Stresses in a 33-inch (.840 m) railroad car wheel in response to static rail loadings are presented on the basis of experimental work and theoretical predictions. In regions away from the contact area, the theoretical predictions are verified by experiment. The rail load stresses are compared to theoretically damaging thermal loads, and a possible method of analysis of fatigue damage from the combined loading is discussed.
It is generally understood that uneven heating of the tread of a wheel during braking is possible. A method has been devised to measure the intensity and frequency of hot spots on the wheel tread surface. After a description of the measurement apparatus and technique, results of a study of hot spots during constant speed brake applications with single composition shoes are presented. Possible lowering of the hot spot level by increasing the conformability of the brake shoe is studied by cutting one slot across each pad of a brake shoe. This method of hot spot study may be useful for future analysis and improvement of brake shoes.
Ursa is the largest TLP in the Gulf of Mexico having 98.000 tons displacement and is the deepest TLP in the world located in 3,800 feet-of-water, MC Block 809. The URSA tendon and foundation design, fabrication and installation were built on the wealth of experience of previously installed TLPs1,2,3,11. In this paper, we focus on the new challenges that had to be met for this record setting project. Unique features of the Ursa Tendons, Foundation and Installation include:More tendons, 16 (4/corner) versus 12 (3/corner);Larger tendons, 32"OD × 1.5" wall (compared to the previous 26" × 1.3" and 28" × 1.2" wall)Longer Tendon Main Body Sections than the previous TLP's, resulting in 283.5' individual sections. This reduced the number of connections required and offshore handling time.New tendon top connector devdoped for Ursa resulting in simpler operations and significant cost savings.The foundation system consists of 16 individual piles. They are 417' in length and 96" OD constructed from 60-ksi material.The potential for significant fatigue-damage accumulation due to pile driving required special design and fabrication solutions.Design, Construction, and Installation strategy developed early on helped reduce cycle time, cost, and accommodated changes during construction.On site temporary mooring of the TLP was accomplished using a Flex-Yoke system.Improved procedures for tendon handling, stabbing and tensioning were developed. Introduction The Ursa TLP tendon, foundation and installation design and fabrication extended over a period of 3 years. In order to meet the fast-tract project schedule, material orders had to be placed early, before design completion. Design decisions were focused on reducing both cost and schedule, taking advantage of learnings from the previous TLP's, Early attention was given to the TLP installation design to allow modifications to be incorporated into the planned schedule, tendon design and pile driving requirements. The modification brought out by the site and water depth change6,7,9 were significant. New soil information had to be obtained, designs verified, installation procedures adjusted and schedules maintained. Tendon Design, Fabrication and Transportation TLP and Tendon Sizing After concept selection in the summer of 1995, the TLPSIZE program was used to size and optimize the URSA TLP. For the initial site, the water depth was determined to be 3,950 feet. Later, due to the site relocation, the water depth was reduced to 3,S00 feet7. Cost optimization was focused on sizing the hull and tendons such that the minimum tendon bottom tension was slightly above zero and the tendon met stress, collapse, and fatigue design criteria with minimal steel cross section area and maximized buoyancy. The program was calibrated based on technical and cost data from the MARS TLP.
This paper continues to document the design, development, and test of a friction-based (non-adhesive) post-installable fiber-optic strain sensing system for oil and gas applications — especially those that require deployment on existing subsea structures. (Ref: OMAE2017-61494 Development and Testing of a Friction-Based Post-Installable Sensor for Subsea Fiber-Optic Monitoring Systems [1]). The prototype fiber-optic monitoring system collects a wide range of real-time data, which can be used to determine structural loading, fatigue, temperature, pressure, and flow assurance on operational platforms. The primary challenge of a post-installed instrumentation monitoring system is to ensure secure coupling between the sensors and the structure of interest for reliable measurements. Friction-based coupling devices have the potential to overcome installation challenges caused by marine growth and soil contamination on subsea structures, flowlines, or risers. This particular design solution is compatible with structures that are suspended in the water column and those that are resting on the seabed. In addition, the system can be installed by commercial divers in shallow depths or by remotely operated vehicles in deep-water applications. Operational limitations of the initial design concept were identified in the previous series of tests (2016–2017), and several innovative enhancements have been implemented which resulted in significant improvements in sensor system coupling and strain measurement correlation with traditional strain measuring devices. This paper provides a summary of the notable prototype design changes, full-scale test article buildup, and detailed performance data recorded during tension and compression loading that simulated representative offshore conditions. The test results were positive and demonstrated the effectiveness of the design enhancements. Compromises made during mounting of the sensing elements resulted in better performance in tension than compression. These effects are well understood and are fully discussed, and do not influence the viability of the design changes. This study is part of a continuing collaboration between the Houston-based NASA-Johnson Space Center and Astro Technology, Inc. within a study called Clear Gulf. The primary objective of the Clear Gulf study is to develop advanced instrumentation technologies that will improve operational safety and reduce the risk of hydrocarbon spillage. NASA provided unique insights, expansive test facilities, and technical expertise to advance these technologies that would benefit the environment, the public, and commercial industries.
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