Thermal insulation material layered defect test block, preparation calibration method and sensitivity test method

Abstract

The present application relates to a kind of heat insulation material layered defect test block, preparation calibration method and sensitivity test method, belong to material detection field, solve the problem that existing heat insulation material is difficult to be accurately preset in internal layered defect in forming process.Test block includes matrix, the upper surface of matrix is provided with one or more grooves, groove includes upper surface opening and one side opening, the upper surface of matrix is provided with matrix cover plate matched with matrix;Each groove has stopper matched with groove in each groove, the upper surface of each stopper is correspondingly provided with stopper cover plate, the edge of stopper cover plate overlaps with the upper surface of matrix cover plate, stopper cover plate is connected with matrix cover plate by bolt, and elastic gasket is arranged between stopper cover plate and matrix cover plate;The height of stopper is not less than the sum of the depth of groove, the thickness of matrix cover plate and the thickness of elastic gasket, and there is gap between the lower surface of stopper and the bottom surface of groove.The layered gap thickness of the test block is accurate and adjustable.

Description

Technical Field

[0001] This invention relates to the field of nondestructive testing technology for composite materials, and in particular to a test block for delamination defects in thermal insulation materials, its preparation and calibration method, and its sensitivity testing method. Background Technology

[0002] Aerogel-based thermal insulation materials have been widely used in the aircraft industry due to their excellent thermal insulation properties. However, during the molding process, delamination defects may occur inside the thermal insulation material, affecting its final performance. Therefore, it is necessary to detect internal delamination defects in the thermal insulation material before and after assembly to ensure the safe operation of the aircraft.

[0003] Aerogel-based thermal insulation materials are porous, low-density composite materials. Conventional methods such as ultrasound, X-ray, infrared, magnetic particle, eddy current, and infiltration cannot detect internal delamination defects. Currently, the feasible detection methods are industrial CT and terahertz. However, when using industrial CT and terahertz to detect delamination defects, it is necessary to specify the thickness of the delamination gap, the size of the delamination, and the depth of the delamination. The size of the delamination thickness will affect the detection resolution of industrial CT and terahertz. Different thermal insulation materials with different structures, thicknesses, and usage conditions have different requirements for the thickness, size, and depth of internal delamination defects. Therefore, before testing actual thermal insulation products, it is necessary to prepare a delamination defect comparison test block that meets the product testing requirements, based on the hot spots of internal delamination defects in the product to be tested. The test block should be pre-filled with delamination defects of the same size, depth, and thickness as required by the product to be tested, and the internal delamination defects should be calibrated. The sensitivity of industrial CT and terahertz methods for detecting internal delamination defects in this type of thermal insulation material is then tested using this test block to evaluate whether the selected testing equipment and testing parameters meet the requirements for detecting internal defects in thermal insulation materials, and to ensure the reliability of the test results.

[0004] However, the molding process of thermal insulation materials based on aerogel is complex, making it difficult to precisely pre-set delamination defects of a certain size inside during the molding process. Due to its poor rigidity, it is difficult to directly generate delamination gaps of a certain size and thickness inside the thermal insulation material through mechanical processing. Summary of the Invention

[0005] Based on the above analysis, the present invention aims to provide a test block for delamination defects in thermal insulation materials, a method for preparing and calibrating the test block, and a method for testing the detection sensitivity of delamination defects in thermal insulation materials using industrial CT or terahertz methods. This is intended to solve the problem that existing thermal insulation materials based on aerogel are difficult to precisely pre-install delamination defects of a certain size inside during the molding process.

[0006] On one hand, an embodiment of the present invention provides a test block for delamination defects in thermal insulation materials. The test block for delamination defects in thermal insulation materials includes a substrate. One or more grooves are provided on the upper surface of the substrate. Each groove includes an upper surface opening and a side opening. A substrate cover plate matching the upper surface of the substrate is provided on the upper surface of the substrate.

[0007] Each groove is provided with a plug that matches the groove, and a plug cover plate is provided above each plug. The edge of the plug cover plate overlaps with the upper surface of the base cover plate. The plug cover plate and the base cover plate are connected by bolts, and an elastic gasket is provided between the plug cover plate and the base cover plate.

[0008] The height of the blocking block is not less than the sum of the depth of the groove, the thickness of the base cover plate, and the thickness of the elastic gasket, and there is a gap between the lower surface of the blocking block and the bottom surface of the groove.

[0009] Preferably, the substrate is a cuboid and the groove is a square groove.

[0010] Preferably, a groove is provided on the upper surface of the substrate, the depth of the groove in the direction perpendicular to the upper surface of the substrate is equal to the maximum depth of delamination defects that need to be detected inside the product, and the length and width of the groove are the minimum dimensions of delamination defects that need to be detected inside the product.

[0011] Preferably, the upper surface of the substrate is provided with a plurality of grooves, the depth of the plurality of grooves in the direction perpendicular to the upper surface of the substrate includes the maximum depth at which delamination defects need to be detected inside the product, and the length and width of the plurality of grooves include the minimum size at which delamination defects need to be detected inside the product.

[0012] Preferably, the length and width of the block are equal to the length and width of the groove.

[0013] Preferably, the materials of the substrate and the plug are the same as or similar to the material of the product being tested.

[0014] Preferably, the thickness of the base cover plate and the block cover plate is 2-4 mm.

[0015] Preferably, the substrate cover plate and the block cover plate are respectively one of aluminum alloy, glass fiber resin matrix composite material and carbon fiber resin matrix composite material.

[0016] On the other hand, embodiments of the present invention provide a method for preparing and calibrating a test block for delamination defects in the above-mentioned thermal insulation material, the method comprising:

[0017] (a) Preparation of the substrate, plug, substrate cover plate and plug cover plate;

[0018] (b) Place the base cover plate on the upper surface of the base, place the plug block in the groove of the base, place the plug block cover plate and the plug block in the same position, and place the elastic gasket between the plug block cover plate and the base cover plate. Fix the plug block cover plate and the base cover plate with bolts.

[0019] (c) Place a feeler gauge with the same thickness as the defect to be measured between the lower surface of the block and the bottom surface of the groove, and adjust the bolts to make the upper surface of the feeler gauge contact the lower surface of the block and the lower surface of the feeler gauge contact the bottom surface of the groove.

[0020] (d) Perform a high-resolution CT scan on the test block obtained in the step, measure the height of the delamination gap through the CT slice image, and continue to adjust the bolts according to the measurement value so that the lower surface of the block is completely parallel to the bottom surface of the groove. Remove the feeler gauge to obtain the prepared and calibrated test block of the thermal insulation material delamination defect.

[0021] Thirdly, embodiments of the present invention also provide a method for testing the detection sensitivity of delamination defects in thermal insulation materials using industrial CT or terahertz methods. The method uses thermal insulation material delamination defect test blocks obtained by the above-mentioned preparation and calibration method for thermal insulation material delamination defect test blocks for testing.

[0022] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0023] 1. The thermal insulation material delamination defect test block of the present invention can adjust the delamination gap thickness of the test block by adjusting bolts. During the preparation process, the delamination gap thickness of the test block can be precisely controlled by feeler gauge and CT calibration, so that the same test block can be adapted to the defect detection requirements of different delamination thicknesses by adjusting bolts.

[0024] 2. The thermal insulation material delamination defect test block of the present invention is calibrated by industrial CT. The thickness of the delamination gap can be adjusted according to the measurement results of CT images. This avoids the insufficiency of using feeler gauges to measure only the minimum thickness between the lower surface of the block and the bottom surface of the groove. It can ensure the consistency of the delamination gap thickness between the lower surface of the block and the bottom surface of the groove (between surfaces).

[0025] 3. The thermal insulation material delamination defect test block and its preparation and calibration method of the present invention can adjust the gap thickness on the same test block by means of bolts, thereby preparing delamination defects of different thicknesses. It is applicable to different delamination defect detection requirements of this type of thermal insulation material and has strong versatility.

[0026] 4. The thermal insulation material delamination defect test block of the present invention can be used to evaluate the sensitivity of delamination defect detection by both industrial CT and terahertz methods.

[0027] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0028] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0029] Figure 1 This is a schematic diagram of the substrate according to one embodiment of the present invention;

[0030] Figure 2 This is a schematic diagram of a base cover plate according to one embodiment of the present invention;

[0031] Figure 3 This is a schematic diagram of the blocking block of the present invention;

[0032] Figure 4 This is a schematic diagram of the blocking cover plate of the present invention;

[0033] Figure 5 This is a schematic diagram of the substrate and substrate cover plate assembly according to one embodiment of the present invention;

[0034] Figure 6 This is a schematic diagram of the block and block cover plate assembly of the present invention;

[0035] Figure 7 This is a schematic diagram of a test block showing a delamination defect in a thermal insulation material according to one embodiment of the present invention;

[0036] Figure 8 This is a schematic diagram of the discrete structure of a test block for delamination defects in thermal insulation material according to another embodiment of the present invention;

[0037] Figure 9 This is a schematic diagram of the combination of the matrix and the matrix cover plate, and the combination of the plug block and the plug block cover plate in a test block for delamination defects of thermal insulation material according to another embodiment of the present invention.

[0038] Figure 10 This is a schematic diagram of a test block showing a delamination defect in a thermal insulation material according to another embodiment of the present invention;

[0039] Figure 11 An industrial CT image of a test block with delamination defects in thermal insulation material according to another embodiment of the present invention;

[0040] Figure 12 The image shows a CT scan of the composite material cabin from Example 4.

[0041] Figure 13 for Figure 12 A magnified view of a portion of the test block;

[0042] Figure 14 The results are from the terahertz reflection method of the layered test block in Example 5.

[0043] Figure label:

[0044] 1-Base; 2-Groove; 3-Block; 4-Base cover plate; 5-Block cover plate; 6-Bolt; H0-Base thickness; H1-Groove depth; L1-Groove length; W1-Groove width; H2-Block height; L2-Block length; W2-Block width; H3-Base cover plate thickness; L3-Length of opening on base cover plate corresponding to groove; W3-Width of opening on base cover plate corresponding to groove; H4-Block cover plate thickness; L4-Block cover plate length; W4-Block cover plate width; D-Gap thickness between lower surface of block and bottom surface of groove; 7-Bus; 8-Insulation material delamination defect test block; 9-Delamination defect with a thickness of 0.1mm; 10-Delamination defect with a thickness of 0.2mm; 11-Delamination defect with a thickness of 0.3mm; 12-Delamination defect with a thickness of 0.4mm. Detailed Implementation

[0045] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0046] The molding process of thermal insulation materials based on aerogel is complex, making it difficult to precisely pre-set delamination defects of a certain size inside during the molding process. Due to its poor rigidity, it is difficult to directly generate delamination gaps of a certain size and thickness inside the thermal insulation material through mechanical processing.

[0047] Existing technologies relate to methods for preparing delamination defect test blocks for ultrasonic testing of resin composite materials. Since ultrasound cannot propagate in air, these methods employ either pre-embedding a polytetrafluoroethylene (PTFE) film within the composite material or pre-embedding a metal sheet of a certain thickness at the edge of the composite material, which is then removed after molding to form the delamination defect. However, both methods suffer from stress concentration and deformation at the defect location, making it impossible to control the thickness of the delamination gap during preparation. The actual delamination thickness in the test block often differs significantly from the theoretical thickness, making it impossible to accurately prepare a delamination defect of a specific thickness. Furthermore, the delamination defect prepared by pre-embedding the PTFE film is not air at the defect location, but rather PTFE. When using industrial CT, ultrasound, terahertz, or other methods to detect defects, the properties of the PTFE film differ significantly from those of air, making it impossible to verify the detection effectiveness for air delamination defects within actual products.

[0048] For industrial CT and terahertz detection methods, delamination defects can only be detected when the air gap thickness reaches a certain value. Furthermore, the detectable delamination thickness is related to the material of the object being tested and the depth of the defect. Ultrasonic delamination test blocks cannot be used for detecting delamination defects in thermal insulation materials, and their preparation methods are also unsuitable for preparing delamination defects in thermal insulation materials. Therefore, to reliably detect internal delamination defects in thermal insulation materials, it is crucial to prepare defect comparison test blocks that meet the requirements for defect detection. However, currently, there are no reported methods in relevant literature for accurately preparing delamination defects in thermal insulation materials.

[0049] Based on this, the present invention provides a test block for delamination defects in thermal insulation materials. The test block for delamination defects in thermal insulation materials includes a substrate 1. One or more grooves 2 are provided on the upper surface of the substrate 1. Each groove 2 includes an upper surface opening and a side opening. A substrate cover plate 4 matching the upper surface of the substrate 1 is provided on the upper surface of the substrate 1. That is, the substrate cover plate 4 is provided with an opening corresponding to the upper surface opening of the groove 2.

[0050] Each groove 2 is provided with a block 3 that matches the groove 2. A block cover plate 5 is provided above each block 3. The edge of the block cover plate 5 overlaps with the upper surface of the base cover plate 4. The block cover plate 5 and the base cover plate 4 are connected by bolts 6, and an elastic gasket is provided between the block cover plate 5 and the base cover plate 4.

[0051] The height H2 of the block 3 is not less than the sum of the depth H1 of the groove 2, the thickness H3 of the base cover plate 4, and the thickness of the elastic gasket. There is a gap between the lower surface of the block 3 and the bottom surface of the groove 2.

[0052] Compared with existing technologies, the thermal insulation material delamination defect test block provided by this invention allows for adjustment of the delamination gap thickness (i.e., the gap thickness between the lower surface of the block and the bottom surface of the groove) via adjusting bolts. This allows for precise control of the delamination gap thickness, and the same test block can be adjusted via bolts to accommodate defect detection requirements of different delamination thicknesses. Adjusting the gap thickness on the same test block via bolts allows for the creation of delamination defects of varying thicknesses, making it suitable for detecting different delamination defects in thermal insulation materials and demonstrating strong versatility. Furthermore, the thermal insulation material delamination defect test block of this invention can be used to evaluate the sensitivity of delamination defect detection using both industrial CT and terahertz methods.

[0053] For example, the substrate 1 is rectangular, and the thickness H0 of the substrate 1 is not less than the thickness of the product being tested.

[0054] The shape of the groove 2 can be set according to the shape of the defect. For example, the groove 2 is a square groove.

[0055] The dimensions of the square groove are H1×L1×W1, and the value of H1×L1×W1 can be determined according to the detection requirements.

[0056] In one implementation, such as Figure 1-7 As shown, a groove 2 is provided on the upper surface of the substrate 1. The depth H1 of the groove 2 in the direction perpendicular to the upper surface of the substrate 1 is equal to the maximum depth of the delamination defect that needs to be detected inside the product. The length L1 and width W1 of the groove 2 are the minimum dimensions of the delamination defect that needs to be detected inside the product.

[0057] In this invention, "size" refers to length and width.

[0058] Furthermore, multiple test blocks for delamination defects in thermal insulation materials can be included, with each test block having a groove 2 of varying depth, length, and width. This can meet the requirements for detecting delamination defects of different depths, sizes, and thicknesses. However, different thicknesses of delamination defects can be set within the same groove by adjusting bolts. That is, for the same groove, once the depth and size (length and width) are fixed, the depth and size of the delamination defect corresponding to that groove are fixed, but the thickness of the delamination defect corresponding to that groove can be adjusted by bolts. For example, after preparing a defect with a depth of 10mm and a size of 10×10mm, if it is required to detect a defect with a thickness of 0.3mm, the bolts can be adjusted to make the thickness D of the delamination gap 0.3mm, and this test block is named A1. If the defect depth and size remain unchanged, and it is required to detect a defect with a thickness of 0.2mm, there is no need to remake the defect test block. Based on test block A1, adjusting the bolts can obtain a test block with a delamination gap thickness D of 0.2mm. That is, the same groove in the same test block can be used to meet the requirements for detecting defects of the same depth, size, and different thicknesses.

[0059] In another implementation, such as Figure 8-11 As shown, the upper surface of the substrate 1 is provided with a plurality of grooves 2. The depth of the plurality of grooves 2 in the direction perpendicular to the upper surface of the substrate 1 includes the maximum depth at which delamination defects need to be detected inside the product. The length and width of the plurality of grooves 2 include the minimum dimensions at which delamination defects need to be detected inside the product.

[0060] In other words, multiple grooves 2 are set on the same substrate, each with a different depth and size, which can be set according to the depth and size range of delamination defects to be detected. However, within the same groove 2, delamination defects of different thicknesses can be set by adjusting the bolts 6.

[0061] Furthermore, it can include multiple test blocks for delamination defects in the insulation material, and the depth, length, and width of the groove 2 of each test block can be different. This can meet the requirements for detecting delamination defects of multiple different depths, sizes, and thicknesses.

[0062] In this invention, the dimensions of the blocking block 3 are H2×L2×W2. The length L2 and width W2 of the blocking block 3 are equal to the length L1 and width W1 of the groove 2, and the blocking block 3 can be placed exactly into the groove 2 of the base 1. The height H2 of the blocking block 3 is not less than the sum of the depth H1 of the groove 2, the thickness H3 of the base cover plate 4, and the thickness of the elastic gasket, so that the up-and-down movement of the blocking block 3 in the groove 2 can be controlled by adjusting the bolt 6.

[0063] It should be noted that the materials of the substrate 1 and the plug 3 are the same as or similar to the material of the product being tested. "Same material" means that the materials of the substrate 1 and the plug 3 have the same composition and density as the product being tested; "similar material" means that the materials of the substrate 1 and the plug 3 have slightly different composition and density than the product being tested. In this case, the substrate 1 and the plug 3 can also be used to test the product being tested. For composite materials of different shapes, structures, and batches of the same material, their material composition and density may differ slightly (slight difference generally means that the material composition is the same, and the density difference is within ±10%), and the same test block can still be used for testing, improving the versatility of the test.

[0064] In this invention, the thickness H3 of the substrate cover plate 4 and the thickness H4 of the blocking cover plate 5 are 2-4 mm respectively. If the substrate cover plate 4 and the blocking cover plate 5 are too thin, their rigidity is poor, they are prone to deformation, and it is impossible to ensure that the upper and lower surfaces of the layer gap remain parallel planes; if the substrate cover plate 4 and the blocking cover plate 5 are too thick, on the one hand, it wastes materials, and on the other hand, when using micro-CT for calibration, the excessive thickness will affect the X-ray penetration effect.

[0065] In this invention, the base cover plate 4 and the block cover plate 5 are made of materials with good rigidity, which are not easily deformed under bolt pre-tightening force and natural environment, ensuring that the upper and lower surfaces of the layer gap formed between the block 3 and the base 1 are parallel planes, and the distance between the planes is the thickness of the layer, avoiding the upper and lower surfaces of the layer gap not being parallel due to deformation, which would make it impossible to characterize the thickness of the layer gap.

[0066] For example, the substrate cover plate 4 and the block cover plate 5 are respectively one of aluminum alloy, glass fiber resin matrix composite material and carbon fiber resin matrix composite material.

[0067] In this invention, the base cover plate 4 matches the upper surface of the base 1. That is, the base cover plate 4 is provided with an opening corresponding to the groove 2 of the base 1. The length L3 of the opening is equal to the length L1 of the groove 2, and the width W3 of the opening is equal to the width W1 of the groove 2.

[0068] Furthermore, the upper surface of the substrate 1 is bonded to the substrate cover plate 4 with an adhesive or adhesive film.

[0069] In this invention, the edge of the block cover plate 5 overlaps with the upper surface of the base cover plate 4. That is, the dimensions of the block cover plate 5 are H4×L4×W4. The length L4 of the block cover plate 5 is not less than the length L2 of the block 3, and the width W4 of the block cover plate 5 is greater than the width W2 of the block 3. The block cover plate 5 completely covers the upper surface of the block 3 and leaves an area for connection with the base cover plate 4 by bolts.

[0070] Furthermore, the block 3 and the block cover plate 5 are bonded together with adhesive or adhesive film.

[0071] Specifically, the base 1 and the base cover plate 4, and the block 3 and the block cover plate 5 are combined together. The base cover plate 4 is provided with threaded holes, and the block cover plate 5 is provided with through holes. The base cover plate 4 and the block cover plate 5 are fixed together by bolts 6.

[0072] In this invention, an elastic gasket (not shown in the figure) is provided between the base cover plate 4 and the block cover plate 5 in the fixing area of ​​the bolt 6. The gap thickness D between the block 3 and the bottom surface of the groove 2 is controlled by adjusting the working thickness of the elastic gasket by adjusting the bolt 6.

[0073] For example, the elastic washer is a wave-shaped elastic washer, which can be fitted onto the bolt 6.

[0074] Secondly, the present invention also provides a method for preparing and calibrating the above-mentioned test block for delamination defects in thermal insulation materials, the method comprising:

[0075] (a) Preparation of substrate 1, plug 3, substrate cover plate 4 and plug cover plate 5;

[0076] (b) Cover the upper surface of the substrate 1 with the substrate cover plate 4 and bond it with adhesive or film; place the block 3 in the groove 2 of the substrate 1, and place the block cover plate 5 in the same position as the block 3, or first bond the upper surface of the block cover plate 5 to the block 3 with adhesive or film, and then place the block 3 with the block cover plate 5 bonded to it into the groove 2; place the elastic gasket between the block cover plate 5 and the substrate cover plate 4, and fix the block cover plate 5 and the substrate cover plate 4 with bolts 6;

[0077] (c) Place a feeler gauge with the same thickness as the defect to be measured between the lower surface of the block 3 and the bottom surface of the groove 2. Adjust the bolt 6 so that the upper surface of the feeler gauge contacts the lower surface of the block 3 and the lower surface of the feeler gauge contacts the bottom surface of the groove 2.

[0078] (d) Perform a high-resolution CT scan on the test block obtained in step c, measure the height of the delamination gap through the CT slice image, and continue to adjust the bolt 6 according to the measurement value so that the lower surface of the block 3 is completely parallel to the bottom surface of the groove 2. Remove the feeler gauge to obtain the prepared and calibrated test block of the thermal insulation material delamination defect.

[0079] The feeler gauge is only suitable for preliminary measurement. Because the plug 3 is pressed on the feeler gauge by the bolt 6 and the elastic washer, the plug 3 will be subject to a certain preload. After the feeler gauge is pulled out, the air gap may change. Moreover, the feeler gauge can only guarantee the minimum thickness of the delamination gap. It cannot guarantee that the lower surface of the plug 3 at the delamination gap is parallel to the bottom surface of the groove 2. As long as part of the lower surface of the plug 3 is pressed on the feeler gauge, the delamination thickness is considered to be approximately equal to the feeler gauge thickness. However, the thickness of each position of the delamination gap can be observed by CT. It can be seen that the thickness of the delamination defect may be different at different positions. Therefore, the delamination gap between the lower surface of the plug 3 and the bottom surface of the groove 2 can be adjusted according to the CT image to ensure the consistency of the gap thickness between the surfaces.

[0080] This invention uses industrial CT to calibrate the test block, and can adjust the thickness of the layer gap according to the measurement results of CT images. This avoids the insufficiency of using only a feeler gauge to measure the minimum thickness between the lower surface of the block 3 and the bottom surface of the groove 2. It can ensure the consistency of the layer gap thickness between the lower surface of the block 3 and the bottom surface of the groove 2 (between surfaces). That is, the layer gap thickness of the test block can be precisely controlled by using feeler gauge and CT calibration.

[0081] Thirdly, the present invention also provides a detection sensitivity test method for detecting delamination defects in thermal insulation materials using industrial CT or terahertz methods. The method uses thermal insulation material delamination defect test blocks obtained by the above-mentioned preparation and calibration method for thermal insulation material delamination defect test blocks for testing.

[0082] The following specific embodiments further illustrate the present invention's thermal insulation material delamination defect test block, its preparation and calibration method, and its sensitivity testing method.

[0083] Example 1

[0084] A flat sheet component made of silica aerogel thermal insulation material, with dimensions of 100mm × 200mm, a thickness of 20mm, and a density of 0.8g / cm³. 3 It is necessary to detect delamination defects with a thickness of 0.2mm and a size of not less than 20mm × 20mm.

[0085] The preparation and calibration of test blocks for delamination defects in this thermal insulation material includes the following steps:

[0086] 1. Preparation of Layered Defect Test Block Components

[0087] like Figure 8 As shown, the substrate is made of the same material as the insulation material and processed into a cuboid with a length of 300mm, a width of 60mm, and a thickness of 30mm. The delamination defect to be inspected must be at least 20mm × 20mm in size. To enhance the versatility of the test block, five square grooves, each 20mm deep and with area dimensions of 10mm × 10mm, 20mm × 20mm, 30mm × 30mm, 40mm × 40mm, and 50mm × 50mm respectively, are prepared on the test block. This satisfies the requirement for detecting delamination defects with a minimum size of 10mm × 10mm and a maximum size of 50mm × 50mm.

[0088] The base cover plate is made of aluminum alloy with a thickness of 4mm, a length of 300mm, and a width of 60mm. The shape is machined to be the same as the upper surface of the base, so that it can cover the uncut area on the upper surface of the base. A threaded hole with a diameter of 4mm also needs to be machined on the base cover plate.

[0089] The bolt diameter is 4mm, the inner diameter of the elastic wave washer is 4mm, the outer diameter is 8mm, the thickness of the wave washer is 0.3mm, and the free height is 1.1mm. Therefore, the working height is between 0.3mm and 1.1mm.

[0090] The plug is made of the same material as the base material. The thickness of the plug is equal to the thickness of the corrugated washer (0.3mm) plus the thickness of the base cover plate (4mm) and the depth of the base square groove (20mm), so the thickness of the plug is 24.3mm. A total of 5 square plugs with a thickness of 24.3mm and area dimensions of 10mm×10mm, 20mm×20mm, 30mm×30mm, 40mm×40mm, and 50mm×50mm are processed.

[0091] The block cover is made of aluminum alloy with a thickness of 4mm and area dimensions of 10mm×36mm, 20mm×46mm, 30mm×56mm, 40mm×66mm, and 50mm×76mm. After the block cover is bonded to the block, a through hole area with a processing diameter of 4mm is left to facilitate connection with the base cover.

[0092] A threaded hole with a diameter of 4mm is machined on the base cover plate, and a through hole with a diameter of 4mm is machined on the block cover plate. The base cover plate and the block cover plate are connected together by a spiral.

[0093] 2. Assembly of layered defect test block components

[0094] Apply 0.2mm of adhesive to the uncut square groove area on the upper surface of the substrate, cover it with an aluminum alloy substrate cover plate, and place it in an oven to cure. Remove it after curing is complete.

[0095] Apply 0.2mm of adhesive to the upper surface of the block and cover it with the block cover plate. Select M4×8mm bolts to fix the block cover plate to the base cover plate and tighten the bolts. At this time, the cover plate presses the block tightly. Place it in an oven to cure. After curing, remove it and unscrew the bolts.

[0096] The assembled base and base cover plate, block and block cover plate are as follows: Figure 9 As shown.

[0097] 3. Layer gap adjustment

[0098] Insert a 0.2mm feeler gauge inside the square groove. Place a wave-shaped elastic washer in the threaded area between the base cover plate and the plug cover plate. Gradually tighten the bolts, continuously measuring the gap width with the feeler gauge. Stop tightening the bolts when the gap width reaches 0.2mm. The assembled layered test block is shown below. Figure 10 As shown, a layered gap of a certain thickness is formed between the lower surface of the block and the bottom surface of the groove of the substrate.

[0099] 4. Calibration of layer gap thickness

[0100] Because measuring with a feeler gauge can only guarantee a minimum thickness of 0.2mm for the layer gap, it cannot guarantee that the surface of the plug at the layer gap is parallel to the bottom of the groove. Therefore, for Figure 10 The test block was subjected to high-resolution industrial CT scanning. The actual thickness of the delamination defect between the block and the substrate was measured based on the industrial CT image. The bolts were adjusted according to the actual thickness until the thickness of the delamination gap between the block and the substrate was controlled at 0.2 mm (the lower surface of the block was completely parallel to the bottom surface of the groove).

[0101] Example 2

[0102] The rotating chamber component made of silica aerogel insulation material has a diameter of 600mm, a wall thickness of 20mm, and a density of 0.8g / cm3. It is necessary to detect a delamination defect with a thickness of 0.2mm and a size of 30mm.

[0103] The calibration delamination defect test block was prepared according to the method of Example 1. The difference is that the test block contains delamination defects with a size of 30mm×30mm, a delamination depth of 10mm, and thicknesses of 0.1mm, 0.2mm, 0.3mm, and 0.4mm, respectively. In this example, two test blocks are included, and each test block is set with two defects. One test block contains defects with thicknesses of 0.1mm and 0.2mm, respectively, and the other test block contains defects with thicknesses of 0.3mm and 0.4mm, respectively.

[0104] Example 3

[0105] For silica aerogel insulation materials with a thickness of 20mm, it is necessary to detect delamination defects with a thickness of 0.2mm or more and a size of not less than 20mm × 20mm.

[0106] The calibration delamination defect test block was prepared according to the method of Example 1, except that 5 test blocks were prepared, and a delamination defect was set on each test block.

[0107] Example 4

[0108] The calibrated test block prepared in Example 2 was used for industrial CT inspection. The test block and the thermal insulation composite cabin component were scanned together using industrial CT to obtain industrial CT tomographic images of the tested area. This ensured that the industrial CT tomographic images contained the tested area and the target delamination defects with thicknesses of 0.1 mm, 0.2 mm, 0.3 mm, and 0.4 mm within the test block. The CT inspection images are shown below. Figure 12 and 13 As shown, layered defects of different thicknesses can be observed in the test block on the CT image.

[0109] The minimum identifiable delamination thickness in the analysis sample is determined, and this minimum delamination thickness represents the sensitivity of industrial CT scans for detecting delamination defects in this thermal insulation composite component. Figure 13 It can be seen that the minimum delamination thickness that can be identified from CT images is 0.2 mm. Therefore, the sensitivity of industrial CT for detecting delamination defects in the thermal insulation composite material cabin component is 0.2 mm, and it can effectively detect delamination defects with a thickness of not less than 0.2 mm.

[0110] Example 5

[0111] Terahertz detection was performed using the calibrated test block prepared in Example 1. The delamination defect test block from step 1 was detected using the terahertz reflection method, and detection images of the delamination defect test block were obtained. The smallest area of ​​the delamination defect that could be identified in the image was observed, thus determining the detection sensitivity for delamination defects in composite material components with a delamination gap thickness of 0.2 mm and a thickness not exceeding 20 mm. The results are as follows... Figure 14 As shown, the terahertz method can detect defects with a size of 10mm×10mm. Its sensitivity for detecting the thickness of layered defects is better than 0.2mm, and its sensitivity for detecting the area is better than 10mm×10mm.

[0112] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A test block for delamination defects in thermal insulation materials, characterized in that, The test block for the delamination defect of the thermal insulation material includes a substrate (1), and one or more grooves (2) are provided on the upper surface of the substrate (1). The groove (2) includes an upper surface opening and a side opening. A substrate cover plate (4) matching the upper surface of the substrate (1) is provided on the upper surface of the substrate (1). Each groove (2) is provided with a block (3) that matches the groove (2), and a block cover plate (5) is provided above each block (3). The edge of the block cover plate (5) overlaps with the upper surface of the base cover plate (4). The block cover plate (5) and the base cover plate (4) are connected by bolts (6), and an elastic gasket is provided between the block cover plate (5) and the base cover plate (4). The elastic gasket has a minimum compression thickness and a free height. The height of the block (3) is not less than the sum of the depth of the groove (2), the thickness of the base cover plate (4) and the minimum compressible thickness of the elastic gasket. There is a gap between the lower surface of the block (3) and the bottom surface of the groove (2). The gap between the lower surface of the block (3) and the bottom surface of the groove (2) is changed by tightening the bolt (6). The elastic gasket is a wave-shaped elastic washer, which is sleeved on the bolt (6); The block (3) and the block cover plate (5) are bonded together by adhesive or adhesive film; The upper surface of the substrate (1) is provided with a groove (2), the depth of the groove (2) in the direction perpendicular to the upper surface of the substrate (1) is equal to the maximum depth of the delamination defect that needs to be detected inside the product, and the length and width of the groove (2) are the minimum dimensions of the delamination defect that needs to be detected inside the product. Alternatively, the upper surface of the substrate (1) is provided with a plurality of grooves (2), the depth of the plurality of grooves (2) in the direction perpendicular to the upper surface of the substrate (1) includes the maximum depth of the product inside which delamination defects need to be detected, and the length and width of the plurality of grooves (2) include the minimum size of the product inside which delamination defects need to be detected; The aforementioned thermal insulation material delamination defect test block is used to evaluate the sensitivity of delamination defect detection using both industrial CT and terahertz methods.

2. The test block for delamination defects in thermal insulation material according to claim 1, characterized in that, The base (1) is a cuboid, and the groove (2) is a square groove.

3. The test block for delamination defects in thermal insulation material according to claim 1, characterized in that, The length and width of the block (3) are equal to the length and width of the groove (2).

4. The test block for delamination defects in thermal insulation material according to claim 1, characterized in that, The materials of the substrate (1) and the plug (3) are the same as or similar to the materials of the product being tested.

5. The test block for delamination defects in thermal insulation material according to claim 1, characterized in that, The thicknesses of the base cover plate (4) and the block cover plate (5) are 2-4 mm respectively.

6. The test block for delamination defects in thermal insulation material according to claim 5, characterized in that, The substrate cover plate (4) and the block cover plate (5) are respectively one of aluminum alloy, glass fiber resin matrix composite material and carbon fiber resin matrix composite material.

7. The method for preparing and calibrating test blocks for delamination defects in thermal insulation materials according to any one of claims 1-6, characterized in that, The method includes: (a) Preparation of the substrate (1), the plug (3), the substrate cover plate (4) and the plug cover plate (5); (b) Cover the upper surface of the substrate (1) with the base cover plate (4), and glue the upper surface of the block cover plate (5) and the block (3) with adhesive or film. Then put the block (3) with the block cover plate (5) glued on into the groove (2), and place the elastic gasket between the block cover plate (5) and the base cover plate (4). Fix the block cover plate (5) and the base cover plate (4) with bolts (6). (c) Place a feeler gauge with the same thickness as the defect to be measured between the lower surface of the block (3) and the bottom surface of the groove (2), and adjust the bolt (6) so that the upper surface of the feeler gauge contacts the lower surface of the block (3) and the lower surface of the feeler gauge contacts the bottom surface of the groove (2). (d) Perform a high-resolution CT scan on the test block obtained in step (c), measure the height of the delamination gap through the CT slice image, and continue to adjust the bolt (6) according to the measurement value so that the lower surface of the plug (3) is completely parallel to the bottom surface of the groove (2). Take out the feeler gauge to obtain the prepared and calibrated test block of the thermal insulation material delamination defect.

8. A method for testing the sensitivity of industrial CT or terahertz methods to detect delamination defects in thermal insulation materials, characterized in that, The method uses a test block of thermal insulation material with delamination defects obtained by the preparation and calibration method described in claim 7 for testing.

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