scholarly journals Validation of Puncture Simulations of Railroad Tank Cars Using Full-Scale Impact Test Data

2018 ◽  
Author(s):  
Michael Carolan ◽  
Benjamin Perlman ◽  
Francisco González
Keyword(s):  
Model Validation ◽  
Transportation Systems ◽  
Full Scale ◽  
Impact Testing ◽  
Material Behavior ◽  
Fe Model ◽  
Impact Tests ◽  
Validation Criteria ◽  
Simulation Results ◽  
The Impact

The U.S. Department of Transportation’s Federal Railroad Administration (FRA) has sponsored a series of full-scale dynamic shell impact tests to railroad tank cars. Currently, there are no required finite element (FE) model validation criteria or procedures in the field of railroad tank car puncture testing and simulation. Within the shell impact testing program sponsored by FRA, comparisons made between test measurements and simulation results have included the overall force-time or force-indentation histories, the puncture/non-puncture outcomes, the rigid body motions of the tank car, the internal pressures within the lading, and the energy absorbed by the tank during the impact. While qualitative comparisons (e.g. the shapes of the indentation) and quantitative comparisons (e.g. peak impact forces) have been made between tests and simulations, there are currently no requirements or guidelines on which specific behaviors should be compared, or what measurable level of agreement would be acceptable demonstration of model validation. It is desirable that a framework for model validation, including well-defined criteria for comparison, be developed or adopted if simulation is to be used without companion shell impact testing for future tank car development. One of the challenges to developing model validation criteria and procedures for tank car shell puncture is the number of complex behaviors encountered in this problem, and the variety of approaches that could be used in simulating these behaviors. The FE models used to simulate tank car shell impacts include several complex behaviors, each of which can introduce uncertainty into the overall response of the model. These behaviors include dynamic impacts, non-linear steel material behavior, including ductile tearing, two-phase (water and air) fluid-structure interaction, and contact between rigid and deformable bodies. Several candidate qualitative and quantitative comparisons of test measurements and simulations results are discussed in this paper. They are applied to two recently-completed shell impact tests of railroad tank cars sponsored by FRA. For each test, companion FE simulation was performed by the Volpe National Transportation Systems Center. The process of FE model development, including material characterization, is discussed in detail for each FE model. For each test, the test objectives, procedures, and key instrumentation are summarized. For each set of test and simulations, several corresponding results are compared between the test measurements and the simulation results. Additionally, this paper includes discussion of approaches to model validation employed in other industries or areas of transportation where similar modeling aspects have been encountered.

Comparison of Methodologies for Finite Element Model Validation of Railroad Tank Car Side Impact Tests

2020 ◽  
Author(s):  
Shaun Eshraghi ◽  
Michael Carolan ◽  
Benjamin Perlman ◽  
Francisco González
Keyword(s):  
Finite Element ◽  
Model Validation ◽  
Full Scale ◽  
Impact Testing ◽  
Material Behavior ◽  
Side Impact ◽  
Impact Tests ◽  
Dynamic Impacts ◽  
Simulation Results ◽  
National Cooperative

Abstract The U.S. Department of Transportation’s Federal Railroad Administration (FRA) has sponsored a series of full-scale dynamic shell impact tests on railroad tank cars. For each shell impact test a pre-test finite element (FE) model is created to predict the overall force-time or force-displacement histories of the impactor, puncture/non-puncture outcomes of the impacted tank shell, global motions of the tank car, internal pressures within the tank, and the energy absorbed by the tank during the impact. While qualitative comparisons (e.g. the shapes of the indentation) and quantitative comparisons (e.g. peak impact forces) have been made between tests and simulations, there are currently no standards or guidelines on how to compare the simulation results with the test results, or what measurable level of agreement would be an acceptable demonstration of model validation. It is desirable that a framework for model validation, including well-defined criteria for comparison, be developed or adopted if FE analysis is to be used without companion full-scale shell impact testing for future tank car development. One of the challenges to developing model validation criteria and procedures for tank car shell puncture is the number of complex behaviors encountered in this problem, and the variety of approaches that could be used in simulating these behaviors. The FE models used to simulate tank car shell impacts include several complex behaviors, which increase the level of uncertainty in simulation results, including dynamic impacts, non-linear steel material behavior, two-phase (water and air) fluid-structure interaction, and contact between rigid and deformable bodies. Approaches to model validation employed in other areas of transportation where validation procedures have been documented are applied to railroad tank car dynamic shell impact FE simulation results. This work compares and contrasts two model validation programs: Roadside Safety Verification and Validation Program (RSVVP) and Correlation and Analysis Plus (CORA). RSVVP and CORA are used to apply validation metrics and ratings specified by the National Cooperative Highway Research Program Project 22-24 (NCHRP 22-24) and ISO/TS 18571:2014 respectively. The validation methods are applied to recently-completed shell impact tests on two different types of railroad tank cars sponsored by the FRA. Additionally, this paper includes discussion on model validation difficulties unique to dynamic impacts involving puncture.

A Base Study to Investigate MASH Conservativeness of Occupant Risk Evaluation

2020 ◽  
Vol 6 (2) ◽  
Author(s):  
Nathan Schulz ◽  
Chiara Silvestri Dobrovolny ◽  
Stefan Hurlebaus ◽  
Harika Reddy Prodduturu ◽  
Dusty R. Arrington ◽  
...  
Keyword(s):  
Risk Evaluation ◽  
Injury Risk ◽  
Evaluation Criteria ◽  
Oblique Impact ◽  
Full Scale ◽  
Crash Test ◽  
Fe Model ◽  
Vehicle Interior ◽  
Space Model ◽  
The Impact

Abstract The manual for assessing safety hardware (MASH) defines crash tests to assess the impact performance of highway safety features in frontal and oblique impact events. Within MASH, the risk of injury to the occupant is assessed based on a “flail-space” model that estimates the average deceleration that an unrestrained occupant would experience when contacting the vehicle interior in a MASH crash test and uses the parameter as a surrogate for injury risk. MASH occupant risk criteria, however, are considered conservative in their nature, due to the fact that they are based on unrestrained occupant accelerations. Therefore, there is potential for increasing the maximum limits dictated in MASH for occupant risk evaluation. A frontal full-scale vehicle impact was performed with inclusion of an instrumented anthropomorphic test device (ATD). The scope of this study was to investigate the performance of the flail space model (FSM) in a full-scale crash test compared to the instrumented ATD recorded forces which can more accurately predict the occupant response during a collision event. Additionally, a finite element (FE) model was developed and calibrated against the full-scale crash test. The calibrated model can be used to perform parametric simulations with different testing conditions. Results obtained through this research will be considered for better correlation between vehicle accelerations and occupant injury. This becomes extremely important for designing and evaluating barrier systems that must fit within geometrical site constraints, which do not provide adequate length to redirect test vehicles according to MASH conservative evaluation criteria.

A Study for Evaluating Local Damage to Reinforced Concrete Panels Subjected to Oblique Impact: Part 2 — Simulation Analysis of the Experimental Results of Local Damage Caused by Impact of Deformable Projectiles

2017 ◽  
Author(s):  
Akemi Nishida ◽  
Yoshimi Ohta ◽  
Haruji Tsubota ◽  
Yinsheng Li
Keyword(s):  
Reinforced Concrete ◽  
Simulation Analysis ◽  
Impact Load ◽  
Oblique Impact ◽  
Local Damage ◽  
Impact Tests ◽  
Rigid Projectile ◽  
Oblique Impacts ◽  
Simulation Results ◽  
The Impact

Many empirical formulae have been proposed for evaluating the local damage to reinforced concrete structures caused by rigid projectile impact. Most of these formulae are based on impact tests perpendicular to the target structures. To date, few impact tests oblique to the target structures have been conducted. In this study, we aim to obtain a new formula for evaluating the local damage caused by oblique impacts based on previous experimental and simulation results. We analyze and simulate the local damage owing to impact by deformable projectiles. The experimental and simulation results were in good agreement and confirmed the validity of the proposed analytical method. Furthermore, the internal energy of the deformable projectile absorbed upon impact was approximately 60% of the total energy. In comparison to a rigid projectile, it is possible to reduce the impact load and consequently the damage to the target.

Investigation of the Effects of Core Thickness on Low Velocity Impact Behaviors of Aluminum Honeycomb Composites

2021 ◽  
Author(s):  
Kasım Karataş ◽  
Okan Özdemir
Keyword(s):  
Sheet Material ◽  
Energy Levels ◽  
Impact Testing ◽  
Low Velocity Impact ◽  
Core Material ◽  
Low Velocity ◽  
Velocity Impact ◽  
Impact Tests ◽  
Aluminum Honeycomb ◽  
The Impact

Honeycomb structures are used where the weight to strength ratio is important. They are also preferred to absorb the energy from the blows received. In this study, low velocity impact behavior of aluminum honeycomb composites with different core thicknesses were investigated. Aluminum honeycombs used in this study are AL3003 honeycombs of 10 mm and 15 mm thicknesses. Glass fiber reinforced epoxy sheets with a thickness of 2 mm were used as the surface sheet material. Composite plates were produced by vacuum infusion method. The upper and lower face plates were cut in dimensions of 100x100 mm. The cut plates were attached to the core material with adhesive and a sandwich structure was formed. After bonding, low velocity impact tests were performed on these test samples at 40J, 100J and 160J energy levels using the composite CEAST Fractovis Plus impact testing machine. According to the results obtained from the impact tests, at higher energy levels, 15 mm thick composites have 10-15% higher energy absorption capacity than 10 mm.

Evaluation of Testing Uncertainties for the Impact Resistance of Machine Guards

2021 ◽  
Author(s):  
Luca Landi ◽  
Eckart Uhlmann ◽  
Robert Hoerl ◽  
Simon Thom ◽  
Giuseppe Gigliotti ◽  
...  
Keyword(s):  
Probabilistic Approach ◽  
Impact Resistance ◽  
Impact Testing ◽  
Ductile Material ◽  
Projectile Energy ◽  
Ballistic Limit ◽  
Worst Case ◽  
Impact Tests ◽  
Velocity Reduction ◽  
The Impact

Abstract Machine guards provide protection against ejection of parts during operation, such as chips or workpiece fragments. They are considered safe if the impact resistance is at least as high as the resulting projectile energy in the worst case of damage. To protect the machine operator, the impact resistance of machine guards is determined according to ISO standards. The bisection method can be used to determine the impact resistance through impact tests. However, this method is inaccurate for a small number of impact tests and does not provide an indication of uncertainties in the determination. Moreover, the result of testing is validated in different ways depending from the standard utilized for testing.Relevant uncertainties affecting impact testing and a new probabilistic approach for assessing the impact resistance using the Recht & Ipson equation are presented. With multiple impact tests at different initial velocities a Recht & Ipson best-fit curve and a confidence interval for a ballistic limit can be obtained, which is used to determine the impact resistance by defining a velocity reduction coefficient. This method can be applied to any machine guard made of ductile material. This paper validates the Recht & Ipson method by performing impact tests with a standardized 2.5 kg projectile on polycarbonate sheets of different thicknesses. Determination of the ballistic limit showed good agreement with experimental results. With the ballistic limits, the velocity reduction coefficients have been found to determine the impact resistances. Therefore, an alternative method for standardized tests to determine the impact resistance was found.

Development of Analytical Models for Railroad Tank Car Impact and Puncture Behaviors

2012 ◽  
Author(s):  
Steven W. Kirkpatrick ◽  
Joseph M. Munaretto ◽  
Virginia Phan ◽  
Robert A. MacNeill
Keyword(s):  
Full Scale ◽  
Impact Testing ◽  
Analytical Models ◽  
Impact Behavior ◽  
Wide Range ◽  
Significant Research ◽  
Detailed Simulation ◽  
Puncture Force ◽  
Tank Geometry ◽  
The Impact

There has been significant research in recent years to analyze and improve the impact behavior and puncture resistance of railroad tank cars. Much of this research has been performed using detailed nonlinear finite element analyses supported by full scale impact testing. This use of detailed simulation methodologies has significantly improved our understanding of the tank impact behaviors and puncture safety. However, the performance of the detailed analyses or full scale testing can require significant computer or financial resources to evaluate a wide range of impact scenarios. This paper describes the development of analytical models that can predict the impact and puncture behavior of a pressurized railroad tank car. The methodology applied is to first develop a model that can predict the force-deflection behavior obtained from a general impact at any point on the tank. Separately, a characteristic puncture force is determined as a function of the tank geometry, impactor geometry, and impact conditions. Combined, these models can be applied to predict the impact and puncture behavior of the tank.

Gear Tooth Impact Testing

2003 ◽  
Author(s):  
S. B. Rao ◽  
R. C. Noss ◽  
D. R. McPherson ◽  
E. C. DeMeter
Keyword(s):  
Gear Tooth ◽  
Impact Resistance ◽  
Real Life ◽  
Impact Testing ◽  
Drop Tower ◽  
Strain Rates ◽  
Dynamic Problems ◽  
Gear Teeth ◽  
Impact Tests ◽  
The Impact

It is very difficult, if not impossible, to estimate the impact resistance of gear teeth from standard impact test data. This is because of the in-homogenous nature of most gear teeth, with a high-Carbon case and a low-Carbon core, and its complex geometry. While gears are subject to impact loading in “real life” and current research efforts are significantly focused on developing alternate materials for gears, in a variety of applications, a need to characterize the impact resistance of a gear tooth under varying strain rates has consequently arisen. In order to meet this need an existing drop tower has been modified and instrumented to test gear teeth under varying strain rates to induce various modes of fracture. This paper describes the analytical model developed to represent the drop tower and the gear holding fixture, which was utilized to evaluate various design alternatives to design a system where strain rates could be varied. Based on the results of the model, a system was implemented and a preliminary set of impact tests conducted. While some dynamic problems were encountered, these tests show that the system is performing largely as required. The source of the dynamic problems encountered was also examined and changes to the system to overcome these problems are planned. Data obtained in the impact tests conducted will also be presented to demonstrate the capability of the system.

scholarly journals A Meso Level FE Model for the Impact Bullet - Yarn

2019 ◽  
Vol 56 (1) ◽  
pp. 22-31
Author(s):  
Catalin Pirvu ◽  
Andrea Elena Musteata ◽  
George Ghiocel Ojoc ◽  
Simona Sandu ◽  
Lorena Deleanu
Keyword(s):  
Thermal Effect ◽  
Failure Process ◽  
The Other ◽  
Fe Model ◽  
Elastic Recoil ◽  
Aramid Fibers ◽  
Fiber Failure ◽  
Lead Alloys ◽  
Simulation Results ◽  
The Impact

This paper presents a study based on simulating the impact between a yarn (or a single fiber with greater dimensions) and a bullet, the impact velocity being 400 m/s. The characteristics of the involved materials are taken from literature. The yarn is considered isotrope, but the values of the characteristics are close to those of aramid fibers and cooper and lead alloys used for manufacturing the bullets. Analysing the yarn failure caused by a bullet, this FE model allows for identfying the stages in the failure process. First, the yarn is pushed by the bullet and the local elongation of the yarn is tacking place. The yarn rupture occurs in the �strangled� zones, caused by the stretch of the yarn directly supporting the impact. The breaking of the yarn in the thinned zone (more pronounced asymmetric breaking) and it is visible that the yarn elastic recoil starts next the bullet. The friction between the yarn and the bullet is only on the conical surface of the bullet in the tapered zone of the bullet. The yarn is detaching from the bullet (the contact zones between the bullet and the yarn in polymeric matrix become smaller, justifying a neglectable influence of the thermal effect). The yarn has no more contact with the bullet. This step is in the favor of the assumption that, in the actual multi-yarn impact, the other layers of yarns maintain the bullet and the first yarns in contact and this is why bunch of fibers (fragments of the failed yarns) are pressed against the bullet and remain on it. The simulation results were qualitatively validated by SEM investigations of fiber failure under the same conditions as the model.

Relative Motion Between Ski and Boot Under Impact Testing of Ski Bindings

1980 ◽  
Vol 102 (4) ◽  
pp. 695-700
Author(s):  
M. Diel ◽  
C. D. Mote
Keyword(s):  
Relative Motion ◽  
Displacement Transducer ◽  
Impact Testing ◽  
System Response ◽  
Two Dimensional ◽  
Lateral Impact ◽  
Binding System ◽  
Impact Tests ◽  
Transducer Design ◽  
The Impact

The relative translation and rotation of a snow ski and boot under lateral impact of the ski is critical to the function of the ski release binding. The binding couples the ski and ski boot during skiing and releases them under potentially excessive loading of the skier’s leg. A displacement transducer was developed to measure the general, two dimensional translation and rotation of the boot relative to the ski during laboratory impact tests of bindings. The requirement that the boot and ski separate upon release of the binding complicates the transducer design. Lateral impacts were applied with a pendulum at the “ski tip”, at the “ski tail” and at the “boot toe” positions on the ski. The model leg, ankle and ski response were recorded. Significant differences in leg-ski-binding system response were observed with two commercial bindings and with the impact locations on the ski.

scholarly journals The Contribution of Infrared Thermography to Impact Testing of Composite Materials†

Proceedings ◽  
2019 ◽  
Vol 27 (1) ◽  
pp. 29
Author(s):  
Carosena Meola
Keyword(s):  
Composite Materials ◽  
Infrared Thermography ◽  
Infrared Imaging ◽  
Impact Testing ◽  
Imaging Device ◽  
Impact Tests ◽  
Different Types ◽  
Infrared Cameras ◽  
The University ◽  
The Impact

This work wants to give an overview on information gathered at the University of Naples Federico II in the last ten years by monitoring the impact tests of composite materials with infrared thermography. Many tests have been carried out involving several different types of composites and different infrared cameras. The obtained results show that IRT can be advantageously used to both validate previously obtained data and to get new data that can be exploited for understanding more on the impact damaging of composite materials. This bears witness for the advantages of having an infrared imaging device within the testing instrumentation.

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