CN112699465A

CN112699465A - ABAQUS-based multi-bolt connection knot building model method

Info

Publication number: CN112699465A
Application number: CN202011599346.XA
Authority: CN
Inventors: 郭轩; 张楠; 张引利
Original assignee: Xian Aircraft Design and Research Institute of AVIC
Current assignee: Xian Aircraft Design and Research Institute of AVIC
Priority date: 2020-12-29
Filing date: 2020-12-29
Publication date: 2021-04-23

Abstract

The invention belongs to the technical field of airplane structure modeling, and particularly relates to a multi-bolt connection structure modeling method based on ABAQUS. The method comprises the following steps: establishing a finite element model of the multi-bolt connection structure, wherein a bolt fastener is simulated at the bolt position through a BUSHING unit; obtaining a bolt load-displacement curve; and according to the bolt load-displacement curve, giving the rigidity and strength parameters of the bolt to the BUSHING unit.

Description

ABAQUS-based multi-bolt connection knot building model method

Technical Field

The invention belongs to the technical field of airplane structure modeling, and particularly relates to a multi-bolt connection structure modeling method based on ABAQUS.

Background

In aircraft structural engineering, the bolt connection is widely used for the assembly of aircraft parts. For complex aerospace structures, the number of bolt fasteners is often hundreds or thousands, and when numerical simulation is performed, if the real structure of the bolt is considered, the calculation cost is remarkably increased, and the problem of convergence occurs. In the past, a bolt structure is equivalent through a spring element, the spring element can only define the rigidity property of a unit, only can simulate the linear elasticity stage of the bolt connecting structure, cannot simulate the state of the bolt connecting structure after entering plasticity, and cannot simulate bolt damage and load redistribution.

Disclosure of Invention

The purpose of the invention is: a multi-bolt connection structure building method based on ABAQUS is designed, and a load distribution and force transmission path when the multi-bolt connection structure bears is determined through numerical simulation, so that reference is provided for engineering practice.

In order to solve the technical problem, the technical scheme of the invention is as follows:

a multi-bolt connection structure building method based on ABAQUS comprises the following steps:

establishing a finite element model of the multi-bolt connection structure, wherein a bolt fastener is simulated at the bolt position through a BUSHING unit;

obtaining a bolt load-displacement curve;

and according to the bolt load-displacement curve, giving the rigidity and strength parameters of the bolt to the BUSHING unit.

Establish many bolted connection structure's finite element model, pass through BUSHING unit simulation bolt fastener in the bolt position, include:

importing a bolt connection structure digital model into ABAQUS, establishing a finite element model, and determining a bolt connection position in the model;

and a BUSHING unit is established at the bolt connection position to connect all the components of the structure.

According to bolt load-displacement curve, give bolt rigidity and intensity parameter busHING unit, include:

obtaining elastic parameters, plastic parameters and breaking loads of the bolt under each displacement in a bolt load-displacement curve;

and endowing the elastic parameters, the plastic parameters and the breaking load of the bolt to the BUSHING unit to define the elastic rigidity, the plastic parameters and the breaking criterion of the BUSHING unit.

According to bolt load-displacement curve, give bolt rigidity and intensity parameter busHING unit, still include:

the area of influence of the BUSHING unit is defined as the radius of the bolt fastener.

After the bolt rigidity and strength parameters are given to the BUSHING unit according to the bolt load-displacement curve, the method further comprises the following steps:

applying a displacement boundary condition and a load boundary condition;

and carrying out verification calculation on the finite element model endowed with the parameters.

Establishing a finite element model of a multi-bolt connection structure, comprising:

and importing the three-dimensional model of the multi-bolt connection structure into ABAQUS, dividing the imported model into grids, and establishing a Bushing unit as a bolt fastener at the position of a bolt connection hole to connect the upper plate and the lower plate.

Coordinates of discrete points extracted from the bolt load-displacement curve are given to the BUSHING unit.

A computer readable storage medium having stored thereon computer instructions which, when executed by a processor, implement the above-described method.

Has the advantages that: the method can quickly and accurately establish the simplified finite element model of the bolt structure, thereby obtaining the external load response, the nail load distribution, the force transmission path and the like of the structure and providing reference for engineering design.

Drawings

The following detailed description of embodiments of the invention is provided in conjunction with the appended drawings, in which:

FIG. 1 is a three-dimensional digital model of a test piece;

FIG. 2 is a load-displacement curve of a single nail structure extrusion test;

FIG. 3 is a schematic diagram of a BUSHING unit;

Detailed Description

The invention provides a multi-bolt connection knot construction model method based on ABAQUS, which comprises the following steps:

step one, establishing a full-size finite element model, and simulating a bolt fastener at the bolt position through a BUSHING unit.

And step two, obtaining a bolt load-displacement curve through an extrusion test, and endowing the rigidity and strength parameters of the bolt to the BUSHING unit.

The first step is specifically as follows:

1. and (4) importing a bolt connection structure digital model into ABAQUS, and determining a bolt connection position.

2. And a BUSHING unit is established at the bolt connection position to connect all the components of the structure.

The second step is specifically as follows:

1. obtaining a bolt load-displacement curve through a single nail shear test, and obtaining the linear rigidity, the plasticity parameters and the failure criterion of the bolt in the curve;

2. and endowing the elastic parameters, the plastic parameters and the breaking load of the bolt to the BUSHING unit, and defining the elastic rigidity, the plastic parameters and the breaking criterion of the BUSHING unit.

3. The area of influence of the BUSHING unit is defined as the radius R of the bolt fastener.

4. Applying a displacement boundary condition and a load boundary condition.

The invention is adopted to establish a bolt connection simplified model by combining commercial finite element software ABAQUS, and the specific method of the finite element model is as follows:

1. importing a CATIA three-dimensional digital-analog (figure 1) into finite element modeling software ABAQUS;

2. outputting a model bolt point coordinate from a CATIA three-dimensional digital analog, and inputting the model bolt point coordinate into ABAQUS to establish a bolt connection point position;

3. the method is characterized in that a BUSHING unit is established, the BUSHING unit is a double-node unit, one node selects a bolt point on a connecting piece, the other node selects a bolt point on a connected piece, and by the method, the BUSHING unit can play a role of a bolt to connect two parts together (figure 2);

4. and obtaining a load-displacement curve (figure 3) through a standard extrusion test of the single-nail connection structure, and extracting the slope of a linear section of the curve, a coordinate point of a nonlinear section and a maximum load point of the curve.

5. Giving parameters to the BUSHING unit, wherein the elastic rigidity of the BUSHING unit is the slope of a linear section of a load-displacement curve, the plastic parameters are coordinate points of a nonlinear section of the load-displacement curve, software can automatically fit the coordinate points and give the fitted curve to the BUSHING unit, and the damage parameters are maximum load points obtained in the load-displacement curve;

6. giving the BUSHING unit an area of influence whose diameter is equal to the nominal diameter of the bolt (fig. 2);

7. repeating the steps 3-6 to simulate all bolt fasteners in the structure;

8. dividing the finite element model into grids, wherein structural members are all C3D8R solid units, and applying displacement and load boundary conditions according to the actual load distribution condition;

9. the calculation can obtain a simplified model of the bolt connection structure, and stress distribution, nail load distribution and the like can be checked in the result.

According to the modeling method, the bolt fastener is simulated through the BUSHING unit, and a simplified finite element model of the bolt connection structure is obtained. Through the power transmission path and the nail load distribution of the analysis structure, reference is provided for engineering design. The method aims at large-scale structures with more fasteners, and shortens the calculation time and reduces the calculation cost while ensuring the calculation accuracy.

Claims

1. A multi-bolt connection structure building method based on ABAQUS is characterized by comprising the following steps:

obtaining a bolt load-displacement curve;

2. The method of claim 1, wherein creating a finite element model of a multi-bolt joint structure, simulating bolt fasteners at bolt locations by a BUSHING unit, comprises:

3. The method of claim 1, wherein assigning bolt stiffness and strength parameters to the BUSHING unit according to a bolt load-displacement curve comprises:

4. The method of claim 3, wherein assigning bolt stiffness and strength parameters to the BUSHING unit according to a bolt load-displacement curve, further comprises:

5. The method of claim 1, wherein after assigning the bolt stiffness and strength parameters to the BUSHING unit according to the bolt load-displacement curve, the method further comprises:

applying a displacement boundary condition and a load boundary condition;

6. The method of claim 2, wherein establishing a finite element model of a multi-bolt connection structure comprises:

7. The method of claim 1, wherein coordinates of discrete points extracted from the bolt load-displacement curve are assigned to the BUSHING unit.

8. A computer-readable storage medium having computer instructions stored thereon, wherein the instructions, when executed by a processor, implement the method of any of claims 1-7.