Creep damage calculation method and model under variable load history

Abstract

The invention discloses a creep damage calculation method and model under variable load history. The method includes: acquiring the creep strain-time curve, minimum creep rate epsilon<c>m, fracture creep strain epsilon<c>f and fracture life tf of a material under different temperature and stress according to a uniaxial creep test; selecting a creep constitutive equation, and using uniaxial creep test fitting to obtain the creep constitutive parameters of the material; acquiring parameters A and B according to two simple two-stage variable load creep test data fitting; recording deformation increment generated by each stage of load according to the multi-stage variable load creep test of the material; calculating creep damaged generated of the n-1 stage before the multi-stage variable loadcreep test of the material; according to the variable load creep damage calculation model, if the acting time of the nth-stage load is known, predicting the deformation of the material under the nth-stage load, and if the nth-stage load is loaded until fracture occurs, predicting the acting time of the nth-stage load. The method can precisely consider the loading history.

Description

technical field [0001] The invention relates to a calculation method and model of creep damage under variable load history, and belongs to the technical field of high-temperature structural strength. Background technique [0002] During the development and use of aero-engines, life tests are usually required. With the continuous improvement of the life of aero-engines, the cost of 1:1 full life cycle test runs is getting higher and higher, and the cycle is getting longer and longer. It is even difficult in engineering. accept. In order to save money and shorten the development period, it is necessary to adopt the technology of accelerated task test run. During the test run of the acceleration task, it is necessary to simulate the load of the engine. It is classified according to the type of damage to the structure of the aero-engine, and the loads it bears mainly include low-cycle fatigue, thermal shock, creep and vibration. In order to shorten the test run time in the ac...

AI Technical Summary

Problems solved by technology

However, during the working process of the aero-engine, the creep load on the high-temperature components is not constant. Using the calculation method of creep damage under constant load, the results obtained will inevitably have large errors. It is necessary to establish a Creep damage calculation method provides effective support for accurate acceleration task test run spectrum preparation

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