CN-119885716-B - Gear structure strength reliability assessment method under multiple failure modes

CN119885716BCN 119885716 BCN119885716 BCN 119885716BCN-119885716-B

Abstract

The application provides a method for evaluating the reliability of the strength of a gear structure of an aircraft transmission system, which belongs to the technical field of evaluation of gear structures of the transmission system of the aircraft, and specifically comprises the steps of establishing a finite element model of the gear structure of the transmission system of the aircraft to obtain strength response parameters of the gear structure under the action of input load, establishing a probability model of relevant parameters of the gear structure according to a probability statistics theory, establishing a function of the gear structure based on strength failure, respectively establishing reliability function functions of the gear structure of the transmission system under each failure mode according to three failure modes of the gear structure and combining the strength failure function, namely obtaining failure areas of the gear structure under each failure mode, establishing a strength reliability analysis model of the gear structure of the transmission system by adopting a subset simulation method, and carrying out reliability analysis on the gear structure of the transmission system to obtain the failure probability of the system. By the processing scheme, the calculated amount can be reduced to a large extent, and the calculation efficiency is improved.

Inventors

NAN HUA
WANG XIAOJIE
BAI YANG
Dou Pengshan

Assignees

兰州万里航空机电有限责任公司

Dates

Publication Date: 20260508
Application Date: 20241212

Claims (5)

1. The method for evaluating the reliability of the structural strength of the gear in the multiple failure modes is characterized by comprising the following steps of: Step 1, establishing a finite element model of a gear structure of an aircraft transmission system to obtain strength response parameters of the gear structure under the action of input load ; Step 2, establishing a probability model of related parameters of the gear structure according to a probability statistical theory; Step 3, establishing a functional function of the gear structure based on strength failure In which, in the process, The permissible parameters of the materials chosen for the structure, The strength response parameter of the gear structure under the action of input load is as follows; Step 4, according to three failure modes of the gear structure and combining strength failure function functions, respectively establishing reliability function functions of the gear structure of the transmission system under failure modes of main stress caused strength failure, strain caused strength failure and shear stress caused strength failure 、 And ; Step5, obtaining failure areas of the gear structure under each failure mode, wherein the failure areas of the three failure modes are respectively failure areas under strength failure caused by main stress Failure zone under strain induced strength failure Failure zone under shear stress induced failure in strength ; Step 6, establishing a strength reliability analysis model of the gear structure of the transmission system by adopting a subset simulation method, and carrying out reliability analysis on the gear structure of the transmission system to obtain the failure probability of the system; The step 6 specifically includes: acquiring the total failure domain of a gear structure of a transmission system Is the sum of the failure zones in three modes: ; For failure domains Introduction of Is a series of critical values of (2) Constructing failure event with nested relation by introduced critical value , ; And (2) and According to the inclusion relation of the multiplication theorem and the event, the following failure probability calculation formula can be obtained: ; Order the , , ; Finally, the failure probability of the gear structure of the transmission system is obtained 。
2. The method for evaluating the reliability of the structural strength of a gear in multiple failure modes according to claim 1, wherein in said step 2, the structural parameters of the gear include the input load of the gear structure Thickness of (a) Tooth width Relative roughness of Modulus of elasticity ; Input load Thickness of (a) Tooth width Relative roughness of Modulus of elasticity Is the joint probability density function of (2) Wherein the load is input As the interval variable(s), 。
3. The method for evaluating the reliability of the strength of a gear structure in a multiple failure mode according to claim 2, wherein the function of the strength failure based gear structure in step 3 includes a random variable at the same time Sum interval variable The functional function of the gear structure based on strength failure is: ; Wherein, the Is the thickness of the gear structure , Is the tooth width of the gear structure , Is the relative roughness of the gear structure , Modulus of elasticity for gear structure , Input load for gear structure 。
4. A method for evaluating reliability of gear structure strength in multiple failure modes according to claim 3, wherein in step 4, the reliability functions of the gear structure of the transmission system in the three failure modes are respectively: The reliability function under the failure of strength failure caused by main stress is that ; The reliability function under the failure of strain-induced strength failure is that ; The reliability function under the failure of strength failure caused by shear stress is that 。
5. The method for evaluating reliability of structural strength of gears in multiple failure modes according to claim 4, wherein in said step 5: the failure areas of the three failure modes are respectively: failure zone under failure of principal stress induced strength failure ; Failure zone in strain induced strength failure ; Failure zone under shear stress induced failure in strength 。

Description

Gear structure strength reliability assessment method under multiple failure modes Technical Field The application relates to the field of gear structure evaluation of an aircraft transmission system, in particular to a gear structure strength reliability evaluation method under a multi-failure mode. Background Gears are critical components in an aircraft transmission system, the transmission system can be invalid due to the structural failure of the gears of the aircraft transmission system, the aircraft is in fault if the aircraft is light, and the tragic personnel death is caused if the aircraft is heavy. In order to prolong the service life and improve the flight safety, it is necessary to evaluate the reliability of the strength of the gear structure of the transmission system of the aircraft in multiple failure modes. The method for evaluating the reliability of the gear structure of the transmission system of the aircraft generally adopts a method combining theoretical analysis and calculation with Monte Carlo simulation. The strength of the gear structure is analyzed through theory, and then the failure probability is calculated directly through a Monte Carlo method, so that the reliability of the structure is estimated. The method has good effect on the single failure mode of the gear structure, but has the problems of long calculation time, narrow application range, difficult simulation of the coupling effect of the multiple failure modes and the like on the problem of the failure of the gear structure under the multiple failure modes. The reason for this is that the gear structure is complex and variable in failure. Therefore, there is a need for an improved method for evaluating the reliability of a gear structure in a conventional multiple failure mode. However, it should be noted that the probability model of the Monte Carlo simulation method has obvious superiority, but has strict requirements on the parameter statistical information quantity, and the cost and time for acquiring the data information of the objective uncertainty factor of the structural parameter are high for the gear structure of the transmission system, and the data are difficult to use due to the difference of materials and manufacturing processes. The information of the distribution density of the structural parameter information in the actual engineering problem is usually lacking, the requirement of the Monte Carlo simulation method on large sample size cannot be met, once the probability distribution assumption of the parameter is not matched with the actual situation, the structural reliability analysis by adopting a random model is meaningless, and obviously, the Monte Carlo simulation method cannot be considered for the small probability problem in the multiple failure modes. Disclosure of Invention In view of the above, the application provides a method for evaluating reliability of structural strength of a gear in a multiple failure mode, which solves the problems in the prior art, can reduce the calculated amount to a greater extent and improves the calculation efficiency. The application provides a gear structural strength reliability assessment method under a multiple failure mode, which adopts the following technical scheme: a method for evaluating the reliability of the structural strength of a gear in a multi-failure mode comprises the following steps: Step1, establishing a finite element model of a gear structure of an aircraft transmission system, and obtaining an intensity response parameter S of the gear structure under the action of an input load; Step 2, establishing a probability model of related parameters of the gear structure according to a probability statistical theory; step 3, establishing a functional function g= [ S ] -S of the gear structure based on strength failure, wherein [ S ] is an allowable parameter of a structural selected material; Step 4, according to three failure modes of the gear structure and combining strength failure function functions, respectively establishing reliability function g (x) of the gear structure of the transmission system under each failure mode: step 5, obtaining failure areas of the gear structure in each failure mode; And 6, establishing a strength reliability analysis model of the gear structure of the transmission system by adopting a subset simulation method, and carrying out reliability analysis on the gear structure of the transmission system to obtain the failure probability of the system. Optionally, in the step 2, the gear structure related parameters include an input load T, a thickness h, a tooth width b, a relative roughness f, and an elastic modulus E of the gear structure; The joint probability density function of the input load T, the thickness h, the tooth width b, the relative roughness f and the elastic modulus E is f (T, h, b, f, E), wherein the input load T is an interval variable, and T epsilon [ T 0,T1 ]. Optionally, the function of the g