Periodic Reporting for period 2 - Gearbodies (Innovative Technologies for Inspecting Carbodies and for Development of Running Gear)
Periodo di rendicontazione: 2022-01-01 al 2023-06-30
The GEARBODIES project has addressed several issues related to the maintenance of carbodies and running gear elements such as bearings and elastomer-based components. This main goal is set within the greater context of enabling cost-efficient and reliable long-lasting trains to ultimately foster the modal shift towards rail. In order to achieve said goal, the project is focused on extending the overhaul periods and improving maintenance processes that would lead to reduction of the life-cycle cost (LCC). The project is divided into two distinct workstreams (WS) which address particular issues.
WS1 focused on reducing the inspection time of composite carbodies to boost its use in the manufacture of new rail vehicles. The main objective of WS1 was to design and develop a Modular Prototype Platform (MPP) capable of inspecting railway carbon fiber-reinforced polymer (CFRP) carbodies, using techniques such as infrared thermography (IRT) and ultrasonic testing (UT) to detect a high number of defects within a 12-hour period.
WS2.1 focused on improving the durability of elastomer-based running gear components, which at the time need to be replaced in considerably low time intervals as a result of fast worn out. Short durability is caused by fatigue, friction, wear, and degradation due to ultraviolet radiation. The main objective of WS2.1 was to test the impact of new materials in the durability of elastomer-based components.
WS2.2 focused on prolonging the lifetimes of journal bearings in an attempt to extend inspection intervals. New geometries, materials and lubricants were explored during the project.
WS1 focused on reducing the inspection time of composite carbodies to boost its use in the manufacture of new rail vehicles. The main objective of WS1 was to design and develop a Modular Prototype Platform (MPP) capable of inspecting railway carbon fiber-reinforced polymer (CFRP) carbodies, using techniques such as infrared thermography (IRT) and ultrasonic testing (UT) to detect a high number of defects within a 12-hour period.
WS2.1 focused on improving the durability of elastomer-based running gear components, which at the time need to be replaced in considerably low time intervals as a result of fast worn out. Short durability is caused by fatigue, friction, wear, and degradation due to ultraviolet radiation. The main objective of WS2.1 was to test the impact of new materials in the durability of elastomer-based components.
WS2.2 focused on prolonging the lifetimes of journal bearings in an attempt to extend inspection intervals. New geometries, materials and lubricants were explored during the project.
WS1: Non-destructive testing (NDT) techniques for inspecting CFRP train carbodies were tested. Samples with artificial Teflon defects were created to simulate damages from track ballast impact or operational loads. Infrared thermography (IRT) and ultrasonic testing (UT) techniques were explored, with optical lock-in and halogen lamp thermography proving most effective. A modular and multifunctional inspection platform was developed, integrating IRT and UT systems, and an image fusion tool was designed to process and visualize results. Validation involved functional testing and integration of hardware and software into the inspection platform, enabling partially automated scanning of entire car bodies.
WS2.1: The work was carried out in four interconnected phases. The first phase focused on analyzing existing technologies and defining specifications for elastomer-based components. The second phase employed the Analytic Hierarchy Process (AHP) for the final selection of two components: conical spring in primary suspension and bush in the swingarm. The third phase involved lab-scale development of technologies, including nanotechnology solutions, to improve component durability. The fourth phase included manufacturing prototypes of the components based on the outcomes of the lab-scale developments and their testing.
WS2.2: An extra-long lifetime concept of a bearing was developed under the idea of minimizing frictional heat generation during rolling, thereby reducing grease operating temperature. Novel materials for rollers and rings, specifically High-Entropy Alloys (HEA), were explored. Theoretical calculations and simulations were conducted, and four selected alloys were subjected to tests. Cage polymeric materials were researched by testing the properties of Polyether-ether-ketone (PEEK) and glass-reinforced polyamide PA66. The project considered the use of oil, that promised low friction and, particularly in high-speed trains where oil-lubricated gearboxes are common, the potential to significantly extend lubricant lifetime through circulation, filtration, and cooling during operation. A novel sealed-housing concept for oil lubrication was also conceived.
WS2.1: The work was carried out in four interconnected phases. The first phase focused on analyzing existing technologies and defining specifications for elastomer-based components. The second phase employed the Analytic Hierarchy Process (AHP) for the final selection of two components: conical spring in primary suspension and bush in the swingarm. The third phase involved lab-scale development of technologies, including nanotechnology solutions, to improve component durability. The fourth phase included manufacturing prototypes of the components based on the outcomes of the lab-scale developments and their testing.
WS2.2: An extra-long lifetime concept of a bearing was developed under the idea of minimizing frictional heat generation during rolling, thereby reducing grease operating temperature. Novel materials for rollers and rings, specifically High-Entropy Alloys (HEA), were explored. Theoretical calculations and simulations were conducted, and four selected alloys were subjected to tests. Cage polymeric materials were researched by testing the properties of Polyether-ether-ketone (PEEK) and glass-reinforced polyamide PA66. The project considered the use of oil, that promised low friction and, particularly in high-speed trains where oil-lubricated gearboxes are common, the potential to significantly extend lubricant lifetime through circulation, filtration, and cooling during operation. A novel sealed-housing concept for oil lubrication was also conceived.
WS1: Inspection of monolithic samples detected defects up to 10 mm (IRT) and 15 mm (UT), while the sandwich samples revealed defects only in the front skin or disbonding between the skin and foam core. The results indicated that IRT is more effective for surface defects, while UT detects deeper flaws. According to the tests, the MPP would be capable of inspecting a carbody in 12 hours using IRT and 6 hours using UT. Despite the progress made in GEARBODIES, further work is required to detect defects through foam and to achieve a fully automated (hard- and software) inspection platform.
The LCC was estimated for two automation scenarios: the LCC was 14% lower with mid automation and 53 % with full automation. These savings are driven by reductions in inspection times, energy consumption and the time needed to review the results if automation is increased which outweigh the greater investment cost required for enhanced automation.
WS2.1: Carbon Nanotubes (CNTs) was incorporated into elastomeric formulations, resulting in significant enhancements in mechanical properties, such as tear and tensile strength, elongation at break, and hardness. These improvements suggest an increase lifetime of the elastomer components. However, the application of nanotechnology to reinforce the interface between elastomeric and metallic parts did not show improvements in adhesion strength. The fatigue tests for the prototypes demonstrated variations in stiffness, suggesting the need for further optimization of elastomeric formulations and the potential need of components redesign.
Based on an extension of the maintenance interval from every four to every five bogie overhauls the LCC of bushes was estimated to decrease by 24.3%. The fatigue tests for the conical springs suggested that the durability of the components had not increased. To inform future research on conical springs it was estimated that if the component could be replaced every other bogie overhaul rather than each time as they are at present then the LCC of the components would decrease by 44.1%.
WS2.2: Despite theoretical expectations from the bearing prototype, rig tests analysis didn't fully confirm the anticipated advantages. Therefore, further short-to-medium-term development is recommended, with a focus on the conventional tapered-roller layout. Research indicated potential incremental improvements through optimization of component geometry, including roller geometry, contact roller and ring, cage geometry, and surface tolerances of the rings. The results indicated that all tested HEAs generally outperformed the state-of-the-art steel used as a reference. Polyether-ether-ketone (PEEK) emerged as a promising candidate, being compared with the widely used glass-reinforced polyamide PA66. PEEK exhibited interesting properties, such as lower absorption from the surrounding environment and lower variations of key properties with aging.
The present value of LCC was estimated to decrease by 43% with the ‘focused concept’ bearing which is based on what is thought to be possible in the short medium term based on the testing done in the project. These savings are driven by the reduced frequency of interventions which means that fewer components need to be purchased and less labour and energy are required for the installation and reconditioning of the bearings.
The LCC was estimated for two automation scenarios: the LCC was 14% lower with mid automation and 53 % with full automation. These savings are driven by reductions in inspection times, energy consumption and the time needed to review the results if automation is increased which outweigh the greater investment cost required for enhanced automation.
WS2.1: Carbon Nanotubes (CNTs) was incorporated into elastomeric formulations, resulting in significant enhancements in mechanical properties, such as tear and tensile strength, elongation at break, and hardness. These improvements suggest an increase lifetime of the elastomer components. However, the application of nanotechnology to reinforce the interface between elastomeric and metallic parts did not show improvements in adhesion strength. The fatigue tests for the prototypes demonstrated variations in stiffness, suggesting the need for further optimization of elastomeric formulations and the potential need of components redesign.
Based on an extension of the maintenance interval from every four to every five bogie overhauls the LCC of bushes was estimated to decrease by 24.3%. The fatigue tests for the conical springs suggested that the durability of the components had not increased. To inform future research on conical springs it was estimated that if the component could be replaced every other bogie overhaul rather than each time as they are at present then the LCC of the components would decrease by 44.1%.
WS2.2: Despite theoretical expectations from the bearing prototype, rig tests analysis didn't fully confirm the anticipated advantages. Therefore, further short-to-medium-term development is recommended, with a focus on the conventional tapered-roller layout. Research indicated potential incremental improvements through optimization of component geometry, including roller geometry, contact roller and ring, cage geometry, and surface tolerances of the rings. The results indicated that all tested HEAs generally outperformed the state-of-the-art steel used as a reference. Polyether-ether-ketone (PEEK) emerged as a promising candidate, being compared with the widely used glass-reinforced polyamide PA66. PEEK exhibited interesting properties, such as lower absorption from the surrounding environment and lower variations of key properties with aging.
The present value of LCC was estimated to decrease by 43% with the ‘focused concept’ bearing which is based on what is thought to be possible in the short medium term based on the testing done in the project. These savings are driven by the reduced frequency of interventions which means that fewer components need to be purchased and less labour and energy are required for the installation and reconditioning of the bearings.