CN-122024950-A - Calculation method and system for fatigue creep interaction coupling damage factor of material

CN122024950ACN 122024950 ACN122024950 ACN 122024950ACN-122024950-A

Abstract

The application discloses a method and a system for calculating a fatigue creep interaction coupling damage factor of a material, and belongs to the technical field of mechanical property testing and life prediction of materials. The method comprises the steps of obtaining alternating fatigue damage factors of a material in unit time under a stress amplitude of a fixed maximum stress and a fixed minimum stress, obtaining creep damage factors of the material in unit time under different constant holding stresses within a preset stress range, obtaining fatigue creep interaction fracture life of the material under holding time, and calculating the fatigue creep interaction coupling damage factors of the material based on the fatigue creep interaction fracture life, the alternating fatigue damage factors in unit time and the creep damage factors in unit time. The application obtains the coupling damage factor, quantifies the nonlinear interaction promotion effect between the fatigue load and the creep load retention by using the coupling damage factor, breaks through the limitation of the traditional linear accumulation damage theory and solves the problem that the coupling damage is difficult to quantify in the prior art.

Inventors

PENG WENYA
WANG YING
ZHAO CHUNLING
PEI HAONAN
LENG KUN
SU ZHIMIN
LI WEI

Assignees

中国航发湖南动力机械研究所

Dates

Publication Date: 20260512
Application Date: 20260113

Claims (10)

1. The method for calculating the fatigue creep interaction coupling damage factor of the material is characterized by comprising the following steps of: acquiring an alternating fatigue damage factor of a material in unit time under a stress amplitude of a fixed maximum stress and a fixed minimum stress; obtaining creep damage factors of the material in unit time under different constant holding stresses within a preset stress range; Acquiring the fatigue creep interaction fracture life of the material under the load-holding time; and calculating the fatigue creep interaction coupling damage factor of the material based on the fatigue creep interaction fracture life, the alternating fatigue damage factor in unit time and the creep damage factor in unit time.
2. The method for calculating a material fatigue creep interaction coupling damage factor according to claim 1, wherein the calculation formula of the material fatigue creep interaction coupling damage factor is as follows: Wherein N fc is fatigue creep interaction fracture life, D f is unit time alternating fatigue damage factor, t h is fixed load retention time, sigma is load retention stress, t is variable of load retention time, and D coupling is coupling damage factor; representing the creep damage factor as a function of the stress-time function sigma (t) for each cyclic loading stage; indicating the total creep damage integral over the material's entire fatigue creep interaction lifetime.
3. The method of calculating a material fatigue creep interaction coupling damage factor according to claim 1, wherein the predetermined stress range is bounded by the fixed maximum stress and the fixed minimum stress.
4. The method for calculating a material fatigue creep interaction coupling damage factor according to claim 1, wherein the alternating fatigue damage factor per unit time is calculated from alternating fatigue fracture life at a stress amplitude of a fixed maximum stress and a fixed minimum stress; The calculation expression of the fatigue damage factor is as follows: D f =1/N f wherein N f is the alternating fatigue fracture life under the stress amplitude of the fixed maximum stress and the fixed minimum stress, and D f is the alternating fatigue damage factor per unit time.
5. The method for calculating a material fatigue creep interaction coupling damage factor according to claim 1, wherein the creep damage factor per unit time is calculated according to creep rupture stress-life curves under different constant holding stresses within a preset stress range.
6. The method for calculating a material fatigue creep interaction coupling damage factor according to claim 5, wherein the calculation expression of the creep damage factor per unit time is as follows: D C(σ) =1/tr(σ) wherein tr (sigma) is a creep rupture stress-life curve under different constant holding stresses within a predetermined stress range, Is creep damage factor per unit time.
7. The method of calculating a material fatigue creep interaction coupling damage factor according to claim 1, wherein the fatigue creep interaction fracture life is obtained from a material fatigue creep interaction test having a fixed maximum stress, a fixed minimum stress and a fixed dwell time, wherein the fatigue creep interaction is a fatigue creep interaction in an up-dwell condition or a down-dwell condition.
8. The method for calculating a fatigue creep interaction coupling damage factor of a material according to claim 1, wherein the material is a metal material.
9. The method of calculating a material fatigue creep interaction coupling damage factor according to claim 1, wherein the coupling damage factor is used to quantify a nonlinear interaction between fatigue load and creep load retention.
10. A computing system for material fatigue creep interaction coupling damage factor, comprising: The database module is used for acquiring alternating fatigue damage factors of the material in unit time under the stress amplitude of the fixed maximum stress and the fixed minimum stress, acquiring creep damage factors of the material in unit time under different constant holding stresses within a preset stress range, and acquiring fatigue creep interaction fracture life of the material under the holding time; The calculation module is used for calculating the fatigue creep interaction coupling damage factor of the material based on the fatigue creep interaction fracture life, the alternating fatigue damage factor in unit time and the creep damage factor in unit time.

Description

Calculation method and system for fatigue creep interaction coupling damage factor of material Technical Field The application belongs to the technical field of material mechanical property test and life prediction, and particularly relates to a method and a system for calculating a material fatigue creep interaction coupling damage factor. Background In high temperature structural components such as aeroengines and gas turbines, metallic materials are often subjected to both cyclic loads (fatigue) and sustained static loads (creep). There is a strong interaction between fatigue and creep, significantly affecting the service life of the material. The current commonly used life prediction method is mostly based on linear accumulated damage criteria, such as Miner rule and Robinson rule, and under the fatigue-creep interaction working condition, the two are generally added together (D fatigue+ Dcreep =1) to be used as a failure criterion, and nonlinear coupling effect between fatigue and creep is not fully considered, so that the prediction result is deviated from conservation or unsafe. As disclosed in CN115691720a, a method for calculating creep fatigue damage under variable load history introduces a load interaction factor θ to consider the influence of a multi-stage load sequence, but the damage accumulation model is still linear in nature, and the prediction result is biased to be conservative or unsafe. Disclosure of Invention In order to solve the problems, the application provides a method and a system for calculating a fatigue creep interaction coupling damage factor of a material. A first object of the present application is to provide a method for calculating a fatigue creep interaction coupling damage factor of a material, comprising: acquiring an alternating fatigue damage factor of a material in unit time under a stress amplitude of a fixed maximum stress and a fixed minimum stress; obtaining creep damage factors of the material in unit time under different constant holding stresses within a preset stress range; Acquiring the fatigue creep interaction fracture life of the material under the load-holding time; and calculating the fatigue creep interaction coupling damage factor of the material based on the fatigue creep interaction fracture life, the alternating fatigue damage factor in unit time and the creep damage factor in unit time. In a specific embodiment of the application, the calculation formula of the fatigue creep interaction coupling damage factor of the material is as follows: Wherein N fc is fatigue creep interaction fracture life, D f is unit time alternating fatigue damage factor, t h is fixed load retention time, sigma is load retention stress, t is variable of load retention time, and Dcoupling is coupling damage factor; representing the creep damage factor as a function of the stress-time function sigma (t) for each cyclic loading stage; indicating the total creep damage integral over the material's entire fatigue creep interaction lifetime. In a specific embodiment of the present application, the preset stress range is defined by the fixed maximum stress and the fixed minimum stress. In a specific embodiment of the application, the unit time alternating fatigue damage factor is calculated according to the alternating fatigue fracture life under the stress amplitude of fixed maximum stress and fixed minimum stress; The calculation expression of the fatigue damage factor is as follows: Df=1/Nf wherein N f is the alternating fatigue fracture life under the stress amplitude of the fixed maximum stress and the fixed minimum stress, and D f is the alternating fatigue damage factor per unit time. In a specific embodiment of the application, the creep damage factor per unit time is calculated according to creep rupture stress-life curves under different constant holding stresses within a preset stress range. In a specific embodiment of the present application, the calculation expression of the creep damage factor per unit time is as follows: DC(σ)=1/tr(σ) wherein tr (sigma) is a creep rupture stress-life curve under different constant holding stresses within a predetermined stress range, Is creep damage factor per unit time. In a specific embodiment of the application, the fatigue creep interaction fracture life is obtained from a material fatigue creep interaction test having a fixed maximum stress, a fixed minimum stress and a fixed dwell time period, wherein the fatigue creep interaction is a fatigue creep interaction under either an up-dwell condition or a down-dwell condition. In a specific embodiment of the present application, the material is a metal material; The metal material is nickel-based superalloy. In a specific embodiment of the application, the coupling damage factor is used to quantify the nonlinear interaction between fatigue loading and creep retention. A second object of the present application is to provide a computing system for material fatigue creep interacti