Rail Vehicle / Component Projects |
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Coupler Height Mismatch Test
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SA investigated the effects of coupler height mismatch on tank car stub sills. The objective of the project
was the evaluation of the impact performance of M-901 G gears, versus M-901 E gears.
As part of this project, initial static tests were used to calibrate the strain gages and to establish the criticality of the
various forces on the tank car stub sill. Impact tests were conducted at three different coupler mismatch levels
with the tank car as the anvil car, at impact speeds ranging from 1 to 8.5 mph.
Strain data and
acceleration data were measured at four locations on the tank car.
SA used data from the static analysis to fine tune the
LS-DYNA finite element model
of the tank car. The revised model was used to perform impact analysis of tank
cars.
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Fatigue & Fracture Analysis of Frame Tank Container
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SA was asked by a frame tank manufacturer to examine and analyze
the large volumes of test data collected during a series of over-the-road (OTR) tests of a
frame tank container. The frame had been instrumented to collect strain data at critical locations, in order to determine
why the frame was cracking in revenue service.
SA performed a statistical
analysis to determine critical locations/channels. For the critical locations, data from the various valid runs were combined, after being
normalized for miles traveled. The data was then used in carrying out fatigue analysis
(histograms & rainflow counts).
Subsequently, SA developed appropriate software and evaluated fatigue damage
based on British Standard
(BS 5400) codes. Fatigue life was also evaluated using
AAR specifications. Based on the results of these analyses, the customer was
able to improve the design of the frame tank.
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Failure Analysis (Evaluation of Intermodal Trailers)
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A major highway trailer manufacturer contracted SA to help develop/improve the trailer sub-frame maintenance and inspection
procedures.
A sample of trailer subframes was visually inspected and thickness measurements were made to
identify susceptible trailer types and problem areas. A Weibull reliability analysis was performed for expected minimum
thickness for a 90% probability with 95% confidence, to be used for subsequent structural, fatigue & crack growth analyses.
SA developed and implemented detailed tests to acquire load environment data for the trailers under roadway use and
loading/unloading operations for local roads, interstate highways and loading/unloading operations in a rail yard.
The trailer sub-frames were analyzed to evaluate stress concentrations and peak stress levels.
Fatigue analyses of the sub-frames were then conducted using standard industry procedures and unit stress data were derived. This analysis established the design fatigue life of the subframe, based on expected mileage per year. Crack growth analysis
was used to estimate the growth rate of a crack or flaw on a trailer sub-frame under normal operating conditions. This analysis
helped in establishing the necessary inspection intervals.
Based on the series of analyses and tests conducted, SA developed a detailed inspection protocol for the client's use.
Operating restrictions for long and short operations were also developed and recommended to the client.
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Over The Road Test (Locomotive Ride-Quality Evaluations)
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A major class I railroad in the US needed to measure the ride-quality of a locomotive and two
TOFC cars that were part of a special train that was traveling cross-county. SA identified
suitable locations on the specified locomotive and cars for ride quality instrumentation and
installed self-contained sensor and data acquisition (DAQ) boxes for this special over-the-road
test. To meet the customer’s tight schedule, SA procured and programmed the necessary
equipment, and installed it on the train within the deadline. The programming consisted of
setting up suitable sample rates, trigger levels, periodic data intervals, over-write setups, etc. The DAQ boxes were selected
with particular attention to the peak ‘g’ levels expected
and the data filtering requirements.
The DAQ boxes used for this study measure and store, time-histories of longitudinal, lateral
and vertical (tri-axial) accelerations in a burst mode; i.e., time history segments are recorded
when pre-set trigger levels are exceeded. Each time-history segment is time stamped for easy
identification. The units were programmed to
overwrite data that had lower magnitudes of acceleration, whenever the memory
limits were exceeded. This ensured that data with the
highest magnitudes was retained at the end of the test. The DAQ boxes are quite robust and are
designed to hold up very well in the harsh railroad environment.
At the end of the test, the DAQ units were retrieved from the train. SA then downloaded the
data from the DAQ boxes and converted it for customer to perform analysis.
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Vibration Test - Brake Pipe Anchor
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SA had the opportunity to work on a new design for a brake pipe anchor which required
structural design and fatigue life validation. This new anchor was designed to be more economical to manufacture,
while retaining the performance of the previous design.
As part of the validation process, SA performed a Finite Element
Analysis (FEA) of the new design considering various mounting configurations and
load cases. Subsequently, fatigue analysis was conducted using a measured load
environment to evaluate the life of the component (in millions of miles). Based
on our analysis and recommendations, the customer further refined their design
to ensure that no stress risers were present near regions of high stress.
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Safety Testing of Passenger Railcar
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New trainsets designed for passenger service in the United States need to satisfy the Federal Railroad
Administration’s (FRA) Code of Federal Regulations (CFR), which aim to ensure a minimum level of safety for
railroad passengers. Specifically, the FRA Passenger Equipment Safety Standards 49 CFR Part 238, subpart C
(Specific Requirements for Tier I Passenger Equipment) refer to strength requirements of passenger cars that
may be established through testing. As part of the test effort Static End Compression Tests, Vertical/Anti-climbing Tests, Transverse Corner Post Tests and Longitudinal Corner Post Tests were conducted.
SA also performed a crash-worthiness analysis of a transit car collision post under a projectile
type load (similar to a recent incident involving a truck carrying steel coils and a commuter train). The dynamic
modeling and analysis was done using LS-DYNA. The analyses were conducted for different speeds of impact, and
different collision heights. The meshing was created using HyperMesh and the post-processing was done with FEMB.
Energy absorption levels and the travel of the projectile after failure of the posts were evaluated.
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High Speed Freight Truck
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SA has conceptualized, designed, analytically investigated and prototyped a
high-speed truck for freight service.
The high-speed truck (HST) intended for 70-ton, regular freight and bi-modal operation is an innovative truck that will
provide safe and stable service operations at speeds up to 150 mph with performance envelope and design features as
below:
Performance Envelope:
Design Features:
The truck uses a rigid frame and an independent, compliant, primary
suspension for its basic architecture. A pendulum suspension provides significant lateral decoupling between the axles and the
car body to eliminate lateral instability. Compliant primary suspension between the frame and the pedestal provides axle steering
capabilities for a superior curving performance. Viscous damping in the suspension provides a well-controlled vertical (twist
& roll
and pitch & bounce) dynamic behavior for both loaded and empty configurations. 36 inch wheels provide adequate heat dissipation capacity
for tread-only brake system for operations at speeds up to 110 mph
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Combined tread and disc brake system for safe operations at speeds
of up to 150 mph
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The truck uses many field-proven and off-the-shelf components
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TriCoupler Development
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SA has developed an advanced coupler which provides electrical and pneumatic connections
between two cars, in addition to the mechanical connection (TriCoupler).
SA undertook a detailed study of the coupler contours, coupler internals,
allowable wear limits and slack between couplers. Subsequently, SA
developed detailed designs of the TriCoupler components and fabricated two sets
for laboratory and field testing. Numerous laboratory tests were carried
out to improve the reliability and robustness of the TriCoupler design.
SA then conducted numerous yard tests using the TriCoupler prototypes and
finally conducted an over-the-road test. The TriCoupler has performed
remarkably well in the field testing and promises to be a key 'enabling'
technology for achieving more efficient and safe railroad operations.
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Automatic Cut Lever
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SA developed a remotely controlled cut lever that retains all normal manual functions
of a cut lever.
This advanced cut lever provides
the ability to remotely unlock couplers without having to get in between cars and manually lift cut levers.
The remotely controlled cut lever design eliminates potential injury to crews while cutting cars from
a train.
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Tank Head Puncture Simulation
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In derailments with car pile-up, cars separate and strike each other with couplers intruding into the adjacent cars.
In the derailment caused by broken rail, a rail can impact and puncture the car body structure.
One of the major risks in such derailments of hazardous material carrying cars is the puncturing of the tank head
from an impacting coupler or a broken rail.
In this project, finite element simulation was carried out to evaluate the adequacy of the tank car head shield thickness
to withstand an impacting coupler or a broken rail up to 30 mph impact. The tank head
shield was modeled in LS-DYNA for puncture simulation.
The case of coupler impacting the tank head was simulated as a blunt object at 30 mph. The simulation results showed
that at the given impact speed, the tank head structure is strong enough to preclude any possibility of puncture or
major deformations.
However, when the case of a broken rail was simulated as a projectile impacting the tank head at 30 mph, the tank head punctured
and the rail penetrated into the tank.
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Thermal Analysis - Retrofit Design of Sill Pad Extensions on Tank Cars
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Cracking and local buckling problems in the vicinity of the inboard sill pad terminations have been observed on certain
tank cars. Increased defect rates have been observed under loading and unloading conditions at low ambient temperatures. The scope of this project
was to predict the probable cause and evaluate potential remedies to the observed cracking
problem. The primary remedy considered for alleviating the problem was the extension of the sill pad by a suitable length.
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Detection of Derailed Wheel And Wheel Defects
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To improve railroad safety and efficiency, a study was undertaken to develop and
demonstrate an On-Board Monitoring System for freight trains.
The goal of the analytical work was to develop an estimate of the magnitude of vertical
acceleration for a derailed wheel. Since a derailed wheel runs over crossties and can experience free fall
conditions between the ties, traditional vehicle tools models for such an analysis are not suitable. As a result,
LS-Dyna was selected for conducting a set of parametric simulations.
Power Spectral Density analysis of the derailed wheel simulations showed that the derailed wheel
tread and wheel defect related acceleration signals can be separated in frequency regime to a significant degree. Most
derailed wheel acceleration cycles are of higher amplitude than those due to wheel defects. The number of high amplitude
cycles/wheel revolution is much larger for the derailed wheel than a wheel with tread defects.
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Knuckle-Open Retrofit
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SA developed the Knuckle-Open retrofit design that automatically opens the coupler knuckle completely upon lifting of the coupler lock.
Benefits
include maximum gathering range and confidence that the knuckle will be open for acceptance of the next mating
coupler.
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Freight Car Hand Brake Sensor
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SA has developed the freight car hand brake sensor to be used in conjunction with a freight car vertical wheel Type N or Type O hand brake to indicate
that the brake is released.
Benefits include the ability to remotely monitor hand brakes for released or
not-released states, which would reduce wheel slid flats and track
damage and improve efficiency in operations.
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