Method and system for characterizing wear damage on a rolling-element bearing

A method for estimating wear damage of a rolling-element bearing comprising an inner race, an outer race, and a plurality of rolling elements between the inner and outer races, the method comprising:

• calculating, using a processor, a first length of a spall cavity on the rolling-element bearing based on a geometry of the rolling-element bearing, the first length corresponding to a first relationship between the spall cavity and the plurality of rolling elements;
• calculating, using a processor, a second length of the spall cavity on the rolling-element bearing based on the geometry of the rolling-element bearing, the second length corresponding to a second relationship between the spall cavity and the plurality of rolling elements;
• determining, using a processor, an accumulated mass of spall particles ejected from the rolling-element bearing during operation of the rolling-element bearing;
• generating, using a processor, a first indication when the accumulated mass of the spall particles exceeds a first predetermined threshold, the first predetermined threshold being based on the first length of the spall cavity;
• and
• generating, using a processor, a second indication when the accumulated mass of the spall particles exceeds a second predetermined threshold, the second predetermined threshold being based on the second length of the spall cavity.

A system for estimating wear damage of a rolling-element bearing comprising:

• a debris sensor configured to generate a debris signal representative of a size of debris particles passing through a fluid passageway;
• and
• a computing system in operable communication with the debris sensor, the computing system being configured to:
• determine an accumulated mass of the debris particles passing through the fluid passageway based on the debris signal;
• and
• generating an indication when the accumulated mass of the debris particles exceeds a predetermined threshold,
• wherein the predetermined threshold of the accumulated mass is based on at least one geometric attribute of a damage feature on the rolling-element bearing, and the at least one geometric attribute of the damage feature is based on a geometry of the rolling-element bearing,
• wherein the generating of the indication is based on a weighting scheme, and the weighting scheme is represented by a function with a first slope corresponding to a predetermined threshold of a first value and a second slope corresponding to a predetermined threshold with a second value, the first value of the predetermined threshold being less than the second value of the predetermined threshold and the first slope being greater than the second slope, and
• the at least one geometric attribute of the damage feature may be expressed according to at least one of:
• 2√{square root over (2rp−p2)}, where r is the radius of the plurality of rolling elements and p is a depth of the damage feature,
• πr/3, where r is the radius of the plurality of rolling elements, and
• 2
• ⁢
• (
• π
• ⁢
• ⁢
• R
• N
• +
• r
• )
• ,
• where r is the radius of the plurality of rolling elements, R is the radius of the outer race, and N is the number of rolling elements in the plurality of rolling elements.