CN113916651B - Method for testing transverse tensile strength of brittle fiber with inner core - Google Patents
Method for testing transverse tensile strength of brittle fiber with inner core Download PDFInfo
- Publication number
- CN113916651B CN113916651B CN202110870079.3A CN202110870079A CN113916651B CN 113916651 B CN113916651 B CN 113916651B CN 202110870079 A CN202110870079 A CN 202110870079A CN 113916651 B CN113916651 B CN 113916651B
- Authority
- CN
- China
- Prior art keywords
- fiber
- tensile strength
- sample
- load
- fiber sample
- 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.)
- Active
Links
- 239000000835 fiber Substances 0.000 title claims abstract description 150
- 238000012360 testing method Methods 0.000 title claims abstract description 25
- 238000000034 method Methods 0.000 title claims abstract description 22
- 238000007906 compression Methods 0.000 claims abstract description 13
- 230000006835 compression Effects 0.000 claims abstract description 12
- 238000004458 analytical method Methods 0.000 claims abstract description 11
- 238000012669 compression test Methods 0.000 claims abstract description 11
- 239000000523 sample Substances 0.000 claims description 50
- 239000011162 core material Substances 0.000 claims description 26
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 18
- 229910052802 copper Inorganic materials 0.000 claims description 18
- 239000010949 copper Substances 0.000 claims description 18
- 239000004033 plastic Substances 0.000 claims description 9
- 230000003287 optical effect Effects 0.000 claims description 8
- 238000006073 displacement reaction Methods 0.000 claims description 7
- 238000013519 translation Methods 0.000 claims description 6
- 238000010586 diagram Methods 0.000 claims description 5
- 229920001651 Cyanoacrylate Polymers 0.000 claims description 3
- 229910001209 Low-carbon steel Inorganic materials 0.000 claims description 3
- 244000137852 Petrea volubilis Species 0.000 claims description 3
- 239000004830 Super Glue Substances 0.000 claims description 3
- 238000005452 bending Methods 0.000 claims description 3
- 238000006243 chemical reaction Methods 0.000 claims description 3
- 239000002657 fibrous material Substances 0.000 claims description 3
- 230000007935 neutral effect Effects 0.000 claims description 3
- 230000003068 static effect Effects 0.000 claims description 3
- 238000010408 sweeping Methods 0.000 claims description 3
- 230000007704 transition Effects 0.000 claims description 3
- 238000012800 visualization Methods 0.000 claims description 3
- 239000002904 solvent Substances 0.000 claims description 2
- 238000004364 calculation method Methods 0.000 abstract description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical group [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 8
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 8
- 229910010271 silicon carbide Inorganic materials 0.000 description 7
- 239000003733 fiber-reinforced composite Substances 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 230000006978 adaptation Effects 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000011218 segmentation Effects 0.000 description 2
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 1
- 229920000049 Carbon (fiber) Polymers 0.000 description 1
- 239000011157 advanced composite material Substances 0.000 description 1
- 229920006231 aramid fiber Polymers 0.000 description 1
- 238000000418 atomic force spectrum Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- 239000004917 carbon fiber Substances 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007123 defense Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000003365 glass fiber Substances 0.000 description 1
- 239000003292 glue Substances 0.000 description 1
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 1
- 230000002787 reinforcement Effects 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/08—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces
-
- 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
- G06F2111/00—Details relating to CAD techniques
- G06F2111/10—Numerical modelling
-
- 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)
- General Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- Immunology (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- Analytical Chemistry (AREA)
- Chemical & Material Sciences (AREA)
- Pathology (AREA)
- Life Sciences & Earth Sciences (AREA)
- Computer Hardware Design (AREA)
- Evolutionary Computation (AREA)
- Geometry (AREA)
- General Engineering & Computer Science (AREA)
- Health & Medical Sciences (AREA)
- Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
Abstract
The invention discloses a method for testing transverse tensile strength of brittle fibers with inner cores, which comprises the steps of firstly, carrying out a radial compression test on a fiber sample by using a nano indenter to obtain a breaking load; then establishing a fiber compression model, and calculating a load contact angle when the fiber sample is broken; finite element analysis is carried out on a fiber compression test, the circumferential stress distribution of a fiber sample perpendicular to a radial surface is obtained, and finally the transverse tensile strength of the fiber is obtained; the transverse tensile strength testing method provided by the invention considers the influence of the limited contact area and the stress step generated by the existence of the fiber inner core aiming at the fiber tensile strength with the inner core, has higher calculation precision, can calculate different fiber transverse tensile strengths by modifying the contact surface angle and damaging the load according to the actual condition, and is efficient, convenient and fast.
Description
Technical Field
The invention relates to the technical field of tensile strength testing, and mainly relates to a method for testing transverse tensile strength of brittle fibers with inner cores.
Background
The advanced composite material taking aramid fiber, carbon fiber, boron fiber and high-performance glass fiber as reinforcement has very high specific strength, specific stiffness and high-temperature strength, is wear-resistant and corrosion-resistant, and has a relatively simple forming process, so that the composite material is widely applied to high and new technology common use in China, national defense industry and national major projects, and has a very wide development prospect.
The fibers of the fiber-reinforced composite material have relatively high mechanical properties in the axial direction, but have relatively poor mechanical properties in the transverse direction, and are easily damaged when the fibers are in a complex load environment. It is therefore necessary to study the transverse properties of the fibers, and the most straightforward way to study the transverse properties of fiber-reinforced composites is to test the transverse tensile strength of the fibers by a transverse compression test of the individual fibers.
Jeffrey i.eldridge1(Eldridge, j.i., wieing, j.p., Davison, T.S. & pinderra, m. -j.transverse string of SCS-6Silicon Carbide fibers, j.am. c.soc.76, 3151-3154 (1993)), studies were made on the transverse tensile Strength of carbon core-containing Silicon Carbide fibers before and after heat treatment, and it was found that the maximum hoop stress of the fibers was concentrated at the interface between the carbon core and the Silicon Carbide, that cracking of the Silicon Carbide fibers occurred on the radial surface under load, that cracks grew along the circumference of the carbon core, stopped when reaching the outer circumference of the Silicon Carbide fiber, and that the axial tensile Strength of the fibers after heat treatment decreased greatly while the transverse tensile Strength of the fibers increased slightly, but this study was calculated using the ideal standardized cylindrical wire load method without considering the limited contact area and the stress step due to the presence of the carbon core of the fibers. The transverse tensile strength of the coreless brittle fibers was investigated by sun shiga 2 (sun shiga et al, a method for predicting transverse tensile strength of coreless brittle fibers, 13 (2020)), and it was found that the fiber fracture surface without the core was a vertical radial surface of the load-applied fiber. The transverse stretching of the coreless fiber is calculated and predicted by adopting a mathematical analytic formula method, but the transverse stretching strength of the fiber with the inner core is difficult to predict by directly adopting a mathematical analytic method due to the complex stress distribution condition of the fiber with the inner core.
It is therefore necessary to perform compression testing on the core-containing fiber and, based thereon, to propose a method for predicting the transverse tensile strength of the fiber using finite elements.
Disclosure of Invention
The purpose of the invention is as follows: aiming at the problems in the prior art, the invention provides a method for testing the transverse tensile strength of brittle fibers with inner cores.
The technical scheme is as follows: in order to realize the purpose, the invention adopts the technical scheme that:
a method for testing transverse tensile strength of brittle fibers with inner cores comprises the following steps:
step S1, preparing a test fiber sample, and determining a focal plane and calibrating a pressure head position of the nanoindentor;
step S2, carrying out radial compression test on the fiber sample by using a nano-indenter to obtain a breaking load F cr ；
S3, establishing a fiber compression model, and calculating a load contact angle alpha when the fiber sample is broken; finite element analysis is carried out on a fiber compression test, the circumferential stress distribution of a fiber sample perpendicular to a radial surface is obtained, and finally the transverse tensile strength sigma of the fiber is obtained cr T 。
Further, the step of preparing the test fiber sample in step S1 includes:
s1.1, cutting a fiber sample to be 3cm in length for later use;
s1.2, adhering a copper sheet to a low-carbon steel base of a nanoindentor to assist fiber positioning; sequentially grinding the copper sheet to the same height as the fibers by using 500-mesh, 800-mesh and 1000-mesh sand paper, determining a focal plane on the copper sheet, and calibrating the position of a pressure head; after the sample is ground to be free of scratches, the fiber sample is laid to be parallel to the copper sheet, namely the diameter of the fiber sample is equal to the height of the copper sheet; after the fibers and the copper sheet are confirmed to be parallel under an optical microscope, the two ends of the fibers are fixed by super glue.
Further, the breaking load F cr The acquisition method comprises the following steps:
s2.1, moving the position of a sample stage by using an X-Y translation stage, observing the position of a fiber sample under an optical microscope until a pressure head is aligned with a test fiber, and verifying the alignment condition of the fiber sample and the pressure head;
s2.2, observing the tail end of the fiber sample, controlling the nanoindentor to compress the fiber sample at a fixed speed, recording the engineering load F and the corresponding displacement x, drawing a function diagram, and recording the damage load F cr 。
Further, the step S3 is to obtain the fiber transverse direction tensile strength σ cr T The method comprises the following specific steps:
step S3.1, calculating the load contact angle alpha when the fiber sample breaks as follows:
wherein b represents the contact surface width, R represents the outer diameter of the fiber, F represents the engineering load per unit length, E T Represents the transverse modulus of elasticity, E L Representing the longitudinal modulus of elasticity, v, of a sample of fibres LT Represents the Poisson's ratio;
s3.2, obtaining the circumferential stress distribution of the fiber sample perpendicular to the radial surface by adopting finite element analysis according to the load contact angle alpha, thereby obtaining the transverse tensile strength sigma of the fiber cr T (ii) a The method comprises the following specific steps:
step S3.2.1, establishing a fiber compression model;
drawing a semi-cylinder with the diameter of D and the stretching length of l according to the size of the fiber; before setting the attribute, creating a sketch on the circular end face of the semi-cylinder, and segmenting a fiber inner core with the diameter d and a fiber part contacted with a pressure head according to the sketch;
step S3.2.2, creating and assigning fiber material properties;
according to the different selected fiber sample material and inner core material, the elastic modulus of the fiber sample is set to be E sic Poisson ratio of v sic (ii) a The elastic modulus of the inner core is E core Poisson ratio of v core ；
Step S3.2.3, establishing an analysis step;
selecting a general static type, setting the maximum increment step number to be 1000, setting the initial increment step size to be 0.01, and keeping the others default; of the field outputs, a first field output includes: translation and rotation U, reaction force and moment RF, concentrated force and bending moment CF; the second field output includes: stress component and invariant S, plastic strain PE, equivalent plastic strain PEEQ, plastic strain PEMAG, logarithmic strain component LE and state STATUS; the third field output includes: contact stress cstrs, contact displacement CDISP; the history output remains default;
step S3.2.4, creating a load;
setting boundary condition types on the bottom surfaces of the semi-cylinders to be symmetrical, setting a global coordinate system YSYMM, and inputting loads on the contact surfaces;
step S3.2.5, mesh division;
setting the global seed approximate unit size as Q, and setting the local seed approximate unit size for dividing to contact a pressure head as Q; selecting a hexahedron as the shape of the grid, and dividing the grid by a neutral axis algorithm for sweeping minimum grid transition;
step S3.2.6, creating and submitting a job;
step S3.2.7, displaying a visualization result;
a cylindrical coordinate system is established in the center of the semi-circle surface, and the circumferential stress result is converted into stress distribution under the coordinate system; creating a path, and drawing a tensile stress distribution diagram of a vertical radial surface corresponding to the load contact angle along the path;
step S3.2.8, setting the position of the maximum value of the boundary display in the option cloud picture to obtain the maximum transverse tensile strength sigma of the fiber cr T 。
Has the beneficial effects that:
(1) the fiber transverse tensile strength testing method provided by the invention has high calculation precision, does not adopt a method of calculating the linear load of an ideal standardized cylinder, but considers the influence of a limited contact area and a stress step generated due to the existence of a fiber inner core.
(2) The method has efficient and convenient calculation process, and can calculate the transverse tensile strength of the fiber only by modifying the contact surface angle and damaging the load.
(3) The method can effectively calculate the transverse compression strength of the brittle fiber with the core, and lays a good foundation for the strength calculation of the brittle fiber reinforced composite material with the core.
Drawings
FIG. 1 is a flow chart of the test provided by the present invention;
FIG. 2 is a sketch of an auxiliary segmentation in an embodiment of the present invention;
FIGS. 3a-3b are schematic representations of fiber failure in the circumferential direction of the carbon core after fiber compression testing in an embodiment of the present invention;
FIG. 4 is a schematic representation of a SiC fiber with a carbon core in an embodiment of the invention;
FIG. 5 is a schematic representation of a fiber compression test in an example of the invention;
FIG. 6 is a graph of F-x function for a typical fiber compression process;
FIG. 7 is a schematic representation of a fiber compression axial force profile in an embodiment of the present invention;
FIG. 8 is a schematic view of a fiber compression model in an embodiment of the invention;
fig. 9 is a graph of the vertical radial surface tensile stress at 2 ° 41' 46 "for an embodiment of the present invention.
Detailed Description
The invention will be further explained by providing an example of testing the transverse tensile strength of a silicon carbide fiber with a carbon core in combination with the accompanying drawings. It is emphasized that the test method provided by the present invention is applicable to a variety of brittle fibers with an inner core.
Firstly, preparing a test fiber sample, and determining a focal plane and calibrating a pressure head position of the nanoindentor.
Cutting the fiber to about 3cm for later use; because the size of the single fiber is small, the rectangular copper sheet needs to be adhered to the mild steel base by strong glue to help the fiber positioning. And sequentially grinding the copper sheet to the same height as the fibers by using 500-mesh, 800-mesh and 1000-mesh sand paper, determining a focal plane on the copper sheet, and calibrating the position of a pressure head. After grinding to no scratch, the fiber sample was laid parallel to the copper sheet, i.e. the fiber sample diameter was equal to the copper sheet height, as shown in fig. 5. After the fibers and the copper sheet are confirmed to be parallel under an optical microscope, the two ends of the fibers are fixed by super glue.
Then, a radial compression test is carried out on the fiber sample by using a nano-indenter to obtain a failure load F cr 。
The position of the sample fiber was observed using an optical microscope, and the sample stage was moved using an X-Y translation stage until an indenter having a diameter of 350 μm was aligned with the test fiber. The alignment of the fiber sample and indenter was again verified by viewing from a television image of an optical microscope. An optical microscope was placed to observe the fiber ends while video recording was performed on the images projected onto the computer screen. The nanoindenter was controlled to compress the sample fiber at a rate of 0.2 μm/s and the engineering load (F) and displacement (x) were recorded as a function of the displacement by computer. Determining the critical load F of the damaged radial surface according to the function image cr As shown in fig. 6.
Finally, establishing a fiber compression model, and calculating a load contact angle alpha when the fiber sample is broken; finite element analysis is carried out on a fiber compression test, the circumferential stress distribution of a fiber sample perpendicular to a radial surface is obtained, and finally the transverse tensile strength sigma of the fiber is obtained cr T . In particular, the amount of the solvent to be used,
first, finite element analysis was performed on the fiber compression test, and the plane in which the tensile stress in the circumferential direction is the largest was determined to be a vertical radial plane, i.e., a failure plane where θ is 0, as shown in fig. 7.
The load contact angle α at which the fiber sample breaks is calculated as follows:
obtaining a critical load F at which failure occurs cr Suppose F cr 30N/mm, substituting the formula:
wherein b represents the contact face width, R represents the fiber outer diameter F represents the engineering load per unit length, E T Representing the transverse modulus of elasticity of the fiber, E L Representing the longitudinal modulus of elasticity, v, of a sample of fibres LT Representing the poisson's ratio.
The contact angle is calculated as:
then obtaining the maximum radial tensile stress value of the fiber under the contact angle alpha through finite element software, thereby obtaining the transverse tensile strength sigma of the fiber cr T 。
In this embodiment, since the finite element software has no unit and is a uniform unit, the model size is μm, the force unit is N, and the elastic modulus is N/μm 2 The time is s.
The fiber model was established as follows:
a half cylinder with a diameter of 142 and a drawn length of 200 was drawn according to the size of the fiber. Before setting the attributes, a sketch is created on the circular end face of the semi-cylinder, and the sketch and the segmentation result are drawn according to the calculated contact angle auxiliary line, as shown in fig. 2. The fiber core with a diameter of 33 and the SiC part contacted by the indenter are cut according to a sketch. The fiber compression model is shown in fig. 8.
Creating fiber material properties:
the elastic modulus of the SiC fiber is 420 GPa-0.42N/mum 2 The Poisson's ratio is 0.15; the elastic modulus of the carbon core is 35 GPa-0.035N/mum 2 The Poisson's ratio was 0.15. Assigning respective material properties to respective portions.
The steps of creating the analysis are as follows:
selecting a general static type, setting the maximum increment step number to be 1000, setting the initial increment step size to be 0.01, and keeping the others in default; of the field outputs, a first field output includes: translation and rotation U, reaction force and moment RF, concentrated force and bending moment CF; the second field output includes: stress component and invariant S, plastic strain PE, equivalent plastic strain PEEQ, plastic strain PEMAG, logarithmic strain component LE and state STATUS; the third field output includes: contact stress cstrs, contact displacement CDISP; the history output remains default.
And (4) creating a load, setting boundary condition type selection symmetry on the bottom surface of the semi-cylinder, and setting a global coordinate system YSYMM. The arc length l ═ α R ═ 0.04705577538 × 71 ═ 3.341 μm, obtained by using the contact angle; the applied linear load is divided by the arc length to obtain the pressure intensity of the contact surface, namely:
the pressure input to the finite element software was p 0.008979N/. mu.m 2.
The grid is divided as follows:
the global seed approximation unit size is 2 and the partial local seed approximation unit size divided to contact the indenter is set to 1. And selecting a hexahedron as the shape of the grid, and dividing the grid by a neutral axis algorithm for sweeping the minimum grid transition.
And after the grid is divided, the operation is created and submitted, and finally, a visualization result is displayed:
at the center of the half-circle, a cylindrical coordinate system is created and the circumferential stress results are converted to a stress distribution below the coordinate system, as shown in fig. 7. A path is created from the semi-cylindrical circle center to the contact vertex, and a vertical radial surface tensile stress distribution diagram of α ═ 2 ° 41' 46 "is drawn along this path, as shown in fig. 9.
Setting the position of the maximum value of the boundary display in the option cloud picture, wherein the maximum hoop tensile stress can be obtained as follows:
σ cr T ＝1.118×10 -3 Gpa。
the above description is only of the preferred embodiments of the present invention, and it should be noted that: it will be apparent to those skilled in the art that various modifications and adaptations can be made without departing from the principles of the invention, and such modifications and adaptations are intended to be within the scope of the invention.
Claims (3)
1. A transverse tensile strength testing method for brittle fibers with inner cores is characterized by comprising the following steps:
step S1, preparing a test fiber sample, and determining a focal plane and calibrating a pressure head position of the nanoindentor;
step S2, carrying out radial compression test on the fiber sample by using a nano-indenter to obtain a breaking load F cr ；
S3, establishing a fiber compression model, and calculating a load contact angle alpha when the fiber sample is broken; finite element analysis is carried out on a fiber compression test, the circumferential stress distribution of a fiber sample perpendicular to a radial surface is obtained, and finally the transverse tensile strength sigma of the fiber is obtained cr T (ii) a In particular, the amount of the solvent to be used,
step S3.1, calculating the load contact angle α when the fiber sample breaks as follows:
wherein b represents the contact surface width, R represents the outer diameter of the fiber, F represents the engineering load per unit length, E T Representing the transverse modulus of elasticity of the fiber, E L Representing the modulus of elasticity, v, in the machine direction of a fiber sample LT Represents the Poisson's ratio;
s3.2, obtaining the circumferential stress distribution of the fiber sample perpendicular to the radial surface by adopting finite element analysis according to the load contact angle alpha, thereby obtaining the transverse tensile strength sigma of the fiber cr T (ii) a The method comprises the following specific steps:
step S3.2.1, establishing a fiber compression model;
drawing a semi-cylinder with the diameter D and the stretching length l according to the size of the fiber; before setting the attribute, creating a sketch on the circular end face of the semi-cylinder, and segmenting a fiber inner core with the diameter d and a fiber part contacted with a pressure head according to the sketch;
step S3.2.2, creating and assigning fiber material properties;
setting the elastic modulus of the fiber sample to be E according to the difference between the selected fiber sample material and the selected inner core material sic Poisson ratio of v sic (ii) a The elastic modulus of the inner core is E core Poisson ratio of v core ；
Step S3.2.3, establishing an analysis step;
selecting a general static type, setting the maximum increment step number to be 1000, setting the initial increment step size to be 0.01, and keeping the others in default; of the field outputs, a first field output includes: translation and rotation U, reaction force and moment RF, concentration force and bending moment CF; the second field output includes: stress component and invariant S, plastic strain PE, equivalent plastic strain PEEQ, plastic strain PEMAG, logarithmic strain component LE and state STATUS; the third field output includes: contact stress cstrs, contact displacement CDISP; the history output remains default;
step S3.2.4, creating a load;
setting boundary condition types on the bottom surfaces of the semi-cylinders to be symmetrical, setting a global coordinate system YSYMM, and inputting loads on the contact surfaces;
step S3.2.5, grid division;
setting the size of a global seed approximate unit as Q, and dividing a local seed approximate unit for contacting a pressure head into Q; selecting a hexahedron in the shape of the grid, and dividing the grid by a neutral axis algorithm for sweeping the minimum grid transition;
step S3.2.6, creating and submitting a job;
step S3.2.7, displaying a visualization result;
a cylindrical coordinate system is established in the center of the semi-circular surface, and the circumferential stress result is converted into stress distribution under the coordinate system; creating a path, and drawing a tensile stress distribution diagram of a vertical radial surface corresponding to the load contact angle along the path;
step S3.2.8, setting the position of the maximum value of the boundary display in the option cloud picture to obtain the maximum transverse tensile strength sigma of the fiber cr T 。
2. The method for testing transverse tensile strength of brittle fibers with inner cores as claimed in claim 1, wherein the step of preparing the test fiber sample in step S1 comprises the steps of:
s1.1, cutting a fiber sample to be 3cm in length for later use;
s1.2, adhering a copper sheet to a low-carbon steel base of a nanoindentor to assist fiber positioning; sequentially adopting 500-mesh, 800-mesh and 1000-mesh sand paper to polish the copper sheet to be as high as the fiber, determining a focal plane on the copper sheet and calibrating the position of a pressure head; after the sample is ground to be free of scratches, the fiber sample is laid to be parallel to the copper sheet, namely the diameter of the fiber sample is equal to the height of the copper sheet; after the fibers and the copper sheet are confirmed to be parallel under an optical microscope, the two ends of the fibers are fixed by super glue.
3. The method for testing transverse tensile strength of brittle fibers with inner cores as claimed in claim 1, wherein the breaking load F cr The acquisition method comprises the following steps:
s2.1, moving the position of a sample stage by using an X-Y translation stage, observing the position of a fiber sample under an optical microscope until a pressure head is aligned with a test fiber, and verifying the alignment condition of the fiber sample and the pressure head;
s2.2, observing the tail end of the fiber sample, controlling the nanoindentor to compress the fiber sample at a fixed speed, recording the engineering load F and the corresponding displacement x, drawing a function diagram, and recording the damage load F cr 。
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110870079.3A CN113916651B (en) | 2021-07-30 | 2021-07-30 | Method for testing transverse tensile strength of brittle fiber with inner core |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110870079.3A CN113916651B (en) | 2021-07-30 | 2021-07-30 | Method for testing transverse tensile strength of brittle fiber with inner core |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113916651A CN113916651A (en) | 2022-01-11 |
| CN113916651B true CN113916651B (en) | 2022-07-26 |
Family
ID=79232998
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110870079.3A Active CN113916651B (en) | 2021-07-30 | 2021-07-30 | Method for testing transverse tensile strength of brittle fiber with inner core |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113916651B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112255963B (en) * | 2020-09-24 | 2022-05-13 | 江苏理工学院 | Laying track planning method and device for fiber composite material on cylindrical surface |
| CN114414371B (en) * | 2022-01-18 | 2024-03-22 | 天津大学 | Device and method for testing transverse compressive bearing capacity of FRP (fiber reinforced Plastic) rib-clamping piece |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104537259A (en) * | 2015-01-12 | 2015-04-22 | 北京航空航天大学 | Transverse isotropy fiber material performance prediction method based on micro-mechanical model |
| CN111855401A (en) * | 2020-06-28 | 2020-10-30 | 南京航空航天大学 | Method for predicting transverse tensile strength of coreless brittle fiber |
| CN112632819A (en) * | 2020-12-18 | 2021-04-09 | 沈阳航空航天大学 | Method for predicting basic mechanical property parameters of continuous fiber reinforced composite material |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7971491B2 (en) * | 2009-03-09 | 2011-07-05 | The Boeing Company | Apparatus and method for transverse tensile strength testing of materials at extreme temperatures |
| CN111209704B (en) * | 2020-01-07 | 2022-10-21 | 吉林大学 | Carbon fiber composite material dynamic shear strength testing method based on off-axis stretching |
-
2021
- 2021-07-30 CN CN202110870079.3A patent/CN113916651B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104537259A (en) * | 2015-01-12 | 2015-04-22 | 北京航空航天大学 | Transverse isotropy fiber material performance prediction method based on micro-mechanical model |
| CN111855401A (en) * | 2020-06-28 | 2020-10-30 | 南京航空航天大学 | Method for predicting transverse tensile strength of coreless brittle fiber |
| CN112632819A (en) * | 2020-12-18 | 2021-04-09 | 沈阳航空航天大学 | Method for predicting basic mechanical property parameters of continuous fiber reinforced composite material |
Non-Patent Citations (3)
| Title |
|---|
| SiC单纤维增强TC17复合材料横向拉伸性能研究;刘佳琳，等;《金属学报》;20181231;第54卷(第12期);1809-1817 * |
| TRANSVERSE STRENGTH OF SCS-6 SILICON-CARBIDE FIBERS;ELDRIDGE, JI，et al;《JOURNAL OF THE AMERICAN CERAMIC SOCIETY》;19931231;第76卷(第12期);3151-3154 * |
| 碳纤维复合材料横向拉伸件加强段铺层设计研究;燕展;《电子技术》;20201130;第49卷(第11期);44-46 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113916651A (en) | 2022-01-11 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN113916651B (en) | Method for testing transverse tensile strength of brittle fiber with inner core | |
| Smits et al. | Design of a cruciform specimen for biaxial testing of fibre reinforced composite laminates | |
| CN110501126B (en) | Beam structure damage identification method based on support counterforce and deflection curvature | |
| US7080561B2 (en) | Visual documentation of micro-cracks during tensile coupon testing | |
| Kalteremidou et al. | Effect of multiaxiality, stacking sequence and number of off-axis layers on the mechanical response and damage sequence of carbon/epoxy composite laminates under static loading | |
| Aratama et al. | Microscopic observation of voids and transverse crack initiation in CFRP laminates | |
| CN212110919U (en) | Concrete axle draws testing arrangement | |
| Zhao et al. | The effects of fiber orientation on failure behaviors of 2D C/SiC torque tube | |
| CN106596296A (en) | Single fiber interfacial shear strength testing method and device | |
| Wang et al. | Influence of realistic microscopic fiber misalignments on compressive damage mechanisms of 3D angle-interlock woven composites: In-situ measurements and numerical simulations | |
| Yu et al. | Transverse tensile mechanical experimental method and behavior of ceramic matrix mini-composites | |
| Jiang et al. | In-situ micro-CT damage analysis of carbon and carbon/glass hybrid laminates under tensile loading by image reconstruction and DVC technology | |
| Creighton et al. | The compressive strength of highly-aligned carbon-fibre/epoxy composites produced by pultrusion | |
| Liu et al. | An approach to design high-performance unidirectional CFRPs based on a new sensitivity analysis model | |
| Ten Busschen et al. | Mechanics of the segmentation of an embedded fiber, part I: experimental investigations | |
| CN108535099A (en) | A method of interface shear strength between characterization high-performance fiber and non-transparent resin matrix | |
| CN111855401A (en) | Method for predicting transverse tensile strength of coreless brittle fiber | |
| CN107389458A (en) | Balancing gate pit based on carbon fibre composite | |
| Alva et al. | High pressure burst testing of SiC f-SiC m composite nuclear fuel cladding | |
| Böhm et al. | Experimental investigation of the strain rate dependent behaviour of 2D biaxially and triaxially reinforced braided composites | |
| Rahman et al. | Effect of laser cutting on mechanical performance of woven glass fiber reinforced plastic composites | |
| Huang et al. | Damage failure analysis of flexible-oriented three-dimensional woven composites with void defects: An experimental and numerical study | |
| Wang et al. | A simple method for measuring the monofilament diameter of continuous filament yarn with high bending stiffness via synthetic laser imaging | |
| Benchekchou et al. | Stresses around fasteners in composite structures in flexure and effects on fatigue damage initiation part 1: cheese-head bolts | |
| CN113218767A (en) | In-situ test method for interface shear strength of fiber reinforced ceramic matrix composite |
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 | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |