Certified Maintenance and Reliability Technician (CMRT) Practice Test

The term that describes the process of a bearing wearing out over time due to repetitive stresses and strains associated with its operation is known as normal fatigue failure. Bearings are subjected to cyclic loading during their operation, and over time, this repeated stress can lead to microscopic cracks forming in the material of the bearing. As these cracks propagate, they can result in flaking, pitting, or eventual failure of the bearing. This is a common mode of failure in rolling element bearings.

While other types of failures may also occur, they do not specifically describe the progressive wear that typically affects bearings. For instance, overload failure occurs when a component exceeds its load capacity, leading to immediate failure rather than a gradual wear process. Surface wear failure is more specific to the loss of material due to friction and abrasion, which may not necessarily align with the fatigue process. Passivation failure involves the chemical treatment of materials and isn’t relevant to mechanical wear in bearings. Hence, normal fatigue failure accurately captures the gradual deterioration that occurs due to the cyclic loading characteristic of bearing operation.