Nanjing University of Aeronautics and Astronautics

Yingdong Song

Xu Zhao

Xuming Niu

Guoqiang Yu

Xiguang Gao

Zhigang Sun

Yaning Chang

Qiuhong Peng

Sheng Zhang

Lu Zhang

Mofei Chen

Xiaoting Shi

Zheng Ni

Chao You

Chengqian Dong

Hongnian Dong

Chenyang Liu

Jinkang Du

Fangxiao Song

Chuyang Xie

Yunfa Jia

The present disclosure provides an optimized designing method for a laminate preform of a ceramic matrix composite e. With overall consideration of a strength requirement of a component, a geometric shape and properties of the laminate preform, the method includes: optimizing, based on a corresponding mechanical formula, a fiber volume fraction of each laminate constituting the preform and a fiber direction in the laminate, and selecting a preferred microscopic structure for each laminate, thereby taking full advantage of material performance. The method is applicable for optimized design of various components of the ceramic matrix composite.

Optimized designing method for laminate preform of ceramic matrix composite

Disclosed is a method for structural damage monitoring for whole-machine life test of small turboshaft engine, comprising: determining a failure mode based on load borne by typical components of the small turboshaft engine in a service process and common failure forms, screening a structural damage index of a non-major component based on a coupling relationship between structural damages, selecting a destructive damage of components in the small turboshaft engine and an indirect damage causing changes in material properties of key component, planning a structural damage monitoring means based on the failure mode, the structural damage index, the destructive damage, and the indirect damage, designing an accelerated mission test platform of the small turboshaft engine, and designing a torque automatic loading scheme of an eddy current dynamometer, and testing the small turboshaft engine, and performing damage monitoring of the small turboshaft engine based on the planned structural damage monitoring means.

Methods for structural damage monitoring for whole-machine life test of small turboshaft engines

A method is provided for calculating gaseous diffusion and oxidation evolution of a ceramic matrix composite (CMC) structure, which includes determining temperature and load distribution in a structural member; determining matrix crack distribution in the structure; establishing an equivalent diffusion coefficient model of a fiber bundle scale to predict a gas flow channel in a fiber bundle: averaging a total amount of gaseous diffusion in the channel to establish the equivalent diffusion coefficient model of the fiber bundle composite scale related to the matrix crack distribution; establishing a representative volume element (RVE) model; establishing an equivalent diffusion coefficient model of a RVE scale; calculating the distribution of the gas concentration and oxidation products in the structure; calculating a growth thickness of an oxide at cracks and pores in each element; and updating sealing conditions of the gas channel, and calculating a new equivalent diffusion coefficient field and the distribution of the oxidation products again.

Method for calculating gaseous diffusion and oxidation evolution of ceramic matrix composite (CMC) structure

Disclosed is an equivalent acceleration method of creep loads based on a consistent failure mode. The equivalent acceleration method includes obtaining corresponding tensile strengths; obtaining corresponding creep rupture time; establishing rupture time law, minimum creep rate law and rupture strain law; calculating the value of parameter p in creep damage accumulation model; and dividing the failure mode consistency interval of creep load under variable temperature and variable load. The damage caused by the creep load in the failure mode consistency interval is calculated by using the multi-grade variable temperature and variable load creep nonlinear damage accumulation model, the damage is accelerated to the maximum creep load state in the failure mode consistency interval according to the principle of damage equivalence, and finally the equivalent acceleration of creep load is realized.

Equivalent acceleration method of creep loads based on consistent failure mode

Disclosed is a method for compiling an equivalent acceleration spectrum of creep under variable temperatures and loads. The method includes following steps: respectively carrying out a material high-temperature tensile test, material high-temperature creep tests and creep tests under two-stage variable temperatures and loads, and calculating values of a parameter p in a creep damage accumulation model under two-stage variable temperatures and loads; based on a nonlinear damage accumulation model under multi-stage variable temperatures and loads, calculating a damage D caused by a multi-stage variable temperatures and loads creep load spectrum by utilizing values of parameter p; based on the principle of consistency of damage D, transforming the multi-stage variable temperatures and loads creep load spectrum into an equivalent acceleration spectrum of a first-order maximum creep load, and finally compiling the equivalent acceleration spectrum of creep under variable temperatures and loads.

Method for compiling equivalent acceleration spectrum of creep under variable temperatures and loads

A high-temperature biaxial strength tester for a CMC turbine vane includes a test stand, a thermal insulation box, a vane fixture, a biaxial loading device, thermocouples, a multi-channel thermometer, quartz lamps, a digital image correlation (DIC) system, and a cooling circulation system. The biaxial loading device includes two loading mechanisms arranged at 90&#xb0; to each other. Each of the two loading mechanisms includes an electric cylinder and a ceramic push rod. One end of the ceramic push rod is connected to the electric cylinder, and the other end of the ceramic push rod extends into the thermal insulation box to contact an outer platform of the CMC turbine vane. The electric cylinder is provided with a load-displacement sensor. The thermocouples are arranged on the thermal insulation box. The quartz lamps are arranged inside the thermal insulation box. The multi-channel thermometer is connected to the thermocouples.

High-temperature biaxial strength tester for ceramic matrix composite (CMC) turbine vane and test method thereof

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Nanjing, China

Yingdong Song