Engine bearings are small and relatively inexpensive components of internal combustion engines however, failure of an engine bearing commonly leads to serious reconditioning works of the engine including its disassembling, regrinding the crankshaft and replacing the bearings. The major type of engine bearing failure is fatigue. Fatigue of engine bearing materials is caused by running the bearing at a load above the fatigue limit. The requirements to engine bearing materials compromise between high mechanical strength (fatigue strength, hardness) and antifriction properties (seizure resistance, conformability, embedability), which are characteristic for soft materials. In order to meet such contradictory demands the bearing materials are designed to have composite structure. Particulate composite having a relatively hard matrix (copper, aluminium) with particles of a soft phase (tin, bismuth, lead, and carbon nano tube ). If the bearing loading excesses its fatigue strength, fatigue cracks form in bearing material (engine bearing failure), spread to the back bearing layer and may result in flaking out of the material. Fatigue strength of engine bearing materials is evaluated in fatigue test rigs. Stock engines, street performance and circle track racing engines may use conventional aluminium-tin-silicon bi-metal or copper based tri-metal bearings depending on the load and crankshaft materials (AlSi bi-metal – for nodular cast iron shafts, tri-metal - for forged steel shafts). High strength tri-metal materials (e.g. sputter bearings) are recommended for applications with high bearing loading where conventional tri-metal material undergoes fatigue. Today, copper based bearing alloys are manufactured by either casting or sintering technology. We realized new technology nano-soldering pseudo-composite Unidirectional Carbon nFiber (UCnF) Reinforced Shape Memory Polymers(SMPs) Nanostrip Multilayers to improve bearing performances and decrease bearing failure/fatigue.
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