Simulation Methodology for Occupant Safety Assessment of Indian Railway Passenger Coach

2018 ◽  
Author(s):  
Prajakta Prabhune ◽  
Anindya Deb ◽  
G. Balasubramani
Keyword(s):  
Motor Vehicle ◽  
Fe Model ◽  
Dynamic Impact ◽  
Rigid Barrier ◽  
Actual Structure ◽  
Simulation Methodology ◽  
Occupant Safety ◽  
Railway Passenger ◽  
Indian Railway ◽  
Crash Behaviour

This work intends to lay the groundwork for Computer Aided Engineering (CAE)-based occupant safety of a typical tier-III Indian Railway (IR) passenger coach in a collision accident. Our previous work presented in International Crashworthiness Conference 2010 under the title “Simulation of Crash Behaviour of a Common Indian Railway Passenger Coach” provided crashworthiness assessment of a typical tier-III passenger coach structure for representative head-on collision scenarios namely, against an identical passenger coach and against a stationary locomotive. These scenarios were envisioned to be part of a bigger accident scenario e.g - head-on collision between two trains moving towards each other. Analysis of involved chain of events for entire rolling stock and resulting internal collisions between individual passenger cars was out of scope of this work and necessary inputs were obtained from available literature on the same. This work used a full scale Finite Element (FE) simulation model and commercial explicit solver LS-Dyna. FE model was validated using International Railway Union (UIC) code OR566 specified proof loads for design. Simulation methodology used for dynamic impact was validated by component level crushing experiments using a drop tower facility. Material modelling incorporated strain rate effect on yield strength which is essential for obtaining accurate structural deformations under dynamic impact loading. Contacts were modelled using the penalty method option provided by the solver. This model was simulated for collisions at 30, 40 and 56 km/h against a stationary rigid barrier. Collision speeds were chosen to simulate impact energies involved in collision scenarios as mentioned above. The structure was found to exhibit global bending deformation and jackknifing with pivot position at the door section. In this paper, we present an extension of this work — coupled occupant safety simulation and injury assessment. It was accomplished by recording head, neck, chest and knee responses of a Hybrid-III 50th percentile male Anthropomorphic Test Device (ATD) FE model, seated in passenger position on lower berth of the first cabin of a passenger car. Interiors were modelled to represent the actual structure. Dummy model was adapted to passenger cabin’s excessive mobility conditions and responses were revalidated against Federal Motor Vehicle Safety Standards (FMVSS) limits. Injury interpretation was based on Abbreviated Injury Scale (AIS), automotive injury criteria and injury risk curves for Head Injury Criterion (HIC), thoracic spine acceleration, neck bending moment in flexion and extension and knee force. This study provides with estimates of injury and fatality based on computer simulation of accident scenarios. However, attempts of correlating to any available injury and fatality statistics were out of scope of this study.

NUMERICAL SIMULATION AND TESTING OF A COMPOSITE-STIFFENED STRUCTURE UNDER COMBINED BUCKLING LOADS

2010 ◽  
Vol 10 (04) ◽  
pp. 871-884 ◽  
Author(s):  
E. KARACHALIOS ◽  
C. VRETTOS ◽  
Z. MARIOLI-RIGA ◽  
C. BISAGNI ◽  
P. CORDISCO ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Fe Model ◽  
Release Rates ◽  
Actual Structure ◽  
Physical Test ◽  
Buckling Behavior ◽  
Energy Release Rates ◽  
Experimental Findings ◽  
Teflon Film ◽  
Level Of Agreement

Prediction of the buckling behavior of structures is of great interest in the aerospace industry, and extensive research is taking place worldwide in that area. The current work concerns numerical simulation of the collapse test of a closed stiffened composite box subjected to compression followed by torsion. Numerical simulation is performed and the results are correlated with experimental findings. The objective is to validate the numerical model and detect any deficiencies of the modeling procedure. For this purpose, a series of quantities numerically predicted are directly compared with experimental ones: strains, displacements, deformation plots and load–displacement curves. The physical test article also contains artificial stringer–skin debondings realized via Teflon film inserts. The energy release rates are calculated at the debonding front using the virtual crack closure technique. The FE model is slightly stiffer than the actual structure but the numerical results are at a reasonable level of agreement with the experimental data.

Development of a Conjugate Heat Transfer Simulation Methodology for Prediction of Steam Turbine Cool-Down Phenomena and Shell Deflection

2014 ◽  
Author(s):  
Debabrata Mukhopadhyay ◽  
Howard M. Brilliant ◽  
Xiaoqing Zheng
Keyword(s):  
Heat Transfer ◽  
Steam Turbine ◽  
Conjugate Heat Transfer ◽  
Inlet Temperature ◽  
Fe Model ◽  
Simulation Methodology ◽  
Heat Transfer Simulation ◽  
Measured Field ◽  
Over The Top ◽  
Natural Heat Convection

Shell deflection during shutdown, cool-down process is a phenomenon well known to the steam turbine community. The main reason for this phenomenon is slower cooling of the top half shell and a relative faster cooling of the bottom half shell. There are multiple reasons for such thermal behavior of the two half casings, including natural heat convection from the bottom half to the top half, asymmetrical distribution of mass, dissimilar behavior of thermal insulation over the top and the bottom halves, etc. Shell deflection poses considerable challenge to the clearance engineer in terms of configuring operating clearance which ensures rub free operations. Understanding the cool-down process for the rotor is also equally important as the allowable steam inlet temperature during the hot or warm restart will depend on prevailing local temperature of the rotor. This paper describes an exemplary physics-based cool-down prediction methodology capable of accurately capturing the rotor cool-down process. The methodology involves development of a full 3D rotor casing thermal model, integrated conjugate heat transfer FE model and validated with measured field data.

Dynamic Analysis of Indian Railway Integral Coach Factory Bogie

2015 ◽  
Vol 7 (1) ◽  
Author(s):  
Srihari Palli ◽  
Ramji Koona ◽  
Rakesh Chandmal Sharma ◽  
Venkatesh Muddada
Keyword(s):  
Dynamic Response ◽  
Modal Analysis ◽  
Fe Model ◽  
Fe Method ◽  
Harmonic Response ◽  
Natural Modes ◽  
Modes Of Vibration ◽  
Indian Railway ◽  
Secondary Suspension ◽  
Railway Sleeper

Dynamic response of railway coach is a key aspect in the design of coach. Indian railway sleeper and 3 tier AC coaches consist of two railway bogies, where the central distance of the center of gravity between the bogies is 14.9 m. Analysis of railway bogie forms a basis for investigating the behaviour of the coach as a whole. The current work carried out is, vehicle dynamic response in terms of Eigen frequency modal analysis and harmonic analysis of a Indian railway 6 Ton Integral Coach Factory (ICF) bogie using finite element (FE) method. The entire bogie model is discretized using solid92 tetrahedral elements. The primary and secondary suspension systems are modelled as COMBIN14 elements in the FE model of the bogie. Modal analysis of the bogie model using Block Lanczos method in ANSYS is carried out to extract first few natural modes of vibration of the bogie. The roll mode frequency attained in Modal analysis is in good agreement with the fundamental frequency calculated analytically. Sinusoidal excitation is fed as input to bottom wheel points to analyse the harmonic response of the bogie in terms of displacement at different salient locations. Harmonic response results reveal that the bogie left and right locations are more vulnerable than the locations near the centre of gravity of the bogie.

Experimental and Numerical Study on Crashworthiness Parameters of Mild Steel Square Tube under Quasi-Static Axial Compression

2020 ◽  
Vol 12 (2) ◽  
Author(s):  
Shinde Rushikesh ◽  
Mali Kiran ◽  
M. Kathiresan ◽  
Kulkarni Dhananjay
Keyword(s):  
Finite Element ◽  
Numerical Study ◽  
Experimental Testing ◽  
Testing Machine ◽  
Fe Analysis ◽  
Fe Model ◽  
Element Analysis ◽  
Static Test ◽  
Collapse Mode ◽  
Crash Behaviour

In the present research, an experimental and numerical study on the crush response of square tube is presented. The explicit Finite Element Analysis (FEA) in LS-DYNA software is carried out to simulate crash behaviour under the quasi-static test conditions. Compression load is applied quasi-statically in an experimental study on the square tube specimens using Universal Testing Machine (UTM). In quasi-static test the bottom platen speed used is 1 mm/min. From experimental testing symmetric collapse mode is observed in all deformed specimens. The development of the symmetric collapse mode in a Finite Element (FE) model is also observed. Thus fold formation and crush response predicted by FE analysis are observed to be in very good correlation with the results obtained from experimental testing. Furthermore, the effect of the thickness of tube on crashworthiness parameters is investigated. From the FE analysis, it is found that the thickness of the square tube influences significantly the crashworthiness parameters.

Analysis of the Deformation Mode and Determination of the Energy Dissipated by the Resistance Structure of the Vehicles

2015 ◽  
Vol 772 ◽  
pp. 79-83
Author(s):  
Adrian Soica ◽  
Stelian Tarulescu
Keyword(s):  
Motor Vehicle ◽  
Deformation Mode ◽  
Rigid Barrier ◽  
International Regulations ◽  
Complex Solutions ◽  
Energy Dissipated ◽  
The Impact ◽  
Small Overlap ◽  
Resistance Structure

The increasingly tougher international regulations force motor vehicle designers and manufacturers to find complex solutions that should increase the protection of motor vehicle occupants. In this paper the author carries out an analysis on the energy absorption by a front strut-type structure of a motor vehicle involved in head-on collision with a rigid barrier inclined at various angles. Small overlap collisions open new challenges for car manufacturers with a view to developing structures able to absorb the impact and provide safety to the motor vehicle occupants.

Lateral Side Impact Crash Simulation of Restrained 3 Year Old Child

2014 ◽  
Vol 663 ◽  
pp. 590-595 ◽  
Author(s):  
S. Shasthri ◽  
Qasim H. Shah ◽  
V. Kausalyah ◽  
Moumen M. Idres ◽  
Kassim A. Abdullah ◽  
...  
Keyword(s):  
Motor Vehicle ◽  
Model Development ◽  
Developed Countries ◽  
Assessment Model ◽  
Side Impact ◽  
Lateral Side ◽  
Fe Model ◽  
Model Assessment ◽  
Child Fatality ◽  
Injury Mechanisms

Motor vehicle crashes have become the leading cause of death for children in many developed countries and the trend is on the rise in Malaysia. Child anatomy and physiology necessitates a separate restraints system to be implemented during vehicle travel. Although approximately twice as many crashes with a child fatality are frontal compared to lateral, it is shown that side impacts are nearly twice as likely to result in a child fatality as frontal impacts. Due to the complexity and the highly non-linear nature of vehicle crash affecting occupants, much work still remains to be looked into. This is especially so in the study of injury mechanisms towards efforts of improving CRS design as well as vehicle parameters that may offer more effective and robust injury mitigation. The study here presents a methodology which outlines the development and testing of a simulation model where a 3 year old child, restrained in a CRS within a vehicle, is subjected to lateral side impact by a bullet vehicle. A combined environment of both Finite Element as well as Multi-body is used for the model development. A HYBRID III dummy model is used to represent the child while an FE model is used for the CRS model. A hybrid modelling method is utilized for the belt harness system. The model and simulation conditions are set based on the global FMVSS standard. Head injury criterion and Neck injury criterion are primarily considered in the model assessment. Model development as well as validation steps are presented with discussion of the model’s salient features for greater insights in the study of injury mechanisms.

Investigation of Upper Cervical Spine Injury due to Frontal and Rear Impact Loading Using Finite Element Analysis

2014 ◽  
Author(s):  
Tanvir Mustafy ◽  
Kodjo Moglo ◽  
Samer Adeeb ◽  
Marwan El-Rich
Keyword(s):  
Finite Element ◽  
Cervical Spine ◽  
Motor Vehicle ◽  
Spine Injury ◽  
Upper Cervical Spine ◽  
Fe Model ◽  
Facet Joints ◽  
Element Analysis ◽  
Effective Prevention ◽  
Upper Cervical

Predicting neck response and injury resulting from motor vehicle crashes is essential for improving occupant protection, effective prevention, and in the evaluation and treatment of spinal injuries. Injury mechanism of upper cervical spine due to frontal/rear-end impacts was studied using Finite Element (FE) analyses. A FE model of ligamentous (devoid of muscles) occipito-C3 cervical spine was developed. Time and rate-dependent material laws were used for assessing bone and ligament failure. Frontal and rear-end impact loads at two rates of 5G and 10G accelerations were applied to analyze the model response in terms of stress distribution, intradiscal pressure change, and contact pressure in facet joints. Failure occurrence and initiation instants were investigated. Frontal and rear-end impacts increased stresses significantly producing failure in most components for both rates. However, transverse ligament and C2-vertebral endplate only failed under rear-end impact. No failure occurred in cortical bone, dens, disc, anterior or posterior longitudinal ligaments. The spine is more prone to injury under rear-end impact as most of the spinal components failed and failure started earlier. Ligaments and facet joints are the most vulnerable components of the upper cervical spine when subjected to frontal/rear end impacts and injury may occur at small ranges of displacement/rotation.

Dynamics Modeling and Analysis of Riveted Mainframe Computer Structure

2017 ◽  
Author(s):  
Budy Notohardjono ◽  
Richard Ecker ◽  
Shawn Canfield
Keyword(s):  
Test Data ◽  
Dominant Mode ◽  
Mode Shapes ◽  
Dynamic Mode ◽  
Fe Model ◽  
Dynamics Modeling ◽  
Actual Structure ◽  
Beam Elements ◽  
Mainframe Computer ◽  
Riveted Joints

A typical mainframe computer rack is narrow, tall and long. In certain installations, during its functional operation, the server can be subjected to earthquake events. The rack is a steel structure joined together with steel rivets. One of the rack’s functions is to protect the critical components such as the processor, input-output and storage drawers from excessive motion by minimizing the amount of deflection. The riveted joints pose a challenge in accurately representing more than three thousand joints in a finite element (FE) model. In the FE model, bonding together sheet metal regions around the rivet joints will lead to a significantly stiffer model than the actual structure. On the other hand, an accurate representation of the riveted joints will lead to a better representation of the dynamic response of the server rack under vertical and horizontal loadings. This paper presents a method of analyzing rivet joints. The rivet joints are represented by beam elements with cylindrical cross-sections in the FE model. This is accomplished by identifying two parallel or overlapping plates and inserting discrete beam elements at the riveted joint. This method will be used to predict the dynamics modes of the structure. To validate the FE model, a prototype server rack was subjected to side to side vibration tests. A sine sweep vibration test identifies dominant mode shapes and the transmissibility of the input vibration. The results of the tests on the prototype rack serve as input for FE model refinement. The test data show that representing the riveted joints with beams does provide results that closely match the actual test data. A validated FE model will be used to evaluate dominant vibration modes for several configurations of rack weight as well as configurations to stiffen the structure in the side to side direction. The dynamic mode shapes visualize the effect of stiffening brackets on dominant frequencies of the rack. The optimal stiffening design will be the one that results in the minimum deflection under the standard testing profile.

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