CN115345059A - Method and system for predicting mixed connection strength of rubber and screw by considering damage of inserted pin - Google Patents

Method and system for predicting mixed connection strength of rubber and screw by considering damage of inserted pin Download PDF

Info

Publication number
CN115345059A
CN115345059A CN202211066562.7A CN202211066562A CN115345059A CN 115345059 A CN115345059 A CN 115345059A CN 202211066562 A CN202211066562 A CN 202211066562A CN 115345059 A CN115345059 A CN 115345059A
Authority
CN
China
Prior art keywords
damage
carbon fiber
fiber reinforced
composite material
reinforced composite
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202211066562.7A
Other languages
Chinese (zh)
Inventor
骆彬
王青松
张开富
索昊圆
任玉菲
邓力川
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Northwestern Polytechnical University
Original Assignee
Northwestern Polytechnical University
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Northwestern Polytechnical University filed Critical Northwestern Polytechnical University
Priority to CN202211066562.7A priority Critical patent/CN115345059A/en
Publication of CN115345059A publication Critical patent/CN115345059A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]
    • G06F30/20—Design optimisation, verification or simulation
    • G06F30/23—Design optimisation, verification or simulation using finite element methods [FEM] or finite difference methods [FDM]
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2113/00—Details relating to the application field
    • G06F2113/26—Composites
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2119/00—Details relating to the type or aim of the analysis or the optimisation
    • G06F2119/14—Force analysis or force optimisation, e.g. static or dynamic forces

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Evolutionary Computation (AREA)
  • Geometry (AREA)
  • General Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)

Abstract

The invention relates to a method and a system for predicting mixed glue and screw connection strength considering the damage of an inserted pin, which relate to the field of CFRP (carbon fiber reinforced plastics) connection, wherein the method comprises the steps of constructing a three-dimensional finite element model of the interference inserted pin of a mixed glue and screw connection structure made of a carbon fiber reinforced composite material according to tensile strength, shearing strength, the structure size, contact attributes, load and boundary conditions of the connection structure; based on the model, the type I fracture energy and the type II fracture energy, carrying out damage analysis according to contact stress among the interference bolt, the glue layer and the hole wall of the carbon fiber reinforced composite material, and determining a damage distribution and rigidity reduction model; constructing a tensile damage model of the carbon fiber reinforced composite material rubber-spiral mixed connection structure according to damage distribution; and carrying out stress analysis on the steel plate according to failure criteria and a rigidity reduction model to determine the tensile strength. The invention effectively analyzes and predicts the tensile strength of the CFRP rubber-screw mixed connection structure, and reduces the material cost and the preparation period of the test method.

Description

Method and system for predicting mixed connection strength of rubber and screw by considering damage of inserted pin
Technical Field
The invention relates to the field of CFRP (carbon fiber reinforced plastics) connection, in particular to a method and a system for predicting mixed connection strength of a glue bolt considering insertion nail damage.
Background
The rubber-screw hybrid connecting structure is generally used in the assembling process of the overall structure of the composite material, and the performance of the composite material is continuously and deeply studied in recent years, and the problem that the fatigue performance of the connecting structure can be improved and the bearing efficiency of a bolt in the rubber-screw hybrid connecting structure is low can be effectively improved by interference connection. However, the diameter of the shank of the interference bolt is larger than the diameter of the hole before installation, and the interference bolt needs to be installed by means of mechanical external force. Due to the low elongation and the non-uniformity of the composite material, the extrusion of the bolt causes damage to the hole wall of the composite material in different degrees along the axial direction and the circumferential direction, so that the contact relationship between the bolt and the hole wall is substantially changed; too large axial friction force and radial extrusion force also enable the stress concentration degree of the adhesive layer in the interference area to be high, and internal cohesive damage enables cracks to be accelerated to grow and expand under the action of external load, so that the connection structure fails prematurely.
It can be seen from the current state of research at home and abroad that the existing research on the installation process of the interference bolt connection structure mainly focuses on the damage form and stress distribution of the composite material, most of the research is mainly based on test methods, and the related research on performance degradation generated by the interference effect after the glue layer is cured and the influence on the bearing strength of the connection structure is relatively deficient. The finite element method is a method for researching the strength of a Carbon Fiber Reinforced Polymer/Plastic (CFRP) rubber-screw hybrid connection structure, however, in the prediction of the bearing strength of the related composite material connection structure, the damage to a connection part in the installation process of a fastener is ignored, particularly the stress concentration and the cohesive damage of the height of a rubber layer are not considered, so that the assembly contact relation between a bolt and the rubber layer and the hole wall is inaccurate, the stress field of the rubber layer and the hole wall of the composite material has an important influence on the tensile strength of the connection structure, and the existing prediction result is not accurate enough.
Disclosure of Invention
The invention aims to provide a method and a system for predicting the mixed glue and spiral connection strength by considering the damage of inserted nails, which are used for effectively analyzing and predicting the tensile strength of a mixed glue and spiral connection structure of a carbon fiber reinforced composite material and reducing the material cost and the preparation period of a test method.
In order to achieve the purpose, the invention provides the following scheme:
a method for predicting mixed connection strength of a rubber bolt by considering insertion nail damage comprises the following steps:
obtaining the tensile strength, the shear strength, the I-type fracture energy and the II-type fracture energy of the adhesive layer;
constructing a three-dimensional finite element model of the interference plug pin of the carbon fiber reinforced composite material rubber-screw mixed connection structure according to the tensile strength, the shear strength, the structure size of the connection structure, the contact property of the connection structure, the load of the connection structure and the boundary condition of the connection structure; the connecting structure comprises a carbon fiber reinforced composite material, the glue layer and an interference bolt; the contact attribute comprises a coefficient of friction;
based on the interference pin three-dimensional finite element model of the carbon fiber reinforced composite material rubber-screw mixed connection structure, the I-type fracture energy and the II-type fracture energy, performing damage analysis according to contact stress among the interference bolt, the rubber layer and the hole wall of the carbon fiber reinforced composite material, and determining a damage distribution and rigidity reduction model;
constructing a tensile damage model of the carbon fiber reinforced composite material rubber-spiral mixed connection structure according to the damage distribution;
and performing stress analysis on the tensile damage model of the carbon fiber reinforced composite material rubber-screw mixed connection structure according to failure criteria and the rigidity reduction model to determine the tensile strength.
Optionally, the obtaining of the tensile strength, the shear strength, the type I fracture energy, and the type II fracture energy of the glue layer specifically includes:
performing a tensile test on the adhesive layer to obtain tensile strength;
carrying out a shear test on the adhesive layer to obtain the shear strength;
performing a double cantilever beam test on the adhesive layer to obtain I-type fracture energy;
and carrying out a three-point bending test on the adhesive layer to obtain II-type fracture energy.
Optionally, the constructing a three-dimensional finite element model of the interference plug pin of the carbon fiber reinforced composite material rubber-screw hybrid connection structure according to the tensile strength, the shear strength, the structure size of the connection structure, the contact property of the connection structure, the load of the connection structure, and the boundary condition of the connection structure specifically includes:
constructing a three-dimensional geometric model according to the structure size of the connecting structure, the contact property of the connecting structure and the boundary condition of the connecting structure;
determining the displacement of the interference plug pins according to the load of the connecting structure;
determining the stress-strain constitutive relation of the carbon fiber reinforced composite material according to the tensile strength and the shear strength;
and constructing an interference plug pin three-dimensional finite element model of the carbon fiber reinforced composite material rubber-screw mixed connection structure according to the three-dimensional geometric model, the interference plug pin displacement and the stress-strain constitutive relation of the carbon fiber reinforced composite material.
Optionally, the interference pin three-dimensional finite element model based on the carbon fiber reinforced composite material rubber-screw hybrid connecting structure, the type I fracture energy, and the type II fracture energy, performing damage analysis according to contact stress among the interference bolt, the rubber layer, and a hole wall of the carbon fiber reinforced composite material, and determining a damage distribution and stiffness reduction model specifically includes:
performing stress analysis by adopting a secondary stress failure criterion according to a glue layer in the interference insertion nail three-dimensional finite element model of the carbon fiber reinforced composite material glue and screw mixed connection structure, and determining the damage condition of the glue layer; the damage condition comprises damage and non-damage;
when the damage condition of the glue layer is damage, determining the glue layer rigidity reduction in the rigidity reduction model according to the damage variable and the displacement of the glue layer;
determining damage distribution according to the type I fracture energy and the type II fracture energy;
performing stress analysis on the carbon fiber reinforced composite material in the interference plug pin three-dimensional finite element model of the carbon fiber reinforced composite material rubber-screw mixed connection structure by adopting a maximum stress criterion and a three-dimensional Haxin failure criterion to determine the damage condition of the carbon fiber reinforced composite material;
and when the damage condition of the carbon fiber reinforced composite material is damage, determining the rigidity reduction of the carbon fiber reinforced composite material in the damage rigidity reduction model according to the damage rigidity matrix.
A system for predicting the strength of a rubber-screw hybrid connection in consideration of the damage of a plug pin comprises:
the acquisition module is used for acquiring the tensile strength, the shear strength, the I-type fracture energy and the II-type fracture energy of the adhesive layer;
the interference plug pin three-dimensional finite element model building module of the carbon fiber reinforced composite material rubber and screw mixed connection structure is used for building an interference plug pin three-dimensional finite element model of the carbon fiber reinforced composite material rubber and screw mixed connection structure according to the tensile strength, the shearing strength, the structure size of the connection structure, the contact property of the connection structure, the load of the connection structure and the boundary condition of the connection structure; the connecting structure comprises a carbon fiber reinforced composite material, the glue layer and an interference bolt; the contact attribute comprises a coefficient of friction;
the damage analysis module is used for carrying out damage analysis according to contact stress among the interference bolt, the glue layer and the hole wall of the carbon fiber reinforced composite material based on the interference pin three-dimensional finite element model of the carbon fiber reinforced composite material glue and screw mixed connection structure, the I-type fracture energy and the II-type fracture energy, and determining damage distribution and a rigidity reduction model;
the carbon fiber reinforced composite material rubber and screw mixed connection structure tensile damage model building module is used for building a carbon fiber reinforced composite material rubber and screw mixed connection structure tensile damage model according to the damage distribution;
and the stress analysis module is used for carrying out stress analysis on the tensile damage model of the carbon fiber reinforced composite material rubber-screw mixed connection structure according to failure criteria and the rigidity reduction model to determine the tensile strength.
Optionally, the obtaining module specifically includes:
the tensile strength acquisition unit is used for carrying out a tensile test on the adhesive layer to obtain the tensile strength;
the shear strength acquisition unit is used for carrying out a shear test on the adhesive layer to obtain the shear strength;
the I-type fracture energy acquisition unit is used for carrying out a double cantilever beam test on the adhesive layer to obtain I-type fracture energy;
and the II-type fracture energy acquisition unit is used for carrying out a three-point bending test on the adhesive layer to obtain II-type fracture energy.
Optionally, the interference plug pin three-dimensional finite element model building module of the carbon fiber reinforced composite material rubber-screw hybrid connection structure specifically includes:
a three-dimensional geometric model construction unit for constructing a three-dimensional geometric model according to the structural size of the connection structure, the contact property of the connection structure, and the boundary condition of the connection structure;
the interference plug pin displacement determining unit is used for determining the interference plug pin displacement according to the load of the connecting structure;
the carbon fiber reinforced composite material stress-strain constitutive relation determining unit is used for determining the carbon fiber reinforced composite material stress-strain constitutive relation according to the tensile strength and the shearing strength;
the interference plug pin three-dimensional finite element model construction unit of the carbon fiber reinforced composite material rubber and screw mixed connection structure is used for constructing the interference plug pin three-dimensional finite element model of the carbon fiber reinforced composite material rubber and screw mixed connection structure according to the three-dimensional geometric model, the interference plug pin displacement and the carbon fiber reinforced composite material stress-strain constitutive relation.
Optionally, the damage analysis module specifically includes:
the damage condition determining unit of the adhesive layer is used for performing stress analysis according to a secondary stress failure criterion on the adhesive layer in the interference insertion nail three-dimensional finite element model of the carbon fiber reinforced composite material rubber-screw mixed connection structure, and determining the damage condition of the adhesive layer; the injury condition comprises the occurrence of injury and the non-occurrence of injury;
the glue layer rigidity reduction determining unit is used for determining glue layer rigidity reduction in the rigidity reduction model according to damage variables and glue layer displacement when the damage condition of the glue layer is damage;
a damage distribution determination unit for determining a damage distribution from the type I fragmentation energy and the type II fragmentation energy;
the damage condition determining unit is used for performing stress analysis on the carbon fiber reinforced composite material in the three-dimensional finite element model of the interference plug pin of the glue and screw mixed connection structure of the carbon fiber reinforced composite material by adopting a maximum stress criterion and a three-dimensional Harsin failure criterion to determine the damage condition of the carbon fiber reinforced composite material;
and the carbon fiber reinforced composite material rigidity reduction determining unit is used for determining the rigidity reduction of the carbon fiber reinforced composite material in the damage rigidity reduction model according to the damage rigidity matrix when the damage condition of the carbon fiber reinforced composite material is damage.
According to the specific embodiment provided by the invention, the invention discloses the following technical effects:
the method obtains the tensile strength, the shear strength, the I-type fracture energy and the II-type fracture energy of the adhesive layer; constructing a carbon fiber reinforced composite material rubber-screw mixed connection structure interference plug pin three-dimensional finite element model according to the tensile strength, the shear strength, the structure size of the connection structure, the contact property of the connection structure, the load of the connection structure and the boundary condition of the connection structure; based on the interference pin three-dimensional finite element model of the carbon fiber reinforced composite material rubber-screw mixed connection structure, the I-type fracture energy and the II-type fracture energy, performing damage analysis according to contact stress among the interference bolt, the rubber layer and the hole wall of the carbon fiber reinforced composite material, and determining a damage distribution and rigidity reduction model; constructing a tensile damage model of the carbon fiber reinforced composite material rubber-screw mixed connection structure according to the damage distribution; and carrying out stress analysis on the tensile damage model of the carbon fiber reinforced composite material rubber-screw mixed connection structure according to failure criteria and the rigidity reduction model to determine the tensile strength. The tensile strength of the carbon fiber reinforced composite material rubber-spiral mixed connection structure is effectively analyzed and predicted, and the material cost and the preparation period of the test method are reduced.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without inventive exercise.
FIG. 1 is a flow chart of a method for predicting the mixed connection strength of a glue bolt considering the damage of a plug pin in the practical application;
FIG. 2 is a schematic view of an interference plug pin structure according to the present invention;
FIG. 3 is a schematic diagram of a three-dimensional finite element model of an interference plug pin according to the present invention;
FIG. 4 is a schematic view of a nail pressing force-displacement curve in the interference nailing process according to the present invention;
FIG. 5 is a schematic drawing of a finite element model of a carbon fiber reinforced composite material rubber-screw hybrid connection structure considering the damage of a plug pin according to the present invention;
FIG. 6 is a schematic view of a tensile load-displacement curve provided by the present invention;
fig. 7 is a flowchart of a method for predicting the mixed connection strength of the glue bolt considering the damage of the inserted pin according to the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention aims to provide a method and a system for predicting the mixed glue and spiral connection strength by considering the damage of inserted nails, which are used for effectively analyzing and predicting the tensile strength of a mixed glue and spiral connection structure of a carbon fiber reinforced composite material and reducing the material cost and the preparation period of a test method.
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.
As shown in fig. 7, the method for predicting the mixed connection strength of the glue bolt considering the damage of the inserted pin provided by the invention comprises the following steps:
step 701: and obtaining the tensile strength, the shear strength, the type I fracture energy and the type II fracture energy of the adhesive layer.
Step 701 specifically includes: performing a tensile test on the adhesive layer to obtain tensile strength; carrying out a shear test on the adhesive layer to obtain shear strength; performing a double cantilever beam test on the adhesive layer to obtain I-type fracture energy;
and carrying out a three-point bending test on the adhesive layer to obtain II-type fracture energy.
Step 702: constructing a three-dimensional finite element model of the interference plug pin of the carbon fiber reinforced composite material rubber-screw mixed connection structure according to the tensile strength, the shear strength, the structure size of the connection structure, the contact property of the connection structure, the load of the connection structure and the boundary condition of the connection structure; the connecting structure comprises a carbon fiber reinforced composite material, the glue layer and an interference bolt; the contact attribute includes a coefficient of friction.
Step 702, specifically including:
constructing a three-dimensional geometric model according to the structure size of the connecting structure, the contact property of the connecting structure and the boundary condition of the connecting structure; determining the displacement of the interference plug pins according to the load of the connecting structure; determining the stress-strain constitutive relation of the carbon fiber reinforced composite material according to the tensile strength and the shear strength; and constructing a three-dimensional finite element model of the interference plug pin of the carbon fiber reinforced composite material rubber-screw mixed connection structure according to the three-dimensional geometric model, the interference plug pin displacement and the stress-strain constitutive relation of the carbon fiber reinforced composite material.
Step 703: and based on the interference insertion nail three-dimensional finite element model, the I-type fracture energy and the II-type fracture energy of the carbon fiber reinforced composite material rubber-screw mixed connection structure, performing damage analysis according to contact stress among the interference bolt, the rubber layer and the hole wall of the carbon fiber reinforced composite material, and determining a damage distribution and rigidity reduction model.
Step 703 specifically includes:
performing stress analysis by adopting a secondary stress failure criterion according to a glue layer in the interference plug pin three-dimensional finite element model of the carbon fiber reinforced composite material glue and screw mixed connection structure, and determining the damage condition of the glue layer; the injury condition includes the occurrence of injury and the absence of injury.
And when the damage condition of the glue layer is damage, determining the glue layer rigidity reduction in the rigidity reduction model according to the damage variable and the displacement of the glue layer.
And determining the damage distribution according to the type I fracture energy and the type II fracture energy.
And performing stress analysis according to the maximum stress criterion and the three-dimensional Harbin failure criterion of the carbon fiber reinforced composite material in the three-dimensional finite element model of the interference plug pin of the carbon fiber reinforced composite material rubber-screw mixed connection structure, and determining the damage condition of the carbon fiber reinforced composite material.
And when the damage condition of the carbon fiber reinforced composite material is damage, determining the rigidity reduction of the carbon fiber reinforced composite material in the damage rigidity reduction model according to the damage rigidity matrix.
Step 704: and constructing a tensile damage model of the carbon fiber reinforced composite material rubber-screw mixed connection structure according to the damage distribution.
Step 705: and performing stress analysis on the tensile damage model of the carbon fiber reinforced composite material rubber-screw mixed connection structure according to failure criteria and the rigidity reduction model to determine the tensile strength.
In order to overcome the defects that the actual stress state and damage distribution of a glue layer after the installation of an interference bolt is neglected by the conventional prediction method, and the accurate contact relation between the bolt and the glue layer and between the bolt and a composite material hole wall cannot be established, the invention provides a concrete treatment process of a glue-screw mixed connection strength prediction method considering the damage of an inserted pin in practical application.
As shown in FIG. 1, in the embodiment, ERGO7200 structural adhesive and T700/TED-85 carbon fiber reinforced composite material (the layering sequence is [0/45/-45/90 ]] 3s ) And Ti6Al4V bolt material as an example, provides a glue bolt mixed connection strength prediction method considering the damage of inserted pins, which considers the damage of inserted pins and comprises the following steps:
1. respectively carrying out a tensile test, a shear test, a double cantilever beam test and a three-point bending test on a glue layer sample to obtain the tensile strength, the shear strength, the I-type fracture toughness and the II-type fracture toughness of the glue layer, and establishing a glue layer bilinear cohesion constitutive model,
1.1 tensile test was carried out to obtain the normal tensile strength in accordance with the requirements of ASTM-D2095
Figure BDA0003827876250000081
Specifically, a sample with the length of 40mm and the width of 13mm is designed, the sample is glued in a centering way, the thickness of a glue layer is 12mm, a tensile test is carried out, the limit load is 1248N, and therefore the tensile strength of the glue layer is obtained
Figure BDA0003827876250000082
Is 8MPa.
1.2 tensile test to obtain the shear Strength according to the requirements of ASTM-D3165
Figure BDA0003827876250000083
And
Figure BDA0003827876250000084
specifically, a sample with the length of 190.5mm and the width of 25mm is designed, the upper part and the lower part are glued, and the area of a lap joint area is 343mm 2 And carrying out a shear test to obtain the ultimate load of 6174N, so that the two shear strengths of the rubber layer
Figure BDA0003827876250000085
And
Figure BDA0003827876250000086
is 18MPa. The maximum tensile and shear strength allowed by the bond line is obtained in step 1.1 and step 1.2.
1.3 according to HB 7402-96 test standard and HB 7403-96 test standard, carrying out double cantilever beam test and three-point bending test, and obtaining the results from formula (1) and formula (2)
Figure BDA0003827876250000091
Carrying out double cantilever beam test to obtain I-type fracture energy of the adhesive layer
Figure BDA0003827876250000092
Performing three-point bending test to obtain II-type fracture energy of the adhesive layer
Figure BDA0003827876250000093
The calculation formula is as follows:
Figure BDA0003827876250000094
Figure BDA0003827876250000095
wherein:
Figure BDA0003827876250000096
Figure BDA0003827876250000097
wherein, P I 、P II Is an external load; a is the crack length of the adhesive layer; χ is a correction coefficient of the crack length; h is the thickness of the adhesive layer; b is the width of the adhesive layer sample; e 11 Is the elastic modulus of the glue layer in the x direction; e 22 The elastic modulus of the glue layer in the y direction; g 13 The shear modulus in the plane of the glue layer xoz is shown, and gamma is an intermediate parameter.
The bilinear stress-strain constitutive model of the adhesive layer meets the following expression:
[t n t s t t ] T ＝K[δ n δ s δ t ] T (5)
Figure BDA0003827876250000098
wherein K is a glue layer rigidity matrix, t n 、t s 、t t The stress components of the adhesive layer in the normal direction and the two shearing directions are respectively; k is n 、K s 、K t The stiffness of the bond line normal and the two shear directions, respectively, are known, with the two shear directions being the stiffness of the bond line 13 and 23 directions; delta n 、δ s 、δ t The relative displacement components of the glue layer in the normal direction and the two shearing directions are respectively, and the parameters are shown in table 1:
TABLE 1 bond line Material parameters
Figure BDA0003827876250000099
Figure BDA0003827876250000101
Type III energy to failure
Figure BDA0003827876250000102
Effective measurement cannot be obtained through experiments, and the measurement is usually carried out
Figure BDA0003827876250000103
2. According to the structural dimensions, contact properties, loads and boundary conditions of the carbon fiber reinforced composite material, the adhesive layer and the interference bolt, establishing a three-dimensional finite element model of the interference insert pin of the carbon fiber reinforced composite material rubber-bolt mixed connection structure by using ABAQUS finite element software, and establishing a stress-strain constitutive relation of the carbon fiber reinforced composite material. And the tensile strength and the shear strength obtained in the step one provide parameter input for the glue layer model in the step two.
2.1ASTM D-5961 shows the structure as shown in FIG. 2, with the dimensional parameters as shown in Table 2, with (a) in FIG. 2 being a schematic illustration of the glue line structure, (b) in FIG. 2 being a schematic illustration of the interference bolt structure, and (c) in FIG. 2 being a schematic illustration of the carbon fiber composite laminate structure. The three-dimensional geometric models of the carbon fiber reinforced composite material, the glue layer and the bolt are established by using ABAQUS software, as shown in figure 3. The ABAQUS software was used to build three-dimensional geometric models of carbon fiber reinforced composites, bondlines and bolts according to the requirements in ASTM D-5961. Because the length of the bolt polished rod is larger than the thickness of the laminated layer of the connecting structure, the threaded part is ignored, the bolt is simplified into a T-shaped solid model, the parameters of the T-shaped solid model are shown in the table 3, and the identification names of the three-dimensional geometric models are set. Setting the identification name of the glue layer as ADHESIVE-1; the identification names of the carbon fiber reinforced composite materials are PLANE-1 and PLANE-2; the identifying name of the BOLT is BOLT-1.
TABLE 2CFRP rubber-screw hybrid connection structure size parameters
Figure BDA0003827876250000104
L a 、W a 、e a 、r a The width, length, distance from the center of the hole to one end and radius of the glue layer are respectively, R is the diameter of the bolt, L is the diameter of the bolt p 、W p 、e p And r are the length, width, hole center to end distance and radius, respectively, in mm, of the CFRP laminate.
TABLE 3Ti6Al4V bolt Material parameters
Figure BDA0003827876250000105
E is the modulus of elasticity of the bolt and V is the Poisson's ratio.
2.2 set up the biggest tensile strength, shear strength and I type, II type fracture energy of glue film in attribute module to establish bilinear stress-strain constitutive model, the glue film adopts cohesion unit COH3D8, and carbon fiber reinforced composite and bolt adopt reduction integral hexahedron unit C3D8R, and set up the hourglass control of reinforcing in order to reduce the grid distortion.
2.3 in the assembly, the glue layer and the upper and lower composite laminated plates are bound and restrained by using the surface and the surface, friction relations are respectively established between the bolt and the glue layer and between the bolt and the carbon fiber reinforced composite material, a main surface and a secondary surface are defined, and friction coefficients and hard contact are added in contact properties.
2.4 limiting the degrees of freedom of the carbon fiber reinforced composite material and the base in 3 moving directions and the degrees of freedom in 3 rotating directions according to real test conditions, and limiting the bolt to remove 5 degrees of freedom of movement in the z direction; an interfering plug displacement is established in the load module. Wherein, the displacement of the interference plug pin is 8.5mm.
2.5, establishing a stress-strain constitutive relation of the carbon fiber reinforced composite material, wherein the carbon fiber reinforced composite material is modeled into a transverse isotropic material, and the stress-strain constitutive relation can be expressed as follows:
Figure BDA0003827876250000111
wherein:
C 11 ＝E 11 (1-v 23 v 32 )/Δ (8)
C 22 ＝E 22 (1-v 13 v 31 )/Δ (9)
C 33 ＝E 33 (1-v 12 v 21 )/Δ (10)
C 12 ＝E 11 (v 21 +v 31 v 23 )/Δ (11)
C 23 ＝E 22 (v 32 +v 12 v 31 )/Δ (12)
C 13 ＝E 11 (v 31 +v 21 v 32 )/Δ (13)
C 44 ＝2G 12 (14)
C 55 ＝2G 23 (15)
C 66 ＝2G 13 (16)
Δ＝1/(1-v 12 v 21 -v 23 v 32 -v 13 v 31 -2v 21 v 32 v 13 ) (17)
in the formula, σ n 、σ t Respectively, normal stress component (σ) 11 、σ 22 、σ 33 ) And a shear stress component (σ) 12 、σ 13 、σ 23 )；ε n 、ε t Respectively, normal strain component (epsilon) 11 、ε 22 、ε 33 ) And a shear strain component (ε 12 、ε 13 、ε 23 )；C ij ＝C ji (i, j =1,2.. 6); and C ij Is the stiffness coefficient.
E 1 、E 2 、E 3 Is the elastic modulus, G, of a carbon fiber-reinforced composite material 12 、G 13 、G 23 V12, v13 and v23 are Poisson ratios of the carbon fiber reinforced composite material, wherein the corner marks 12, 13 and 23 respectively represent the 12 direction, 13 direction and 23 direction of the carbon fiber reinforced composite material; and v is ij ＝v ji (i, j =1, 2.. 6). Δ is an intermediate variable.
The T700/TED-85 carbon fiber reinforced composite parameters are shown in Table 4.
TABLE 4T700/TED-85 Material parameters and Strength
Figure BDA0003827876250000121
X T Is the tensile strength of the fibre, X C As fiber compressive strength, Y T In-plane matrix tensile Strength, Y C Is the in-plane matrix compressive strength, Z T Out-of-plane matrix tensile strength, Z C Out-of-plane matrix compressive strength, S 12 、S 13 、S 23 The shear strength is in MPa.
3. And (3) combining the three-dimensional finite element model in the second step, and adopting corresponding material failure criteria to perform damage analysis on each adhesive layer and each carbon fiber reinforced composite unit according to the contact stress between the bolt and the adhesive layer and the wall of the composite hole, so as to judge whether the units are damaged. If the material is damaged, adopting a corresponding rigidity reduction model to reduce the rigidity of the current material, and updating the stress; if intact, the cell stiffness remains unchanged.
3.1, carrying out stress analysis on the adhesive layer unit, and judging whether the adhesive layer unit is damaged by adopting a secondary stress failure criterion, wherein the criterion is as follows:
Figure BDA0003827876250000122
in the formula, symbol<>In mecolli brackets, the compressive load did not cause damage to the glue line.
Figure BDA0003827876250000123
And
Figure BDA0003827876250000124
the normal tensile strength of the adhesive layer and the shear strength in the 13 direction and the 23 direction are respectively; t is t n 、T s 、t t The current normal stress of the glue layer under tensile load and the shear stress in the directions 13 and 23 are respectively. If Fa is more than or equal to 1, the glue layer unit is damaged; if F a And (5) the glue layer unit is not damaged.
3.2 if the glue layer unit is damaged and cracks are generated, adopting a mixed mode B-K rule based on fracture toughness to predict the comprehensive expansion action of three crack forms:
Figure BDA0003827876250000131
G T ＝G I +G II (20)
in the formula (I), the compound is shown in the specification,
Figure BDA0003827876250000132
type I and type II fracture energy respectively; g I 、G II Respectively representing the current type I fracture energy and the current type II fracture energy;
Figure BDA0003827876250000133
is the total energy to break; g T The total fracture energy is the sum of the current I-type fracture energy and the current II-type fracture energy when the adhesive layer material is damaged; η is an empirical parameter, and η =1.
Folding and reducing the rigidity of the glue layer unit:
K i ＝(1-D)K (21)
the damaged stress-strain constitutive relation of the adhesive layer unit is as follows:
Figure BDA0003827876250000134
wherein:
Figure BDA0003827876250000135
Figure BDA0003827876250000136
in formula (24), i = n, s, t; d is a damage variable; k i The rigidity matrix is the rigidity matrix of the damaged rubber layer unit;
Figure BDA0003827876250000137
the initial displacement is the initial displacement when the glue layer unit is damaged;
Figure BDA0003827876250000138
is the displacement when the glue layer unit completely fails;
Figure BDA0003827876250000139
the actual displacement of the glue layer unit; delta 1 、δ 2 、δ 3 The normal displacement of the glue line unit and the displacement in the glue line 13 and 23 directions, respectively.
3.3, considering the shearing nonlinear behavior of the carbon fiber reinforced composite material, and combining the maximum stress criterion and the three-dimensional harshness criterion to perform stress analysis on the carbon fiber reinforced composite material unit:
(1) Fibre stretch failure (sigma) 11 ≥0)：
Figure BDA0003827876250000141
(2) Fibre compression failure (sigma) 11 ＜0)：
Figure BDA0003827876250000142
(3) In-plane matrix tensile failure (σ) 22 +σ 33 ≥0)：
Figure BDA0003827876250000143
(4) In-plane matrix compression failure (σ) 22 +σ 33 ＜0)：
Figure BDA0003827876250000144
(5) Out-of-plane substrate tensile failure (σ) 33 ≥0)：
Figure BDA0003827876250000145
(5) Out-of-plane substrate compression failure (, (σ 33 ＜0)：
Figure BDA0003827876250000146
In the formula, σ 11 、σ 22 、σ 33 The main stress in the x direction, the y direction and the z direction respectively; sigma 12 、σ 13 、σ 23 Respectively the in-plane shear stress in the corresponding direction; x c 、X t 、Y c 、Y t 、Z c 、Z t The ultimate tensile strength in the x direction, the y direction and the z direction respectively, subscript t represents stretching, and c represents compression; s 12 、S 13 、S 23 Respectively the shear ultimate strength in the corresponding direction; when F is present ft 、F fc 、F mt 、F mc 、F nt 、F nc When the carbon fiber reinforced composite material is larger than or equal to 1, the carbon fiber reinforced composite material unit is damaged; otherwise, the cell is undamaged.
3.4, the carbon fiber reinforced composite material unit is damaged, a material damage rigidity matrix is activated, and a damage variable is introduced to represent a damage process. When the material is undamaged, the damage variable is 0; when damage occurs, the damage variable increases monotonically, reaching 1 indicating complete failure of the material. Damage stiffness matrix C related to damage variables d Is represented as follows:
Figure BDA0003827876250000151
the stress-strain constitutive relation of the damaged carbon fiber reinforced composite material unit is as follows:
Figure BDA0003827876250000152
wherein:
b 1 ＝1-d f (33)
b 2 ＝1-d m (34)
b 3 ＝1-d s (35)
three independent lesion variables were considered: d is a radical of f 、d m 、d s ；d f Indicating degradation of the fiber direction; d m Indicating degradation in the direction perpendicular to the fibers; d s Indicating a degradation of the shear properties parallel to the fibre direction. The relationship is as follows:
d f ＝1-(1-d FT )(1-d FC ) (36)
d m ＝1-(1-d MT )(1-d MC ) (37)
d s ＝1-(1-d f )(1-smt×d MT )(1-smc×d MC ) (38)
in the formula (d) FT 、d FC Is the damage variable in the fiber draw and compression directions; d MT 、d MC Is the damage variable in the stretching and compressing directions of the matrix; the smt, smc are the coefficients of shear modulus loss due to matrix tensile and compressive failure.
4. Judging whether the nail inserting process is finished or not by combining the interference nail inserting displacement in the step 2.4, if not, increasing the nail inserting load, returning to the step three, and continuing to perform stress analysis; if the nail inserting process is finished, the model stops analyzing; the interference plug pin displacement is a fixed value set manually, the plug pin displacement is divided into a plurality of small displacements by the model according to the complexity of the model during analysis, then the analysis is carried out, the model judges whether the whole analysis process is finished or not when the analysis of one small displacement is finished, if not, the analysis is continued, and the analysis is automatically stopped until the analysis of all the small displacements is finished.
5. After the interference insertion nail three-dimensional finite element model of the carbon fiber reinforced composite material rubber and screw mixed connection structure stops analyzing, comparing a nail pressing force-displacement curve, and verifying the accuracy of the friction coefficient as shown in FIG. 4; and calculating and obtaining the damage distribution of the units in the third step, and extracting the equivalent stress of each glue layer unit and each carbon fiber reinforced composite material unit in the finite element result.
6. According to the three-dimensional anisotropic progressive damage model in the third step, namely the criteria in 3.1 and 3.3, inheriting the unit equivalent stress and damage distribution extracted in the fifth step, establishing corresponding load and boundary conditions, and constructing a tensile damage model of the carbon fiber reinforced composite material rubber-screw mixed connection structure; as shown in fig. 5. The load refers to bolt pretightening force in 6.2; the boundary condition refers to the operation setting in 6.4.
And 6.1, reading the equivalent stress and damage distribution of the rubber layer and the carbon fiber reinforced composite material unit obtained in the step five, and associating the equivalent stress and damage distribution of the unit in a predefined field according to the identification names of the rubber layer and the carbon fiber reinforced composite material in the step 2.1.
6.2, considering the structural size of each part in 2.1 without considering the elastic-plastic damage of the bolt, establishing an I-shaped bolt model, replacing the T-shaped bolt model, and applying bolt pretightening force in the load module; to avoid conflicting bolt section attributes, the bolt section attributes are set to default in the grid module.
6.3 in the contact module, establishing the friction property between the bolt and the glue layer and the composite material hole wall unit which inherit the equivalent stress and the damage, adding hard contact, and taking the friction coefficient as 0.1.
6.4 in the load and boundary module, establish the kinematic coupling reference points of the upper and lower laminates, limit the 6 degrees of freedom of the lower laminate kinematic coupling reference point, limit the 5 degrees of freedom except in the x direction at the upper laminate kinematic coupling reference point, and add quasi-static tensile displacement. Specifically, in a load and boundary module, kinematic coupling reference points RP-1 and RP-2 of an upper laminated plate and a lower laminated plate are established, the degree of freedom of the upper laminated plate and the lower laminated plate is limited, and quasi-static tensile displacement of 3.5mm is added at the reference point RP-1.
7. And (4) combining the failure criterion and the rigidity reduction model in the third step, carrying out stress analysis on the tensile damage model of the carbon fiber reinforced composite material rubber-spiral mixed interference connection structure in the sixth step, and judging whether each rubber layer unit and each composite material unit are damaged or rigidity reduction is carried out. The invention comprises two stages: and (5) interfering the bolt inserting process and the stretching process after the bolt inserting is finished. The two processes respectively correspond to two different finite element models, so that two judgments are required, but the criteria are the same, and the unit in the second tensile model inherits the stress and the damage of the first model, then the stress analysis is carried out again under the action of tensile load, further the damage and the rigidity reduction are obtained, and finally the whole structure fails.
8. Judging whether damage of each glue layer unit and each composite material unit causes failure of the connecting structure, if the connecting structure does not fail, increasing tensile load, and returning to the seventh step; if the connecting structure fails, the model stops analyzing, the tensile load at the moment is the tensile strength of the carbon fiber reinforced composite material rubber-screw mixed interference connecting structure, a tensile load-displacement curve is output, as shown in fig. 6, the prediction effect is shown in table 5, and the prediction error of the tensile strength of the carbon fiber reinforced composite material rubber-screw mixed interference connecting structure is 3.21%. The judgment that the connection structure fails is that the Abaqus software automatically iterates and calculates the unit stiffness for judgment, when the unit is damaged, the stiffness is reduced, the normal stiffness is reduced to 0, but the unit stiffness has a negative value in the stretching process, so that the software cannot assemble a unit stiffness matrix, the analysis automatically stops, and the connection structure is considered to fail at the moment.
TABLE 5 comparison of tensile test and predicted results
Figure BDA0003827876250000171
The invention also provides a system for predicting the mixed connection strength of the glue and the spiral shell by considering the damage of the inserted nail, which comprises the following components:
and the acquisition module is used for acquiring the tensile strength, the shear strength, the I-type fracture energy and the II-type fracture energy of the adhesive layer.
The interference plug pin three-dimensional finite element model building module of the carbon fiber reinforced composite material rubber and screw mixed connection structure is used for building an interference plug pin three-dimensional finite element model of the carbon fiber reinforced composite material rubber and screw mixed connection structure according to the tensile strength, the shearing strength, the structure size of the connection structure, the contact property of the connection structure, the load of the connection structure and the boundary condition of the connection structure; the connecting structure comprises a carbon fiber reinforced composite material, the glue layer and an interference bolt; the contact attribute includes a coefficient of friction.
And the damage analysis module is used for carrying out damage analysis according to the contact stress among the interference bolt, the glue layer and the hole wall of the carbon fiber reinforced composite material based on the interference insertion nail three-dimensional finite element model, the I-type fracture energy and the II-type fracture energy of the carbon fiber reinforced composite material glue and screw mixed connection structure, and determining a damage distribution and rigidity reduction model.
And the carbon fiber reinforced composite material rubber and screw mixed connection structure tensile damage model building module is used for building a carbon fiber reinforced composite material rubber and screw mixed connection structure tensile damage model according to the damage distribution.
And the stress analysis module is used for carrying out stress analysis on the tensile damage model of the carbon fiber reinforced composite material rubber-screw mixed connection structure according to failure criteria and the rigidity reduction model so as to determine the tensile strength.
As an optional implementation manner, the obtaining module specifically includes:
and the tensile strength acquisition unit is used for carrying out a tensile test on the adhesive layer to obtain the tensile strength.
And the shearing strength acquisition unit is used for carrying out a shearing test on the adhesive layer to obtain the shearing strength.
And the I-type fracture energy acquisition unit is used for carrying out a double cantilever beam test on the adhesive layer to obtain I-type fracture energy.
And the II-type fracture energy acquisition unit is used for carrying out a three-point bending test on the adhesive layer to obtain II-type fracture energy.
As an optional implementation manner, the interference plug pin three-dimensional finite element model building module of the carbon fiber reinforced composite material glue and screw mixed connection structure specifically includes:
and the three-dimensional geometric model building unit is used for building a three-dimensional geometric model according to the structure size of the connecting structure, the contact property of the connecting structure and the boundary condition of the connecting structure.
And the interference plug pin displacement determining unit is used for determining the interference plug pin displacement according to the load of the connecting structure.
And the carbon fiber reinforced composite material stress-strain constitutive relation determining unit is used for determining the carbon fiber reinforced composite material stress-strain constitutive relation according to the tensile strength and the shearing strength.
And the interference insertion nail three-dimensional finite element model construction unit of the carbon fiber reinforced composite material rubber and screw mixed connection structure is used for constructing the interference insertion nail three-dimensional finite element model of the carbon fiber reinforced composite material rubber and screw mixed connection structure according to the three-dimensional geometric model, the interference insertion nail displacement and the stress-strain constitutive relation of the carbon fiber reinforced composite material.
As an optional implementation manner, the damage analysis module specifically includes:
the damage condition determining unit of the glue layer is used for carrying out stress analysis according to a secondary stress failure criterion on the glue layer in the interference plug pin three-dimensional finite element model of the carbon fiber reinforced composite material glue and screw mixed connection structure, and determining the damage condition of the glue layer; the injury condition includes the occurrence of injury and the absence of injury.
And the adhesive layer rigidity reduction determining unit is used for determining the adhesive layer rigidity reduction in the rigidity reduction model according to the damage variable and the displacement of the adhesive layer when the damage condition of the adhesive layer is damage.
A damage distribution determination unit for determining a damage distribution based on the type I and type II fragmentation energies.
And the damage condition determining unit is used for carrying out stress analysis on the carbon fiber reinforced composite material in the interference plug pin three-dimensional finite element model according to the maximum stress criterion and the three-dimensional Haxin failure criterion of the carbon fiber reinforced composite material in the glue and screw mixed connection structure interference plug pin three-dimensional finite element model, and determining the damage condition of the carbon fiber reinforced composite material.
And the carbon fiber reinforced composite material rigidity reduction determining unit is used for determining the rigidity reduction of the carbon fiber reinforced composite material in the damage rigidity reduction model according to the damage rigidity matrix when the damage condition of the carbon fiber reinforced composite material is damage.
According to the method, the adhesive layer cohesion degradation and the composite material hole wall interface stress state and damage distribution after the interference bolt is installed are considered, and the accurate prediction of the tensile strength of the connecting structure under the quasi-static displacement loading is realized.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. For the system disclosed by the embodiment, the description is relatively simple because the system corresponds to the method disclosed by the embodiment, and the relevant points can be referred to the description of the method part.
The principles and embodiments of the present invention have been described herein using specific examples, which are provided only to help understand the method and the core concept of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the foregoing, the description is not to be taken in a limiting sense.

Claims (8)

1. A method for predicting the mixed connection strength of a rubber bolt by considering the damage of a plug pin is characterized by comprising the following steps:
obtaining the tensile strength, the shear strength, the type I fracture energy and the type II fracture energy of the adhesive layer;
constructing a carbon fiber reinforced composite material rubber-screw mixed connection structure interference plug pin three-dimensional finite element model according to the tensile strength, the shear strength, the structure size of the connection structure, the contact property of the connection structure, the load of the connection structure and the boundary condition of the connection structure; the connecting structure comprises a carbon fiber reinforced composite material, the glue layer and an interference bolt; the contact attribute comprises a coefficient of friction;
based on the interference pin three-dimensional finite element model of the carbon fiber reinforced composite material rubber-screw mixed connection structure, the type I fracture energy and the type II fracture energy, performing damage analysis according to contact stress among the interference bolt, the rubber layer and the hole wall of the carbon fiber reinforced composite material, and determining a damage distribution and rigidity reduction model;
constructing a tensile damage model of the carbon fiber reinforced composite material rubber-spiral mixed connection structure according to the damage distribution;
and carrying out stress analysis on the tensile damage model of the carbon fiber reinforced composite material rubber-screw mixed connection structure according to failure criteria and the rigidity reduction model to determine the tensile strength.
2. The method for predicting the mixed joint strength of the rubber and the screw considering the nail inserting damage according to claim 1, wherein the obtaining of the tensile strength, the shear strength, the type I fracture energy and the type II fracture energy of the rubber layer specifically comprises:
performing a tensile test on the adhesive layer to obtain tensile strength;
carrying out a shear test on the adhesive layer to obtain the shear strength;
performing a double cantilever beam test on the adhesive layer to obtain I-type fracture energy;
and performing a three-point bending test on the adhesive layer to obtain II-type fracture energy.
3. The method for predicting the hybrid rubber-bolt joint strength considering the damage of the plug pin according to claim 1, wherein the constructing of the three-dimensional finite element model of the interference plug pin of the carbon fiber reinforced composite material hybrid rubber-bolt joint structure according to the tensile strength, the shear strength, the structural size of the joint structure, the contact property of the joint structure, the load of the joint structure and the boundary conditions of the joint structure specifically comprises:
constructing a three-dimensional geometric model according to the structure size of the connecting structure, the contact property of the connecting structure and the boundary condition of the connecting structure;
determining the displacement of the interference plug pins according to the load of the connecting structure;
determining the stress-strain constitutive relation of the carbon fiber reinforced composite material according to the tensile strength and the shear strength;
and constructing an interference plug pin three-dimensional finite element model of the carbon fiber reinforced composite material rubber-screw mixed connection structure according to the three-dimensional geometric model, the interference plug pin displacement and the stress-strain constitutive relation of the carbon fiber reinforced composite material.
4. The method for predicting the mixed glue and screw connection strength considering the damage of the inserted pin according to claim 1, wherein the interference inserted pin three-dimensional finite element model, the type i fracture energy and the type ii fracture energy based on the mixed glue and screw connection structure of the carbon fiber reinforced composite material are subjected to damage analysis according to the contact stress among the interference bolt, the glue layer and the hole wall of the carbon fiber reinforced composite material, and the damage distribution and stiffness reduction model are determined, and specifically comprise:
performing stress analysis by adopting a secondary stress failure criterion according to a glue layer in the interference plug pin three-dimensional finite element model of the carbon fiber reinforced composite material glue and screw mixed connection structure, and determining the damage condition of the glue layer; the damage condition comprises damage and non-damage;
when the damage condition of the glue layer is damage, determining the glue layer rigidity reduction in the rigidity reduction model according to the damage variable and the displacement of the glue layer;
determining damage distribution according to the type I fracture energy and the type II fracture energy;
performing stress analysis on the carbon fiber reinforced composite material in the interference plug pin three-dimensional finite element model of the carbon fiber reinforced composite material rubber-screw mixed connection structure by adopting a maximum stress criterion and a three-dimensional Haxin failure criterion to determine the damage condition of the carbon fiber reinforced composite material;
and when the damage condition of the carbon fiber reinforced composite material is damage, determining the rigidity reduction of the carbon fiber reinforced composite material in the damage rigidity reduction model according to the damage rigidity matrix.
5. A system for predicting the strength of a glue and nut mixed connection in consideration of the damage of a plug pin is characterized by comprising:
the acquisition module is used for acquiring the tensile strength, the shear strength, the type I fracture energy and the type II fracture energy of the adhesive layer;
the interference plug pin three-dimensional finite element model building module of the carbon fiber reinforced composite material rubber and screw mixed connection structure is used for building an interference plug pin three-dimensional finite element model of the carbon fiber reinforced composite material rubber and screw mixed connection structure according to the tensile strength, the shearing strength, the structure size of the connection structure, the contact property of the connection structure, the load of the connection structure and the boundary condition of the connection structure; the connecting structure comprises a carbon fiber reinforced composite material, the glue layer and an interference bolt; the contact attribute comprises a coefficient of friction;
the damage analysis module is used for carrying out damage analysis according to contact stress among the interference bolt, the glue layer and the hole wall of the carbon fiber reinforced composite material based on the interference insert nail three-dimensional finite element model, the type I fracture energy and the type II fracture energy of the carbon fiber reinforced composite material glue and screw mixed connection structure, and determining damage distribution and rigidity reduction models;
the carbon fiber reinforced composite material rubber and screw mixed connection structure tensile damage model building module is used for building a carbon fiber reinforced composite material rubber and screw mixed connection structure tensile damage model according to the damage distribution;
and the stress analysis module is used for carrying out stress analysis on the tensile damage model of the carbon fiber reinforced composite material rubber-screw mixed connection structure according to failure criteria and the rigidity reduction model so as to determine the tensile strength.
6. The system for predicting strength of a glue and screw mixed connection considering the damage of the inserted pin according to claim 5, wherein the obtaining module specifically comprises:
the tensile strength acquisition unit is used for carrying out a tensile test on the adhesive layer to obtain the tensile strength;
the shear strength acquisition unit is used for carrying out a shear test on the adhesive layer to obtain the shear strength;
the I-type fracture energy acquisition unit is used for carrying out a double cantilever beam test on the adhesive layer to obtain I-type fracture energy;
and the II-type fracture energy acquisition unit is used for carrying out a three-point bending test on the adhesive layer to obtain II-type fracture energy.
7. The system for predicting the mixed glue and screw connection strength considering the damage of the plug pin according to claim 5, wherein the interference plug pin three-dimensional finite element model building module of the carbon fiber reinforced composite glue and screw mixed connection structure specifically comprises:
a three-dimensional geometric model construction unit for constructing a three-dimensional geometric model according to the structural size of the connection structure, the contact property of the connection structure, and the boundary condition of the connection structure;
the interference plug pin displacement determining unit is used for determining the interference plug pin displacement according to the load of the connecting structure;
the carbon fiber reinforced composite material stress-strain constitutive relation determining unit is used for determining the carbon fiber reinforced composite material stress-strain constitutive relation according to the tensile strength and the shearing strength;
and the interference insertion nail three-dimensional finite element model construction unit of the carbon fiber reinforced composite material rubber and screw mixed connection structure is used for constructing the interference insertion nail three-dimensional finite element model of the carbon fiber reinforced composite material rubber and screw mixed connection structure according to the three-dimensional geometric model, the interference insertion nail displacement and the stress-strain constitutive relation of the carbon fiber reinforced composite material.
8. The system for predicting strength of a glue and screw hybrid connection considering the damage of a plug pin according to claim 5, wherein the damage analyzing module specifically comprises:
the damage condition determining unit of the glue layer is used for carrying out stress analysis according to a secondary stress failure criterion on the glue layer in the interference plug pin three-dimensional finite element model of the carbon fiber reinforced composite material glue and screw mixed connection structure, and determining the damage condition of the glue layer; the damage condition comprises damage and non-damage;
the glue layer rigidity reduction determining unit is used for determining glue layer rigidity reduction in the rigidity reduction model according to damage variables and glue layer displacement when the damage condition of the glue layer is damage;
a damage distribution determination unit for determining a damage distribution according to the type I fracture energy and the type II fracture energy;
the damage condition determining unit is used for performing stress analysis on the carbon fiber reinforced composite material in the three-dimensional finite element model of the interference plug pin of the glue and screw mixed connection structure of the carbon fiber reinforced composite material by adopting a maximum stress criterion and a three-dimensional Harsin failure criterion to determine the damage condition of the carbon fiber reinforced composite material;
and the carbon fiber reinforced composite material rigidity reduction determining unit is used for determining the rigidity reduction of the carbon fiber reinforced composite material in the damage rigidity reduction model according to the damage rigidity matrix when the damage condition of the carbon fiber reinforced composite material is damage.
CN202211066562.7A 2022-09-01 2022-09-01 Method and system for predicting mixed connection strength of rubber and screw by considering damage of inserted pin Pending CN115345059A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202211066562.7A CN115345059A (en) 2022-09-01 2022-09-01 Method and system for predicting mixed connection strength of rubber and screw by considering damage of inserted pin

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202211066562.7A CN115345059A (en) 2022-09-01 2022-09-01 Method and system for predicting mixed connection strength of rubber and screw by considering damage of inserted pin

Publications (1)

Publication Number Publication Date
CN115345059A true CN115345059A (en) 2022-11-15

Family

ID=83956433

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202211066562.7A Pending CN115345059A (en) 2022-09-01 2022-09-01 Method and system for predicting mixed connection strength of rubber and screw by considering damage of inserted pin

Country Status (1)

Country Link
CN (1) CN115345059A (en)

Similar Documents

Publication Publication Date Title
Campilho et al. Using a cohesive damage model to predict the tensile behaviour of CFRP single-strap repairs
Zhang et al. Behavior of preloaded RC beams strengthened with CFRP laminates
Glišović et al. Numerical analysis of glulam beams reinforced with CFRP plates
Mousa et al. Flexural behavior of full-scale composite structural insulated floor panels
CN109684724A (en) A kind of viscous compound steel skeleton construction analysis method of riveting of the more material vehicle bodies of car
Parikh et al. Application of GFRP on preloaded retrofitted beam for enhancement in flexural strength
CN117171881A (en) Method for researching influence of random hole geometric deviation on strength of aircraft panel connection structure
Aljazaeri et al. Numerical study on flexural behavior of concrete beams strengthened with fiber reinforced cementitious matrix considering different concrete compressive strength and steel reinforcement ratio
Różyło et al. Experimental research in the aspect of determining the mechanical and strength properties of the composite material made of carbon-epoxy composite
Min et al. Hybrid FRP-timber thin-walled Cee section columns under axial compression: Numerical modelling
Lamberti et al. Cyclic behaviour modelling of GFRP adhesive connections by an imperfect soft interface model with damage evolution
CN115345059A (en) Method and system for predicting mixed connection strength of rubber and screw by considering damage of inserted pin
CN105550418B (en) CFRP plate reinforces the calculation method for setting the Ultimate flexural strength of core beam
Hosseinpour et al. Statistical evaluation of the monotonic models for FRP confined concrete prisms
Alhussein et al. Simulation of the effect laminate sequence on delamination mode-I with elastic couplings
CN105550420B (en) Double muscle reinforce the calculation method for setting the Ultimate flexural strength of core beam
CN105424479B (en) Galvanized steel plain sheet puts the computational methods of the Ultimate flexural strength of core beam with CFRP plate composite consolidations
Qingyuan et al. Progressive bearing failure analysis and strength prediction method for the initial assembly and tensile process of composite bolted joints
Napoli RC structures strengthened with mechanically fastened FRP systems
Shi et al. Short-term axial behavior of preloaded concrete columns strengthened with fiber reinforced polymer laminate
Krour et al. An improved closed-form solution to interfacial stresses in RC beams strengthened with a composite plate
Corti et al. NUMERICAL MODELING OF TIMBER‐STEEL HYBRID STRUCTURES: CHALLENGES AND INNOVATIVE STRATEGIES
Xie et al. A feasible methodology for engineering applications in damage tolerance of composite sandwich structures
Pan et al. Analytical and numerical modelling of FRP debonding from concrete substrate under pure shearing
Wang A multi-scale progressive damage model for laminates

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination