Non-intrusive monitoring device and method for testing in-plane and thickness-direction integrated permeability of three-dimensional fabric preform

Abstract

The invention discloses a non-intrusive monitoring in-plane and thickness-direction integrated permeability testing device and method for a three-dimensional fabric preform. The device comprises a permeability testing die cavity system, a lifting compaction system, a vacuum generation system, a liquid injection and cleaning system and a signal detection and observation system. The non-intrusive sensing system has no influence on system sealing and permeability test liquid flowing in a three-dimensional fabric preform medium; a sample central point liquid injection mode can avoid a competitive effect caused by contact between permeability test liquid and the mold; accurate regulation and control of a compaction state are realized through a compression test of the three-dimensional fabric preform; the method is suitable for a three-dimensional fabric preform which is small in internal gap and cannot be provided with an intrusive sensor; the integrated measurement of the in-plane and thickness-direction permeability is realized, and a plurality of sets of molds do not need to be designed; and a liquid inlet pipeline and a cleaning pipeline are introduced, so that the test can be repeatedly carried out conveniently.

Description

Technical Field

[0001] The present invention relates to the field of testing the permeability characteristics of composite material reinforcement phases, and particularly to a non-invasive monitoring three-dimensional fabric preform in-plane and thickness-direction integrated permeability testing device and method that combines steady-state linear flow in the in-plane direction with unsteady point injection flow in the thickness direction and has controllable compaction force. Background Art

[0002] Three-dimensional fabric fiber preforms have the advantages of no delamination, variable cross-section, and near-net shape forming. The liquid molding process of three-dimensional fabric composites injects resin under pressure into a closed mold cavity to infiltrate the fabric preform and then cures and demolds to form a complex-shaped composite material, which can achieve high-efficiency and low-cost preparation of complex-shaped composites. However, during the process of resin flowing and impregnating the fabric preform, defects such as pores, dry spots, and resin enrichment are likely to form. Permeability can measure the ability of a porous medium to allow fluid to pass through, and it is the core parameter of the flow control equation of the porous medium. The local permeability difference is also the key factor for the formation of structural pores. The accurate determination of the three-dimensional fabric permeability helps to carry out simulation research on resin flowing and impregnating the fiber preform, and to achieve the prediction of defects such as pores and the optimization and control of the molding process.

[0003] Traditional permeability testing schemes usually focus on in-plane permeability testing. For example, patent documents CN106841005A and CN111337402A. However, due to the anisotropy of the mesoscopic structure of the three-dimensional fabric preform, the permeability in the thickness direction cannot be replaced by the in-plane permeability. Moreover, the measurement of the flow front in the thickness direction has the characteristics of short travel and inability to directly observe. Determining the permeability in the thickness direction has become a test difficulty. The measurement of the thickness-direction permeability is usually based on the one-dimensional unsteady line injection flow method (such as patent document CN117664826A) and its variants (such as the lamination method in patent document CN101819129A). However, when the resin contacts the mold edge in this method, an obvious race effect is likely to occur, which severely restricts the measurement accuracy of the permeability in the short-range case. Patent document CN103954743A discloses an invasive method of measuring the flow front in the thickness direction by embedding and pasting a fiber Bragg grating pressure sensor on an aluminum alloy thin plate. However, the invasive method is only applicable to laminated structures and is difficult to be extended to the general case of three-dimensional fabric preforms. Moreover, the invasive sensor method changes the original flow law of the resin and affects the accuracy of the test results. Therefore, it is necessary to propose a thickness-direction permeability measurement method based on the three-dimensional unsteady point injection flow method and build an in-plane / thickness-direction integrated permeability testing device. Summary of the Invention

[0004] In view of the above technical problems and deficiencies existing in the art, the present invention provides a non-invasive monitoring three-dimensional fabric preform in-plane / thickness-direction integrated permeability testing device and method that combines Darcy equation steady-state linear flow and non-steady-state radial flow to avoid race conditions and has controllable compaction force.

[0005] The specific technical solutions are as follows:

[0006] [1] A non-invasive monitoring three-dimensional fabric preform in-plane and thickness-direction integrated permeability testing device, comprising:

[0007] A permeability testing cavity system, including a transparent upper mold and a transparent lower mold; the transparent upper mold and the transparent lower mold are designed to be detachably and sealedly connected; the three-dimensional fabric preform is cuboid-shaped and placed between the transparent upper mold and the transparent lower mold; the upper surface of the transparent upper mold corresponding to the top surface of the three-dimensional fabric preform is provided with an opening, and holes I and II are respectively opened on the two side walls of the transparent upper mold corresponding to the two opposite side surfaces of the three-dimensional fabric preform, and the connection line of holes I and II is parallel to the trend of the other two opposite side surfaces of the three-dimensional fabric preform; the transparent lower mold is used to carry the three-dimensional fabric preform and is provided with hole one on the lower surface, and hole one and the opening on the upper surface of the transparent upper mold are vertically corresponding.

[0008] A lifting compaction system, used to control the vertical position of the transparent upper mold and / or the transparent lower mold and adjust the compaction degree of the three-dimensional fabric preform.

[0009] A vacuum generating system, connected to the opening on the upper surface of the transparent upper mold and / or hole I, used to provide a vacuum suction force.

[0010] A liquid injection and cleaning system, connected to hole one of the transparent lower mold and / or hole II, used to provide a permeability test liquid and a cleaning liquid for the permeability testing cavity system.

[0011] A signal detection and observation system, used for collecting the pressure difference of the permeability test liquid, the flow rate of the permeability test liquid, and the impregnation video signal, as well as processing the time-domain flow front signal.

[0012] In some embodiments, for the non-invasive monitoring three-dimensional fabric preform in-plane and thickness-direction integrated permeability testing device, the side wall of the transparent upper mold is marked with an ultraviolet photolithography scale for displaying the thickness of the three-dimensional fabric preform.

[0013] In some embodiments, for the non-invasive monitoring three-dimensional fabric preform in-plane and thickness-direction integrated permeability testing device, hole one and the opening on the upper surface of the transparent upper mold are respectively at the central positions of the lower surface of the transparent lower mold and the upper surface of the transparent upper mold, corresponding to the central axis of the three-dimensional fabric preform.

[0014] In some embodiments, for the non-invasive monitoring three-dimensional fabric preform in-plane and thickness-direction integrated permeability testing device, the lifting and compaction system includes a first ball screw linear guide slide, an upper locking ring, a second ball screw linear guide slide, and a lower locking ring;

[0015] The first ball screw linear guide slide and the upper locking ring are connected to the transparent upper mold by bolts for fixing the transparent upper mold;

[0016] The second ball screw linear guide slide and the lower locking ring are connected to the transparent lower mold by bolts for vertically adjusting the transparent lower mold to cooperate with the transparent upper mold to compact the three-dimensional fabric preform.

[0017] In some embodiments, for the non-invasive monitoring three-dimensional fabric preform in-plane and thickness-direction integrated permeability testing device, the vacuum generating system includes a vacuum pump, a liquid collecting buffer barrel, and a connecting pipe; the vacuum pump is connected to the liquid collecting buffer barrel, and the liquid collecting buffer barrel is connected to one end of the connecting pipe;

[0018] The liquid injection and cleaning system includes a permeability test liquid barrel, a liquid injection flow valve, a cleaning liquid barrel, a cleaning flow valve, a thickness-direction outlet on-off valve, and an in-plane-direction outlet on-off valve;

[0019] The signal detection and observation system includes an inlet flowmeter, an outlet flowmeter, a vacuum pressure gauge, a camera lens, a light source, a data acquisition and processing system, and an observation screen; the vacuum pressure gauge is arranged on the connecting pipeline between the vacuum pump and the liquid collecting buffer barrel; one end of the outlet flowmeter is connected to the other end of the connecting pipe, and the other end of the outlet flowmeter is connected to the opening on the upper surface of the transparent upper mold through the thickness-direction outlet on-off valve and to hole I through the in-plane-direction outlet on-off valve; one end of the inlet flowmeter is connected to hole one and / or hole II of the transparent lower mold, and the other end of the inlet flowmeter is connected to the permeability test liquid barrel through the liquid injection flow valve and to the cleaning liquid barrel through the cleaning flow valve; the camera lens is aligned with the permeability test cavity system, and the light source is used to provide a light environment required for the camera lens to collect signals; the data acquisition and processing system is connected to the vacuum pressure gauge, the inlet flowmeter, the outlet flowmeter, the camera lens, and the observation screen for processing the collected impregnation video signals and time-domain flow front signals and presenting them on the observation screen. The vacuum pressure gauge can be used to collect the pressure difference of the permeability test liquid, and the inlet flowmeter and the outlet flowmeter can be used to collect the flow rate of the permeability test liquid.

[0020] In some embodiments, for the non-invasive monitoring three-dimensional fabric preform in-plane and thickness-direction integrated permeability testing device, the non-invasive monitoring three-dimensional fabric preform in-plane and thickness-direction integrated permeability testing device further includes a cutting tooling for preparing three-dimensional fabric preforms with the internal yarn orientation at various angles to the outer shape direction of the three-dimensional fabric preform.

[0021] [2] A method for testing the in-plane permeability of a three-dimensional fabric preform by non-invasive monitoring, using the integrated in-plane and thickness-direction permeability testing device for three-dimensional fabric preforms by non-invasive monitoring described in [1];

[0022] The method for testing the in-plane permeability of a three-dimensional fabric preform by non-invasive monitoring includes:

[0023] Compacting the three-dimensional fabric preform to the required degree through a lifting and compaction system;

[0024] The vacuum generating system is connected to Hole I to provide a vacuum suction force;

[0025] The liquid injection and cleaning system provides a permeability test liquid, and the permeability test liquid flows through Hole II and Hole I in sequence;

[0026] The signal detection and observation system observes the pressure difference of the permeability test liquid and the flow rate of the permeability test liquid;

[0027] Calculate the permeability K of the three-dimensional fabric preform in the in-plane direction i based on the following formula (1) i :

[0028]

[0029] In formula (1), the in-plane direction i is consistent with the direction from Hole II to Hole I, is the volume flow rate of the permeability test liquid at equilibrium and stability during the test, η is the viscosity of the permeability test liquid, x is the distance between Hole II and Hole I, A is the side area of the three-dimensional fabric preform corresponding to Hole II, and ΔP is the pressure difference of the permeability test liquid between steady-state Hole II and Hole I.

[0030] In some embodiments, for the method for testing the in-plane permeability of a three-dimensional fabric preform by non-invasive monitoring described in [2], between any two adjacent independent permeability measurements, a cleaning liquid is injected into the permeability test cavity system through the liquid injection and cleaning system to clean and dry the mold and the three-dimensional fabric preform.

[0031] In some embodiments, for the method for testing the in-plane permeability of a three-dimensional fabric preform by non-invasive monitoring described in [2], the three-dimensional fabric preform is preset to be anisotropic, with two directions having local peak permeability characteristics, corresponding to the in-plane principal direction 1 and the in-plane principal direction 2 of the three-dimensional fabric preform respectively, and their respective corresponding in-plane principal direction permeabilities K1 and K2 are calculated based on the radial method, specifically including:

[0032] Prepare a first three-dimensional fabric preform, and record the cutting direction of the first three-dimensional fabric preform as the reference direction;

[0033] Prepare a second three-dimensional fabric preform, and its cutting direction forms a 45° angle with the reference direction;

[0034] Prepare a third three-dimensional fabric preform, the cutting direction of which forms a 90° angle with the reference direction;

[0035] Place the first three-dimensional fabric preform on the transparent lower mold, and calculate the in-plane permeability K of the first three-dimensional fabric preform according to Equation (1) 0 ;

[0036] Place the second three-dimensional fabric preform on the transparent lower mold, and calculate the in-plane permeability K of the second three-dimensional fabric preform according to Equation (1) 45 ;

[0037] Place the third three-dimensional fabric preform on the transparent lower mold, and calculate the in-plane permeability K of the third three-dimensional fabric preform according to Equation (1) 90 ;

[0038] Calculate the permeabilities K1 and K2 of the in-plane principal directions 1 and 2 of the three-dimensional fabric preform according to the following Equations (2) to (4):

[0039]

[0040] [3] A method for testing the thickness-direction permeability of a three-dimensional fabric preform by non-invasive monitoring, using the non-invasive monitoring integrated in-plane and thickness-direction permeability testing device for three-dimensional fabric preforms described in [1];

[0041] The method for testing the thickness-direction permeability of a three-dimensional fabric preform by non-invasive monitoring includes:

[0042] Compress the three-dimensional fabric preform to the required degree through the lifting and compaction system;

[0043] The vacuum generation system is connected to the openings on the upper surface of the transparent upper mold to provide a vacuum suction force;

[0044] The liquid injection and cleaning system provides a permeability test liquid, and the permeability test liquid flows through the first hole of the transparent lower mold and the openings on the upper surface of the transparent upper mold in sequence;

[0045] The signal detection and observation system collects the pressure difference of the permeability test liquid, the flow rate of the permeability test liquid and the impregnation video signal, and processes the time-domain flow front signal, and performs M samplings during the period when the permeability test liquid enters the first hole of the transparent lower mold and has not flowed out of the openings on the upper surface of the transparent upper mold;

[0046] Taking the moment when the permeability test liquid reaches the first hole of the transparent lower mold as the zero moment and starting timing from this moment, calculate the thickness-direction permeability K of the three-dimensional fabric preform at the m-th sampling according to the following Equations (5) to (9) z,m , m = 1, 2, …, M, and then calculate K according to the following Equation (10)z As the permeability in the thickness direction of the final three-dimensional fabric preform:

[0047]

[0048]

[0049] Where: ΔP m is the hydraulic pressure difference for permeability testing between the first hole of the transparent lower mold and the opening on the upper surface of the transparent upper mold during the m-th sampling, t m is the time during the m-th sampling, r inlet is the radius of the first hole of the transparent lower mold, η is the viscosity of the permeability testing liquid, V f is the percentage of the fiber volume content in the three-dimensional fabric preform under the current compaction state, K e,m is the in-plane equivalent permeability during the m-th sampling, ξ f,m is the ellipsoidal coordinate parameter of the three-dimensional fabric preform being penetrated during the m-th sampling, satisfying and z f,m are respectively the in-plane equivalent flow front and the thickness-direction flow front of the three-dimensional fabric preform during the m-th sampling, x f,m 、y f,m are respectively the flow fronts in the directions of the major semi-axis and the minor semi-axis of the ellipsoid of the three-dimensional fabric preform being penetrated, located in the plane of the three-dimensional fabric preform during the m-th sampling;

[0050] z f,m is calculated according to the following formula (11):

[0051]

[0052] In formula (11), is the instantaneous volume flow rate of the permeability testing liquid at the first hole of the transparent lower mold during the m-th sampling.

[0053] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0054] 1) The non-invasive sensing system adopted by the present invention will not affect the system sealing and the flow of permeability testing liquids such as silicone oil in the three-dimensional fabric preform medium, significantly improving the testing accuracy;

[0055] 2) The liquid injection method at the center point in the thickness direction of the sample adopted by the preferred scheme of the present invention can avoid the race effect caused by the contact between permeability testing liquids such as silicone oil and the mold, significantly improving the testing accuracy;

[0056] 3) The present invention realizes the precise control of the compaction state through the compression test of the three-dimensional fabric preform;

[0057] 4) The present invention is particularly applicable to three-dimensional fabric preforms with relatively small internal voids where it is impossible to install intrusive sensors, significantly reducing the measurement difficulty;

[0058] 5) The present invention realizes the integrated measurement of in-plane and thickness-direction permeability without the need to design multiple sets of molds;

[0059] 6) The present invention introduces two sets of pipelines for liquid injection and cleaning, facilitating the repeated conduct of tests. Description of the Drawings

[0060] Figure 1 FIG. is a schematic structural diagram of an in-plane and thickness-direction integrated permeability test device for a three-dimensional fabric preform in the specific embodiment of the present invention, where: (a) is a top view structural diagram of the device during in-plane direction permeability test, and (b) is a side view structural diagram of the device during thickness-direction permeability test; in the figure: 1 - transparent upper mold, 2 - transparent lower mold, 3 - seal, 4 - three-dimensional fabric preform, 5 - first ball screw linear guide slide, 6 - upper locking ring, 7 - second ball screw linear guide slide, 8 - lower locking ring, 9 - vacuum pump, 10 - liquid collection buffer barrel, 11 - vacuum pressure gauge, 12 - connecting pipe, 13 - permeability test liquid barrel, 14 - liquid injection flow valve, 15 - cleaning liquid barrel, 16 - cleaning flow valve, 17 - thickness-direction outlet on-off valve, 18 - in-plane direction outlet on-off valve, 19 - inlet flowmeter, 20 - outlet flowmeter, 21 - camera lens, 22 - light source, 23 - data acquisition and processing system, 24 - observation screen.

[0061] Figure 2 FIG. is a schematic structural diagram of the cutting tooling in the specific embodiment of the present invention. Specific Embodiments

[0062] The present invention will be further described below in conjunction with the drawings and specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. The operating methods without specific conditions noted in the following embodiments are usually in accordance with conventional conditions or in accordance with the conditions recommended by the manufacturer.

[0063] See Figure 1 , an in-plane and thickness-direction integrated permeability test device for a three-dimensional fabric preform with non-intrusive monitoring, comprising a permeability test cavity system, a lifting and compaction system, a vacuum generation system, a liquid injection and cleaning system, and a signal detection and observation system.

[0064] The permeability test cavity system includes a transparent upper mold 1 and a transparent lower mold 2. The transparent upper mold 1 and the transparent lower mold 2 are designed to be detachably and sealingly connected, and specifically, the sealing connection can be achieved through the cooperation of a seal 3 (such as a sealing ring, etc.). The three-dimensional fabric preform 4 is cuboid-shaped and is placed between the transparent upper mold 1 and the transparent lower mold 2. The upper surface of the transparent upper mold 1 corresponding to the top surface of the three-dimensional fabric preform 4 is provided with an opening. On the two side walls of the transparent upper mold 1 corresponding to the two opposite side surfaces of the three-dimensional fabric preform 4 respectively, a hole I and a hole II are opened, and the connection line of the hole I and the hole II is parallel to the trend of the other two opposite side surfaces of the three-dimensional fabric preform 4. The side wall of the transparent upper mold 1 is marked with ultraviolet lithography scales for displaying the thickness of the three-dimensional fabric preform 4 inside it. The transparent lower mold 2 is used to carry the three-dimensional fabric preform 4, and a hole one is opened on the lower surface. The hole one and the opening on the upper surface of the transparent upper mold 1 are vertically corresponding, and the hole one and the opening on the upper surface of the transparent upper mold 1 are respectively at the center positions of the lower surface of the transparent lower mold 2 and the upper surface of the transparent upper mold 1, corresponding to the central axis of the three-dimensional fabric preform 4.

[0065] The lifting and compaction system is used to control the vertical positions of the transparent upper mold 1 and / or the transparent lower mold 2 and adjust the compaction degree of the three-dimensional fabric preform 4. The lifting and compaction system includes a first ball screw linear guide slide 5, an upper locking ring 6, a second ball screw linear guide slide 7, and a lower locking ring 8. The first ball screw linear guide slide 5 and the upper locking ring 6 are connected to the transparent upper mold 1 through bolts for fixing the transparent upper mold 1. The second ball screw linear guide slide 7 and the lower locking ring 8 are connected to the transparent lower mold 2 through bolts for adjusting the transparent lower mold 2 up and down to cooperate with the transparent upper mold 1 to compact the three-dimensional fabric preform 4.

[0066] The vacuum generating system is connected to the opening on the upper surface of the transparent upper mold 1 and / or the hole I for providing vacuum suction. The vacuum generating system includes a vacuum pump 9, a liquid collecting buffer bucket 10, and a connecting pipe 12.

[0067] The liquid injection and cleaning system is connected to the hole one and / or the hole II of the transparent lower mold 2 for providing a permeability test liquid and a cleaning liquid for the permeability test cavity system. The liquid injection and cleaning system includes a permeability test liquid bucket 13, a liquid injection flow valve 14, a cleaning liquid bucket 15, a cleaning flow valve 16, a through-off valve 17 in the thickness direction, and a through-off valve 18 in the in-plane direction.

[0068] The signal detection and observation system is used for collecting the pressure difference of the permeability test liquid, the flow rate of the permeability test liquid, and the impregnation video signal, as well as processing the time-domain flow front signal. The signal detection and observation system includes an inlet flowmeter 19, an outlet flowmeter 20, a vacuum pressure gauge 11, a camera lens 21, a light source 22, a data acquisition and processing system 23, and an observation screen 24.

[0069] The vacuum pump 9 is connected to the liquid collection buffer barrel 10. The vacuum pressure gauge 11 is arranged on the connecting pipeline between the vacuum pump 9 and the liquid collection buffer barrel 10. One end of the liquid collection buffer barrel 10 is connected to one end of the connecting pipe 12. One end of the outlet flowmeter 20 is connected to the other end of the connecting pipe 12. The other end of the outlet flowmeter 20 is connected to the opening on the upper surface of the transparent upper mold 1 through the thickness-direction outlet on-off valve 17 and connected to hole I through the in-plane-direction outlet on-off valve 18. One end of the inlet flowmeter 19 is connected to hole one and / or hole II of the transparent lower mold 2. The other end of the inlet flowmeter 19 is connected to the permeability test liquid barrel 13 through the injection liquid flow valve 14 and connected to the cleaning liquid barrel 15 through the cleaning liquid flow valve 16. The camera lens 21 is aligned with the permeability test cavity system. The light source 22 is used to provide the bright environment required for the camera lens 21 to collect signals. The data acquisition and processing system 23 is connected to the vacuum pressure gauge 11, the inlet flowmeter 19, the outlet flowmeter 20, the camera lens 21 and the observation screen 24, and is used to process the collected impregnation video signals and time-domain flow front signals and present them on the observation screen. The pressure difference of the permeability test liquid can be collected by the vacuum pressure gauge 11, and the flow rate of the permeability test liquid can be collected by the inlet flowmeter 19 and the outlet flowmeter 20.

[0070] Based on the universal testing machine and the compression tooling, the load-displacement response curve under the compression condition of the three-dimensional fabric preform 4 can be obtained, and the compression amount of the three-dimensional fabric preform 4 under the specified pressure state can be deduced.

[0071] The non-invasive monitoring three-dimensional fabric preform in-plane and thickness-direction integrated permeability testing device of this embodiment further includes a cutting tooling, which is used to prepare three-dimensional fabric preforms with the internal yarn orientation at various angles to the outer shape direction of the three-dimensional fabric preform. See Figure 2 , fix the hollow manganese steel tool B on the flat upper mold A. The flat upper mold A is connected to the guide sleeve C. Place the buffer pad E and the three-dimensional fabric preform 4 on the flat lower mold F in sequence. The flat lower mold F is connected to the column D. Subsequently, connect the guide sleeve C and the column D. The whole cutting tooling is placed in the flat press. The three-dimensional fabric preform 4 is placed in the designed direction, and the pressure is gradually increased until the tool B touches the buffer pad E to achieve cutting. Place the cut three-dimensional fabric preform 4 on the platform of the transparent lower mold 2. By observing the ultraviolet photolithography scale on the side wall of the transparent upper mold 1, the rocker of the second ball screw linear guide slide 7 drives the transparent lower mold 2 to press the three-dimensional fabric preform 4 until it just touches the transparent upper mold 1. Further increase the compression amount to realize the regulation of the specified pressure state, so that the lower surface of the three-dimensional fabric preform 4 is closely attached to the transparent lower mold 2, and lock the second ball screw linear guide slide 7.

[0072] Combined with Figure 1 (a), the non-invasive monitoring three-dimensional fabric preform in-plane direction permeability testing method using the above non-invasive monitoring three-dimensional fabric preform in-plane and thickness-direction integrated permeability testing device includes:

[0073] The three-dimensional fabric preform 4 is compacted to the required degree by a lifting and compaction system;

[0074] The vacuum generating system is connected to Hole I to provide a vacuum suction force;

[0075] The liquid injection and cleaning system provides a permeability test liquid, and the permeability test liquid flows through Hole II and Hole I in sequence;

[0076] The signal detection and observation system observes the pressure difference of the permeability test liquid and the flow rate of the permeability test liquid;

[0077] Calculate the permeability K of the three-dimensional fabric preform in the in-plane direction i based on the following formula (1) i :

[0078]

[0079] In formula (1), the in-plane direction i is consistent with the direction from Hole II to Hole I, is the volume flow rate of the permeability test liquid at equilibrium and stability during the test, η is the viscosity of the permeability test liquid, x is the distance between Hole II and Hole I, A is the side area of the three-dimensional fabric preform corresponding to Hole II, and ΔP is the pressure difference of the permeability test liquid between the steady-state Hole II and Hole I, which can be obtained through the vacuum pressure gauge 11.

[0080] During specific operation, when measuring the in-plane direction permeability, close the liquid injection flow valve 14, the cleaning flow valve 16, and the thickness direction outlet on-off valve 17, open the in-plane direction outlet on-off valve 18, connect and turn on the signal detection and observation system, pump to a system vacuum degree close to 0.1 MPa through the vacuum pump 9, maintain the vacuum environment for 2 to 3 minutes, inject dimethyl silicone oil with a viscosity of 100 cs dyed with oil-soluble pigment into the permeability test liquid bucket 13, open the liquid injection flow valve 14, and the silicone oil flows through the liquid injection flow valve 14, the inlet flowmeter 19, the three-dimensional fabric preform 4, the in-plane direction outlet on-off valve 18, and the outlet flowmeter 20 into the liquid collection buffer bucket 10. Adjust the camera lens 21 and the light source 22 to ensure the best shooting state.

[0081] Between any two adjacent independent permeability measurements, inject a cleaning liquid into the permeability test cavity system through the liquid injection and cleaning system to clean and dry the mold and the three-dimensional fabric preform 4. Specifically, between two adjacent independent permeability measurements, it is necessary to inject alcohol into the cleaning liquid bucket 15, close the liquid injection flow valve 14, open the cleaning flow valve 16, clean for 1 to 2 minutes, take out the hose in the cleaning liquid bucket 15, unlock the second ball screw linear guide slide 7 and the lower locking ring 8, take out the three-dimensional fabric preform and the transparent lower mold 2 for drying, then put in a new three-dimensional fabric preform, bolt-connect the transparent lower mold 2 and the seal 3 to the lower locking ring 8, and conduct the test.

[0082] For the anisotropic three-dimensional fabric preform 4, the three-dimensional fabric preform 4 has two directions with local peak permeability characteristics, corresponding to the in-plane principal direction 1 and the principal direction 2 of the three-dimensional fabric preform 4 respectively. The in-plane principal direction permeabilities K1 and K2 corresponding to them are calculated based on the radial method, specifically including:

[0083] Prepare a first three-dimensional fabric preform, and record the cutting direction of the first three-dimensional fabric preform as the reference direction;

[0084] Prepare a second three-dimensional fabric preform, the cutting direction of which forms a 45° angle with the reference direction;

[0085] Prepare a third three-dimensional fabric preform, the cutting direction of which forms a 90° angle with the reference direction;

[0086] Place the first three-dimensional fabric preform on the transparent lower mold, and calculate the in-plane direction permeability K of the first three-dimensional fabric preform according to Equation (1) 0 ;

[0087] Place the second three-dimensional fabric preform on the transparent lower mold, and calculate the in-plane direction permeability K of the second three-dimensional fabric preform according to Equation (1) 45 ;

[0088] Place the third three-dimensional fabric preform on the transparent lower mold, and calculate the in-plane direction permeability K of the third three-dimensional fabric preform according to Equation (1) 90 ;

[0089] Calculate the permeabilities K1 and K2 of the in-plane principal direction 1 and the principal direction 2 of the three-dimensional fabric preform according to the following Equations (2) to (4):

[0090]

[0091]

[0092] Combined with Figure 1 (b), the non-invasive monitoring method for the thickness direction permeability of the three-dimensional fabric preform using the above-mentioned non-invasive monitoring device for the integrated in-plane and thickness direction permeability of the three-dimensional fabric preform includes:

[0093] Compress the three-dimensional fabric preform 4 to the required degree through the lifting and compaction system;

[0094] The vacuum generating system is connected to the opening on the upper surface of the transparent upper mold 1 to provide a vacuum suction force;

[0095] The liquid injection and cleaning system provides a permeability test liquid, and the permeability test liquid flows through the first hole of the transparent lower mold 2 and the opening on the upper surface of the transparent upper mold 1 in sequence;

[0096] The signal detection and observation system conducts hydraulic pressure difference tests for permeability, collects the flow rate of the permeability test liquid and the impregnation video signal, and processes the time-domain flow front signal. M samplings are performed during the period when the permeability test liquid enters the hole 1 of the transparent lower mold 2 and has not yet flowed out of the opening on the upper surface of the transparent upper mold 1.

[0097] Taking the moment when the permeability test liquid reaches the hole 1 of the transparent lower mold 2 as the zero moment and starting timing from this moment, calculate the permeability K in the thickness direction of the three-dimensional fabric preform 4 at the m-th sampling according to the following formulas (5) - (9): z,m , m = 1, 2, …, M, and then calculate K according to the following formula (10): z As the final permeability in the thickness direction of the three-dimensional fabric preform 4:

[0098]

[0099] Where: ΔP m is the hydraulic pressure difference of the permeability test liquid between the hole 1 of the transparent lower mold 2 and the opening on the upper surface of the transparent upper mold 1 at the m-th sampling, which can be obtained through the vacuum pressure gauge 11, t m is the time at the m-th sampling, r inlet is the radius of the hole 1 of the transparent lower mold 2, η is the viscosity of the permeability test liquid, V f is the percentage of the fiber volume content in the three-dimensional fabric preform 4 under the current compaction state, K e,m is the in-plane equivalent permeability at the m-th sampling, ξ f,m is the ellipsoidal coordinate parameter of the three-dimensional fabric preform 4 being penetrated at the m-th sampling, satisfying and z f,m are the in-plane equivalent flow front and the thickness-direction flow front of the three-dimensional fabric preform 4 at the m-th sampling respectively, x f,m 、y f,m are the flow fronts in the major semi-axis and minor semi-axis directions of the ellipsoid penetrated by the three-dimensional fabric preform 4 in the plane of the three-dimensional fabric preform 4 at the m-th sampling respectively;

[0100] z f,m is calculated according to the following formula (11):

[0101]

[0102] In formula (11), is the instantaneous volume flow rate of the permeability test liquid at the hole 1 of the transparent lower mold 2 at the m-th sampling.

[0103] For example, M can be 10.

[0104] In addition, it should be understood that after reading the above description of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application.

Claims

1. A three-dimensional fabric preform in-plane and thickness-direction integrated permeability testing device for non-invasive monitoring, characterized in that, Comprising: A permeability test cavity system, including a transparent upper mold and a transparent lower mold; the transparent upper mold and the transparent lower mold are designed to be detachably and hermetically connected; the three-dimensional fabric preform is cuboid-shaped and placed between the transparent upper mold and the transparent lower mold; the upper surface of the transparent upper mold corresponding to the top surface of the three-dimensional fabric preform is provided with an opening, and holes I and II are respectively opened on the two side walls of the transparent upper mold corresponding to the two opposite side surfaces of the three-dimensional fabric preform, and the connection line of holes I and II is parallel to the trend of the other two opposite side surfaces of the three-dimensional fabric preform; the lower surface of the transparent lower mold for carrying the three-dimensional fabric preform is provided with a hole 1, and hole 1 is vertically corresponding to the opening on the upper surface of the transparent upper mold. A lifting and compaction system, used to control the vertical position of the transparent upper mold and / or the transparent lower mold and adjust the compaction degree of the three-dimensional fabric preform. A vacuum generating system, connected to the opening on the upper surface of the transparent upper mold and / or hole I, used to provide a vacuum suction force. A liquid injection and cleaning system, connected to hole 1 of the transparent lower mold and / or hole II, used to provide a permeability test liquid and a cleaning liquid for the permeability test cavity system. A signal detection and observation system, used for collecting the pressure difference of the permeability test liquid, the flow rate of the permeability test liquid, and the impregnation video signal, as well as processing the time-domain flow front signal.

2. The in-plane and thickness-direction integrated permeability testing device for the three-dimensional fabric preform of non-invasive monitoring according to claim 1, wherein The side wall of the transparent upper mold is marked with an ultraviolet photolithography scale, used to display the thickness of the three-dimensional fabric preform.

3. The in-plane and thickness-direction integrated permeability testing device for the three-dimensional fabric preform of non-invasive monitoring according to claim 1, characterized in that Hole 1 and the opening on the upper surface of the transparent upper mold are respectively at the central positions on the lower surface of the transparent lower mold and the upper surface of the transparent upper mold, corresponding to the central axis of the three-dimensional fabric preform.

4. The in-plane and thickness-direction integrated permeability testing device for the three-dimensional fabric preform of non-invasive monitoring according to claim 1, wherein The lifting and compaction system includes a first ball screw linear guide slide, an upper locking ring, a second ball screw linear guide slide, and a lower locking ring. The first ball screw linear guide slide and the upper locking ring are connected to the transparent upper mold by bolts, used to fix the transparent upper mold. The second ball screw linear guide slide and the lower locking ring are connected to the transparent lower mold by bolts, used to adjust the transparent lower mold up and down to cooperate with the transparent upper mold to compact the three-dimensional fabric preform.

5. The in-plane and thickness-direction integrated permeability testing device for the three-dimensional fabric preform of non-invasive monitoring according to claim 1, characterized in that, The vacuum generating system includes a vacuum pump, a liquid collection buffer barrel, and a connecting pipe; the vacuum pump is connected to the liquid collection buffer barrel, and the liquid collection buffer barrel is connected to one end of the connecting pipe. The liquid injection and cleaning system includes a permeability test liquid barrel, a liquid injection flow valve, a cleaning liquid barrel, a cleaning flow valve, a through-off valve in the thickness direction, and a through-off valve in the in-plane direction. The signal detection and observation system includes an inlet flowmeter, an outlet flowmeter, a vacuum pressure gauge, a camera lens, a light source, a data acquisition and processing system, and an observation screen; the vacuum pressure gauge is arranged on the connecting pipeline between the vacuum pump and the liquid collection buffer tank; one end of the outlet flowmeter is connected to the other end of the connecting pipeline, and the other end of the outlet flowmeter is connected to the opening on the upper surface of the transparent upper mold through a thickness-direction outlet on-off valve and connected to hole I through an in-plane direction outlet on-off valve; one end of the inlet flowmeter is connected to hole 1 and / or hole II of the transparent lower mold, and the other end of the inlet flowmeter is connected to the permeability test liquid tank through a liquid injection flow valve and connected to the cleaning liquid tank through a cleaning flow valve; the camera lens is aligned with the permeability test cavity system, and the light source is used to provide a bright environment required for the camera lens to collect signals; the data acquisition and processing system is connected to the vacuum pressure gauge, the inlet flowmeter, the outlet flowmeter, the camera lens, and the observation screen, and is used to process the collected impregnation video signals and time-domain flow front signals and present them on the observation screen.

6. The in-plane and thickness-direction integrated permeability testing device for the three-dimensional fabric preform of non-invasive monitoring according to claim 1, wherein, The non-invasive monitoring three-dimensional fabric preform in-plane and thickness-direction integrated permeability test device further includes a cutting tooling, and the cutting tooling is used to prepare three-dimensional fabric preforms with internal yarn orientations at various angles to the outer shape direction of the three-dimensional fabric preform.

7. A method for testing the in-plane permeability of a three-dimensional fabric preform for non-invasive monitoring, characterized in that, Use the non-invasive monitoring three-dimensional fabric preform in-plane and thickness-direction integrated permeability test device according to any one of claims 1 to 6; The non-invasive monitoring three-dimensional fabric preform in-plane direction permeability test method includes: Compress the three-dimensional fabric preform to the required degree through a lifting and compaction system; The vacuum generation system is connected to hole I to provide a vacuum suction force; The liquid injection and cleaning system provides a permeability test liquid, and the permeability test liquid flows through hole II and hole I in sequence; The signal detection and observation system observes the pressure difference of the permeability test liquid and the flow rate of the permeability test liquid; Calculate the permeability \(K\) of the 3D fabric preform in the in-plane direction \(i\) based on the following formula (1) i :[[-END]] In formula (1), the in-plane direction i is consistent with the direction from hole II to hole I. is the volume flow rate of the permeability test liquid at equilibrium and stability during the test, η is the viscosity of the permeability test liquid, x is the distance between hole II and hole I, A is the side area of the three-dimensional fabric preform corresponding to hole II, and ΔP is the pressure difference of the permeability test liquid between steady-state hole II and hole I.

8. The method for testing the in-plane direction permeability of the three-dimensional fabric preform for non-invasive monitoring according to claim 7, characterized in that, Between any two adjacent independent permeability measurements, the liquid injection and cleaning system injects a cleaning liquid into the permeability test cavity system to clean and dry the mold and the three-dimensional fabric preform.

9. The method for testing the in-plane direction permeability of a three-dimensional fabric preform for non-invasive monitoring according to claim 7 or 8, characterized in that, The three-dimensional fabric preform is preset to be anisotropic and has two directions with local peak permeability characteristics, which respectively correspond to the in-plane main direction 1 and the main direction 2 of the three-dimensional fabric preform. The in-plane main direction permeabilities K1 and K2 corresponding to them are calculated based on the radial method, specifically including: Prepare a first three-dimensional fabric preform, and record the cutting direction of the first three-dimensional fabric preform as the reference direction; Prepare a second three-dimensional fabric preform, and its cutting direction forms a 45° angle with the reference direction; Prepare a third three-dimensional fabric preform, and its cutting direction forms a 90° angle with the reference direction; Place the first three-dimensional fabric preform on the transparent lower mold, and calculate the in-plane permeability K of the first three-dimensional fabric preform according to Equation (1). 0 ; Place the second three-dimensional fabric preform on the transparent lower mold, and calculate the in-plane permeability K of the second three-dimensional fabric preform according to Equation (1). 45 ; Place the third three-dimensional fabric preform on the transparent lower mold, and calculate the in-plane permeability K of the third three-dimensional fabric preform according to Equation (1). 90 ; Calculate the permeabilities K1 and K2 of the in-plane main direction 1 and the main direction 2 of the three-dimensional fabric preform according to the following formulas (2) to (4):

10. A method for testing the thickness-direction permeability of a three-dimensional fabric preform for non-invasive monitoring, characterized in that, Use the non-invasive monitoring three-dimensional fabric preform in-plane and thickness-direction integrated permeability test device according to any one of claims 1 to 6; The non-invasive monitoring three-dimensional fabric preform thickness-direction permeability test method includes: Compress the three-dimensional fabric preform to the required degree through a lifting and compaction system; The vacuum generation system is connected to the opening on the upper surface of the transparent upper mold to provide a vacuum suction force; The liquid injection and cleaning system provides a permeability test liquid, and the permeability test liquid flows through the first hole of the transparent lower mold and the opening on the upper surface of the transparent upper mold in sequence; The signal detection and observation system conducts the acquisition of the pressure difference of the permeability test liquid, the flow rate of the permeability test liquid, and the impregnation video signal, as well as the processing of the time-domain flow front signal, and performs M samplings during the period when the permeability test liquid enters the first hole of the transparent lower mold and has not flowed out of the opening on the upper surface of the transparent upper mold; Record the moment when the permeability test liquid reaches the first hole of the transparent lower mold as the zero moment and start timing from this moment. Calculate the permeability K in the thickness direction of the three-dimensional fabric preform at the m-th sampling according to the following formulas (5) to (9) z,m , where m = 1, 2, …, M, and then calculate K according to the following formula (10) z As the final permeability in the thickness direction of the three-dimensional fabric preform: F(ξ f,m , π / 2) = F1(ξ f,m ) + F2(ξ f,m ) (7) Where: ΔP m is the hydraulic pressure difference for permeability test between the first transparent lower die hole and the opening on the upper surface of the transparent upper die during the m-th sampling, t m is the time during the m-th sampling, r inlet is the radius of the first transparent lower die hole, η is the viscosity of the permeability test liquid, V f is the percentage of the fiber volume content in the three-dimensional fabric preform under the current compaction state, K e,m is the in-plane equivalent permeability during the m-th sampling, ξ f,m is the ellipsoidal coordinate parameter of the three-dimensional fabric preform being penetrated during the m-th sampling, satisfying and z f,m are respectively the in-plane equivalent flow front and the thickness-direction flow front of the three-dimensional fabric preform during the m-th sampling, x f,m 、y f,m are respectively the flow fronts in the major semi-axis and minor semi-axis directions of the ellipsoid where the three-dimensional fabric preform is penetrated during the m-th sampling located in the plane of the three-dimensional fabric preform; z f,m Calculated according to the following formula (11): In formula (11), is the instantaneous volume flow rate of the permeability test liquid at a certain position of the transparent lower die hole during the m-th sampling.

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