Manufacturing method of multi-layer composite material sandwich panel

Abstract

The invention discloses a manufacturing method of a multi-layer composite material sandwich panel, and belongs to the technical field of composite materials, and the manufacturing method comprises the following steps: firstly forming by using a mold, then pressurizing, heating and curing to form a sandwich layer, and finally bonding a panel and a back plate; the sandwich board comprises a sandwich layer, a panel and a back board, wherein the panel and the back board are bonded on the two sides of the sandwich layer, and the sandwich layer is formed by filling fillers into a metal spring woven mesh surface support body and bonding the metal spring woven mesh surface support body. The filler is injected into the metal spring woven mesh surface supporting body to form the sandwich layer, the manufactured sandwich plate has the advantages of being light in weight, capable of being formed at a time, uniform in protection performance, resistant to repeated strike, simple in manufacturing process and the like, and when the sandwich plate is applied to armored equipment, good protection can be provided, maneuvering performance can be improved, and the service life of the armored equipment can be prolonged. And the cruising ability of the ground unmanned equipment can be further improved. The manufacturing process is simple, modular design can be achieved, the protection effect is good, the weight is light, and the large development prospect is achieved in the field of individual soldier protection devices.

Description

Technical Field

[0001] The invention belongs to the technical field of composite materials, and in particular relates to a method for manufacturing a multi-layer composite sandwich panel. Background Art

[0002] Currently, the most common armor protection structure used in armored vehicles is a "sandwich" structure of ceramics, aluminum foam, and armor steel, with the aluminum foam as the core layer. This structure suffers from poor secondary impact resistance, poor uniformity, heavy weight, and complex manufacturing processes. Therefore, there is an urgent need to develop a new lightweight composite armor material to provide armored vehicles with better protection. Summary of the Invention

[0003] In order to solve the above problems, the present invention provides a method for manufacturing a multi-layer composite sandwich panel.

[0004] To achieve the above object, the technical solutions adopted by the present invention are as follows: A method for manufacturing a multi-layer composite sandwich panel comprises the following steps: (1) Spring stress relief annealing (2) Braided metal spring braided mesh support The springs are linked in pairs to weave a layer of spring mesh, and then multiple layers are woven to make a multi-layer metal spring mesh support body; (3) Filling with PEEK material Inject half of the PEEK material into the mold, flatten it, and place the metal spring woven mesh support. Then add the other half of the PEEK material and close the mold. (4) Cold pressing and exhaust First, apply 5-7MPa of pressure to the mold, release it after compaction, then apply pressure again, and release it again; gradually increase the pressure during the process until the thickness of the sandwich layer reaches the process thickness and then stop cold pressing; (5) Hot pressing The mold is heated to 385-390℃ in a box-type resistance furnace. After the material is melted, the pressure needs to be repeatedly increased and released, and pressed down multiple times until the thickness of the finished sandwich layer is reached. (6) Cooling While maintaining the pressure, cool the mold at a rate of 40°C per minute. Release the pressure when the temperature of the sandwich layer in the mold is lower than 200°C. (7) Paste the front panel and back panel The face plate and the back plate are bonded on both sides of the sandwich layer to form a new multi-layer composite sandwich panel.

[0005] Furthermore, in step (4), the cold pressing process is carried out in three stages, with the intermediate layer being gradually pressed to the process thickness at pressing speeds of 10 mm / min, 10 mm / min, and 5 mm / min, respectively.

[0006] Furthermore, in step (5), the hot pressing process is as follows: first, the pressure is increased to 3 MPa for 15 minutes, and then the pressure is released; then, the pressure is increased to 6 MPa for 15 minutes, and then the pressure is released; finally, the pressure is increased to 8 MPa and the pressure is maintained for 60 minutes; 1) Hot pressing stage I - heating stage: start heating to 385℃, press down 8mm at a speed of 0.05mm / min during the heating process, and control the pressure within 1.5MPa; 2) Hot pressing stage II - temperature holding stage: press down 6 mm at a pressing speed of 0.2 mm / min at a temperature of 385°C, and control the pressure within 3 MPa;

[0007] 3) Hot pressing stage III: Press down 4 mm at a temperature of 385°C at a speed of 0.05 mm / min and the pressure is controlled within 6 MPa; 4) Hot pressing stage IV - furnace cooling pressing stage: press down 1mm at a pressing speed of 0.1mm / min, and control the pressure within 8MPa; After multiple pressings, the thickness of the sandwich layer is reached.

[0008] Furthermore, the metal spring braided mesh support body is braided from several layers of springs, the springs of each layer are arranged in parallel and connected in pairs, and the springs of two adjacent layers are connected in pairs up and down.

[0009] Furthermore, the spring is a right-handed compression spring.

[0010] Furthermore, the material of the spring is 65Mn or 0Cr19Ni10.

[0011] Compared with the prior art, the present invention has the following technical advances: By injecting fillers into a metal spring mesh support, this invention creates a novel multi-layer composite sandwich panel. While maintaining similar performance to traditional composite armor, it also boasts advantages such as lightweight, one-shot molding, uniform protective performance, resistance to repeated strikes, and a simple manufacturing process. When used in armored equipment, the multi-layer composite sandwich panel can provide superior protection and improved maneuverability, and can even enhance the endurance of unmanned ground equipment. Furthermore, the present invention boasts a simple manufacturing process, modular design, excellent protective effectiveness, and lightweight, promising future development in the field of individual soldier protective gear. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention.

[0013] In the attached figure: Figure 1 A schematic structural diagram of a multi-layer composite sandwich panel manufactured according to an embodiment of the present invention; Figure 2 is the chemical structural formula of polyetheretherketone; In the picture: 1-Metal spring woven mesh support; 2-Filling; 3-Panel; 4-Backboard. DETAILED DESCRIPTION

[0014] The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments. The embodiments of the present invention will be described below with reference to the accompanying drawings.

[0015] The present invention provides a method for manufacturing a multi-layer composite sandwich panel. The steps for manufacturing the multi-layer composite sandwich panel are as follows: (1) Spring stress relief annealing Place the spring in a box-type resistance furnace and heat it to 250℃, keep it warm for 30 minutes, and then gradually cool it down with the furnace temperature.

[0016] (2) Braided metal spring braided mesh support The right-handed compression springs formed by right-handed rotation of the spring are hooked together in pairs, and this process is repeated to weave a corresponding layer of spring mesh according to the size requirements, and then multiple layers are woven to make a multi-layer metal spring mesh support.

[0017] (3) Filling with PEEK material The PEEK material was dried in an electric blast drying oven, that is, dried at 150°C for 3 hours, or dried at 120°C overnight (10 hours).

[0018] Inject half of the PEEK material into the mold, flatten it, and place the metal spring woven mesh support. Then add the other half of the PEEK material and close the mold.

[0019] To ensure that the mold cavity is filled, the mold must be filled with 102% of the theoretical weight of PEEK (the additional 2% material is used to make the mold overflow); during the mold closing process, instantaneous high pressure should be avoided to protect the mold and facilitate exhaust.

[0020] (4) Cold pressing and exhaust Place the filled and closed mold into the universal testing machine. Applying a pressure of 5-7 MPa to the mold in advance helps to expel air from the mold before heating, shortening the melting time and improving the performance and surface quality of the test piece.

[0021] The specific process is: first compact under 1MPa pressure, then release after compaction, then pressurize, and then release (30s / time), gradually increasing the pressure during the process until the thickness of the sandwich layer is pressed to 40mm and then stop cold pressing. The specific cold pressing process is as follows: Cold pressing stage I: Press the middle layer to 60 mm at a pressing speed of 10 mm / min.

[0022] Cold pressing stage II: Press the middle layer to 50 mm at a pressing speed of 10 mm / min.

[0023] Cold pressing stage III: Press the middle layer to 40 mm at a pressing speed of 5 mm / min.

[0024] (5) Hot pressing The mold is heated to 385-390°C in a box-type resistance furnace, and the holding time is initially set to 90 minutes.

[0025] The specific process is: after the material is melted, it needs to be repeatedly pressurized and released, through the following hot pressing stages II, III, and IV, first increase the pressure to 3MPa for 15 minutes, and then release the pressure; then increase the pressure to 6MPa for 15 minutes, and then release the pressure; finally increase the pressure to 8MPa and maintain the pressure for 60 minutes.

[0026] 1) Hot pressing stage I - heating stage: start heating to 385°C, press down 8mm at a speed of 0.05mm / min during the heating process, and control the pressure within 1.5MPa.

[0027] 2) Hot pressing stage II - temperature holding stage: press down 6 mm at a pressing speed of 0.2 mm / min at a temperature of 385°C, and control the pressure within 3 MPa.

[0028] 3) Hot pressing stage III: Press down 4 mm at a pressing speed of 0.05 mm / min at a temperature of 385°C and the pressure is controlled within 6 MPa.

[0029] 4) Hot pressing stage IV - furnace cooling pressing stage: press down 1 mm at a pressing speed of 0.1 mm / min and control the pressure within 8 MPa.

[0030] (6) Cooling While maintaining pressure, cool the mold at a rate of 40°C per minute. Note that the cooling rate should not be too fast. Ensure that the temperature of the specimen is below 200°C before releasing the pressure.

[0031] The length, width, height and weight of the obtained sandwich layer were measured, and its physical parameters such as surface density and volume density were calculated. The length, width and height of the obtained sandwich layer were 150×150×20 mm, and the mass was 682 g.

[0032] (7) Paste the front panel and back panel The face plate 3 and the back plate 4 are bonded on both sides of the sandwich layer to form a multi-layer composite sandwich panel. Figure 1 As shown, the front panel 3 and the back panel 4 are bonded and fixed on both sides of the sandwich layer, and the sandwich layer is formed by filling the metal spring woven mesh support body 1 with the filler 2 and bonding it.

[0033] The metal spring braided mesh support 1 is constructed from several layers of springs, with the springs in each layer arranged side by side and interconnected in pairs. Adjacent layers of springs are interconnected in pairs. The springs are right-handed compression springs made of 65Mn or 0Cr19Ni10. This multi-layered braided metal spring mesh support significantly enhances support effectiveness.

[0034] In addition, filler 2 is made of PEEK material. PEEK, also known as polyetheretherketone, is a crystalline, opaque, light brown-gray aromatic super-heat-resistant thermoplastic resin. It is generally made by polycondensation of 4,4'-difluorobenzophenone or 4,4-dichlorobenzophenone and hydroquinone salt or sodium salt as raw materials. The chemical structure of polyetheretherketone is as follows: Figure 2 As shown, it has high temperature resistance, flame retardancy, radiation resistance, hydrolysis resistance, plasticity and good mechanical properties. At the same time, it has extremely excellent physical and mechanical properties, good vibration reduction ability, and makes outstanding contributions to reducing mass and improving performance.

[0035] The PEEK material used in the embodiments of the present invention is purchased from Jilin Zhongyan High Performance Engineering Plastics Co., Ltd., and its specific performance parameters are shown in the following table:

[0036] The multi-layer composite sandwich panel produced by the present invention has the following advantages: 1. The specific strength and specific stiffness of multi-layer composite sandwich panels are relatively high. The following table shows the physical parameters of multi-layer composite sandwich panels:

[0037] It can be seen that the new sandwich material effectively reduces weight by over 75% compared to steel, and the degree of weight reduction increases slightly with increasing height. This is because the density of the spring material is basically the same as that of steel. The weight reduction effect mainly depends on the PEEK content. Given a certain spring mass, a taller sandwich layer means less flash during molding, and a higher PEEK content means a lower density. However, the PEEK content should be controlled between 58% and 61% to achieve a balance between lightweight and protective performance.

[0038] 2. Excellent vibration damping performance. The sandwich layer material fully utilizes the shock-absorbing effect of springs. Using a spring mesh as the internal support for the metal matrix, the product's metal matrix provides high damping at the interface between the sandwich layer and the matrix, resulting in excellent vibration damping performance. When subjected to strong external impacts, the multi-layer composite sandwich panel provides excellent shock absorption and protection.

[0039] An impact tester was used to impact the foam aluminum and multi-layer composite sandwich panels respectively. The appropriate impact test height was selected. After calculation, the initial impact height was set at 800mm. If none of the test samples were damaged, the subsequent test impact heights were increased by an amount d (100mm) until one of the samples was damaged. If all of the test samples were damaged, the subsequent test impact heights were reduced by an amount d (100mm) until only one of the samples was damaged. A comparative conclusion on the relative impact resistance of the two was drawn (see the drop hammer impact test below for details).

[0040] After determining the impact resistance of the multi-layer composite sandwich panel and foam aluminum, we selected multi-layer composite sandwich panel samples for impact resistance test limit test, and set the initial impact height to 1200mm. During the test, if the first sample was not damaged, the height was increased by an increment d (100mm) when impacting the second sample. If the first sample was damaged, the height was reduced by an increment d (100mm) when impacting the second sample. The test was repeated in this way to determine the impact resistance of the material (see the impact resistance test below for details).

[0041] The performance test uses a drop hammer impact test to evaluate the protective properties of multi-layer composite sandwich panels. This test is conducted using an impact testing machine. This machine is designed to simulate impact environments for composite sandwich panels. It measures the degree of impact damage sustained by the product during use and can meet the impact test requirements for three types of pulses: half-sine wave (basic waveform), post-peak sawtooth wave, and trapezoidal wave.

[0042] The drop weight impact test process is as follows: The open-cell aluminum foam was cut into specimens of 150×150×20mm and subjected to comparative impact tests with multi-layer composite sandwich panels. The equipment used was a CL-50 impact test bench equipped with a KCL-2000 impact bench measurement and control instrument.

[0043] In the impact comparison experiment between multi-layer composite sandwich panel samples and foam aluminum, the initial impact height was set at 800mm.

[0044] First test: Drop hammer impact at 800mm height, no damage to the multi-layer composite sandwich panel or foam aluminum; Second test: Drop hammer at 900mm height. The multi-layer composite sandwich panel showed no damage, but the aluminum foam was slightly compressed. The third test: The hammer was dropped from a height of 1000mm. The multi-layer composite sandwich panel showed no obvious damage, but the foam aluminum collapsed. The fourth test: The hammer was dropped from a height of 1100mm. The multi-layer composite sandwich panel showed no obvious damage, but the foam aluminum showed obvious collapse. The fifth test: The hammer was dropped from a height of 1200mm. The multi-layer composite sandwich panel showed no obvious damage, but the foam aluminum exhibited severe collapse. The multi-layer composite sandwich panel samples were subjected to impact test limit test, and the initial impact height was set to 1200mm.

[0045] First test: The multi-layer composite sandwich panel showed no damage after being dropped from a height of 1200mm. Second test: The multi-layer composite sandwich panel was not damaged by the impact of the falling hammer at a height of 1200mm. The third test: The multi-layer composite sandwich panel was not damaged after the hammer was dropped from a height of 1300mm. The fourth test: The multi-layer composite sandwich panel was not damaged by the impact of the falling hammer at a height of 1300mm. The fifth test: The hammer was dropped from a height of 1400mm, resulting in slight cracks on the surface of the multi-layer composite sandwich panel. The sixth test: The hammer was dropped from a height of 1400mm, and the surface cracks of the multi-layer composite sandwich panel became more severe.

[0046] 3. Composite materials offer excellent safety. PEEK-filled sandwich panels contain internal springs that provide support and support. When such a sandwich panel is overloaded and a small number of fractures occur, the load is quickly redistributed and transferred to the intact springs, preventing the entire structure from losing its load-bearing capacity immediately.

[0047] 4. Simple molding process. Multilayer composite sandwich panels are generally suitable for integral molding and have a simple process. The steps for manufacturing multilayer composite sandwich panels are first forming the panels in a mold, then curing them under pressure and heat. During the manufacturing process, the matrix is transformed from powder to sheet, resulting in minimal material loss, and is less likely to cause microcracks during molding. Furthermore, residual stress after curing is minimal.

[0048] In summary, the multi-layer composite sandwich panels produced by this invention maintain similar performance to traditional composite armor while offering advantages such as lightweight, one-shot molding, uniform protective performance, resistance to repeated strikes, and a simple manufacturing process. Armor made from this material can be used to address vulnerable areas of armored vehicles such as tanks, self-propelled artillery, and infantry fighting vehicles, providing both superior protection and improved mobility. It can also enhance the endurance of unmanned ground equipment. Furthermore, this material's simple manufacturing process, modular design, excellent protective effectiveness, and light weight offer significant development prospects in the field of individual protective gear.

[0049] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A method for manufacturing a multi-layer composite sandwich panel, characterized in that: The following steps are involved: (1) Spring stress relief annealing (2) Braided metal spring braided mesh support The springs are linked in pairs to weave a layer of spring mesh, and then multiple layers are woven to make a multi-layer metal spring mesh support body; (3) Filling with PEEK material Inject half of the PEEK material into the mold, flatten it, and place the metal spring woven mesh support. Then add the other half of the PEEK material and close the mold. (4) Cold pressing and exhaust First, apply 5-7MPa of pressure to the mold, release it after compaction, then apply pressure again, and release it again; gradually increase the pressure during the process until the thickness of the sandwich layer reaches the process thickness and then stop cold pressing; (5) Hot pressing The mold is heated to 385-390℃ in a box-type resistance furnace. After the material is melted, the pressure needs to be repeatedly increased and released, and pressed down multiple times until the thickness of the finished sandwich layer is reached. (6) Cooling While maintaining the pressure, cool the mold at a rate of 40°C per minute. Release the pressure when the temperature of the sandwich layer in the mold is lower than 200°C. (7) Paste the front panel and back panel The face sheet and the back sheet are bonded to both sides of the sandwich layer to form a multi-layer composite sandwich panel.

2. The method for manufacturing a multi-layer composite sandwich panel according to claim 1, characterized in that: In step (4), the cold pressing process is carried out in three stages, with the middle layer gradually pressed to the process thickness at a pressing speed of 10 mm / min, 10 mm / min, and 5 mm / min respectively.

3. The method for manufacturing a multi-layer composite sandwich panel according to claim 1, characterized in that: In step (5), the hot pressing process is as follows: first, the pressure is increased to 3 MPa for 15 minutes, and then the pressure is released; then the pressure is increased to 6 MPa for 15 minutes, and then the pressure is released; finally, the pressure is increased to 8 MPa and the pressure is maintained for 60 minutes; 1) Hot pressing stage I - heating stage: start heating to 385℃, press down 8mm at a speed of 0.05mm / min during the heating process, and control the pressure within 1.5MPa; 2) Hot pressing stage II - temperature holding stage: press down 6 mm at a speed of 0.2 mm / min at 385°C, and control the pressure within 3 MPa; 3) Hot pressing stage III: Press down 4 mm at a temperature of 385°C at a speed of 0.05 mm / min and the pressure is controlled within 6 MPa; 4) Hot pressing stage IV - furnace cooling pressing stage: press down 1mm at a pressing speed of 0.1mm / min, and control the pressure within 8MPa; After multiple pressings, the thickness of the sandwich layer is reached.

4. The method for manufacturing a multi-layer composite sandwich panel according to claim 1, characterized in that: The metal spring braided mesh support body is braided from a plurality of layers of springs. The springs of each layer are arranged in parallel and are hooked in pairs. The springs of two adjacent layers are hooked in pairs in the upper and lower directions.

5. The method for manufacturing a multi-layer composite sandwich panel according to claim 1, characterized in that: The spring is a right-handed compression spring.

6. The method for manufacturing a multi-layer composite sandwich panel according to claim 1, characterized in that: The material of the spring is 65Mn or 0Cr19Ni10.

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