CN-121980850-A - Optimization design method of continuous SiC fiber reinforced titanium-aluminum matrix composite fastener based on finite element method

CN121980850ACN 121980850 ACN121980850 ACN 121980850ACN-121980850-A

Abstract

The invention belongs to the technical field of composite material structural design and analysis, and particularly relates to an optimal design method of a continuous SiC fiber reinforced titanium-aluminum matrix composite material fastener based on a finite element method. The method simulates and optimizes the bearing capacity of the fastener at room temperature and high temperature by establishing a parameterized finite element model taking key parameters such as the diameter of a composite material core, a reinforcing scheme, the strength of the composite material and the like into consideration. The core lies in optimizing the diameter of the composite material core, the reinforcing scheme, the strength of the composite material and other key design parameters through finite element analysis so as to design the fastener with high bearing capacity. The invention can effectively shorten the research and development period, reduce the test cost and provide theoretical guidance for the performance prediction and process optimization of the fastener.

Inventors

JIA QIUYUE
WANG YUMIN
LI MUSHI
YANG RUI

Assignees

中国科学院金属研究所

Dates

Publication Date: 20260505
Application Date: 20251230

Claims (8)

1. The optimization design method of the continuous SiC fiber reinforced titanium aluminum matrix composite fastener based on the finite element method is characterized by comprising the following steps of: Establishing a parameterized finite element model, defining the geometric characteristics of a fastener, and defining the diameter (D_core) of a composite material core, the reinforcing scheme (R_core) of the composite material core in the longitudinal section of the fastener and the strength (sigma_b) of the composite material as key design variables; performing thermal-force coupling field finite element analysis, and simulating stress distribution of the composite material core and the sheath of the fastener under room temperature and high temperature tensile load; Thirdly, based on finite element analysis results, carrying out multi-objective optimization on the diameter (D_core), the reinforcing scheme (R_core) and the strength (sigma_b) of the composite material core by taking maximization of the tensile force of the fastener and minimization of the stress of the composite material core as optimization targets, and determining an optimal parameter combination; And step four, determining the final structure of the fastener according to the optimized design parameters, and guiding the actual preparation process.
2. The method of optimizing design of a continuous SiC fiber reinforced titanium aluminum matrix composite fastener based on finite element method according to claim 1, wherein in step one, the ratio of the diameter of the composite core (d_core) to the outer diameter of the fastener (d_outer) is optimized in the range of 0.25 to 0.75.
3. The method for optimizing design of continuous SiC fiber reinforced titanium aluminum matrix composite fasteners based on finite element method according to claim 1, characterized in that in step one, the reinforcement scheme (r_core) of the composite core is defined by the length of the composite core and the distance from the end, both types of exposed and embedded.
4. The method of optimizing design of a continuous SiC fiber reinforced titanium aluminum matrix composite fastener based on finite element method according to claim 1, wherein in step one, the composite strength (σ_b) is directly related to the fastener tensile force, the optimization range is 200MPa to 2200MPa, and as σ_b increases, the fastener tensile force increases in positive correlation.
5. The method for optimally designing a continuous SiC fiber reinforced titanium aluminum matrix composite fastener based on the finite element method according to claim 1, wherein in the first step, the continuous SiC fiber reinforced titanium aluminum matrix composite is SiC f /Ti 2 ainb or SiC f /Ti 3 Al composite, the composite is regarded as a transverse isotropic elastic material, and the titanium aluminum matrix is regarded as an elastoplastic material.
6. The method for optimally designing a continuous SiC fiber reinforced titanium aluminum matrix composite fastener based on a finite element method according to claim 1, wherein in the first step, the interface characteristics are simulated by Cohesive units or a strong interface model.
7. The method for optimizing design of continuous SiC fiber reinforced titanium aluminum matrix composite fasteners based on the finite element method according to claim 1, wherein in the second step, the high-temperature stretching behavior of the fastener chamber is simulated through finite elements, the high temperature is 800 ℃ and above, the stress distribution and the interface stress state of the composite core and the sheath are mainly analyzed, and the stretching force of the fastener is improved through optimizing the diameter, the position and the strength of the composite core.
8. The optimization design method of the continuous SiC fiber reinforced titanium aluminum matrix composite fastener based on the finite element method, which is characterized in that in the third step, the parameterized scanning, the genetic algorithm or the response surface method is adopted to carry out multi-parameter collaborative optimization, so that the maximization of the tensile force of the designed fastener under the action of the room high-temperature tensile load is ensured.

Description

Optimization design method of continuous SiC fiber reinforced titanium-aluminum matrix composite fastener based on finite element method Technical Field The invention belongs to the technical field of composite material structural design and analysis, and particularly relates to an optimization design method of a continuous SiC fiber reinforced titanium aluminum matrix composite material fastener based on a finite element method. Background The continuous SiC fiber reinforced titanium aluminum matrix composite material (such as SiC f/Ti2 AlNb or SiC f/Ti3 Al) combines the high specific strength and low thermal expansion coefficient of the SiC fiber and the excellent high-temperature performance of the titanium aluminum matrix, is an ideal high-temperature fastener material, can be used at more than 800 ℃ and can replace high-temperature alloy to realize remarkable weight reduction. However, its design faces challenges in that the tensile force of a composite "sandwich" structured fastener (with a composite reinforcing core inside and a titanium-aluminum-based alloy sheath outside) is highly dependent on the diameter of the composite core, its location in the fastener (reinforcing location), and the strength of the composite core, among other key parameters. If these parameters are improperly designed, they can result in: (1) The thermal expansion behavior is not ideal and the expected low expansion effect is not achieved. (2) The stress concentration at the root of the nut is that the nut and the screw are broken under the action of room temperature tensile load. (3) The screw thread bearing capacity is insufficient, namely the distance between the diameter of the composite material core and the minor diameter of the screw thread is too small, the screw thread bearing capacity is insufficient, and the composite material loses the reinforcing effect. (4) The interfacial shear force is too low, namely the high-temperature interfacial shear strength is low, and when the interfacial area between the composite material core and the sheath at the nut is too small, the interfacial shear force is lower than the tensile force of the fastener, so that the composite material core of the fastener can be pulled out at high temperature, and the tensile force is low. The patent of publication No. CN118768867A proposes a processing method of a monofilament SiC fiber reinforced Ti 2 AlNb composite material high-temperature fastener, the coaxiality of a composite material reinforced core and an outer sheath is ensured through reference positioning, the optimization of processing procedures and technological parameters is only involved, and a monofilament fiber system is adopted, so that the accurate matching of the tensile property cannot be realized through the regulation and control of design variables, and the performance bottleneck of a design level is difficult to solve. The patent of publication No. CN119640163A proposes a high-strength low-stress continuous SiC fiber reinforced Ti 3 Al composite material, a preparation method and application thereof, and the strength and stress state of the continuous SiC fiber reinforced titanium aluminum-based composite material are improved by introducing an interface layer and optimizing a matrix component, but the material is only concerned with the performance optimization of the material, so that the design key parameters of the characteristics of a sandwich structure (an inner composite material reinforced core and an outer titanium aluminum-based alloy sheath) of a fastener are difficult to adapt, and the bearing requirement of the fastener under a specific service condition cannot be met. The patent of publication No. CN120542146A proposes a finite element modeling method considering the fit clearance of a bolt, only the fit clearance of a general bolt is simulated, and a beam unit, a gap unit and the like are adopted to simulate the load and displacement of the bolt connection, so that the method is difficult to adapt to a specific material system of a continuous SiC fiber reinforced titanium aluminum matrix composite material, and cannot solve the special problems of non-ideal thermal expansion behavior, concentrated stress at the root of a nut, insufficient thread bearing capacity, excessively low interface shearing force and the like. In the prior art, the design of the fastener is mostly dependent on experience trial and error, and the cost is high and the period is long. Although the finite element method is used for composite material analysis, the macroscopic mechanical behavior is focused, and the system simulation and optimization of the correlation of key geometric and material parameters such as the diameter, the reinforcing scheme, the strength and the like of a composite material core and the tensile force of a fastener are lacked. Therefore, there is an urgent need for a method that can precisely quantify and optimize these critical design parameters. Disclosu