, even in the low frequency range of operation.

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.

scholarly journals Comfort Level Refinement of Military Tracked Vehicle Crew through Optimal Control Study

2018 ◽  
Vol 68 (3) ◽  
pp. 265
Author(s):  
N. V. Ramamurthy ◽  
B. K. Vinayagam ◽  
J. Roopchand
Keyword(s):  
Degrees Of Freedom ◽  
Ride Comfort ◽  
Controller Design ◽  
Research Work ◽  
Comfort Level ◽  
Lumped Parameter Model ◽  
Tracked Vehicle ◽  
Machine Model ◽  
Seat Suspension ◽  
Suspension Model

Military tracked vehicle and crew are modelled together in this paper as integrated man-machine lumped parameter model, by integrating the simplified 5 degrees of freedom (DoF) tracked vehicle model, including seat and 4 DoF human bio-dynamic model, thus resulting in a 9 DoF simplified vehicle-occupant model. Then the natural frequency of major mass segment namely the chassis mass is obtained through simulation study, for a known road input. The value obtained is compared with that of an earlier research work, for validation of said man-machine model. Then focusing our study locally at crew seat location, parameters of crew seat suspension for ride comfort are optimised using the optimal digital state space controller designed for this purpose by implementing it in a 2 DoF occupant - seat suspension model and its Simulink model constructed. Simulation results illustrate the attainment of the goal by meeting the controller design requirements.

scholarly journals Design Issues and Challenges in Indoor MIMO Antenna Systems

2020 ◽  
Vol 8 (6) ◽  
pp. 3842-3846
Keyword(s):  
High Speed ◽  
Mimo Systems ◽  
Mimo System ◽  
Multiple Input Multiple Output ◽  
Research Work ◽  
Antenna System ◽  
Design Parameters ◽  
Future Research ◽  
Design Issues ◽  
Mimo Antenna

The promising solution for next generation wireless communication system is multiple input multiple output (MIMO) system. It can transmit and receive data from different channels simultaneously without any need of additional frequency band. In this paper the design issues and challenges in MIMO antenna system for different applications have been reviewed. The major applications of MIMO systems include Wi-Fi, High Speed Packet Access, LTE, WiMAX (4G), and also MIMO has been used in power line communication. Implementation of MIMO antenna system is dependent on important parameters such as: Peak gain, Average Gain, Mutual Coupling, Envelop Correlation Coefficient (ECC), Total Active Reflection Coefficient (TARC), Signal polarization and Miniaturization of antenna system. Hence an optimal MIMO antenna design to suit for communication applications in an indoor environment is a challenging task. This paper proposes comparative study for the different MIMO antenna parameters. The different modeling techniques for MIMO antenna system are surveyed and areas for future research work in line with tradeoffs between different design parameters are suggested.

scholarly journals Technology-Oriented Optimization of the Secondary Design Parameters of Robots for High-Speed Machining Applications

2010 ◽  
Author(s):  
Se´bastien Briot ◽  
Anatol Pashkevich ◽  
Damien Chablat
Keyword(s):  
Machine Tools ◽  
High Speed ◽  
Degrees Of Freedom ◽  
Parallel Robots ◽  
Design Parameters ◽  
Speed Up ◽  
Parallel Kinematic ◽  
Parallel Kinematic Machine Tools ◽  
Accuracy Constraints ◽  
Three Degrees Of Freedom

In this paper, a new methodology for the optimal design of the secondary geometric parameters (shape of links, size of the platform, etc.) of parallel kinematic machine tools is proposed. This approach aims at minimizing the total mass of the robot under position accuracy constraints. This methodology is applied to two translational parallel robots with three degrees-of-freedom (DOF): the Y-STAR and the UraneSX. The proposed approach is able to speed up the design process and to help the designer to find more quickly a set of design parameters.

Bearings Influence on the Dynamic Behavior of HSM Spindle

2012 ◽  
Author(s):  
David Noel ◽  
Mathieu Ritou ◽  
Sebastien Le Loch ◽  
Benoit Furet
Keyword(s):  
Dynamic Behavior ◽  
High Speed ◽  
Degrees Of Freedom ◽  
Experimental Tests ◽  
Operating Conditions ◽  
Design Parameters ◽  
Mechanics Model ◽  
Bearing Stiffness ◽  
Rough Milling ◽  
The Impact

The aeronautic industry requires high speed and high power spindles to obtain high material removal rates during long rough milling operations. The weakness of HSM spindle is the bearings, although high precision hybrid ball bearings have been developed to achieve this critical application. Inadequate use of spindles inevitably leads to shortened lifetimes. Choosing the operating conditions is a required step before machining applications. It can be achieved through either experimental tests or numerical modeling that leads to stability lobe diagrams. Stability of cuts relies on the dynamic behavior of the spindle, which is particularly due to the eigenfrequencies of the tool-shaft assembly. The frequencies depend on bearing stiffness that can change under operating conditions. That is why the impact of cutting conditions and bearing parameters on its stiffness are studied in the paper. A five degrees of freedom model of angular ball bearing is briefly presented. A complete bearing model is introduced. The originality of the approach is the complete technological modeling, notably of the radial expansions of inner and outer rings of bearing. A non-linear expression is established from continuum mechanics model. The influence of geometry of bearing, operating conditions and design parameters of spindle on the bearing stiffness are established and analysed. Then, modal analyses of the tool-spindle assembly are carried out in relation to the varying bearing stiffness. Finally, significance of the approach is demonstrated through the analyses of Frequency Response Function.

Nonlinear dynamic study and vibration reduction of a power turret gear train with modified design parameters

2014 ◽  
Vol 229 (10) ◽  
pp. 1745-1759 ◽  
Author(s):  
Lijiao Xu ◽  
Nan Chen
Keyword(s):  
Nonlinear Dynamic ◽  
High Speed ◽  
Degrees Of Freedom ◽  
Vibration Reduction ◽  
Numerical Control ◽  
Gear Train ◽  
Design Parameters ◽  
Contact Ratio ◽  
Mesh Stiffness ◽  
Gear Mesh

This work presents the nonlinear dynamic characteristics and vibration reduction of a numerical control power turret three-stage gear transmission system composed of four spur gears. Considering translational and rotational motions, the nonlinear lumped-parameter and multi-degrees of freedom models of modified and unmodified transmission systems are introduced to study the dynamic behavior while the time-varying mesh stiffness and backlash of gear mesh pairs are involved as internal excitations. For the requirement of high speed and low vibration, high contact ratio by modifying design parameters is suggested in this study. By numerical method, the dynamic vibration responses are calculated. Results in the time and frequency domains show that the vibration amplitudes and mesh forces are efficiently decreased after modification. The influences of key parameters, such as mesh stiffness, damping, backlash, and torque on the dynamic response are also studied here. To demonstrate the effectiveness of the proposed model, the vibration tests are conducted by two physical prototypes of the power turret. The values of vibration acceleration at different tests points and speeds are obtained and analyzed. Experimental results validate that the vibration of turret is decreased by the design improvement of gear system.

A Coupled Finite Element–Wave Based Approach for the Steady-State Dynamic Analysis of Acoustic Systems

2003 ◽  
Vol 11 (02) ◽  
pp. 285-303 ◽  
Author(s):  
B. van Hal ◽  
W. Desmet ◽  
D. Vandepitte ◽  
P. Sas
Keyword(s):  
Finite Element ◽  
Steady State ◽  
Degrees Of Freedom ◽  
Complex Geometry ◽  
Low Frequency ◽  
Response Analysis ◽  
Frequency Range ◽  
Application Range ◽  
State Dynamic ◽  
High Convergence Rate

The finite element method (FEM) is widely accepted for the steady-state dynamic response analysis of acoustic systems. It exhibits almost no restrictions with respect to the geometrical features of these systems. However, it is limited to the low-frequency range due to the rapidly growing model size for increasing frequencies. An alternative method is the wave based method (WBM), which is based on the indirect Trefftz approach. It exhibits better convergence properties than the FEM and therefore allows accurate predictions at higher frequencies. However, the applicability is limited, since the high computational efficiency only appears for systems of moderate geometrical complexity. In order to benefit from the advantageous features of both methods, i.e. the wide application range of the FEM and the high convergence rate of the WBM, the coupling between both methods is proposed. Only the parts of the problem domain with a complex geometry are modeled using the FEM, while the remaining parts are described with a wave based model. The resulting hybrid model contains less degrees of freedom, which allows a further model refinement. The proposed coupled approach has the potential to cover the mid-frequency range, where it is still difficult to obtain satisfactory prediction results with currently existing deterministic techniques.

The Structure Dynamic Optimum Design of the Frame for High Speed Conveying Manipulator Based on Sensitivity Analysis

2013 ◽  
Vol 415 ◽  
pp. 431-435 ◽  
Author(s):  
Feng Wei Xue ◽  
Ji Ping Zhou ◽  
Ke Wang ◽  
Jun Yong Zhan
Keyword(s):  
Sensitivity Analysis ◽  
High Speed ◽  
Global Sensitivity Analysis ◽  
Dynamic Properties ◽  
Dynamic Performance ◽  
Frame Structure ◽  
Design Parameters ◽  
Global Sensitivity ◽  
Important Design ◽  
The Ideal

To improve dynamic properties of frame structure uses the method of sensitivity analysis of optimizing the thicknesses. And adopting the way of combining the partial sensitivity analysis with global sensitivity analysis finds out important design parameters, which can ensure the ideal dynamic performance of the frame structure and make the frame light in weight.

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