CN116858695A - Method for testing in-plane shear performance of sandwich structure composite material - Google Patents
Method for testing in-plane shear performance of sandwich structure composite material Download PDFInfo
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- CN116858695A CN116858695A CN202310754937.7A CN202310754937A CN116858695A CN 116858695 A CN116858695 A CN 116858695A CN 202310754937 A CN202310754937 A CN 202310754937A CN 116858695 A CN116858695 A CN 116858695A
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- reinforcing plate
- test panel
- plane shear
- test
- composite material
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- 238000012360 testing method Methods 0.000 title claims abstract description 114
- 238000000034 method Methods 0.000 title claims abstract description 25
- 239000002131 composite material Substances 0.000 title claims abstract description 17
- 230000003014 reinforcing effect Effects 0.000 claims abstract description 95
- 239000000463 material Substances 0.000 claims description 9
- 239000011180 sandwich-structured composite Substances 0.000 claims description 8
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 claims description 6
- 238000011056 performance test Methods 0.000 claims description 4
- 229910000838 Al alloy Inorganic materials 0.000 claims description 3
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 3
- 239000003365 glass fiber Substances 0.000 claims description 3
- 239000002904 solvent Substances 0.000 claims description 3
- 239000003822 epoxy resin Substances 0.000 claims 1
- 229920000647 polyepoxide Polymers 0.000 claims 1
- 238000005488 sandblasting Methods 0.000 claims 1
- 238000013461 design Methods 0.000 abstract description 9
- 239000011162 core material Substances 0.000 description 14
- 238000004519 manufacturing process Methods 0.000 description 3
- 239000004593 Epoxy Substances 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 239000000835 fiber Substances 0.000 description 2
- 238000010998 test method Methods 0.000 description 2
- 244000137852 Petrea volubilis Species 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 229920006332 epoxy adhesive Polymers 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 238000003801 milling Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
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
- G01N3/24—Investigating strength properties of solid materials by application of mechanical stress by applying steady shearing forces
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
-
- 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
- G01N3/02—Details
- G01N3/04—Chucks
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0014—Type of force applied
- G01N2203/0025—Shearing
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/04—Chucks, fixtures, jaws, holders or anvils
Abstract
The invention relates to a method for testing in-plane shear performance of a sandwich structure composite material, which comprises the following steps: preparing a test piece with a sandwich structure, wherein the test piece with the sandwich structure comprises a core plate, a non-test panel and a test panel, wherein the non-test panel and the test panel are adhered to the upper end face and the lower end face of the core plate; bonding three reinforcing plates, namely a middle reinforcing plate and two side reinforcing plates, on the test panel at intervals along the width, wherein a gap is formed between the middle reinforcing plate and the corresponding side reinforcing plate, and the middle reinforcing plate and the two side reinforcing plates extend out of the test panel in opposite directions respectively; saw slits corresponding to the gaps one by one are formed in the non-test panel, and the depth of each saw slit extends into the test piece; the problems of complex and low testing efficiency of the existing civil aviation cabin floor test fixture are solved through the design.
Description
Technical Field
The invention relates to the field of material mechanical property testing, in particular to a method for testing in-plane shear performance of a sandwich structure composite material.
Background
The sandwich structure composite material has the advantages of high specific stiffness, light weight, strong designability and the like, and is widely applied to the fields of aviation, aerospace, rail transit and the like. In the field of aerospace composite manufacturing, sandwich structured composite materials are used to manufacture wallboard, leading edge, passenger, cargo compartment floors, and the like. Wherein, the passenger cabin floor of civil aircraft belongs to secondary load bearing structure spare, needs to evaluate its in-plane shear performance.
A common test method for civil aviation cabin floors is ASTM D8067, which has a complex test fixture, as shown in patents 201520711183.8 and 201810279052.5. The tool clamp of the test method is complex, and the matching precision is high; the test specimens and the reinforcing sheets (2 reinforcing sheets are needed for each specimen) are subjected to numerical control milling to form a specified shape, and then are bonded by using an epoxy adhesive and punched on the test piece to adapt to the fixture; the fitting test piece and the test fixture need to be installed before testing. The process is complex, the operation is complex, the fixture is difficult to adapt after the test piece is punched, 40 screw nuts (specific torque) are needed to be screwed on each test piece, and the test efficiency is low.
Accordingly, there is an urgent need in the present invention to provide a method for testing in-plane shear performance of a composite material in a sandwich structure.
Disclosure of Invention
The invention aims to provide a method for testing in-plane shear performance of a sandwich structure composite material, which solves the problems of complex clamp and low testing efficiency of the existing civil aviation cabin floor test clamp.
The in-plane shear performance test method for the sandwich structure composite material comprises the following steps:
preparing a test piece with a sandwich structure, wherein the test piece with the sandwich structure comprises a core plate, a non-test panel and a test panel, wherein the non-test panel and the test panel are adhered to the upper end face and the lower end face of the core plate;
bonding three reinforcing plates, namely a middle reinforcing plate and two side reinforcing plates, on the test panel at intervals along the width, wherein a gap is formed between the middle reinforcing plate and the corresponding side reinforcing plate, and the middle reinforcing plate and the two side reinforcing plates extend out of the test panel in opposite directions respectively; saw slits corresponding to the gaps one by one are formed in the non-test panel, and the depth of each saw slit extends into the test piece;
preparing a clamp for clamping the reinforcing plates at two sides, wherein the clamp comprises a long plate, one side of the long plate is provided with a slot, the slot is connected with the reinforcing plate at the coming side through a detachable connecting piece, and the long plate is also provided with a second connecting hole for connecting with a stretching mechanism on a stretching machine;
the extending ends of the clamp and the middle reinforcing plate are respectively connected with a stretching mechanism on a stretching machine, and are loaded to a test piece to be destroyed according to a formulaObtaining in-plane shear strength of a test piece; wherein tau is in-plane shear strength in N/mm; f is a limit load, and the unit is N; b is the width of the test piece in mm, and the in-plane shear strength of the core material 1 is obtained.
Preferably, the kerf width is 2.5mm-3mm.
Preferably, both the non-test panel and the test panel are glass fiber reinforced epoxy panels.
Preferably, the test panel has a thickness of 0.2mm to 0.6mm.
Preferably, the detachable connecting piece comprises reinforcing plate connecting holes which are positioned on the long plate and correspond to the clamp connecting holes one by one, and fixing bolts which are in threaded connection with the reinforcing plate connecting holes, and the reinforcing plate connecting holes are communicated with the slots.
Preferably, the gap width between the middle reinforcing plate and the adjacent side reinforcing plate is 2.9mm-3.1mm.
Preferably, the length of the reinforcing plates is 95mm-125mm, the width is 22mm-24mm, and the thickness is 1.3mm-1.7mm.
Preferably, the reinforcing plate is made of aluminum alloy.
Preferably, the thickness of the clamp is 8mm-10mm; the width of the slot is 1.7mm-2.3mm, and the depth is 35mm-45mm.
Preferably, the reinforcing plate is sandblasted and then cleaned with volatile solvents such as acetone and alcohol.
Preferably, when the thickness of the test panel is consistent with that of the non-test panel, any one panel is selected to be stuck with the first reinforcing plate, the second reinforcing plate and the third reinforcing plate, and the other panels are provided with saw cuts; when the thickness of the test panel is inconsistent with that of the non-test panel, the thinner panel is selected to be adhered to the first reinforcing plate, the second reinforcing plate and the third reinforcing plate, and the thicker panel is selected to be provided with saw cuts.
Compared with the prior art, the method for testing the in-plane shear performance of the sandwich structure composite material has the following steps:
the method has the advantages of simple test piece processing mode, high assembly efficiency and simple calculation steps, so as to meet the requirements of in-plane shear test for efficiently evaluating the civil aviation cabin floor, and the method is also suitable for in-plane shear performance test evaluation of the general composite material sheet surface.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flow chart of a method for testing in-plane shear performance of a sandwich composite material according to the present invention;
FIG. 2 is a schematic view (perspective view) of the structure of the test piece according to the present invention;
FIG. 3 is a schematic view (perspective view) of the kerf structure of the present invention;
FIG. 4 is a schematic view (perspective view) of the assembly of the test piece of the present invention with the first reinforcing plate, the second reinforcing plate and the third reinforcing plate;
FIG. 5 is a schematic view (perspective view) of the structure of the clamp according to the present invention;
fig. 6 is an assembly schematic view (perspective view) of the jig and the first reinforcing plate, the second reinforcing plate and the third reinforcing plate according to the present invention.
Reference numerals illustrate:
1. a core plate; 2. a non-test panel; 21. sawing; 3. a test panel; 31. a middle reinforcing plate; 311. a first connection hole; 32. a side end reinforcing plate; 321. a clamp connection hole; 33. a gap; 4. a clamp; 41. a slot; 42. a second connection hole; 43. reinforcing plate connecting holes; 44. and (5) fixing bolts.
Detailed Description
The following description of the embodiments of the present invention will be made apparent and fully in view of the accompanying drawings, in which some, but not all embodiments of the invention are shown. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, are merely for convenience of describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.
The invention provides a method for testing in-plane shear performance of a sandwich structure composite material, which comprises the following steps: preparing a test piece with a sandwich structure, wherein the test piece with the sandwich structure comprises a core plate 1, a non-test panel 2 and a test panel 3, wherein the non-test panel 2 and the test panel 3 are adhered to the upper end face and the lower end face of the core plate 1;
three reinforcing plates are bonded on the test panel 3 along the width at intervals, namely a middle reinforcing plate 31 and two side reinforcing plates 32, a gap 33 is arranged between the middle reinforcing plate 31 and the corresponding side reinforcing plate 32, the middle reinforcing plate 31 and the two side reinforcing plates 32 extend out of the test panel 3 in opposite directions respectively, wherein a first connecting hole 311 is formed in the extending end of the middle reinforcing plate 31, and a clamp connecting hole 321 is formed in the extending end of the two side reinforcing plates 32;
saw slits 21 which are in one-to-one correspondence with the gaps 33 are arranged on the non-test panel 2, and the depth of each saw slit 21 extends into the core material 1;
preparing a clamp 4 for clamping the reinforcing plates 32 at two sides, wherein the clamp 4 comprises a long plate, one side of the long plate is provided with a slot 41, the slot 41 is connected with the reinforcing plate 32 at the coming side through a detachable connecting piece, and the long plate is also provided with a second connecting hole 42 for connecting with a stretching mechanism on a stretching machine;
the extending ends of the clamp 4 and the middle reinforcing plate 31 are respectively connected with a stretching mechanism on a stretching machine, and are loaded to the core material 1 to be destroyed according to the formula
Obtaining in-plane shear strength of a test piece; wherein tau is in-plane shear strength in N/mm; f is a limit load, and the unit is N; b is the width of the test piece in mm, and the in-plane shear strength of the core material 1 is obtained.
According to the invention, through the design, the core material 1 is processed into a cuboid which is (75+/-1) mm long and (75+/-1) mm thick and is not processed in the thickness direction of (75+/-1) mm, the fiber direction of the panel of the core material 1 is parallel to the edge direction of the core material 1, the upper end surface and the lower end surface of the core material 1 are respectively a non-test panel 2 and a test panel 3, the test panel 3 is polished by (120-300 meshes) sand paper, but the fibers of the test panel 3 cannot be exposed or damaged, then a middle reinforcing plate 31 and two side reinforcing plates 32 are stuck on the test panel 3, a gap 33 between the two side reinforcing plates 32 and the middle reinforcing plate 31 is 2.5-3 mm, then saw slits 21 corresponding to the upper and the lower gaps 33 are formed on the non-test panel 2, and the saw slits 21 extend into the core material 1;
the clamp 4 is connected with the side end reinforcing plate 32, the stretching mechanism of one side testing machine is connected with the first connecting hole 311 of the middle reinforcing plate 31, the stretching mechanism of the other side testing machine is connected with the clamp 4, and the testing machines on the two sides stretch from the left side and the right side respectively until the testing panel 3 bonded with the three reinforcing plates is damaged, so that the in-plane shear performance test of the sandwich structure composite material is completed.
The kerf 21 of this embodiment has a width of 2.5mm-3mm.
According to the invention, through the design, the non-test panel 2 is damaged, so that the performance measured by the method can only be the test panel 3 bonded with the reinforcing plate, and the experimental accuracy is ensured.
The non-test panel 2 and the test panel 3 of the present embodiment are both glass fiber reinforced epoxy panels.
The test panel 3 of this embodiment has a thickness of 0.2mm to 0.6mm.
Through the design, the invention ensures that experiments are carried out smoothly, and if the test panel 3 is too thick, the test accuracy can be affected.
The detachable connection member of the present embodiment includes reinforcing plate connection holes 43 located on the long plate in one-to-one correspondence with the jig connection holes 111, and fixing bolts 44 screwed with the respective reinforcing plate connection holes 43, the reinforcing plate connection holes 43 penetrating the insertion grooves 41.
According to the invention, through the design, the clamp 4 can be recycled, and the manufacturing cost is saved.
The width of the gap 33 between the middle reinforcing plate 31 and the adjacent side reinforcing plate 32 in this embodiment is 2.9mm to 3.1mm.
Through the design, the distance between the reinforcing plates cannot be too large, otherwise, the damage mode is affected, and the test data is inaccurate.
The length of the reinforcing plates of the embodiment is 95mm-125mm, the width is 22mm-24mm, and the thickness is 1.3mm-1.7mm.
The reinforcing plates of the embodiment are all made of aluminum alloy.
Through the design, the reinforcing plate is not broken when the testers at the two sides stretch from the left side and the right side respectively, and the smooth performance of the experiment is ensured.
The thickness of the clamp 4 of the embodiment is 8mm-10mm; the slot 41 has a width of 1.7mm-2.3mm and a depth of 35mm-45mm.
Through the design, the invention ensures that the side end reinforcing plate 32 can be inserted into the slot 41 and the overall stability of the clamp 4.
The reinforcing plate of this example was sandblasted and then cleaned with a volatile solvent such as acetone or alcohol.
Through the design, the surface of the reinforcing plate is cleaned and roughened, and the mechanical property and fatigue resistance of the reinforcing plate are improved.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the invention.
Claims (10)
1. The in-plane shear performance test method for the sandwich structure composite material is characterized by comprising the following steps of: the method comprises the following steps:
preparing a test piece with a sandwich structure, wherein the test piece with the sandwich structure comprises a core plate (1), a non-test panel (2) and a test panel (3), wherein the non-test panel (2) and the test panel (3) are adhered to the upper end face and the lower end face of the core plate (1);
three reinforcing plates are bonded on the test panel (3) along the width interval, namely a middle reinforcing plate (31) and two side end reinforcing plates (32), a gap (33) is formed between the middle reinforcing plate (31) and the corresponding side end reinforcing plate (32), the middle reinforcing plate (31) and the two side end reinforcing plates (32) extend out of the test panel (3) towards opposite directions respectively, wherein a first connecting hole (311) is formed in the extending end of the middle reinforcing plate (31), and a clamp connecting hole (321) is formed in the extending end of the two side end reinforcing plates (32); saw slits (21) which are in one-to-one correspondence with the gaps (33) are formed in the non-test panel (2), and the depth of each saw slit (21) extends into the test piece (1);
preparing a clamp (4) for clamping the reinforcing plates (32) at the two sides, wherein the clamp (4) comprises a long plate, one side of the long plate is provided with a slot (41), the slot (41) is connected with the reinforcing plate (32) at the coming side through a detachable connecting piece, and the long plate is also provided with a second connecting hole (42) for connecting with a stretching mechanism on a stretching machine;
the extending ends of the clamp (4) and the middle reinforcing plate (31) are respectively connected with a stretching mechanism on a stretching machine, and are loaded to the test piece (1) to be destroyed according to the formula
Obtaining in-plane shear strength of a test piece; wherein tau is in-plane shear strength in N/mm; f is a limit load, and the unit is N; b is the width of the test piece in mm, and the in-plane shear strength of the test piece (1) is obtained.
2. The method for in-plane shear performance testing of a sandwich structured composite material of claim 1, wherein: the width of the saw kerf (21) is 2.5mm-3mm.
3. The method for in-plane shear performance testing of a sandwich structured composite material of claim 2, wherein: the non-test panel (2) and the test panel (3) are both glass fiber reinforced epoxy resin panels.
4. A method for in-plane shear performance testing of a sandwich structured composite material according to claim 3, wherein: the thickness of the test panel (3) is 0.2mm-0.6mm.
5. The method for in-plane shear performance testing of a sandwich structure composite material of claim 4, wherein: the detachable connecting piece comprises reinforcing plate connecting holes (43) which are positioned on the long plate and correspond to the clamp connecting holes (321) one by one, and fixing bolts (44) which are in threaded connection with the reinforcing plate connecting holes (43), and the reinforcing plate connecting holes (43) are communicated with the slots (41).
6. The method for in-plane shear performance testing of a sandwich structure composite material of claim 5, wherein: the width of the gap (33) between the middle reinforcing plate (31) and the adjacent side reinforcing plate (32) is 2.9mm-3.1mm.
7. The method for in-plane shear performance testing of a sandwich structured composite material of claim 6, wherein: the length of the reinforcing plate is 95mm-125mm, the width is 22mm-24mm, and the thickness is 1.3mm-1.7mm.
8. The method for in-plane shear performance testing of a sandwich structured composite material of claim 7, wherein: the reinforcing plate is made of aluminum alloy.
9. The method for in-plane shear performance testing of a sandwich structured composite material of claim 8, wherein: the thickness of the clamp (4) is 8mm-10mm; the width of the slot (41) is 1.7mm-2.3mm, and the depth is 35mm-45mm.
10. The method for in-plane shear performance testing of a sandwich structured composite material of claim 9, wherein: the reinforcing plate is subjected to sand blasting treatment and then is cleaned by volatile solvents such as acetone, alcohol and the like.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310754937.7A CN116858695A (en) | 2023-06-26 | 2023-06-26 | Method for testing in-plane shear performance of sandwich structure composite material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310754937.7A CN116858695A (en) | 2023-06-26 | 2023-06-26 | Method for testing in-plane shear performance of sandwich structure composite material |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116858695A true CN116858695A (en) | 2023-10-10 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310754937.7A Pending CN116858695A (en) | 2023-06-26 | 2023-06-26 | Method for testing in-plane shear performance of sandwich structure composite material |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116858695A (en) |
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2023
- 2023-06-26 CN CN202310754937.7A patent/CN116858695A/en active Pending
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