Bruce T, Long H, Dwyer-Joyce R S
Department of Mechanical Engineering, The University of Sheffield, Sheffield, S1 3JD UK.
Tribol Lett. 2018;66(3):111. doi: 10.1007/s11249-018-1068-0. Epub 2018 Jul 30.
Wind turbine gearbox (WTG) bearings can fail prematurely, significantly affecting wind turbine operational availability and the cost of energy production. The current most commonly accepted theory of failure mechanism is that the bearing subsurface is weakened by ) networks that eventually lead to the flaking away of material from the bearing surface. Subsurface damage due to rolling contact fatigue (RCF) is thought to be the main cause of premature failure, resulting from the initiation of micro-cracks, often at non-metallic inclusions or other material defects, which then propagate to the bearing surface. This study proposes a hypothesis that impact loading together with high levels of surface traction and contact pressure are important factors contributing to the initiation of micro-cracks and (WEAs) at non-metallic inclusions which may lead to the formation of WEC networks. Both repeated impact and twin-disc RCF tests were designed to investigate inclusion-initiated micro-cracks and WEAs at subsurface in order to test this hypothesis. This led to the recreation of inclusion-initiated micro-cracks and WEAs in tested specimens, similar to the subsurface damage observed at inclusions in failed WTG bearing raceways. Tests were carried out to determine threshold levels of contact pressure, surface traction, and impact loading required for the formation of inclusion-initiated micro-cracks and WEAs.
风力涡轮机齿轮箱（WTG）轴承可能会过早失效，这会显著影响风力涡轮机的运行可用性以及能源生产成本。当前最被广泛接受的失效机理理论是，轴承次表面会因（此处原文缺失相关内容）网络而被削弱，最终导致材料从轴承表面剥落。滚动接触疲劳（RCF）导致的次表面损伤被认为是过早失效的主要原因，这是由于微裂纹的萌生，通常始于非金属夹杂物或其他材料缺陷，然后扩展到轴承表面。本研究提出一个假设，即冲击载荷以及高水平的表面牵引力和接触压力是导致在非金属夹杂物处萌生微裂纹和（此处原文缺失相关内容）（WEAs）的重要因素，这可能会导致（此处原文缺失相关内容）网络的形成。为了验证这一假设，设计了重复冲击试验和双盘RCF试验，以研究夹杂物引发的次表面微裂纹和WEAs。这使得在测试样本中重现了夹杂物引发的微裂纹和WEAs，类似于在失效的WTG轴承滚道夹杂物处观察到的次表面损伤。进行了试验以确定形成夹杂物引发的微裂纹和WEAs所需的接触压力、表面牵引力和冲击载荷的阈值水平。
