Dynamic precision analysis and experimental verification of high-speed precision punch press

2016 ◽  
Vol 230 (20) ◽  
pp. 3655-3662 ◽  
Author(s):  
Fengfeng Hu ◽  
Yu Sun ◽  
Binbin Peng
Keyword(s):  
Elastic Wave ◽  
Dynamic Model ◽  
High Speed ◽  
Impact Factors ◽  
Superposition Method ◽  
Bottom Dead Center ◽  
Dynamic Precision ◽  
Modal Superposition Method ◽  
The Impact ◽  
Punch Press

In order to investigate the impact factors and their affection on high-speed precision multilink punch press (MPP), the dynamic model with different joint clearance was established, and the influence of different clearance and speed on the dynamic positional repeatability of bottom dead center (BDC) was analyzed. The elastic dynamic model of high-speed MPP was established, the affection of the elastic deformation and elastic wave on the positional repeatability of the BDC were presented by using modal superposition method to solve dynamic equation. Meanwhile, experiments on the dynamic repeatability of the BDC of the punch during working were completed. At last, the comparison of the experimental results with the analyzed results was given, and based on which, it can be concluded that the clearance, elastic wave and deformation are the key factors of the dynamic repeatability precision of the BDC.

Dynamic model for high-speed rotors based on their experimental characterization

2017 ◽  
Vol 2 (4) ◽  
pp. 25
Author(s):  
L. A. Montoya ◽  
E. E. Rodríguez ◽  
H. J. Zúñiga ◽  
I. Mejía
Keyword(s):  
Dynamic Model ◽  
High Speed ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Experimental Characterization ◽  
Rotating Systems ◽  
Computing Performance ◽  
The Impact ◽  
Stiffness Distribution ◽  
Good Agreement

Rotating systems components such as rotors, have dynamic characteristics that are of great importance to understand because they may cause failure of turbomachinery. Therefore, it is required to study a dynamic model to predict some vibration characteristics, in this case, the natural frequencies and mode shapes (both of free vibration) of a centrifugal compressor shaft. The peculiarity of the dynamic model proposed is that using frequency and displacements values obtained experimentally, it is possible to calculate the mass and stiffness distribution of the shaft, and then use these values to estimate the theoretical modal parameters. The natural frequencies and mode shapes of the shaft were obtained with experimental modal analysis by using the impact test. The results predicted by the model are in good agreement with the experimental test. The model is also flexible with other geometries and has a great time and computing performance, which can be evaluated with respect to other commercial software in the future.

scholarly journals Examining partial proportional odds model in analyzing severity of high-speed railway accident

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Jing Wang ◽  
Yinghan Wang ◽  
Yichuan Peng ◽  
Jian John Lu
Keyword(s):  
High Speed ◽  
Proportional Odds Model ◽  
Impact Factors ◽  
Proportional Odds ◽  
High Speed Railway ◽  
Severity Level ◽  
Content Type ◽  
Factors Affecting ◽  
Partial Proportional Odds Model ◽  
The Impact

Purpose The operation safety of the high-speed railway has been widely concerned. Due to the joint influence of the environment, equipment, personnel and other factors, accidents are inevitable in the operation process. However, few studies focused on identifying contributing factors affecting the severity of high-speed railway accidents because of the difficulty in obtaining field data. This study aims to investigate the impact factors affecting the severity of the general high-speed railway. Design/methodology/approach A total of 14 potential factors were examined from 475 data. The severity level is categorized into four levels by delay time and the number of subsequent trains that are affected by the accident. The partial proportional odds model was constructed to relax the constraint of the parallel line assumption. Findings The results show that 10 factors are found to significantly affect accident severity. Moreover, the factors including automation train protection (ATP) system fault, platform screen door and train door fault, traction converter fault and railway clearance intrusion by objects have an effect on reducing the severity level. On the contrary, the accidents caused by objects hanging on the catenary, pantograph fault, passenger misconducting or sudden illness, personnel intrusion of railway clearance, driving on heavy rain or snow and train collision against objects tend to be more severe. Originality/value The research results are very useful for mitigating the consequences of high-speed rail accidents.

scholarly journals Nonlinear Dynamic Analysis and Chaos Prediction of Grinding Motorized Spindle System

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Weitao Jia ◽  
Feng Gao ◽  
Yan Li ◽  
Wenwu Wu ◽  
Zhongwei Li
Keyword(s):  
Nonlinear Dynamic ◽  
High Speed ◽  
Chaotic Behavior ◽  
Nonlinear Dynamic Analysis ◽  
Phase Portraits ◽  
Impact Factors ◽  
Nonlinear Dynamic Model ◽  
Motorized Spindle ◽  
Spindle System ◽  
The Impact

The paper determines the impact factors of dynamics of a motorized spindle rotor system due to high speed: centrifugal force and bearing stiffness softening. A nonlinear dynamic model of the grinding motorized spindle system considering the above impact factors is constructed. Through system simulation including phase portraits and Poincaré map, the periodic behavior and chaotic behavior of the nonlinear grinding motorized spindle system are revealed. The threshold curve of chaos motion is obtained through the Melnikov method. The conclusion can provide a theoretical basis for researching deeply the dynamic behaviors of the grinding motorized spindle system.

A Mini-Network Simulation Approach to Investigate the Capacity and Safety Aspects of National Rail Network

2021 ◽  
Author(s):  
Hamed Pouryousef ◽  
Monique Stewart ◽  
Som P. Singh ◽  
Anand Prabhakaran
Keyword(s):  
High Speed ◽  
Network Simulation ◽  
Network Capacity ◽  
Impact Factors ◽  
Simulation Approach ◽  
Analytical Technique ◽  
Rail Network ◽  
Advanced Technologies ◽  
The Impact ◽  
The U.S

Abstract Over the last decades there have been major technology advancements in the railroad industry to improve the operational safety as well as performance of freight trains in shared-use corridors. This study was focused on developing a methodology that allows evaluation of the impact of such advanced technologies over the safety and capacity aspects of the U.S. rail network using a benchmark mini-network simulation approach. A hypothetical mini-network of 5,000 miles of track with characteristics typical of the North American rail network was developed. Two hundred thirty two (232) daily trains, including a mix of intercity passenger, commuter, High Speed Rail and 78 freight trains, were used to simulate the traffic flow. Several network capacity and safety related parameters; network delay, network velocity, track utilization level, number of stops at stations, number of braking for route reservations, and number of stops at signals were analyzed in this study. The results of the benchmark network simulations were then extended to the U.S. rail network, using an analytical technique with assumptions for important parameters and impact factors such as total route miles, freight train-miles, number of sidings/yards, congestion level and age of fleets. The results indicate that the methodology is able to quantify the improvement in network capacity and safety features that can be obtained when advanced technologies are deployed on freight trains.

Analysis of Vibration Characteristics of Friction Plate Based on Rigid-Flexible Coupling Model

2013 ◽  
Vol 572 ◽  
pp. 480-484
Author(s):  
Shen Long Li ◽  
Jiang Li Pan ◽  
Hua Bing Yin
Keyword(s):  
Dynamic Model ◽  
High Speed ◽  
Element Model ◽  
Coupling Model ◽  
Vibration Characteristics ◽  
Composition Analysis ◽  
Coupling Vibration ◽  
Flexible Coupling ◽  
Friction Plate ◽  
The Impact

The stability and reliability of the shift friction plate are the main condition to guarantee the normal working for the planetary gearbox. But the failures of the friction plate, such as fracture or broken plastic deformation, often appear during the real vehicle testing process. Currently, most studies focus on chemical composition analysis and fracture analysis for the fractured friction plate, but less study for shock damage. In this paper, we develop a multi-body dynamic model, a finite element model and a rigid-flexible coupling dynamic model to analyze and compare the vibration characteristics of the friction plate with three different support forms. The variation law of the impact force and frequency can be obtained for the tooth portion of the friction plate with different support forms. Finally, it can provide theoretical guidance for studying the failure of friction plate at high speed. Keywords: Friction Plate; Rigid-flexible Coupling; Vibration Characteristics

scholarly journals Speed Effects on Inherent Rotating Frequency of Motorized Spindle System

2011 ◽  
Vol 2-3 ◽  
pp. 900-905 ◽  
Author(s):  
Bo Wang ◽  
Wei Sun ◽  
Kun Peng Xu ◽  
Bang Сhuan Wen
Keyword(s):  
Centrifugal Force ◽  
High Speed ◽  
Impact Factors ◽  
Motorized Spindle ◽  
Spindle System ◽  
High Speeds ◽  
Radial Stiffness ◽  
Bearing Stiffness ◽  
Coupling Factors ◽  
The Impact

The paper determines the impact factors of high-speed spindle system including the centrifugal force, gyroscopic moments and the bearing stiffness softening, etc, then builds the general spindle-bearing FEM considering high speeds. Taking a motorized spindle as example, the effect of centrifugal force, gyroscopic effect, the radial stiffness and the coupling factors are analyzed qualitatively and quantitatively. Finally the research shows the variations of bearing radial stiffness, centrifugal force and gyroscopic moments have a significant effect on dynamics of spindle system in high speeds, while modeling the high speed spindle system, above factors must be considered.

scholarly journals Numerical analysis of beam rail bridges - impact factors in the vertical deflection

2017 ◽  
Vol 2017 (9) ◽  
pp. 11-17 ◽  
Author(s):  
Monika Podwórna
Keyword(s):  
High Speed ◽  
Equations Of Motion ◽  
Impact Factors ◽  
Vertical Deflection ◽  
Lagrange Equations ◽  
High Speeds ◽  
Rail Vehicles ◽  
Non Linear ◽  
Random Track Irregularities ◽  
The Impact

The impact factors in the vertical deflection obtained in dynamic analysis of BTT systems - bridged / track structure / high speed train (BTT) - are discussed. The BTT system is one of 5 bridges spanning from 15 m to 27 m, modelled as simply supported beams loaded by ICE-3 trains traveling at high speeds. The two-dimensional, physically non-linear BTT model includes: viscoelastic suspension of rail vehicles on two independent axle bogies and non-linear one-sided wheel-rail contact springs according to Hertz theory, access zones for composite construction. The BTT system was divided into subsystems loaded with vertical interactions transmitted by elastic or viscoelastic and physically linear or nonlinear constraints. Using Lagrange equations and internal aggregation of subsystems, discretised according to the finite element method, matrix equations of motion of the subsystems were obtained, with explicit linear left sides and nonlinear implicit right sides, which were integrated numerically using the Newmark method with parameters βN=1/4, γN=1/2. The analysis focus on the effect of random track irregularities on the dynamic response of BTT systems.

A Finite Element Methodology to Study Soil–Structure Interaction in High-Speed Railway Bridges

2018 ◽  
Vol 13 (3) ◽  
Author(s):  
Antonio Martínez-De la Concha ◽  
Héctor Cifuentes ◽  
Fernando Medina
Keyword(s):  
Finite Element ◽  
High Speed ◽  
Soil Structure ◽  
Soil Structure Interaction ◽  
Sensitivity Analyses ◽  
Impact Factors ◽  
Structure Interaction ◽  
Finite Element Software ◽  
High Speed Trains ◽  
The Impact

This paper analyzes the dynamic soil–structure interaction (SSI) of a railway bridge under the load transmitted by high-speed trains using the finite element method (FEM). In this type of bridges, the correct analysis of SSI requires proper modeling of the soil; however, this task is one of the most difficult to achieve with the FEM method. In this study, we explored the influence of SSI on the dynamic properties of the structure and the structure's response to high-speed train traffic using commercial finite element software with direct integration and modal superposition methods. High-speed trains are characterized by the high-speed load model (HSLM) in the Eurocode. We performed sensitivity analyses of the influence of several parameters on the model, such as the size and stiffness of the discretized soil, mesh size, and the influence of the dynamic behavior of the excitation. Based on the results, we make some important and reliable recommendations for building an efficient and simple model that includes SSI. We conducted a dynamic analysis of a full model of a general multispan bridge including the piers, abutments, and soil and identified the impact factors that affected the design of the bridge. The analysis revealed that the methodology we propose allows for a more accurate determination of the dynamic effects of the passage of a train over the bridge, compared to the simpler and more widely used analysis of a directly supported isolated deck, which tends to overestimate the impact factors.

scholarly journals A model-based control law for vibration reduction of serial robots with flexible joints

2021 ◽  
Vol 22 ◽  
pp. 38
Author(s):  
Jacques Farah ◽  
Hélène Chanal ◽  
Nicolas Bouton ◽  
Vincent Gagnol
Keyword(s):  
Dynamic Model ◽  
High Speed ◽  
Control Law ◽  
Flexible Joints ◽  
Dynamic Identification ◽  
Model Based Control ◽  
Model Based ◽  
Serial Robots ◽  
Pick And Place ◽  
The Impact

The presence of flexibilities in rotational joints can limit the kinematic performances of manipulators doing high speed tasks as Pick and Place. The problem addressed in this work concerns the vibration control of serial robots with flexible joints performing Pick and Place tasks in order to improve productivity. Based on a dynamic model of a robot with flexible joints, a model-based control law is proposed with its associated tuning methodology. The robot dynamic model is then the key point of our methodology. This dynamic model considers stiffness and damping of each flexible joint. To guarantee its accuracy, a geometrical and dynamic identification procedure is realized. The objective is to show the relevancy of the proposed approach which integrates joint flexibilities in the control law. Theoretical results based on a representative model are used to illustrate the benefit of this model-based control law compare to two other control strategies (Feedforward control and control dedicated to rigid structures). Finally, a sensitivity analysis of this control law is realized to quantify the impact of modelling error and conclude on the criticality of joint damping value on vibration decreasing.

Experimental Study on the Impact Factors of Sewage Sludge Wall Slip

2011 ◽  
Vol 422 ◽  
pp. 580-583
Author(s):  
Zhen Xing Li ◽  
Li Zhang ◽  
Ji Zhong Bai
Keyword(s):  
Sewage Sludge ◽  
Water Content ◽  
Strain Amplitude ◽  
High Speed ◽  
Influence Factors ◽  
Wall Slip ◽  
Impact Factors ◽  
Shear Rates ◽  
Time Stress ◽  
The Impact

The influence factors of sewage sludge wall slip were analyzed by using a rotational rheometer with parallel plate fixtures and with high speed camera. The technique involves checking the gap dependence of the stress/strain data and studying the time/stress data trend of strain stepped scanning. For sewage sludge of water content 80%, in the shearing flow it was found that, as the strain amplitude increasing, the stress data obtained at different gaps, then, at certain strain amplitude, started to diverge, indicating that wall slip occurred. But for sewage sludge of water content 87%, these curves are superimpose, indicating no slip occurred. While scanned sewage sludge water content 80% at different shear rates in 5s and 60s, it found that under 5s and 60s respectively, the shear rate is greater than 10s-1 and 0.5s-1 during time/stress curves appeared peak condition, shows slip occurred.

Sign in / Sign up

Export Citation Format

Share Document