scholarly journals Determination of the force characteristic of head car’s passive safety system – large road vehicle interaction in a collision

2021 ◽  
Vol 2021 (4) ◽  
pp. 118-128
Author(s):  
M.B. Sobolevska ◽  
◽  
D.V. Horobets ◽  
S.A. Syrota ◽  
◽  
...  
Keyword(s):  
High Speed ◽  
Passive Safety ◽  
Force Characteristic ◽  
Front Part ◽  
Road Vehicle ◽  
Passive Protection ◽  
Upper Level ◽  
Energy Absorbing ◽  
The Impact ◽  
Force Characteristics

One of the priorities of the National Economic Strategy of Ukraine for the Period up to 2030 is the development of the transport sector, in particular railway vehicle renewal, the introduction of high-speed railway passenger transport, and railway traffic safety improvement. The home motor-car trains must be renewed in compliance with new home standards harmonized with European ones, among which one should mention the Ukrainian State Standard DSTU EN 15227, which specifies the passive safety of a passenger train in its emergency collisions with different obstacles. New car designs must provide not only effective up-to-date braking systems to prevent emergency collisions, but also passive safety systems with energy-absorbing devices. The main purpose of these devices is to reduce the longitudinal forces in the intercar connections and the car accelerations to an acceptable level for the three collision scenarios specified in the DSTU EN 15227. The Department of Statistical Dynamics and Multidimensional Mechanical Systems Dynamics, Institute of Technical Mechanics of the National Academy of Sciences of Ukraine and the State Space Agency of Ukraine, developed a passive protection concept for home high-speed passenger trains in emergency collisions by the DSTU EN 15227 scenarios, proposals on the passive protection of a motor-car train head car, and honeycomb designs of lower- and upper-level energy-absorbing devices (EAD 1 and UL EAD, respectively), which are integrated into the head car front part and serve to damp the major part of the impact energy in front collisions with obstacles. This paper considers DSTU EN 15227 Scenario 3: a collision of a reference motor-car train at a speed of 110 km/h at a railway crossing with a large 15 t road vehicle, which is simulated as a large-size deformable obstacle (LSDO). The aim of the paper is to determine the force characteristic of the interaction of energy-absorbing devices mounted on the head car front part with a large road vehicle in a collision to assess the compliance of the proposed passive protection with the normative requirements. Finite-element models were constructed to analyze the plastic deformation of the elements of the EAD 1 – LSDO, UL EAD – LSDO, and EAD 1 – UL EAD –LSDO systems in a collision with account for geometric and physical nonlinearities, steel dynamic hardening as a function of the impact speed, and varying contact interaction between the elements of the systems considered. The studies conducted made it possible to determine the force characteristics of energy-absorbing device – obstacle interaction and the total characteristic of the contact force between two lower-level devices and two upper-level ones as a function of the obstacle center of mass displacement in a collision. The proposed mathematical models and the calculated force characteristics may be used in the study of the dynamics of a reference motor-car train – large road vehicle collision with the aim to assess the compliance of the passive protection of the home head car under design with the DSTU EN 15227 requirements.

scholarly journals Analysis of dynamic loads on the cars of a high-speed motor-car train with a passive safety system in its collision with a freight car

2020 ◽  
Vol 2020 (3) ◽  
pp. 79-90
Author(s):  
M.B. Sobolevska ◽  
◽  
N.Yu. Naumenko ◽  
D.V. Horobets ◽  
◽  
...  
Keyword(s):  
Mathematical Model ◽  
High Speed ◽  
Dynamic Loads ◽  
Passive Safety ◽  
Level Energy ◽  
Energy Capacity ◽  
Passive Protection ◽  
Front End ◽  
Freight Car ◽  
Energy Absorbing

The performance characteristics of the cars of a modern home high-speed motor-car train must meet Ukrainian State Standards DSTU EN 12663 and DSTU EN 15227 now in force in Ukraine, which regulate its crashworthiness and passive safety in emergency collisions. An integral part of new cars must be passive safety systems (PSSs) with energy-absorbing devices (EADs), which save the lives of the pasengers and the train crew and reduce car damage in a collision with an obstacle. The aim of this paper is to evaluate dynamic loads on the cars of PSS-equipeed motor-car train in its collision with a freight car according to Scenario 2 of DSTU EN 15227. The scientific novelty of the paper is a mathematical model for the study of a collision of a motor-car train with a freight car based on the authors’ model of a collision of identical motor-car trains (Scenario 1 of DSTU EN 15227) with account for the force characteristic of head car – freight car interaction in an emergency. The proposed mathematical model allows one to obtain the average values of the car accelerations and plastic deformations to compare them with their admissible values according to DSTU EN 15227. The paper presents the results of a study of dynamic loads on the cars of a PSS-equipped motor-car train in its collision at 36 km/h with a 80 t freight car for a reference train with a 80 head car and four intermediate cars of mass 50 t, which is the mass of the majority of cars on the 1,435 mm European railways, and 64 t, which is the typical mass of inremediate cars used in the 1,520 mm Ukrainian railways. The following protective devices developed at the Institute of Technical mechanics of the National Academy of Sciences of Ukraine and the State Space Agenccy of Ukraine are proposed for passive protection: EAD 1 devices of energy capacity 0.95 MJ to be mounted at the coupler level at the head car front end, EAD 2 devices of energy capacity 0.25 MJ and EAD 3 devices of energy capacity 0.3 MJ to be mouned at the coupler level at the head car rear end and at the ends of passenger cars of mass 50 t and 64 t, respectively, and EAD UL upper-level energy-absorbing devices of energy capacity of 0.12 MJ to be mounted at the head car front end under the window. It is shown that by the criteria of DSTU EN 15227 for a train with 50 t intermediate cars it is advisable to use the passive protection according to Scenario 1 (the front end of the head car is equipped wuth two EAD 1 and two EAD UL devices, its rear end is equipped with two EAD 2 devices, and the intermediate cars are equipeed with two EAD 2 devices at the front and at the rear), while for a train with 64 t intermediate cars it is advisable to use the passive protection according to Scebario 2 (the front end of the head car is equipped wuth two EAD 1 and two EAD UL devices, its rear end is equipped with two EAD 3 devices, and the intermediate cars are equipeed with two EAD 3 devices at the front and at the rear). The proposed mathematical model and the results obtained may be used in designing head and intermediate cars for a home motor-car passenger train in accordance with the DSTU EN 15227 requirements.

Study on Vehicle Hook Buffer Mechanism Based on Sequential Image Analysis

2013 ◽  
Vol 365-366 ◽  
pp. 482-485
Author(s):  
Rui Li ◽  
Ping Xu ◽  
Yuan Mu Zhong ◽  
Long Xi Liu
Keyword(s):  
Image Analysis ◽  
Template Matching ◽  
High Speed ◽  
Feature Recognition ◽  
Energy Change ◽  
Sequential Image ◽  
Energy Absorbing ◽  
Sequential Images ◽  
Short Time ◽  
The Impact

As the impact process of train energy absorbing components occurs in a short time, high-speed cameras are used to record it and the amount of deformation and energy change of the energy absorbing components can be obtained by analyzing sequential images. The method of sequential images analysis presented is based on feature recognition of mark points by template matching method. In addition to this, error introduced by the camera positions is corrected to obtain more exact results. During the process of collision, the amount of its deformation is 52mm and its energy change is 2.69KJ when using the sequential image analysis.

scholarly journals Increasing the safery of railway passenger and freight traffic

2021 ◽  
Vol 2021 (2) ◽  
pp. 78-90
Author(s):  
O.M. Markova ◽  
◽  
M.V. Sobolevska ◽  
T.F. Mokrii ◽  
D.V. Horobets ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Safety System ◽  
Passive Safety ◽  
Transport Sector ◽  
Force Characteristic ◽  
Passive Protection ◽  
Railway Traffic ◽  
Freight Traffic ◽  
Passive Safety System ◽  
Starting Point

In 2020, the Ukrainian Government conducted an audit of the Ukrainian economy for nearly 30 years of independence and decided on the vectors of economic development aimed at European and Euro-Atlantic integration. The audit of the Ukrainian railways showed that most of the railway assets are critically worn. The audit and the vectors became a starting point for the development of the National Economic Strategy of Ukraine up to 2030, which was approved on March 3, 2021. One of the priorities of this strategy is the development of the transport sector by a succession of steps, including railway track and vehicle renewal, the introduction of high-speed passenger transport, and increasing railway traffic safety and environment safety on the Urrainian railways. The aim of this paper is to work out recommendations on increasing the safety of passenger and freight traffic in Ukraine. The paper generalizes the experience gained over the years of Ukrainian independence in the fundamental and applied transport-oriented reseach conducted at the Department of Sttistical Dynamics and Multidimensional Mechanical Systems, Institute of Technical Mechanics of the National Academy of Sciences of Ukraine and the State Space Agency of Ukraine. This experience may be useful in the implementation of the above steps on the way to the sustainable development of the Ukrainian railway transport. In the paper, emphasis is on new investigations into the passive propection of the cars of a motor car train in emergency collisions whose scenarios are specified by Ukrainian State Standard DSTU EN 15227. Based on a mathematical model of a collision of identical motor car trains, a mathematical model was developed to simulate a collision of a motor car train with a large vehicle at a crossing with account for a specified force characteristic of interaction of the leading car equipped with a passive safety system with a deformable obstacle. The model developed was used in analyzing dynamic loads on the cars of a motor car train with a passive safety system in its collision at 110 km/h with a 15 t large vehicle at a railway crossing. With consideration for the results of previous investigations into the dynamics of emergency collisions of a motor car train with an identical train and a fright car, recommendations were worked out on the passive protection of a home-made leading car in accordance with the requirements of normative documents. The proposed mathematical models and designs of energy-absorbing devices, the research results, and the practical recommendations worked out may be used in designing new motor car train vehicles for the Ukrainian railways in accordance with the DSTU EN 15227 requirements for passive protection in emergency collisions.

Impact damage assessment of carbon fiber reinforced composite with different stacking sequence

2019 ◽  
Vol 54 (2) ◽  
pp. 193-203
Author(s):  
Rahul S Sikarwar ◽  
R Velmurugan
Keyword(s):  
High Speed ◽  
Stacking Sequence ◽  
High Speed Camera ◽  
Ballistic Limit ◽  
Limit Velocity ◽  
Post Impact ◽  
Damage Extent ◽  
Ballistic Limit Velocity ◽  
Energy Absorbing ◽  
The Impact

This work examines the experimental and analytical investigation of impact on the carbon/epoxy laminates of various stacking sequence. The impact tests were carried out by using gas gun equipped with high-speed camera. Projectile velocities selected were 80 m/s and 30 m/s where 80 m/s was above ballistic limit velocity and 30 m/s was below ballistic limit velocity. The impact process was recorded with high-speed camera which facilitated to identify different energy absorbing mechanisms. High-speed images were also used to measure pre-impact and post-impact velocities of the projectile accompanied by photo diode and aluminum foil method. Total energy absorbed by the laminates, which is the difference between pre-impact and post-impact kinetic energy of the projectile, was calculated for the laminates with different stacking sequences. Damage extent in the laminates of different stacking sequences were also assessed by C-Scan of the laminates. Then effect of stacking sequences on damage extent and energy absorbing capacity was established. An analytical model was proposed to predict the residual velocity of the projectile at above ballistic limit velocity, which was based on the total energy absorbed by different energy absorption mechanisms. The analytical model was validated with experimental results for different stacking sequences. Additionally, effect of fiber orientation on damage shape at below ballistic limit velocity was also studied.

Experimental Study of Energy Absorption of Fluid-Filled Honeycomb Structure

2014 ◽  
Author(s):  
S. Jenson ◽  
M. Ali ◽  
K. Alam ◽  
J. Hoffman
Keyword(s):  
Energy Absorption ◽  
High Speed ◽  
Honeycomb Structure ◽  
High Speed Camera ◽  
Damage Area ◽  
Impact Forces ◽  
Aluminum Honeycomb ◽  
Energy Absorbing ◽  
The Impact ◽  
Absorption Characteristics

The work presented here is a continuation of the study performed in exploring the energy absorption characteristics of non-Newtonian fluid-filled regular hexagonal aluminum honeycomb structures. In the previous study, energy absorbing properties were investigated by using an air powered pneumatic ram, dynamic load cell, and a high speed camera. This study was conducted using a pneumatic ram which was designed to exploit only its kinetic energy during the impact. Experimental samples included an empty honeycomb sample and a filled sample as the filled samples showed the largest difference in energy absorption with respect to the empty samples in the previous study. Therefore, the filled samples were further investigated in this study by measuring the impact forces at the distal end as well as the damage on the impact end. Upon impact, the filled samples were able to reduce the damage area on impact end and were able to lower average and peak forces by 71.9% and 77.4% at the distal end as compared to the empty sample.

scholarly journals Experimental and numerical study of auxetic sandwich panels on 160 grams of PE4 blast loading

2020 ◽  
pp. 109963622096175
Author(s):  
Faizal Arifurrahman ◽  
Richard Critchley ◽  
Ian Horsfall
Keyword(s):  
High Speed ◽  
Numerical Study ◽  
Laser System ◽  
Sandwich Panels ◽  
Local Deformation ◽  
Time Profile ◽  
Polymer Foam ◽  
Mass System ◽  
Energy Absorbing ◽  
The Impact

Mines, specifically as Anti-Tank (AT) mines are a significant threat for defence vehicles. While approaches such as v-shaped hulls are currently used to deflect the blast products from such threats, such a solution is not always usable when hull standoff is limited. As such the development of a low profile, energy absorbing solution is desirable. One approach that has potential to achieve these requirements are sandwich panels. While sandwich panel cores can be constructed from various materials, one material of particular interest are auxetics. Auxetic are materials that exhibit a negative Poisson’s ratio. This material has potential to be an efficient an impact energy absorber by increasing stiffness at local deformation by gathering mass at the impact location. This study investigates the effectiveness of novel auxetic core infills alongside three other panel types (monolithic, air gap, polymer foam sandwich) against buried charges. 160 grams of PE4 were buried in 100 mm depth and 500 mm stand off the target. Laser and High Speed Video (HSV) system were used to capture the deflection-time profile and load cell sensors were used to record the loading profile received by the panels. Experimental works were compared with numerical model. Explicit model were generated in LSDYNA software as ‘initial impulse mine’ keyword. The result found that the auxetic and foam core panels were effective in reducing peak structural loading and impulse by up to 33% and 34% respectively. Air-filled panels were the most effective to reduce the deflection of the rear of the plate, however variation between capture methods (HSV and Laser system) were reported, while numerical modelling provided comparable plate deflections responses. When normalised against panel weight, the air filled panels were experimentally the most efficient per unit mass system with the auxetics being the least effective.

scholarly journals Use of passive safety supporting structures

2019 ◽  
Vol 97 ◽  
pp. 03018 ◽  
Author(s):  
Jarosław Michałek
Keyword(s):  
Traffic Safety ◽  
Road Safety ◽  
High Energy ◽  
Passive Safety ◽  
Support Structures ◽  
Safety Issues ◽  
Road Users ◽  
Energy Absorbing ◽  
The Impact ◽  
Supporting Structures

Road safety issues have been raised for many years in subsequent national and EU documents. An example of a Polish document is the National Road Safety Program for 2013-2020 [1]. The priorities and measures adopted in the document [1] relate mainly to the environment and road furnishings making up the so-called passive road safety. In accordance with PN-EN 12767: 2008 [2], road lighting columns, as well as supporting structures for vertical road marking and traffic safety devices should be constructed in such a way that they do not pose a threat to road users in case of unforeseen situations ending up in a collision. Three categories of passive safety of support structures depending on the level of energy absorption during vehicle impact can be distinguished: high energy absorbing (HE), low energy absorbing (LE) and non-energy absorbing (NE) energy. The article presents an overview of solutions of several countries (USA, Norway, Sweden, Finland, Great Britain, Slovakia and Poland) in the use of support structures that minimize the impact of a collision. Particular attention was paid to the fact that due to the potential risk of secondary injuries sustained by other road users (pedestrians and cyclists) in relation to a specific installation site and designated speed limit, constructions in the HE or NE absorption class or even Class 0 constructions should be used.

scholarly journals SIMULATION OF EMERGENCY COLLISION OF A MAGNETIC LEVITATION TRAIN WITH AN OBSTACLE

2015 ◽  
Vol 1 (1) ◽  
pp. 99-111
Author(s):  
Eldar M RYAZANOV ◽  
Alexander Ed PAVLYUKOV
Keyword(s):  
Traffic Safety ◽  
High Speed ◽  
Magnetic Levitation ◽  
Passive Safety ◽  
Rolling Stock ◽  
Work Effectiveness ◽  
Passive Safety Systems ◽  
Materials Used ◽  
Energy Absorbing ◽  
Safety Systems

In the last decades much attention has been focused on improving the passive safety of automobile, aviation, railway and shipbuilding vehicles by means of development of special energy-absorbing devices (EAD). The operation principle of such devices is to absorb the kinetic energy of the collision with the obstacle by means of the controlled irreversible deformation of its own design [1]. The article proposes to implement these devices and passive safety systems to assess their effectiveness. The solution of this issue was carried out by the authors' methods of numerical simulation of emergency collision of a rolling stock with an obstacle [2-4]. The article demonstrates the simulated emergency crash system of the passenger magnetic levitation train. It consists of a front and undercar crash-modules. The first is mounted on the end part of the head car of the train to absorb the collision energy with a large obstacle in case of an accident. The second is designed to reduce the consequences of collisions with obstacles of relatively small sizes, able to break the floor or damage undercar equipment at high speed. Various designs and materials used for manufacturing of EAD were theoretically investigated using the developed model of emergency collision. In the result the assessment of work effectiveness of the designed emergency crash-system in accordance with the existing regulatory requirements for traffic safety was carried out.

Modeling of Tread Block Contact Mechanics Using Linear Viscoelastic Theory3

2008 ◽  
Vol 36 (3) ◽  
pp. 211-226 ◽  
Author(s):  
F. Liu ◽  
M. P. F. Sutcliffe ◽  
W. R. Graham
Keyword(s):  
High Speed ◽  
Slip Rate ◽  
Material Model ◽  
Contact Forces ◽  
Block Modeling ◽  
Rate Dependent ◽  
Linear Viscoelastic Material ◽  
Linear Viscoelastic ◽  
The Impact ◽  
Good Agreement

Abstract In an effort to understand the dynamic hub forces on road vehicles, an advanced free-rolling tire-model is being developed in which the tread blocks and tire belt are modeled separately. This paper presents the interim results for the tread block modeling. The finite element code ABAQUS/Explicit is used to predict the contact forces on the tread blocks based on a linear viscoelastic material model. Special attention is paid to investigating the forces on the tread blocks during the impact and release motions. A pressure and slip-rate-dependent frictional law is applied in the analysis. A simplified numerical model is also proposed where the tread blocks are discretized into linear viscoelastic spring elements. The results from both models are validated via experiments in a high-speed rolling test rig and found to be in good agreement.

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