Method, apparatus and program product for predicting multiaxial fatigue life

Patent metadata

Field	Value
Publication number	US-12379293-B2
Application number	US-202017790999-A
Country	US
Kind code	B2
Filing date	Aug 4, 2020
Priority date	Jan 6, 2020
Publication date	Aug 5, 2025
Grant date	Aug 5, 2025

Abstract

A method for predicting a multiaxial fatigue life. The method includes: obtaining a first temperature rise value of a to-be-tested material in a first cycle; determining first inherent dissipation energy of the to-be-tested material in the first cycle according to the first temperature rise value and a time constant; and determining the multiaxial fatigue life of the to-be-tested material according to a first proportional value, the first inherent dissipated energy, axial fatigue test parameters and torsional fatigue test parameters; the first proportional value is a ratio of an axial strain amplitude to a torsional strain amplitude of a multiaxial fatigue test, the axial fatigue test parameters are configured to represent an axial fatigue resistance of the to-be-tested material, and the torsional fatigue test parameters are configured to represent a torsional fatigue resistance of the to-be-tested material.

First claim

What is claimed is:

1. A method for predicting multiaxial fatigue life, comprising:
obtaining a first temperature rise value of a to-be-tested material in a first cycle;
determining first inherent dissipated energy of the to-be-tested material in the first cycle according to the first temperature rise value and a time constant;
determining a multiaxial fatigue life of the to-be-tested material according to a first proportional value, the first inherent dissipated energy, axial fatigue test parameters and torsional fatigue test parameters; wherein the first proportional value is a ratio of an axial strain amplitude to a torsional strain amplitude of a multiaxial fatigue test, the axial fatigue test parameters are configured to represent an axial fatigue resistance of the to-be-tested material, and the torsional fatigue test parameters are configured to represent a torsional fatigue resistance of the to-be-tested material.

2. The method according to claim 1 , wherein the axial fatigue test parameters comprise an axial fatigue strength coefficient and an axial fatigue strength exponent, and the axial fatigue test parameters are obtained by:
performing an axial fatigue test on the to-be-tested material until fatigue failure occurs in the to-be-tested material, and determining an axial fatigue life of the to-be-tested material;
obtaining a second temperature rise value of the to-be-tested material in a second cycle;
determining second inherent dissipated energy of the to-be-tested material in the second cycle according to the second temperature rise value and the time constant; and
determining the axial fatigue strength coefficient and the axial fatigue strength exponent of the to-be-tested material according to the second inherent dissipated energy and the axial fatigue life.

3. The method according to claim 2 , further comprising:
stopping performing the axial fatigue test on the to-be-tested material after fatigue failure occurs in the to-be-tested material;
obtaining a first duration from fatigue failure occurring in the to-be-tested material to a surface temperature of the to-be-tested material reaching a preset temperature, and within the first duration, determining a corresponding relationship between the temperature rise values of the to-be-tested material and time according to the surface temperature of the to-be-tested material; and
determining the time constant according to the first duration and the corresponding relationship between the temperature rise and time.

4. The method according to claim 2 , wherein the torsional fatigue test parameters comprise a torsional fatigue strength coefficient and a torsional fatigue strength exponent, and the torsional fatigue test parameters are obtained by:
performing a torsional fatigue test on the to-be-tested material until fatigue failure occurs in the to-be-tested material, and determining a torsional fatigue life of the to-be-tested material;
obtaining a third temperature rise value of the to-be-tested material in a third cycle;
determining third inherent dissipated energy of the to-be-tested material in the third cycle according to the third temperature rise value and the time constant; and
determining the torsional fatigue strength coefficient and the torsional fatigue strength exponent of the to-be-tested material according to the third inherent dissipated energy and the torsional fatigue life.

5. The method according to claim 4 , wherein a formula for calculating the multiaxial fatigue life is:

N

f
,
p

=

(

1
-
k

)

D
A

·

d

1
,
cycle

1
/

L
A

+

k

D
T

·

d

1
,
cycle

1
/

L
T

wherein, N f,p is the multiaxial fatigue life, d 1, cycle is the first inherent dissipated energy, k is a weight coefficient, and k is a specific value is determined by the ratio of the axial strain amplitude to the torsional strain amplitude of the multiaxial fatigue test, D A is equivalent to the axial fatigue strength coefficient, D T is equivalent to the torsional fatigue strength coefficient, L A is equivalent to the axial fatigue strength exponent, and L T is equivalent to the torsional fatigue strength exponent.

6. The method according to claim 1 , wherein the torsional fatigue test parameters comprise a torsional fatigue strength coefficient and a torsional fatigue strength exponent, and the torsional fatigue test parameters are obtained by:
performing a torsional fatigue test on the to-be-tested material until fatigue failure occurs in the to-be-tested material, and determining a torsional fatigue life of the to-be-tested material;
obtaining a third temperature rise value of the to-be-tested material in a third cycle;
determining third inherent dissipated energy of the to-be-tested material in the third cycle according to the third temperature rise value and the time constant; and
determining the torsional fatigue strength coefficient and the torsional fatigue strength exponent of the to-be-tested material according to the third inherent dissipated energy and the torsional fatigue life.

7. The method according to claim 1 , wherein the determining the first inherent dissipated energy according to the time constant and the first temperature rise value comprises:
determining the first inherent dissipated energy according to the first temperature rise value, a second duration of the first cycle, the time constant, a density of the to-be-tested material and a specific heat capacity of the to-be-tested material.

8. The method according to claim 1 , wherein the axial fatigue test parameters comprise an axial fatigue strength coefficient and an axial fatigue strength exponent, the torsional fatigue test parameters comprise a torsional fatigue strength coefficient and a torsional fatigue strength exponent, and a formula for calculating the multiaxial fatigue life is:

N

f
,
p

=

(

Assignees

• Univ Hunan

Inventors

• Wang Xiaogang
• Jiang Chao
• Feng Ensheng

Classifications

• G01N2203/0073

  Fatigue · CPC title

• G01N2203/0008

  High frequencies from 10 000 Hz · CPC title

• G01N2203/0258

  Non axial, i.e. the forces not being applied along an axis of symmetry of the specimen · CPC title

• G01N2203/0021

  Torsional · CPC title

• G01N2203/0218

  Calculations based on experimental data · CPC title