Model for predicting wear and the end of life of a tire

A method for estimating a level of overall wear of a tire of an assembly mounted under running conditions on a vehicle, the tire having a crown which is extended by two sidewalls that end in two beads, exhibiting revolution about a natural axis of rotation, the crown comprising a tread situated radially on an outside of the tire with respect to the natural axis of rotation, the tread having a mean thickness E, and the mounted assembly comprising components including a wheel and the tire delimiting an internal cavity, the method comprising the following steps:

• acquiring a transfer function F of the mounted assembly between a longitudinal stiffness KXXref on a reference ground and influencing factors, as a product of a first function F1 having as influencing factors at least inflation pressure P, temperature T and load Z experienced, and a second, bijective function F2 having at least as influencing factor the thickness E of the tread;
• and
• acquiring a passage function β of the mounted assembly, the passage function being defined for a section of road as a ratio of the longitudinal stiffnesses KXX of the mounted assembly for the same influencing factors, numerator stiffness being evaluated on ground equivalent to the section of road and denominator stiffness being evaluated on a reference ground;
• and, in one and measurement cycle,
• determining at least one force FX experienced by the mounted assembly and at least one rate of slip g % at a wheel center of the mounted assembly, or acquiring parameters Q1 of the vehicle allowing determinations thereof, when the vehicle is running in a straight line involving variations in acceleration on the section of road, the latter being dry;
• determining a load Z1, or acquiring parameters Q2 of the vehicle allowing the determination, experienced by the assembly mounted under running conditions;
• determining a temperature T1 of the assembly mounted under running conditions;
• and
• determining an inflation pressure P1 of the internal cavity of the assembly mounted under running conditions,
• wherein the method further comprises acquisition of a first longitudinal stiffness KXXact of the mounted assembly on actual ground with aid of a first relationship between the forces FX, the rates of slip g % or the parameters Q1,
• wherein the method further comprises acquisition of a second longitudinal stiffness on the reference ground KXXref the second longitudinal stiffness being evaluated with aid of the transfer function F supplied with at least the influencing factors T1, P1, Z1 or the parameters Q2 and at least one characteristic thickness E0 of the tread,
• wherein the method further comprises acquisition of a scalar β1 defined with aid of the passage function β supplied with at least the influencing factors T1, P1, Z1, and
• wherein the thickness E of the tread is determined by a first relationship between the scalar β1, the first longitudinal stiffness KXXact and the second longitudinal stiffness KXXref as follows:
• E
• ⁢
• E
• =
• F
• 2
• -
• 1
• ⁡
• (
• F
• 2
• ⁡
• (
• E
• 0
• )
• *
• K
• xx
• act
• β
• 1
• *
• K
• xx
• ref
• )
• .