Complete air turbine starter containing simulation method based on wheel disc trisection fracture and non-simultaneous flying-out

Abstract

The invention discloses an air turbine starter complete machine containing simulation method based on wheel disc trisection fracture and non-simultaneous flying-out. The method comprises the steps that a finite element model of an air turbine starter complete machine is established; establishing a dynamic material model of a material for each key component of the air turbine starter by considering the strain rate; setting boundary conditions of the finite element model, the flying-out time of each wheel disc fragment and the rotating speed of a turbine disc, and according to the finite element model and the dynamic material model, carrying out air turbine starter complete machine containing simulation of wheel disc trisection fracture and non-simultaneous flying-out; and obtaining a wheel disc trisection fracture complete machine containing process according to a simulation result, and analyzing to obtain a damage process of each key component, a vibration response rule of each shell and a mounting seat, stress distribution and change conditions of each component, and a transmission process and an action rule of an impact load after the wheel disc trisection fracture. The whole machine containing capacity of the air turbine starter can be examined, the accuracy is high, and the reliability is good.

Description

Technical Field

[0001] The present invention relates to the field of air turbine starter containment detection, and in particular to an air turbine starter complete machine containment simulation method based on the non-simultaneous rupture and flying out of a wheel disc in three equal parts. Background Art

[0002] According to airworthiness standards, air turbine starters must undergo a full-machine containment test based on a three-part rotor disc breakage before obtaining airworthiness certification. This test is a crucial safety assessment item in air turbine starter airworthiness certification. The test requires that, within the entire flight envelope and at the maximum possible turbine speed, the fragments resulting from the three-part breakage of the air turbine starter's turbine rotor must be completely contained by the containment structure, and the resulting damage must not endanger flight safety. Furthermore, the sudden imbalance caused by the flying three-part rotor disc generates significant loads and vibration responses on the air turbine starter's mounting flanges and various connections, potentially causing further damage. Full-machine containment testing is the most representative test method and is typically conducted on a dedicated full-machine containment test bench. The test simulates the engine installation and is conducted under intake conditions that produce maximum speed to verify the effectiveness of the containment structure and ensure that it meets airworthiness requirements. Full-machine containment testing for air turbine starters is very costly, necessitating the development of a simulation method for air turbine starter containment. Currently, there is no comprehensive research on full-machine containment simulation for air turbine starters in China, and this work is the first of its kind in China. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this paper proposes a simulation method for the containment of an air turbine starter based on the non-simultaneous ejection of the three-part disc rupture, in accordance with the requirements of airworthiness verification of the containment of the air turbine starter. The specific technical solution is as follows:

[0004] A method for simulating the containment of an air turbine starter based on the non-simultaneous rupture and ejection of a three-part wheel disc comprises the following steps:

[0005] S1: Establish a finite element model of the air turbine starter, in which the air turbine starter is connected to the mounting base;

[0006] S2: Establish a dynamic material model of the materials used in each component of the air turbine starter considering the strain rate;

[0007] S3: Setting the boundary conditions of the finite element model, the flying time of each wheel disc fragment, and the turbine disc speed, and conducting a full-machine containment simulation of the air turbine starter with the wheel disc three-part fragments flying out non-simultaneously based on the finite element model and the dynamic material model;

[0008] S4: Based on the simulation results, the whole machine containment process of the wheel disc being divided into three parts is obtained. After the wheel disc is divided into three parts, the damage process of each key component, the vibration response law of each shell and mounting seat, the stress distribution and change of each component, and the transmission process and action law of the impact load are analyzed. The key components include: turbine disc, turbine shaft, containment ring, intake shell, exhaust shell, and reducer shell.

[0009] Furthermore, the S1 is specifically implemented through the following sub-steps:

[0010] S1.1: Divide the air turbine starter into components, including rotating components, load-bearing components, and transmission components. The rotating components include the turbine rotor, which includes a turbine disc, a turbine shaft, and turbine blades. The load-bearing components include a containment ring, a shear ring, an intake housing, an exhaust housing, a reducer housing, and bearings. The transmission components include planetary gears and an output shaft.

[0011] S1.2: Divide and store finite element meshes based on the structural characteristics of each component, and establish a finite element model of the entire air turbine starter.

[0012] Furthermore, in S1.2, hexahedral meshing is used for components with symmetrical structures, and the components with symmetrical structures include: a turbine disk, a turbine shaft, a containment ring, and an output shaft;

[0013] For components with relatively complex structures, tetrahedral mesh division is used. Components with relatively complex structures include: turbine blades, intake housing, exhaust housing, reducer housing, and bearings.

[0014] Furthermore, the S2 is specifically implemented through the following sub-steps:

[0015] S2.1: Identify the materials used for each component of the air turbine starter.

[0016] S2.2: Using the obtained material as the object, conduct dynamic tensile tests at different strain rates using a split Hopkinson tension bar to obtain the tensile stress-strain curves of the corresponding material at different strain rates, and integrate them to obtain the dynamic tensile stress-strain curves of the corresponding material. Simultaneously, conduct dynamic compression tests at different strain rates using a split Hopkinson compression bar to obtain the compressive stress-strain curves of the corresponding material at different strain rates, and integrate them to obtain the dynamic compressive stress-strain curves of the corresponding material.

[0017] S2.3: Analyze test data to determine the evolution of cumulative damage in the material. Use viscoplasticity theory to characterize the nonlinear mechanical response of the material. Use hydrostatic stress effects to characterize the tensile and compressive anisotropy of the material. Use flow laws to characterize the strain rate effect of the material.

[0018] S2.4: Establish a dynamic material model for the corresponding material based on its dynamic tensile stress-strain curve, dynamic compressive stress-strain curve, viscoplasticity theory, hydrostatic stress effect, and flow law.

[0019] Furthermore, S3 is specifically implemented through the following sub-steps:

[0020] S3.1: Set the boundary conditions of the finite element model according to the installation conditions of each component in the actual scenario;

[0021] S3.2: Set the flying time of each wheel disk fragment and the turbine disk speed, and perform simulation; the flying time of different wheel disk fragments is different.

[0022] Furthermore, in S3.1, the boundary conditions are specifically as follows: the mounting edge of the reducer housing is set as a fixed constraint, and the mounting edge of the intake housing is set as an axial constraint; the intake housing, the exhaust housing, and the reducer housing are connected by bolts, and automatic friction contact is set between the bolts and the bolt holes of each housing, and the end of the bolt is set to the internal thread on the corresponding housing as a rigid connection.

[0023] Furthermore, in said S4, according to the damage of each key component at different moments during the process of the wheel disc being divided into three equal parts and the whole machine being contained, the damage characteristics are analyzed to obtain the damage process of each key component;

[0024] Based on the simulation results of the whole machine containing the wheel three-division fracture, the vibration response of each shell and mounting base at different times after the wheel three-division fracture was obtained and the curves were plotted. The time sequence of the vibration peaks of different components was analyzed to obtain the vibration response pattern of each shell and mounting base.

[0025] Based on the simulation results of the whole machine containing the wheel three-division fracture, the stress distribution of each key component at different times after the wheel three-division fracture is obtained. The change pattern of the stress of each component over time is analyzed to obtain the stress distribution diagram. Based on the stress distribution diagram, the change of the maximum load in each component is analyzed to obtain the transmission process of the impact load.

[0026] Based on the simulation results of the whole machine containment when the wheel is divided into three equal parts, the damage conditions of the connecting components of each shell and the mounting seat are obtained after the wheel is divided into three equal parts. The damage characteristics of the connecting components are analyzed, and the transmission process of the impact load between the shell and the mounting seat is obtained, that is, the action law of the impact load is obtained.

[0027] The beneficial effects of the present invention are:

[0028] This paper proposes, for the first time, a simulation method for the containment of an air turbine starter. This method can reveal the vibration response of the entire engine when the three parts of the disc rupture and fly out non-simultaneously, the stress variations of each component over time, and the transmission path and action patterns of the impact load during the containment of the entire engine. The proposed simulation method is highly accurate and reliable, capable of assessing the containment capability of an air turbine starter, providing an effective method and theoretical support for solving the key technical challenges of airworthiness verification of the containment of an air turbine starter. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a flow chart of a method for simulating the containment of an air turbine starter based on the non-simultaneous rupture and ejection of a three-part wheel disc in an embodiment of the present invention.

[0030] Figure 2 It is a cross-sectional view of the finite element model of the air turbine starter established in an embodiment of the present invention.

[0031] Figure 3 Schematic diagram of a finite element model of a turbine rotor in an embodiment of the present invention.

[0032] Figure 4 1 is the damage deformation process of the containment ring obtained by simulation in an embodiment of the present invention, wherein (a) is the effective stress diagram of the containment ring at the initial moment, i.e., t=0, (b) is the effective stress diagram of the containment ring at t=0.03ms, (c) is the effective stress diagram of the containment ring at t=0.15ms, (d) is the effective stress diagram of the containment ring at t=0.3ms, (e) is the effective stress diagram of the containment ring at t=0.42ms, and (f) is the effective stress diagram of the containment ring at t=1.35ms.

[0033] Figure 5 1 is the damage deformation process of the turbine shaft simulated in an embodiment of the present invention, wherein (a) is the effective stress diagram of the turbine shaft at the initial moment, i.e., t=0, (b) is the effective stress diagram of the turbine shaft at t=0.03ms, (c) is the effective stress diagram of the turbine shaft at t=0.15ms, (d) is the effective stress diagram of the turbine shaft at t=0.3ms, (e) is the effective stress diagram of the turbine shaft at t=0.42ms, and (f) is the effective stress diagram of the turbine shaft at t=1.35ms.

[0034] Figure 6 Schematic diagram of the load transfer path after the impact of the three-divided wheel in the embodiment of the present invention.

[0035] Figure 7Schematic diagrams of the failure structure morphology of key components according to simulation and test results in an embodiment of the present invention, wherein (a) is a schematic diagram of the failure structure morphology of the containment ring according to simulation and test results, (b) is a schematic diagram of the failure structure morphology of the turbine disk according to simulation and test results, and (c) is a schematic diagram of the failure structure morphology of the turbine shaft according to simulation and test results.

[0036] In the figure, there are turbine rotor 1, turbine disk 1-1, turbine shaft 1-2, turbine blade 1-3; load-bearing component 2, containment ring 2-1, shear ring 2-2, intake housing 2-3, exhaust housing 2-4, reducer housing 2-5, front end bearing 2-6, rear end bearing 2-7; transmission component 3, planetary gear 3-1, output shaft 3-2. DETAILED DESCRIPTION

[0037] The present invention will be described in detail below based on the accompanying drawings and preferred embodiments. The purpose and effects of the present invention will become more apparent. The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention.

[0038] like Figure 1 As shown, a method for simulating the whole-machine containment of an air turbine starter based on the non-simultaneous rupture and ejection of a three-part wheel disc comprises the following steps:

[0039] S1: Build a finite element model of the air turbine starter. In this model, the air turbine starter is connected to a mounting base, which is used to connect the air turbine starter to other devices (such as the engine). This is achieved through the following sub-steps:

[0040] S1.1: Disassemble the air turbine starter into its components: rotating component 1, load-bearing component 2, and transmission component 3. The rotating component includes the turbine rotor 1 (including: turbine disk 1-1, turbine shaft 1-2, turbine blades 1-3). The load-bearing component 2 includes: a containment ring 2-1, a shear ring 2-2, a housing (including an intake housing 2-3, an exhaust housing 2-4, and a reducer housing 2-5), and bearings (including a front bearing 2-6 and a rear bearing 2-7). The transmission component 3 includes: a planetary gear 3-1 and an output shaft 3-2.

[0041] Among them, the key components include: turbine disc 1-1, turbine shaft 1-2, containment ring 2-1, intake housing 2-3, exhaust housing 2-4, and reducer housing 2-5.

[0042] S1.2: Based on the actual structure of the air turbine starter and the structural characteristics of each component, finite element meshing is performed and stored, and a finite element model of the air turbine starter is established, such as Figure 2In this embodiment, the total number of elements in the established finite element model is 1,741,112.

[0043] As one example, mesh encryption methods are categorized based on the structural characteristics of the components: Symmetrical components such as the turbine disk 1-1, turbine shaft 1-2, containment ring 2-1, and output shaft 3-2 are meshed using hexahedrons. Complex components such as the turbine blades 1-3 on the turbine disk 1-1, the intake housing 2-3, the exhaust housing 2-4, the reducer housing 2-5, the front bearing 2-6, the rear bearing 2-7, and the planetary gears 3-1 are meshed using tetrahedrons. To ensure the reliability of the calculation results, the containment ring 2-1, the intake housing 2-3, the exhaust housing 2-4, and the reducer housing 2-5 are meshed in at least two layers along the thickness direction.

[0044] The following are examples of how to divide finite element networks of some components and construct finite element models.

[0045] (1) The turbine rotor 1 is an integrated disc-shaft structure and is the main impact component. In order to simulate the three-part rupture situation, the integral turbine disc 1-1 was divided into three parts during the modeling process, and circumferential slots were set at the disc-shaft connection according to the three-part rupture theory and material failure criterion to ensure that the turbine disc 1-1 and the turbine shaft 1-2 maintain a common node integrated connection characteristic. After the rupture, the three-part turbine disc 1-1 flies out at a high speed, carrying high energy, and first hits the load-bearing components such as the casing and the containment ring 2-1. Therefore, a denser grid unit was used in the modeling. The finite element model of the turbine rotor 1 is shown in Figure 2. Figure 3 As shown: the turbine disk 1-1 adopts a hexahedral mesh with a unit size of 1 mm; the turbine blades 1-3 adopt a tetrahedral mesh with a unit size of 0.5 mm; the turbine shaft 1-2 adopts a tetrahedral mesh with a unit size of 3 mm.

[0046] (2) In the finite element model of the load-bearing component 2, the containment ring 2-1 is the main load-bearing component of the impact load. Its structure is mainly used to absorb the energy of the scattered broken turbine fragments. Since the structure of the containment ring 2-1 is a regular rotating body, a high-precision hexahedral mesh is used, and the unit size is set to 2mm. The intake housing 2-3 uses a tetrahedral mesh with a unit size of 1mm because of its complex structure and only bears the impact of a small amount of fragments. The exhaust housing 2-4 has a relatively complex structure and is circumferentially irregular. Therefore, the entire structure is modeled using a tetrahedral mesh with a minimum unit size of 1-2mm. The thin-walled annular body extending forward of the exhaust housing 2-4 is the first structure to be hit by the broken turbine. It is a regular rotating body and has a more important impact on the containment process. Therefore, a hexahedral mesh is used for modeling. The reducer housing 2-5 has a relatively small impact in the containment process. Therefore, a tetrahedral mesh is used for modeling. The overall unit size is large, with an average size of about 2mm. Smaller unit sizes are only used in individual detailed structures.

[0047] The multibody bearing model, consisting of balls, a cage, an inner race, and an outer race, effectively reflects the impact of turbine rotor 1's imbalance on vibration levels and critical speeds. Therefore, solid modeling was performed for the two key bearings supporting turbine rotor 1 (i.e., the primary load bearers of the turbine shaft: front bearing 2-6 and rear bearing 2-7). The inner and outer races, cages, and rolling balls of the bearings were realistically modeled and assigned realistic material parameters. Considering the bearing's structural characteristics, a combination of hexahedral and tetrahedral meshing was used for both bearing #1 (i.e., front bearing 2-6) and bearing #2 (i.e., rear bearing 2-7), with a minimum element size of 1 mm.

[0048] (3) In the finite element model of transmission component 3, according to its structural characteristics and functional requirements, the planetary gear 3-1 adopts a tetrahedral mesh with a unit size of 1 mm; the output shaft 3-2 adopts a hexahedral mesh with a unit size of 3 mm. This mesh configuration can more accurately reflect the structural characteristics and stress conditions of the output shaft.

[0049] S2: Establish a dynamic material model for each component of the air turbine starter, taking strain rate into account. This is achieved through the following sub-steps:

[0050] S2.1: Identify the materials used for each component of the air turbine starter.

[0051] S2.2: Using the materials identified in S2.1, conduct dynamic tension / compression tests at different strain rates using a split-Hopkinson tension / compression bar (SHTB / SHPB) to obtain the tensile / compressive stress-strain curves of the corresponding materials at different strain rates. These curves are then integrated to obtain the dynamic tensile / compressive stress-strain curves of the corresponding materials.

[0052] S2.3: Analyze test data to reveal the evolution law of cumulative damage of materials, use viscoplastic theory to characterize the nonlinear mechanical response of materials, use hydrostatic stress effect to characterize the tensile and compressive anisotropy of materials, and use flow law to characterize the strain rate effect of materials.

[0053] S2.4: Develop a dynamic material model for the corresponding material, combining its dynamic tensile / compressive stress-strain curves with viscoplasticity theory, hydrostatic stress effects, and flow laws.

[0054] In this embodiment, the materials used for various components of the air turbine starter adopt the JC dynamic constitutive model. The 10 material parameters in the JC dynamic constitutive model are obtained through dynamic material tests, as shown in Table 1 below.

[0055] Table 1 JC dynamic constitutive model parameters of the materials used in various components of the air turbine starter

[0056]

[0057] S3: Set the boundary conditions of the finite element model, as well as the ejection time and rotational speed of each disc fragment. Based on the above finite element model and dynamic material model, conduct a complete containment simulation of the air turbine starter with the disc three parts rupturing and ejecting non-simultaneously. This is achieved through the following sub-steps:

[0058] S3.1: Set Boundary Conditions. In a real-world installation scenario, the inlet flange of the air turbine starter's intake housing 2-3 is connected to the air supply intake duct via a clamp, while the flange of the reducer housing 2-5 is connected to the mounting bracket on the engine's accessory transmission gearbox via a clamp. The output shaft 3-2 is splined to the drive shaft within the accessory transmission gearbox. Bolts are used to connect the housings. Based on these real-world installation conditions, the boundary conditions for the finite element model are set as follows:

[0059] Reducer housing 2-5: Due to its large installation rigidity, the flange mounting edge of the reducer housing 2-5 is set as a fixed constraint to reflect its high rigidity support characteristics.

[0060] Intake housing 2-3: The connection between the intake housing 2-3 and the intake pipe mainly provides axial support. Therefore, its flange mounting edge is set as an axial constraint to simulate the actual support conditions.

[0061] Bolted connections: The intake housing 2-3, exhaust housing 2-4, and reducer housing 2-5 are connected by bolts. The bolts are modeled using solids, with automatic frictional contact established between the bolts and the housing bolt holes. The bolt ends connect to the corresponding internal threads on the housing, creating a rigid connection.

[0062] The above boundary conditions ensure the accuracy and realism of the model during the simulation process and reflect the constraints in the actual installation scenario.

[0063] S3.2: Set the ejection time and rotational speed of each disc fragment. Since the material properties of the turbine disc 1-1 are unlikely to be completely consistent at all locations, and the machining accuracy of the prefabricated grooves on the turbine disc 1-1 is unlikely to be exactly the same, the three parts of the actual turbine disc 1-1 will not eject simultaneously when broken. To ensure consistency between the simulation results and the actual situation, the three disc fragments are set to eject sequentially in the simulation. This setting is intended to simulate the sequential ejection of fragments during an actual rupture process, thereby more accurately analyzing the containment performance of the air turbine starter's containment ring 2-1 when faced with disc fragments of different ejection times. In this embodiment, the disc fragments are set to eject at intervals of 0.03ms, meaning the ejection times of the disc fragments are set to 0ms, 0.03ms, and 0.06ms, respectively.

[0064] In this embodiment, the rotation speed of the turbine rotor is set to 72000 r / min according to the maximum free running speed of a certain type of air turbine starter under certain working conditions.

[0065] S4: Based on the simulation test results, the damage process of each key component under the impact of the three-division wheel, the vibration response law of the shell and mounting seat, the impact load transmission process, and the impact load action law are obtained. The specific analysis process is as follows:

[0066] (1) Based on the simulation results, the containment process of the wheel three-division fracture was obtained, and the damage conditions of key components such as the containment ring 2-1, turbine shaft 1-2, shear ring 2-2 and bearing were analyzed; the damage characteristics of key components were analyzed based on the damage conditions, revealing the damage process of key components under the impact of the wheel three-division.

[0067] In this embodiment, the damage process of key components under the impact of the three-part disc is as follows: the turbine rotor 1 begins to fracture under centrifugal force, and the three-part turbine rotor 1 is ejected radially. The turbine rotor fragments first strike the shear ring 2-2, breaking it into approximately three equal parts. During this impact, the trajectory of the turbine rotor fragments changes. At t = 0.06 ms, the turbine rotor fragments strike the thin-walled annular body extending forward of the exhaust casing 2-4, causing it to severely deform. Simultaneously, the shaft end of the turbine rotor 1 deflects under the sudden unbalanced load. By t = 0.15 ms, the thin-walled annular body extending forward of the exhaust casing 2-4 begins to tear due to the impact of the turbine rotor fragments, and the tips of the turbine blades 1-3 begin to strike the containment ring 2-1. Simultaneously, the shaft end of the turbine rotor 1 exhibits significant bending deformation, and the inner ring of the front bearing 2-6 near the end of the turbine disc 1-1 is damaged by the compression of the turbine shaft 1-2. In the following period, turbine rotor fragments continued to fly radially, tearing the thin-walled annular ring extending forward from the exhaust casing 2-4 over a larger area and striking the containment ring 2-1. Turbine blades 1-3 suffered severe bending and torsion deformation or fracture. Due to the compression of turbine shaft 1-2, the inner ring of the front bearing 2-6 fractured and damaged, and the bearing retainer and outer ring also cracked. By t = 0.84 ms, the bent and deformed turbine shaft 1-2 began to turn, gradually bending vertically inward. The turbine rotor fragments became embedded between the guide and containment ring 2-1, until, at t = 1.26 ms, the bending direction became completely vertical and inward. By t = 2 ms, the impact process was essentially complete, with the three turbine rotor fragments converging at the axis center. Containment ring 2-1 did not pierce the entire impact process, indicating that its structure provided sufficient containment. At the same time, due to the turbine rotor 1's rupture, the impact and rebound from the containment ring 2-1, as well as the deflection of its trajectory caused by the impact with the shear ring 2-2, the turbine rotor fragments repeatedly rolled inside the containment ring 2-1 and struck the turbine guide at the rear end, causing varying degrees of damage to the guide's interior. Finally, some of the turbine rotor fragments flew out of the exhaust duct.

[0068] In order to analyze the damage characteristics of key components, the main impact process was taken as the analysis object, and only the structural stress distribution results under the critical state within 0-1.35ms were selected for display and analysis.

[0069] Figure 4The damage and deformation process of containment ring 2-1 at different time points is shown. As can be seen from the figure, turbine disk 1-1 begins to crack at t = 0.03ms and impacts containment ring 2-1 at t = 0.15ms. At this point, turbine blade 1-3 experiences varying degrees of bending, torsional deformation, and fracture damage. While the trisection of the turbine disk remains largely intact, some edges that collide with other load-bearing structures suffer impact damage, and their axial motion trajectory shifts. Containment ring 2-1 exhibits significant plastic deformation during the impact, with a noticeable bulge forming at the point of impact. Overall, containment ring 2-1 exhibits sufficient containment capacity with minimal radial deformation. Containment ring 2-1's original diameter is 94mm, and its maximum circumscribed diameter at the end of the impact reaches 97.47mm, with a deformation rate of 3.69%. This demonstrates that containment ring 2-1 effectively absorbs impact energy throughout the impact, maintaining its structural integrity and functionality.

[0070] Figure 5 The damage and deformation of the turbine shaft 1-2 during the rupture process are shown. As can be seen from the figure, during the rupture of the turbine disk 1-1, the turbine shaft 1-2 was subjected to a huge sudden unbalanced load. The unbalanced load caused a significant deflection at the end of the turbine shaft 1-2, and significant bending deformation occurred under the radial constraint of the supporting bearing. In addition, the material at the connection between the turbine disk 1-1 and the turbine shaft 1-2 broke under the action of the huge centrifugal force load, and rough burrs were formed at the fracture. These deformations and damages caused the turbine shaft 1-2 to bend during rotation, and the shaft head produced a significant rotational displacement in space. The continued rotation of the turbine shaft 1-2 further aggravated the impact on the surrounding structures and increased the overall stress of the system.

[0071] (2) At the same time, based on the simulation results of the whole machine containing the wheel disc being broken into three equal parts, the vibration response of the shell and the mounting seat after the wheel disc is broken into three equal parts is obtained, the vibration peak value and the corresponding time of the peak value of the starter shell and the mounting seat are obtained, the acceleration-time curve is drawn, and the time sequence of the peak value of the acceleration of different components is analyzed to obtain the vibration response law of the starter shell and the mounting seat.

[0072] (3) At the same time, the stress distribution of components such as the turbine disc 1-1, turbine shaft 1-2, bearings and starter housing at each moment after the wheel disc is broken into three equal parts is obtained, and the change law of the stress of each component with time is analyzed. The stress distribution diagram of each component at 6 moments (such as 0, 0.03, 0.06, 0.09, 0.12 and 0.15ms) during the impact process of the turbine rotor three-part fracture is selected, and the change of the maximum load in each component in the stress distribution diagram is analyzed to obtain the impact load transfer process.

[0073] In this embodiment, the stress distribution diagrams at six moments are analyzed as follows: When the turbine disk 1-1 flew off, the material at the connection between the turbine disk 1-1 and the turbine shaft 1-2 generated significant stress under the enormous centrifugal load, reaching the material's ultimate strength. When the turbine blade 1-3 struck the thin-walled annular body extending forward of the exhaust casing 2-4, the enormous impact load generated significant stress on the housing. As the impact intensified, the load on the inner housing extending forward of the exhaust casing 2-4 was transferred to the turbine guide vane and the intake casing 2-3 via the bolted connection structure. Simultaneously, due to the deflection of the disk's trajectory, some of the impact load was directly transferred to the intake casing 2-3 via the guide vane. Furthermore, after the deflected disk struck the shear ring 2-2, the load was transferred to the exhaust casing 2-4 via the shear ring base. When the turbine blade 1-3 shattered the thin-walled annular body extending forward of the exhaust casing 2-4 and impacted the containment ring 2-1, significant stress was generated on the containment ring 2-1, with some of the load also being transferred to the turbine guide vane and the intake casing 2-3 via the bolted connection structure. During the entire process, the impact load of the wheel causes the intake housing 2-3 to be axially displaced relative to the exhaust. Although the intake housing 2-3 and the exhaust housing 2-4 are fixed by long bolts to provide axial constraints, the intake housing 2-3 still gradually generates tensile stress in the axial direction.

[0074] (4) At the same time, the damage condition of the connecting parts between the shell and the mounting seat after the wheel disc is broken into three equal parts is obtained (the connection between the shell and the mounting seat is used to simulate the connection between the air turbine starter and the engine), the damage characteristics of the connecting parts are analyzed, and the transmission process of the impact load between the shell and the mounting seat is explored, that is, the action law of the impact load is revealed.

[0075] In this embodiment, Figure 6 Two primary load transfer paths are shown. In load transfer path 1, the centrifugal impact load generated by the rupture and ejection of turbine disk 1-1 first acts on the thin-walled annular ring extending forward of exhaust casing 2-4. Some of this load is then transferred to the outer wall of exhaust casing 2-4, but the majority of the load is directly transmitted to containment ring 2-1. Containment ring 2-1, in turn, transfers the load to the turbine guide vane and intake casing 2-3 via bolts.

[0076] For load transfer path 2, the radial unbalanced load generated by the rupture of the turbine disk 1-1 is mainly transmitted to the exhaust housing 2-4 through the two supporting bearing seats, and is transmitted to the flange edges of the reducer housing 2-5 and the intake housing 2-3 through the connecting screws of the three housings, and is finally transmitted to the test bench at the mounting seat and the pipe of the intake flange through the clamp connection.

[0077] At the same time, when the sun gear on turbine disk 1-1 on turbine shaft 1-2 breaks, the sudden unbalanced load causes severe deflection of turbine shaft 1-2. The radial unbalanced load from the deflection is further transmitted to the clutch assembly through transmission component 3, and ultimately to output shaft 3-2 through the clutch assembly. Analysis of these paths reveals the mechanisms by which different loads affect key components, providing important insights for system design optimization and fault prevention.

[0078] Finally, by comparing the actual whole machine containment test results with the simulation results of the present invention, the failure structure of each key component is as follows: Figure 7 shown.

[0079] like Figure 7 As shown in (a), the damage results of containment ring 2-1 from simulation and testing agree well. Compared to the original shape of containment ring 2-1, significant dents and deformations appear at locations I and II. These damages are caused by the first two turbine disk fragments that impacted containment ring 2-1. In contrast, the deformation at location III is smaller. This is because the impact energy of the third turbine disk fragment is lower, and when it impacted containment ring 2-1, containment ring 2-1 had already undergone significant elastic-plastic deformation, thus absorbing some of the impact energy. The figure also shows that a large number of fragments from the inner casing of the exhaust casing 2-4 protruding forward are attached to the inner wall of containment ring 2-1. Because the thin-walled annular body of the exhaust casing 2-4 protruding forward is made of cast aluminum alloy, these fragments were rapidly torn apart at the moment of disk rupture and embedded into the groove of containment ring 2-1 under the tremendous impact force. Containment ring 2-1 does not show any significant triangular deformation, indicating that it has a large containment margin.

[0080] like Figure 7 As shown in (b), the damage results of the turbine disk 1-1 from the simulation and the test are in good agreement. Compared to the original appearance of the turbine disk 1-1, the turbine disk 1-1 has shown impact damage on its edge, and the wheel structure has lost pieces and gaps. The turbine blades 1-3 on the turbine disk 1-1 have all shown some degree of bending, twisting, deformation, or fracture. Most of the turbine blades 1-3 have fallen off, with only a few damaged blades 1-3 remaining on the turbine disk 1-1.

[0081] like Figure 7 As shown in (c), the damage results of the turbine shaft 1-2 from the simulation and the test are in good agreement. Compared with the original form of the turbine shaft 1-2, fracture damage occurred on the joint surface between the turbine disk 1-1 and the turbine shaft 1-2. The non-simultaneous flying out of the three equally divided wheels resulted in a huge unbalanced load. The unbalanced load caused the shaft head to deflect significantly, which eventually led to obvious bending deformation at the step of the turbine shaft 1-2.

[0082] In summary, the damage results of key components of the simulation and test results are in good agreement, which proves that the method of the present invention is highly accurate, reliable and effective.

[0083] Those skilled in the art will understand that the foregoing descriptions are merely preferred embodiments of the invention and are not intended to limit the invention. Although the invention has been described in detail with reference to the foregoing examples, those skilled in the art will still be able to modify the technical solutions described in the foregoing examples or substitute equivalents for some of the technical features therein. Any modifications, equivalent substitutions, etc. made within the spirit and principles of the invention shall be included within the scope of protection of the invention.

Claims

1. A method for simulating the complete containment of an air turbine starter based on the non-simultaneous rupture of a three-part wheel disc and its ejection, characterized in that: The following steps are involved: S1: Establish a finite element model of the air turbine starter, in which the air turbine starter is connected to the mounting base; S2: Establish a dynamic material model of the materials used in various components of the air turbine starter considering the strain rate; S3: Setting the boundary conditions of the finite element model, the flying time of each wheel disc fragment, and the turbine disc speed, and conducting a full-machine containment simulation of the air turbine starter with the wheel disc three-part fragments flying out non-simultaneously based on the finite element model and the dynamic material model; S4: Based on the simulation results, the whole machine containment process of the wheel disc being divided into three parts is obtained. After the wheel disc is divided into three parts, the damage process of each key component, the vibration response law of each shell and mounting seat, the stress distribution and change of each component, and the transmission process and action law of the impact load are analyzed. The key components include: turbine disc, turbine shaft, containment ring, intake shell, exhaust shell, and reducer shell.

2. The method for simulating the complete containment of an air turbine starter based on the non-simultaneous rupture and ejection of a three-part wheel according to claim 1 is characterized in that: The S1 is specifically implemented through the following sub-steps: S1.1: Divide the air turbine starter into components, including rotating components, load-bearing components, and transmission components. The rotating components include the turbine rotor, which includes a turbine disc, a turbine shaft, and turbine blades. The load-bearing components include a containment ring, a shear ring, an intake housing, an exhaust housing, a reducer housing, and bearings. The transmission components include planetary gears and an output shaft. S1.2: Divide and store finite element meshes based on the structural characteristics of each component, and establish a finite element model of the entire air turbine starter.

3. The method for simulating the complete containment of an air turbine starter based on the non-simultaneous rupture and ejection of a three-part wheel according to claim 2 is characterized in that: In S1.2, hexahedral meshing is used for components with symmetrical structures, and the components with symmetrical structures include: turbine disk, turbine shaft, containment ring, and output shaft; For components with relatively complex structures, tetrahedral mesh division is used. Components with relatively complex structures include: turbine blades, intake housing, exhaust housing, reducer housing, and bearings.

4. The method for simulating the complete containment of an air turbine starter based on the non-simultaneous rupture and ejection of a three-part wheel disc according to claim 1 is characterized in that: The S2 is specifically implemented through the following sub-steps: S2.1: Identify the materials used for each component of the air turbine starter. S2.2: Using the obtained material as the object, conduct dynamic tensile tests at different strain rates using a split Hopkinson tension bar to obtain the tensile stress-strain curves of the corresponding material at different strain rates, and integrate them to obtain the dynamic tensile stress-strain curves of the corresponding material. Simultaneously, conduct dynamic compression tests at different strain rates using a split Hopkinson compression bar to obtain the compressive stress-strain curves of the corresponding material at different strain rates, and integrate them to obtain the dynamic compressive stress-strain curves of the corresponding material. S2.3: Analyze test data to determine the evolution of cumulative damage in the material. Use viscoplasticity theory to characterize the nonlinear mechanical response of the material. Use hydrostatic stress effects to characterize the tensile and compressive anisotropy of the material. Use flow laws to characterize the strain rate effect of the material. S2.4: Establish a dynamic material model for the corresponding material based on its dynamic tensile stress-strain curve, dynamic compressive stress-strain curve, viscoplasticity theory, hydrostatic stress effect, and flow law.

5. The method for simulating the complete containment of an air turbine starter based on the non-simultaneous rupture and ejection of a three-part wheel disc according to claim 1 is characterized in that: The S3 is specifically implemented through the following sub-steps: S3.1: Set the boundary conditions of the finite element model according to the installation conditions of each component in the actual scenario; S3.2: Set the flying time of each wheel disk fragment and the turbine disk speed, and perform simulation; the flying time of different wheel disk fragments is different.

6. The method for simulating the complete containment of an air turbine starter based on the non-simultaneous rupture and ejection of a three-part wheel disc according to claim 5 is characterized in that: In S3.1, the boundary conditions are specifically as follows: the mounting edge of the reducer housing is set as a fixed constraint, and the mounting edge of the intake housing is set as an axial constraint; the intake housing, the exhaust housing, and the reducer housing are connected by bolts, automatic friction contact is set between the bolts and the bolt holes of each housing, and the ends of the bolts are set as rigid connections with the internal threads on the corresponding housing.

7. The method for simulating the complete containment of an air turbine starter based on the non-simultaneous rupture and ejection of a three-part wheel disc according to claim 1 is characterized in that: In said S4, according to the damage of each key component at different times during the process of the wheel disc being divided into three equal parts and the whole machine being contained, the damage characteristics are analyzed. Obtain the damage process of each key component; Based on the simulation results of the whole machine containing the wheel three-division fracture, the vibration response of each shell and mounting base at different times after the wheel three-division fracture was obtained and the curves were plotted. The time sequence of the vibration peaks of different components was analyzed to obtain the vibration response pattern of each shell and mounting base. Based on the simulation results of the whole machine containing the wheel three-division fracture, the stress distribution of each key component at different times after the wheel three-division fracture is obtained, and the stress variation of each component over time is analyzed to obtain the stress distribution diagram; According to the stress distribution diagram, the change of the maximum load in each component is analyzed to obtain the transmission process of the impact load; Based on the simulation results of the whole machine containment when the wheel is divided into three equal parts, the damage conditions of the connecting components of each shell and the mounting seat are obtained after the wheel is divided into three equal parts. The damage characteristics of the connecting components are analyzed, and the transmission process of the impact load between the shell and the mounting seat is obtained, that is, the action law of the impact load is obtained.

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