Abstract Plain bearings experience cyclic loading during operation, which may cause fatigue failure. In the bearings under study a steel backing has a leaded bronze interlayer, covered by a thin (20 μm) multilayer coating, which consists of several electroplated layers composed of Sn, Ni and Cu. Commercial performance assessments simulate the conditions of engines in a ‘Pass or Fail’ test. A new methodology is proposed to assess the fundamental fatigue behaviour for such complex layered bearings. Accelerated fatigue tests on half-shell bearings have been conducted under 3-point bend, whilst the coated side of the bearings are recorded with an infrared camera. Cyclic tests with strain gauges placed on the coating have been performed to evaluate the strains developing during loading. By combining these tests we can rank different coatings. A compliance based failure criterion is also compared with a failure criterion based on early damage revealed by infrared thermography, showing that the latter is far less conservative. Thus, this methodology allows detection of small scale fatigue cracks in the coatings significantly earlier, facilitating assessment and identification of possible mechanisms to explain the differences in fatigue performance between coatings. This provides valuable information to develop new coatings for future bearing designs.

中文翻译：

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使用锁定热成像对多层涂层进行疲劳评估

摘要 滑动轴承在运行过程中会承受循环载荷，容易引起疲劳失效。在所研究的轴承中，钢背衬有一个含铅青铜夹层，上面覆盖着一层薄 (20 μm) 的多层涂层，该涂层由几个由 Sn、Ni 和 Cu 组成的电镀层组成。商业性能评估模拟发动机在“通过或失败”测试中的条件。提出了一种新方法来评估这种复杂分层轴承的基本疲劳行为。在 3 点弯曲下对半壳轴承进行了加速疲劳试验，同时用红外摄像机记录了轴承的涂层侧。已经进行了在涂层上放置应变计的循环测试，以评估加载过程中产生的应变。通过结合这些测试，我们可以对不同的涂层进行排名。还比较了基于合规性的失效准则与基于红外热成像揭示的早期损坏的失效准则，表明后者远不那么保守。因此，这种方法可以显着更早地检测涂层中的小规模疲劳裂纹，从而有助于评估和识别可能的机制，以解释涂层之间疲劳性能的差异。这为开发用于未来轴承设计的新涂层提供了宝贵的信息。促进评估和识别解释涂层之间疲劳性能差异的可能机制。这为开发用于未来轴承设计的新涂层提供了宝贵的信息。促进评估和识别解释涂层之间疲劳性能差异的可能机制。这为开发用于未来轴承设计的新涂层提供了宝贵的信息。