Locomotive Crash Energy Management Coupling Tests Evaluation and Vehicle-to-Vehicle Test Preparation

2019 ◽  
Author(s):  
Patricia Llana ◽  
Karina Jacobsen ◽  
Richard Stringfellow
Keyword(s):  
Energy Management ◽  
New Technologies ◽  
Test Preparation ◽  
Performance Comparison ◽  
Analytical Models ◽  
Test Results ◽  
Test Procedures ◽  
Vehicle To Vehicle ◽  
Wide Range ◽  
Vehicle Test

Research to develop new technologies for increasing the safety of passengers and crew in rail equipment is being directed by the Federal Railroad Administration’s (FRA’s) Office of Research, Development, and Technology. Crash energy management (CEM) components which can be integrated into the end structure of a locomotive have been developed: a push-back coupler and a deformable anti-climber. These components are designed to inhibit override in the event of a collision. The results of vehicle-to-vehicle override, where the strong underframe of one vehicle, typically a locomotive, impacts the weaker superstructure of the other vehicle, can be devastating. These components are designed to improve crashworthiness for equipped locomotives in a wide range of potential collisions, including collisions with conventional locomotives, conventional cab cars, and freight equipment. Concerns have been raised in discussions with industry that push-back couplers may trigger prematurely, and may require replacement due to unintentional activation as a result of loads experienced during service and coupling. Push-back couplers (PBCs) are designed with trigger loads meant to exceed the expected maximum service and coupling loads experienced by conventional couplers. Analytical models are typically used to determine these trigger loads. Two sets of coupling tests have been conducted that validate these models, one with a conventional locomotive equipped with conventional draft gear and coupler, and another with a conventional locomotive retrofit with a PBC. These tests allow a performance comparison of a conventional locomotive with a CEM-equipped locomotive during coupling, as well as confirmation that the PBC does not trigger at speeds below typical coupling speeds. In addition to the two sets of coupling tests, car-to-car compatibility tests of CEM-equipped locomotives, as well as a train-to-train test are also planned. This arrangement of tests allows for evaluation of the CEM-equipped locomotive performance, as well as comparison of measured with simulated locomotive performance in the car-to-car and train-to-train tests. The conventional coupling tests and the CEM coupling tests have been conducted, the results of which compared favorably with their pre-test predictions. In the CEM coupling tests, the PBC triggered at a speed well above typical coupling speeds. This paper provides a comparison of the conventional coupling test results with the CEM coupling test results. The next test in the research program is a vehicle-to-vehicle impact test. This paper describes the test preparation, test requirements, and analysis predictions for the vehicle-to-vehicle test. The equipment to be tested, track conditions, test procedures, and measurements to be made are described. A model for predicting the behavior of the impacting vehicles and the CEM system has been developed, along with preliminary predictions for the vehicle-to-vehicle test.

scholarly journals Locomotive Crash Energy Management Coupling Tests

2017 ◽  
Author(s):  
Patricia Llana ◽  
David Tyrell
Keyword(s):  
Energy Management ◽  
New Technologies ◽  
Performance Comparison ◽  
The Other ◽  
Analytical Models ◽  
Test Procedures ◽  
Vehicle To Vehicle ◽  
Wide Range ◽  
Draft Gear ◽  
Test Requirements

Research to develop new technologies for increasing the safety of passengers and crew in rail equipment is being directed by the Federal Railroad Administration’s (FRA’s) Office of Research, Development, and Technology. Crash energy management (CEM) components which can be integrated into the end structure of a locomotive have been developed: a push-back coupler and a deformable anti-climber. These components are designed to inhibit override in the event of a collision. The results of vehicle-to-vehicle override, where the strong underframe of one vehicle, typically a locomotive, impacts the weaker superstructure of the other vehicle, can be devastating. These components are designed to improve crashworthiness for equipped locomotives in a wide range of potential collisions, including collisions with conventional locomotives, conventional cab cars, and freight equipment. Concerns have been raised in discussions with industry that push-back couplers may trigger prematurely, and may require replacement due to unintentional activation as a result of service loads. Push-back couplers are designed with trigger loads meant to exceed the expected maximum service loads experienced by conventional couplers. Analytical models are typically used to determine these required trigger loads. Two sets of coupling tests are planned to demonstrate this, one with a conventional locomotive equipped with conventional draft gear and coupler, and another with a conventional locomotive retrofit with a push-back coupler. These tests will allow a performance comparison of a conventional locomotive with a CEM-equipped locomotive during coupling. In addition to the two sets of coupling tests, car-to-car compatibility tests of CEM-equipped locomotives, as well as a train-to-train test are also planned. This arrangement of tests allows for evaluation of the CEM-equipped locomotive performance, as well as comparison of measured with simulated locomotive performance in the car-to-car and train-to-train tests. The coupling tests of a conventional locomotive have been conducted, the results of which compared favorably with pre-test predictions. In the coupling tests of a CEM-equipped locomotive, the coupling speed for which the push-back coupler (PBC) triggers will be measured. A moving, CEM-equipped locomotive will be coupled to a standing cab car. The coupling speed for the first test will be low, approximately 2 mph. The test will then be repeated with the speed increasing incrementally until the PBC triggers. This paper describes the fabrication, retrofit, test requirements, and analysis predictions for the CEM coupling tests. The equipment to be tested, track conditions, test procedures, and measurements to be made are described. A model for predicting the longitudinal forces acting on the equipment and couplers has been developed, along with preliminary predictions for the CEM coupling tests.

scholarly journals Locomotive Crash Energy Management Coupling Tests

2018 ◽  
Author(s):  
Patricia Llana ◽  
Karina Jacobsen
Keyword(s):  
Energy Management ◽  
New Technologies ◽  
Primary Objective ◽  
Performance Comparison ◽  
Analytical Models ◽  
Lumped Mass ◽  
Mass Model ◽  
Subsequent Test ◽  
Wide Range ◽  
The Impact

Research to develop new technologies for increasing the safety of passengers and crew in rail equipment is being directed by the Federal Railroad Administration’s (FRA’s) Office of Research, Development, and Technology. Crash energy management (CEM) components which can be integrated into the end structure of a locomotive have been developed: a push-back coupler and a deformable anti-climber. These components are designed to inhibit override in the event of a collision. The results of vehicle-to-vehicle override, where the strong underframe of one vehicle, typically a locomotive, impacts the weaker superstructure of the other vehicle, can be devastating. These components are designed to improve crashworthiness for equipped locomotives in a wide range of potential collisions, including collisions with conventional locomotives, conventional cab cars, and freight equipment. Concerns have been raised in discussions with industry that push-back couplers may trigger prematurely, and may require replacement due to unintentional activation as a result of service loads. Push-back couplers (PBCs) are designed with trigger loads meant to exceed the expected maximum service loads experienced by conventional couplers. Analytical models are typically used to determine these required trigger loads. Two sets of coupling tests have been conducted to demonstrate this, one with a conventional locomotive equipped with conventional draft gear and coupler, and another with a conventional locomotive retrofit with a push-back coupler. These tests will allow a performance comparison of a conventional locomotive with a CEM-equipped locomotive during coupling. In addition to the two sets of coupling tests, car-to-car compatibility tests of CEM-equipped locomotives, as well as a train-to-train test are also planned. This arrangement of tests allows for evaluation of the CEM-equipped locomotive performance, as well as comparison of measured with simulated locomotive performance in the car-to-car and train-to-train tests. The coupling tests of a conventional locomotive have been conducted, the results of which compared favorably with pre-test predictions. This paper describes the results of the CEM-equipped locomotive coupling tests. In this set of tests, a moving CEM locomotive was coupled to a standing cab car. The primary objective was to demonstrate the robustness of the PBC design and determine the impact speed at which PBC triggering occurs. The coupling speed was increased for each subsequent test until the PBC triggered. The coupling speeds targeted for the test were 2 mph, 4 mph, 6 mph, 7 mph, 8 mph, and 9 mph. The coupling speed at which the PBC triggered was 9 mph. The damage observed resulting from the coupling tests is described. Prior to the tests, a lumped-mass model was developed for predicting the longitudinal forces acting on the equipment and couplers. The test results are compared to the model predictions. Next steps in the research program, including future full-scale dynamic tests, are discussed.

scholarly journals Conventional Locomotive Coupling Tests

2016 ◽  
Author(s):  
Patricia Llana ◽  
Karina Jacobsen ◽  
David Tyrell
Keyword(s):  
New Technologies ◽  
Performance Comparison ◽  
Analytical Models ◽  
Lumped Mass ◽  
Mass Model ◽  
One Dimensional ◽  
Vehicle To Vehicle ◽  
Wide Range ◽  
Draft Gear ◽  
Lumped Mass Model

Research to develop new technologies for increasing the safety of passengers and crew in rail equipment is being directed by the Federal Railroad Administration’s (FRA’s) Office of Research, Development, and Technology. Crash energy management (CEM) components which can be integrated into the end structure of a locomotive have been developed: a push-back coupler and a deformable anti-climber. These components are designed to inhibit override in the event of a collision. The results of vehicle-to-vehicle override, where the strong underframe of one vehicle, typically a locomotive, impacts the weaker superstructure of the other vehicle, can be devastating. These components are designed to improve crashworthiness for equipped locomotives in a wide range of potential collisions, including collisions with conventional locomotives, conventional cab cars, and freight equipment. Concerns have been raised in discussions with industry that push-back couplers may trigger prematurely, and may require replacement due to unintentional activation as a result of service loads. Push-back couplers are designed with trigger loads meant to exceed the expected maximum service loads experienced by conventional couplers. Analytical models are typically used to determine these required trigger loads. Two sets of coupling tests are planned to demonstrate this, one with a conventional locomotive equipped with conventional draft gear and coupler, and another with a conventional locomotive equipped with a push-back coupler. These tests will allow a performance comparison of a conventional locomotive with a CEM-equipped locomotive during coupling. In addition to the two sets of coupling tests, car-to-car compatibility tests of CEM-equipped locomotives, as well as a train-to-train test are also planned. This arrangement of tests allows for evaluation of the CEM-equipped locomotive performance, as well as comparison of measured with simulated locomotive performance in the car-to-car and train-to-train tests. This paper describes the results of the coupling tests of conventional equipment. In this set of tests, a moving locomotive was coupled to a standing cab car. The coupling speed for the first test was 2 mph, the second test 4 mph, and the tests continued with the speed incrementing by 2 mph until the last test was conducted at 12 mph. The damage observed resulting from the coupling tests is described. The lowest coupling speed at which damage occurred was 6 mph. Prior to the tests, a one-dimensional lumped-mass model was developed for predicting the longitudinal forces acting on the equipment and couplers. The model predicted that damage would occur for coupling speeds between 6 and 8 mph. The results of these conventional coupling tests compare favorably with pre-test predictions. Next steps in the research program, including future full-scale dynamic tests, are discussed.

Locomotive Crash Energy Management Vehicle-to-Vehicle Impact Test Results

2020 ◽  
Author(s):  
Patricia Llana ◽  
Karina Jacobsen ◽  
Richard Stringfellow
Keyword(s):  
Energy Management ◽  
Research Program ◽  
Impact Test ◽  
Test Model ◽  
Test Results ◽  
Vehicle To Vehicle ◽  
Vehicle Collision ◽  
Vehicle Impact ◽  
Wide Range ◽  
The Impact

Abstract Research to develop new technologies for increasing the safety of passengers and crew in rail equipment is being directed by the Federal Railroad Administration’s (FRA’s) Office of Research, Development, and Technology. Two crash energy management (CEM) components that can be integrated into the end structure of a locomotive have been developed: a push-back coupler (PBC) and a deformable anti-climber (DAC). These components are designed to inhibit override in the event of a collision. The results of vehicle-to-vehicle override, where the strong underframe of one vehicle, typically a locomotive, impacts the weaker superstructure of the other vehicle, can be devastating and compromise the occupied space. The objective of this research program is to demonstrate the feasibility of these components in improving crashworthiness for equipped locomotives in a wide range of potential collisions, including collisions with conventional locomotives, conventional cab cars, and freight equipment. Concerns have been raised in discussions with industry that push-back couplers may trigger prematurely, or may require replacement due to unintentional activation as a result of loads experienced during service and coupling. PBCs are designed with trigger loads which exceed the expected maximum service and coupling loads experienced by conventional couplers. Analytical models are typically used to determine these trigger loads. Two sets of coupling tests have been conducted that validate these models, one with a conventional locomotive equipped with conventional draft gear and coupler, and another with a conventional locomotive retrofit with a PBC. These tests provide a basis for comparing the coupling performance of a CEM-equipped locomotive with that of a conventional locomotive, as well as confirmation that the PBC triggers at a speed well above typical coupling speeds and at the designed force level. In addition to the two sets of coupling tests, two vehicle-to-vehicle collision tests where one of the vehicles is a CEM-equipped locomotive and a train-to-train collision test are planned. This arrangement of tests allows for evaluation of CEM-equipped locomotive performance, and enables comparison of actual collision behavior with predictions from computer models in a range of collision scenarios. This paper describes the results of the most recent test in the research program: the first vehicle-to-vehicle impact test. In this test, a CEM-equipped locomotive impacted a stationary conventional locomotive. The primary objective of the test was to demonstrate the effectiveness of the components of the CEM system in working together to absorb impact energy and to prevent override in a vehicle-to-vehicle collision scenario. The target impact speed was 21 mph. The actual speed of the test was 19.3 mph. Despite the lower test speed, the CEM system worked exactly as designed, successfully absorbing energy and keeping the vehicles in-line, with no derailment and no signs of override. The damage sustained during the collision is described. Prior to the tests, a finite element model was developed to predict the behavior of the CEM components and test vehicles during the impact. The test results are compared to pre-test model predictions. The model was updated with the conditions from the test, resulting in good agreement between the updated model and the test results. Plans for future full-scale collision tests are discussed.

scholarly journals Conventional Locomotive Coupling Tests: Test Requirements and Pre-Test Analysis

2016 ◽  
Author(s):  
Patricia Llana ◽  
David Tyrell ◽  
Przemyslaw Rakoczy
Keyword(s):  
New Technologies ◽  
Load Capacity ◽  
Test Procedures ◽  
Test Analysis ◽  
One Dimensional ◽  
Vehicle To Vehicle ◽  
Wide Range ◽  
Service Load ◽  
Draft Gear ◽  
Test Requirements

Research to develop new technologies for increasing the safety of passengers and crew in rail equipment is being directed by the Federal Railroad Administration’s (FRA’s) Office of Research, Development, and Technology. Crash energy management (CEM) components which can be integrated into the end structure of a locomotive have been developed: a push-back coupler and a deformable anti-climber. These components are designed to inhibit override in the event of a collision. The results of vehicle-to-vehicle override, where the strong underframe of one vehicle, typically a locomotive, impacts the weaker superstructure of the other vehicle, can be devastating. The components are designed to improve crashworthiness for equipped locomotives in a wide range of potential collisions, including collisions with conventional locomotives, conventional cab cars, and freight equipment. Concerns have been raised in discussions with industry that push-back couplers may trigger prematurely, and may require replacement due to unintentional activation as a result of service loads. It has been shown analytically that push back coupler trigger loads exceed the service load capacity of conventional couplers and draft gears. Two sets of coupling tests are planned to demonstrate this, one with a locomotive equipped with conventional draft gear and coupler and another with a locomotive equipped with a pushback coupler. These tests allow for comparison of conventional with CEM-equipped locomotive measured performance during coupling. In addition to the coupling tests, car-to-car compatibility tests of equipped locomotives and a train-to-train test are also planned. This arrangement of tests allows for evaluation of the CEM-equipped locomotive performance, as well as comparison of measured with simulated locomotive performance in the car-to-car and train-to-train tests. In the coupling tests of conventional equipment, the maximum coupling speed for which there is no damage to either vehicle will be measured. A moving locomotive will be coupled to a standing cab car. The coupling speed for the first test will be 2 mph, the second test 4 mph, and the tests will continue with the speed incrementing by 2 mph until damage occurs to either vehicle. This paper describes the test requirements and analysis predictions for the coupling tests of conventional equipment. The equipment to be tested, track conditions, test procedures, and measurements to be made are described. A one-dimensional model for predicting the longitudinal forces acting on the equipment and couplers has been developed, along with preliminary predictions for the conventional coupling tests. It is expected that damage will occur for coupling speeds between 6 and 8 mph.

Selection and implementation of optimal magnetorheological brake design for a variable impedance exoskeleton robot joint

2016 ◽  
Vol 231 (5) ◽  
pp. 941-960 ◽  
Author(s):  
Ozgur Baser ◽  
Mehmet Alper Demiray
Keyword(s):  
Volume Ratio ◽  
Variable Stiffness ◽  
Humanoid Robots ◽  
Performance Comparison ◽  
Analytical Models ◽  
Exoskeleton Robot ◽  
Wide Range ◽  
Braking Torque ◽  
Variable Damping ◽  
Variable Stiffness Actuators

Next-generation exoskeleton and humanoid robots are expected to behave similar to the human neuro-muscular system to perform stable, flexible, and biomimetic movements. To achieve this goal, the variable stiffness actuators have been widely used in various robots. Using variable damping actuators along with variable stiffness actuators will be extremely beneficial for wide range of stable movements. Magnetorheological (MR) brakes are one of the most promising electromagnetic structures that can provide such variable damping in a relatively small actuator volume. In this paper, we focused on the design, characterization, selection and implementation of T-shaped, inner coil and outer coil multi-pole MR brakes to the ankle of an exoskeleton robot. Analytical models are developed using the magnetic circuit analysis to determine the braking torque. Then, magnetic finite element models are developed and coupled with an optimization algorithm to determine the optimal set of parameters of each MR brake design. Prototypes are manufactured in same size and tested experimentally to characterize the actuators’ torque-to-volume ratio, transient response, hysteresis, torque tracking, energy consumption, and damping performances. The performance comparison of the brakes showed T-shaped multi-pole MR brake design has superior characteristics compared to two other designs. Therefore, T-shaped multi-pole MR brake design is coupled with a variable stiffness actuator and implemented in an ankle joint of an exoskeleton robot and experimentally tested. The results show that the developed new hybrid robot joint is capable of stable movement with a simple control algorithm by changing its stiffness and damping independently.

The Vehicle Autopilot: Simultaneous Robust Control Through Parametric Adaptation

2006 ◽  
Author(s):  
Haftay Hailu ◽  
Sean Brennan
Keyword(s):  
Robust Control ◽  
Design Model ◽  
Control Technique ◽  
Control Synthesis ◽  
State University ◽  
Passenger Vehicles ◽  
Vehicle To Vehicle ◽  
Wide Range ◽  
Parametric Coupling ◽  
Vehicle Test

This work considers the problem of robustly controlling systems that have an implicit parametric coupling, and specifically considers the problem of lateral control of passenger vehicles at highway speeds. Passenger vehicles collectively have a wide range in dynamic behaviors mainly due to the ranges in size between different models. However, as vehicle size increases, the length, mass and mass moments of inertia also increase in predictable relationships that strongly couple these parameters to each other. The proposed control technique exploits this inherent parametric coupling in order to design a single robust controller that can be easily adapted parametrically from vehicle to vehicle. Parameter decoupling in the design model is achieved in the control synthesis step using a dimensional transformation. The resulting design model presents a system representation suitable for robust control of a very wide range of passenger vehicles using only a dimensional rescaling. This method is distinguished from prior work in that the structure of parametric dependence is included in the controller synthesis. The resulting design is tested on a scaled vehicle test setup developed at Pennsylvania State University. Both simulation and experimental results have shown the effectiveness of the technique for the proposed application.

scholarly journals Analysis of fuel consumption of China light duty vehicle test cycle for passenger car(CLTC-P)

2021 ◽  
Vol 268 ◽  
pp. 01029
Author(s):  
Meng Zhou ◽  
Chongzhi Zhong ◽  
Jingyuan Li
Keyword(s):  
Fuel Consumption ◽  
Air Conditioning ◽  
Test Results ◽  
Test Cycle ◽  
Test Procedures ◽  
Light Duty ◽  
Certification Test ◽  
Light Duty Vehicle ◽  
Vehicle Test ◽  
P Cycle

Through the fuel consumption test of several listed vehicles in China, the basic fuel consumption results of cold start under CLTC-P cycle, the fuel consumption results of vehicles under the condition of air conditioning on, and the fuel consumption results of vehicles under the condition of air conditioning off are measured. At the same time, the differences between NEDC cycle and CLTC-P cycle in China's fuel consumption certification test are compared, and the results of fuel consumption test are combined The fuel consumption test results under CLTC-P cycle are higher than those under NEDC cycle, and the fuel consumption test procedures under Chinese condition are more in line with the actual driving situation in China.

Drawing on repeat test takers to study test preparation practices and their links to score gains

2020 ◽  
Vol 37 (4) ◽  
pp. 550-572
Author(s):  
Ute Knoch ◽  
Annemiek Huisman ◽  
Cathie Elder ◽  
Xiaoxiao Kong ◽  
Angela McKenna
Keyword(s):  
Test Performance ◽  
Test Validity ◽  
Test Preparation ◽  
Test Results ◽  
Repeat Test ◽  
Wide Range ◽  
Pearson Test ◽  
Study Test ◽  
Access Test ◽  
Over Time

A key concern of washback research in language testing is with the value of test preparation for facilitating learning and improving test performance. Although test takers may draw on a wide range of preparation activities, the majority of research studies examining test preparation have taken place in classroom settings, leaving self-access approaches largely unexamined. The aim of the current study was to (a) explore possible links between self-access test preparation activities and improved test performance and (b) examine how repeat test takers adjust their test preparation activities from test sitting to test sitting while preparing for the Pearson Test of English (Academic). The study involved the collection and analysis of interviews from 60 recent repeat test takers. The interview data were coded for themes and sub-themes and analyzed for the kind of test preparation activities in which learners engaged, and how these changed over time. The interviews showed that the test takers were strategic in their preparation, by changing their approaches depending on their previous test results. The largest number of significant improvements was identified for speaking, where test takers engaged in a variety of strategies, some of which were construct-irrelevant. The findings are discussed in relation to test validity and washback.

Numerical Evaluation of the Thermal Properties of UD-Fibers Reinforced Composites for Different Morphologies

2020 ◽  
Vol 12 (03) ◽  
pp. 2050032 ◽  
Author(s):  
Toufik Saoudi ◽  
Ahmed El-Moumen ◽  
Toufik Kanit ◽  
Mohamed El Amine Belouchrani ◽  
Noureddine Benseddiq ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Analytical Models ◽  
Reinforced Composites ◽  
Test Results ◽  
Fiber Volume ◽  
Element Analysis ◽  
Unidirectional Fibers ◽  
Random Arrangement ◽  
Wide Range ◽  
Unit Cells

In this paper, the numerical homogenization technique is used to evaluate the representative volume element and to compute the effective transverse thermal properties of unidirectional fibers reinforced composites. Three unit cells are constructed including square, hexagonal and random arrangement. The results obtained by finite element analysis showed the effect of unit cells configurations on the prediction of effective transverse thermal properties of unidirectional fibers composites for a wide range of fiber volume fractions and contrasts of properties. The numerical results are compared to available analytical models in the thermal conductivity of composites and experimental test results from the literature.

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