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CN-122021182-A - Design method for thermal deformation regulation of complex cavity

CN122021182ACN 122021182 ACN122021182 ACN 122021182ACN-122021182-A

Abstract

The invention provides a design method for thermal deformation regulation of a complex cavity, which comprises the steps of establishing a three-dimensional geometric model of the complex cavity, determining a key fit clearance area, acquiring a residual stress field formed in the manufacturing process, introducing a thermal-force coupling finite element model as an initial stress condition, performing transient thermal-force coupling analysis under a wide temperature range temperature cycle boundary condition and an assembly constraint condition to obtain clearance evolution data of the key fit clearance in the whole temperature cycle process, setting a target stability interval or a target evolution function according to assembly precision or sealing, and selecting key structural parameters to establish a response relation between structural parameters and clearance evolution by identifying main influencing factors. According to the invention, coupling analysis of manufacturing residual stress and wide-temperature-range service thermal load is introduced in the structural design stage, and feedforward regulation and control of key fit gaps and active compensation design are realized through offset-driven compensation iteration, so that stability and reliability of a complex cavity fit interface in a wide-temperature-range environment are improved.

Inventors

  • LI WEI
  • SHANG LONG
  • FENG WEI
  • ZHANG TANTAN
  • GUO XUDONG

Assignees

  • 湖南大学

Dates

Publication Date
20260512
Application Date
20260318

Claims (10)

  1. 1. The design method for the thermal deformation regulation of the complex cavity is characterized by comprising the following steps of: step 101, establishing a three-dimensional geometric model of a complex cavity, and determining a key fit clearance area according to an assembly relation; 102, acquiring a residual stress field formed in the manufacturing process of the complex cavity, and introducing the residual stress field into a thermal-force coupling finite element model as an initial stress condition; Step 103, applying a wide temperature range temperature cycle boundary condition and an assembly constraint condition in the thermal-force coupling finite element model; 104, obtaining a structural response result of the complex cavity under the thermal-force coupling condition; Step 105, based on the structural response result, obtaining gap evolution data of the key fit gap in the whole temperature cycle process, and setting a target stability interval or a target evolution function of the key fit gap according to the assembly precision or the sealing/guiding performance requirement, wherein the target stability interval or the target evolution function is used for representing the gap permission change; step 106, performing mechanism decomposition on the change of the key fit clearance, obtaining clearance change components and/or contribution relations thereof caused by the release of manufacturing residual stress, thermal expansion and assembly constraint respectively through a split working condition calculation or equivalent decomposition mode, and identifying main influencing factors according to the clearance change components and/or contribution relations; Step 107, selecting structural parameters related to the main influencing factors as design variables, and establishing a response relation between the design variables and key fit clearance evolution data through thermal-force coupling finite element calculation and/or multiple groups of sample calculation for parameter disturbance on the design variables; 108, constructing a reverse thermal deformation compensation amount for counteracting the deviation by taking the deviation of the gap evolution data relative to the target stable interval or the target evolution function as a driving amount, wherein the reverse thermal deformation compensation amount is an equivalent compensation amount or an equivalent displacement compensation amount determined according to the gap deviation; Step 109, repeatedly executing steps 103 to 108 on the updated structural design scheme until the key fit clearance meets the preset convergence criterion of the target stability interval or the target evolution function within the full temperature range, and obtaining a structural parameter combination meeting the clearance stability; Step 110, under the constraint that the gap stability in step 109 meets the condition, constructing a multi-objective optimization model with structural quality and critical fit gap variation as optimization targets by taking non-critical structural parameters in the structural parameter combination as design variables, and obtaining candidate structural parameter combinations through multi-objective optimization calculation; And 111, under the condition of meeting structural performance constraint conditions, verifying and judging the candidate structural parameter combination based on the overall structural quality and the key fit clearance variation, determining the structural parameter allowable range, and realizing the thermal deformation regulation design of the complex cavity.
  2. 2. The method of claim 1, wherein the critical mating clearance area is a structural interface that forms a mating pair, a sealing pair, or a guiding pair in the complex cavity.
  3. 3. The method of claim 1, wherein the wide temperature range temperature cycle boundary condition is a multi-stage temperature change process simulating a complex cavity service environment, and the multi-stage temperature change process comprises a heating stage, a constant temperature maintaining stage and a cooling stage and is used for acquiring overall process evolution data of a key fit clearance.
  4. 4. The method of claim 1, wherein the residual stress field is the residual stress generated by the complex cavity during the forming, processing or assembling process, and is obtained by an experimental measurement method, a numerical simulation method, an inverse analysis calculation method or a data reconstruction method.
  5. 5. The method of claim 1, wherein the structural response result comprises at least one of a displacement response, a stress response, a contact response, or an energy response.
  6. 6. The method of claim 1, wherein the structural parameters are structural parameters affecting structural response of the complex cavity under thermo-mechanical coupling conditions, including cross-sectional dimension parameters, wall thickness distribution parameters, structural transition region geometry parameters, and hole layout parameters.
  7. 7. The method of claim 1, wherein the multi-objective optimization model of step 110 uses both structural mass and critical fit-clearance variations as optimization objectives or constraints.
  8. 8. The method of claim 1, wherein the multi-objective optimization calculation of step 110 is a calculation of a multi-objective optimization problem that solves for structure quality and critical fit clearance variations in an iterative manner.
  9. 9. The method of claim 1, wherein the mechanism decomposition is performed by calculating gap variation amounts under three conditions of applying only residual stress, applying only temperature cyclic load, and applying only load constraint, respectively, and deriving each component and coupling contribution thereof from the gap variation amounts of the three conditions.
  10. 10. The method of claim 1, wherein the reverse thermal deformation compensation is achieved by adjusting at least one of a local wall thickness distribution, a structural transition zone geometry, a pore layout parameter, or a mating interface initial geometry bias.

Description

Design method for thermal deformation regulation of complex cavity Technical Field The invention belongs to the field of complex cavity structure design, and particularly relates to a complex cavity thermal deformation regulation design method for wide-temperature-range service conditions. Background The complex cavity structure generally has the characteristics of limited space, high integration level of an internal channel, a plurality of precise matching interfaces and the like, and in structural design, the requirements of strength and rigidity are met, and the stability of a key matching gap is ensured. With the improvement of the light-weight level of the equipment, the problems of reduced wall thickness, uneven local rigidity distribution and the like of the complex cavity structure are increasingly outstanding, so that the complex cavity structure is more sensitive to thermal deformation and stress distribution change. During the manufacturing process, complex cavities are often subjected to forming, precision machining, assembly, and the like. The precision machining mode comprises electric spark machining, wire cutting machining, precision milling and other high-energy-density machining modes. In the processing process, because of the concentration of local heat input and the special material removal mode, uneven residual stress distribution is easy to form on the surface layer and the inside of the structure, and even the phenomenon of recast layer or tissue change is accompanied. The residual stress formed is difficult to completely release in the subsequent service stage. When the complex cavity bears the load actions such as wide temperature range temperature change, assembly constraint and the like in the service stage, residual stress formed in the manufacturing stage and the service thermal load are mutually overlapped, so that non-uniform thermal deformation and local stress concentration are easily caused, and further key fit clearance change, instability of a sealing interface or fit precision reduction are caused. The problems are particularly prominent in complex cavity systems with high multi-channel integration and a large number of key matching pairs. For example, in an electro-hydraulic actuator, a valve sleeve complex cavity used for precisely matching a valve core is in a wide temperature range working environment for a long time, and a residual stress field formed in a manufacturing stage and a thermal load in a service stage are mutually coupled to easily cause non-uniform thermal deformation and stress redistribution, so that the clearance fluctuation of a key matching interface is amplified, and the response precision and long-term service stability of a system are further affected. Existing complex cavity design methods focus on strength or stiffness analysis under single load conditions, or compensation by manufacturing stage dimensional corrections. Although some methods introduce thermo-mechanical coupling analysis, only critical fit clearances are generally evaluated as a result quantity, and the whole process evolution characterization and target stability interval setting of the critical fit clearances in the wide temperature range temperature cycle process are lacked. In addition, the existing method lacks a reverse thermal deformation compensation and iterative updating mechanism driven by gap deviation, and is difficult to realize feedforward regulation and active compensation design of gap stability in the structural design stage. Therefore, it is necessary to provide a design method for thermal deformation regulation of a complex cavity, so as to improve the stability of a key fit clearance and the service reliability of the complex cavity under the environment condition of wide temperature range. Disclosure of Invention Aiming at the problems that under the wide temperature range environment condition of a complex cavity, the key fit clearance changes, the stability of a sealing/guiding interface is reduced, the shape stability is insufficient and the like caused by the coupling effect of manufacturing residual stress and service thermal load, the invention provides a thermal deformation regulation design method of the complex cavity. The method comprises the steps of introducing a manufacturing residual stress field as an initial stress condition in a structural design stage, combining a wide temperature range temperature cycle load unfolding thermal-force coupling analysis to obtain overall process evolution data of a key fit gap in a temperature cycle process, further setting a target stability interval or a target evolution function of the key fit gap, constructing a reverse thermal deformation compensation quantity by taking gap deviation as a driving mode, realizing active compensation design of key fit gap stability through iterative updating, and carrying out two-stage multi-objective optimization on non-key structural parameters on the premise of meeting