Discover our innovative approach to structural reliability, where we simulate 4.5 million miles of service using advanced shaker tests. Explore the creation of our custom accelerated fatigue program, and delve into the detailed data cleaning and analysis, expertly conducted with nCode GlyphWorks.
Need to develop an accelerated fatigue test on a rail car that is a different design than the rail car that provided all the customer usage data.
An alternate procedure based on fatigue damage analysis in nCode GlyphWorks. Generate a metric called Road Environment Percent Occurrence Spectra (REPOS). These REPOS data allows creation of a test that replicates a long service life in a condensed period of time.
Reduce test time and cost by eliminating the need for another rail test (4-6 months time-saving typical). Efficiently test any number of similar railcar designs.
The Transportation Technology Center, Inc. (TTCI), headquartered in Pueblo, Colorado, is a wholly owned subsidiary of the Association of American Railroads (AAR). TTCI is a world-class transportation research and testing organization, providing emerging technology solutions for the railway industry throughout North America and the world.
Accelerated fatigue programs are used to simulate decades of revenue service in a period of a few months (or weeks in some cases). They provide a powerful tool for both rail car manufacturers and fleet owners that can be used for both technical and financial decisions in the short term.
The project's main goal was to simulate 4.5 million miles of service in a short period of time based on recorded data obtained during an Over the Road Test (OTR test). A typical OTR test involves putting an instrumented rail car into regular service operation for several months to capture the different excitations experienced by the rail car, and use those excitations to create equivalent inputs to a hydraulic full size shaker to impose the same damage on the structure as seen during the OTR test but in considerably less time.
TTCI performed the shaker test on a computer controlled, electro-hydraulic structural test device used for applying dynamic inputs directly to full-scale railcar bodies, highway vehicles and other heavy structures. The Simuloader uses up to 11 actuators with capacities up to 750,000 lbs and a 6 inch stroke, a longitudinal actuator operating in FORCE control mode, vertical and lateral actuators operating in displacement control mode.
In order to correctly design the accelerated test, the following input signals forming the Environmental Data for both a Fatigue Analysis and an Accelerated Fatigue Test were needed:
TTCI were able to analyze the data gathered during the accelerated test using solely nCode GlyphWorks. "GlyphWorks enables us to import the test data. GlyphWorks fully supports filtering, spikes removal, data editing and offset. All the data treatment is done using standard embedded processes within GlyphWorks that require no customization. It was easy to get our signal data ready to be analyzed for fatigue damage," explains Juan C. Valdes-Salazar, Principal Investigator II at Transportation Technology Center.
The fatigue damage is then calculated from all the strain channels and the resulting damage is correlated with the environmental variables of vertical and lateral accelerations as well as the longitudinal coupler force. Accelerations at the carbody to suspension interface (truck bolster) are analyzed at the corresponding critical damage events to identify the associated carbody motions.
After the fatigue analyses have been performed, the procedure to generate the driver files to be used as inputs for the SMU is the following:
The procedure described in this article allows TTCI to successfully conduct both Fatigue Analyses and Accelerated Fatigue Test using nCode GlyphWorks. "We were able to generate the SMU driver files for the accelerated test by using nCode GlyphWorks. No customization was necessary during the process and we were able to accurately monitor the accelerated test and ensure proper damage was being applied. The results of the accelerated test confirmed the pre-test damage fatigue calculations," concludes Mr. Valdes-Salazar.
This will bring together HBM, Brüel & Kjær, nCode, ReliaSoft, and Discom brands, helping you innovate faster for a cleaner, healthier, and more productive world.
This will bring together HBM, Brüel & Kjær, nCode, ReliaSoft, and Discom brands, helping you innovate faster for a cleaner, healthier, and more productive world.
This will bring together HBM, Brüel & Kjær, nCode, ReliaSoft, and Discom brands, helping you innovate faster for a cleaner, healthier, and more productive world.
This will bring together HBM, Brüel & Kjær, nCode, ReliaSoft, and Discom brands, helping you innovate faster for a cleaner, healthier, and more productive world.
This will bring together HBM, Brüel & Kjær, nCode, ReliaSoft, and Discom brands, helping you innovate faster for a cleaner, healthier, and more productive world.