Hydraulic Grips and Controller for Variable Amplitude Fatigue Testing of Structural Connections, Interfaces, and Cables

众所周知，循环载荷下的疲劳劣化对工程结构的安全性、基础设施维护的社会成本以及机械、车辆和其他机械系统的重量和能量效率具有重大的负面影响。随着新材料、系统和连接技术的出现，在研究和开发这些技术时，必须清楚地了解它们的疲劳行为以及如何改善这种行为，以最大限度地提高性能、安全性和经济性。虽然疲劳退化问题对这些技术的发展提出了挑战，但从社会角度来看，对这项研究的需求从未如此紧迫，因为这一领域的进展被视为未来几十年发展“绿色”和经济可持续建筑，城市基础设施和交通/能源系统的关键。 在此背景下，该提案的共同申请人目前正在监督世界级的研究计划，调查：快速建造/易于重新配置的城市基础设施系统的新连接概念，轻质金属结构的新焊接技术，大跨度桥梁的新电缆连接解决方案，以及能源部门使用的管道系统中焊接连接的性能评估。目前的提案要求为实验疲劳测试框架的组件提供资金，这将使滑铁卢研究人员能够扩大广度，并大大加快这项世界领先研究的步伐。所要求的设备包括：1）一套液压夹具（沿着两套插入件），与我们现有的100 kN疲劳测试架兼容，以及2）一个现代数字控制器，能够在高频下引入复杂的VA加载历史，以实现快速疲劳测试。 如果没有这些设备，申请人计划进行的研究的进展将受到严重阻碍，因为目前滑铁卢和其他地方为其他目的使用的具有一定可比性的试验架的使用率很高。将现有的20世纪70年代老式测试架重新用于新的数字控制器和更安全、更适合应用的夹具组的建议是创新的，并将通过延长现有100 kN测试架的工作部件的使用寿命来节省大量成本，否则现有100 kN测试架的工作部件将未得到充分利用，并且（事实上）保持运行不安全。由此产生的测试系统将被大量的HQP使用，对有限的可用技术支持的需求最小。它将是高度通用的，并可根据需求的变化进行重新配置，预期寿命为15-20年或更长。研究成果将在减少基础设施相关能源消耗和生命周期运营和维护成本方面带来巨大的社会效益。

Fatigue deterioration under cyclic loading is well known to have a major, negative impact on the safety of engineered structures, the societal cost of infrastructure maintenance, and the weight and energy efficiency of machinery, vehicles, and other mechanical systems. As new materials, systems, and connection technologies emerge, it is critical that they be researched and developed with a clear understanding of their fatigue behaviour and how to improve this behaviour in order to maximize performance, safety, and economy. While the problem of fatigue deterioration presents a challenge in the development of these technologies, the need for this research from a societal perspective has never been more pressing, as progress in this area is seen as the key to the development of “greener” and more economically sustainable buildings, urban infrastructure, and transportation / energy systems in the coming decades. Against this background, the co-applicants of this proposal are currently overseeing world-class research programs investigating: new connection concepts for rapidly constructible / easily reconfigurable urban infrastructure systems, new welding technologies for lightweight metal structures, new cable connection solutions for long span bridges, and the performance assessment of welded connections in piping systems used by the energy sector. The current proposal requests funds for components of an experimental fatigue testing frame, which would allow Waterloo researchers to expand the breadth and substantially intensify the pace of this world-leading research. The requested equipment includes: 1) one set of hydraulic grips (along with two sets of inserts) compatible with one of our existing 100 kN fatigue testing frames, and 2) a modern digital controller capable of introducing complex VA loading histories at high frequency to enable rapid fatigue testing. Without this equipment, the progress of the research planned by the applicants will be critically handicapped due to the current high utilization rate of the somewhat comparable test frames at Waterloo and elsewhere for other purposes. The proposal to repurpose an existing 1970s vintage test frame with a new digital controller and a safer and more application-suitable grip set is innovative and will result in a high cost savings by extending the service life of the working parts of an existing 100 kN test frame, which would otherwise be underutilized and (in fact) unsafe to keep in operation. The resulting testing system will be heavily utilized by high numbers of HQP, with minimal demand on the limited available technician support. It will be highly versatile and reconfigurable as needs change, with an expected life of 15-20 years or more. The results of the enabled research will lead to substantial societal benefits in terms of reduced infrastructure-related energy consumption and life-cycle operation and maintenance costs.