Fire bearing coupling test device for ship bearing composite material

Abstract

The invention provides a fire bearing coupling test device for a ship bearing composite material, the fire bearing coupling test device comprises a combustion furnace, the combustion furnace comprises a furnace body, a first sample frame, a first closed frame, a second sample frame, a second closed frame and a loading assembly, the first sample frame and the first closed frame are perpendicular to each other, the second sample frame and the second closed frame are perpendicular to each other, and the loading assembly is arranged in the furnace body. The loading assembly is arranged above the test piece; when the test piece is subjected to a horizontal fire resistance test, a first sample frame and a first closed frame are adopted, the first sample frame and the first closed frame are respectively positioned at the upper end and the side end of the furnace body, and the test piece is arranged in the first sample frame; when the test piece is subjected to a vertical fire resistance test, a second sample frame and a second closed frame are adopted, the second sample frame and the second closed frame are respectively positioned at the side end and the upper end of the furnace body, and the test piece is arranged in the second sample frame. The device can realize fire resistance tests of horizontal test pieces and vertical test pieces, and is high in utilization rate and low in cost.

Description

Technical Field

[0001] The present invention relates to the technical field of fire safety testing of ship composite materials, in particular to a fire-bearing coupling test device for ship load-bearing composite materials. Background Art

[0002] Fiber-reinforced resin-based composites are widely used in key industries such as aerospace, shipbuilding, and construction due to their numerous advantages, including light weight, high specific strength, high specific stiffness, and highly designable structural properties. However, due to the flammable nature of composite materials, their application requires fire protection design and verification assessments. The mechanical strength of the composites must be evaluated during and after fire to ensure their fire safety and structural reliability during service. Performance testing and evaluation is crucial.

[0003] Reliable and effective integration of fire and mechanical performance testing for composite materials is a key issue that needs to be addressed. A combustion furnace is a common test device used in composite fire protection design and verification assessment to evaluate the fire performance of composite materials under different operating conditions. For example, Annex 1, Part 3 of the commonly used standard, the 2010 International Fire Test Procedure (2010 FTP Rules), allows for horizontal and vertical fire resistance testing of composite components to assess their fire safety. Annex 1, Part 11 of the 2010 FTP Rules adds an assessment of load-bearing performance, making it a key standard for fire protection design and verification assessment of ship-bearing structures. However, these two standards are not suitable for rapid material screening due to the large component areas required, long testing cycles, and high costs. Based on this, GB / T 41879 proposes standard requirements for medium-sized fire resistance testing of composite materials, reducing the specimen size to (1000±30) mm. This standard allows for testing of composite components used in small ships, but does not specify the assessment of load-bearing performance under fire. In summary, based on the above standards, the present invention adopts a small-sized (specimen 600-800mm) fire resistance test device to simulate the standard temperature rise curve. Through rapid screening tests, the load-bearing performance and fire resistance performance of composite components when exposed to fire are evaluated to verify the effectiveness of the fire protection design.

[0004] At present, there are few studies on the mechanical properties of composite materials after fire damage, and most of them prepare the fire specimens as small-sized specimens for conventional mechanical testing (such as Chen Yahui. Research on mechanical properties of FRP laminates and foam sandwich composites after fire [D]. Harbin Engineering University, 2017.) or cut the specimens into tensile or compression specimens for testing after fire (such as A. Anjang et al. Post-fire mechanical properties of sandwich composite structures [J]. Composite Structures 132 (2015) 1019-1028).

[0005] The prior art, publication number CN217638795U, discloses a thermal-mechanical coupling test device for composite panels, comprising a loading plate rack, a plate-shaped specimen, a sample loading frame, and a heating furnace arranged in sequence from top to bottom. The prior art has the following main problems: (1) The test device is relatively fixed in structure and is mainly used for horizontally placed specimens, resulting in low flexibility; (2) The test device cannot test the residual strength of composite materials after fire resistance; and (3) The test device is small in size and cannot perform fire evaluation on specimens with a size of 600-800 mm × 600-800 mm. Summary of the Invention

[0006] In light of this, the present invention proposes a coupled fire-bearing test device for ship-bearing composite materials. This device addresses the problems of existing test devices: a relatively fixed structure, primarily for horizontally placed specimens, resulting in low flexibility; an inability to test the residual strength of composite materials after fire resistance; and a relatively small size, making it incapable of fire-bearing evaluation of specimens sized between 600 and 800 mm by 600 and 800 mm.

[0007] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0008] A fire-bearing coupling test device for ship-bearing composite materials includes a combustion furnace, which includes a furnace body, a first sample frame, a first closed frame, a second sample frame, a second closed frame, and a loading assembly. The first sample frame and the first closed frame are perpendicular to each other, and the second sample frame and the second closed frame are perpendicular to each other. The loading assembly is arranged above the specimen; when the specimen is subjected to a horizontal fire resistance test, the first sample frame and the first closed frame are used, and the first sample frame and the first closed frame are respectively located at the upper end and the side end of the furnace body, and the specimen is arranged in the first sample frame; when the specimen is subjected to a vertical fire resistance test, the second sample frame and the second closed frame are used, and the second sample frame and the second closed frame are respectively located at the side end and the upper end of the furnace body, and the specimen is arranged in the second sample frame.

[0009] The present invention is equipped with two sets of sample frames, which can realize fire resistance tests of horizontal specimens and vertical specimens, with high device utilization and low cost.

[0010] Furthermore, the opening size of the first sample frame is (600~800) mm×(600~800) mm, and the size of the first closed frame is (500~900) mm×(500~900) mm; the opening size of the second sample frame is (600~800) mm×(600~800) mm, and the size of the second closed frame is (500~900) mm×(500~900) mm.

[0011] This setting can clamp and fix specimens with a size of 600 to 800 mm × 600 to 800 mm.

[0012] Furthermore, the first sample frame and the first closing frame are connected to the furnace body, and the second sample frame and the second closing frame are connected to the furnace body by means of compression bolts.

[0013] Furthermore, it also includes a side pressure fixture of a mechanical testing machine, which is used to test the side pressure strength of the specimen before and after fire. The side pressure fixture of the mechanical testing machine includes a clamping rod, a top plate, a top sliding plate, a side sliding plate, a corner plate, a bottom sliding plate, and a bottom plate. During the test, the specimen is placed inside the fixture, and the upper end of the specimen is sequentially set to the top sliding plate, the top plate, and the clamping rod, wherein the top sliding plate contacts the specimen, and the lower end of the specimen is sequentially set to the bottom sliding plate and the bottom plate, wherein the bottom sliding plate contacts the specimen, and the left and right ends of the specimen are both set to corner plates and side sliding plates, wherein the side sliding plate contacts the specimen.

[0014] The side pressure fixture in this setting supports the specimen to transfer the load, and the top plate, bottom plate, side plate and sliding plate jointly restrain the specimen. The fixture is adjustable to accommodate different specimen sizes, and the load is transferred to the specimen through the top plate and bottom plate.

[0015] Furthermore, a threaded column is provided at the bottom of the clamping rod, a first threaded hole is provided on the top plate, and the clamping rod is connected to the first threaded hole on the top plate through the threaded column.

[0016] This arrangement can improve the connection firmness between the clamping rod and the top plate.

[0017] Furthermore, the top plate is provided with a first bolt limiting hole, the top sliding plate is provided with a second threaded hole, the top plate and the top sliding plate are connected by a cap bolt, and the cap bolt passes through the first bolt limiting hole and is connected to the second threaded hole in the top sliding plate.

[0018] This setup not only enables testing of specimens of varying thicknesses, but also makes the top sliding plate connection more secure.

[0019] Furthermore, a third threaded hole is provided on the lateral sliding plate, and a second bolt limiting hole is provided on the angle plate. The second bolt limiting hole is located at the side end of the angle plate. The angle plate and the lateral sliding plate are connected with a capped bolt, and the capped bolt passes through the second bolt limiting hole and is connected to the third threaded hole in the lateral sliding plate.

[0020] This setup not only enables testing of specimens of varying thicknesses, but also makes the lateral sliding plate connection more robust.

[0021] Furthermore, a third bolt limiting hole is provided on the angle plate, and the third bolt limiting hole is located at the bottom end of the angle plate. A fourth threaded hole is provided on the base plate, and the angle plate and the base plate are connected by a capped bolt, and the capped bolt passes through the third bolt limiting hole and is connected to the fourth threaded hole of the base plate.

[0022] This setting can accurately limit the test piece and improve the accuracy of the test.

[0023] Furthermore, the system also includes a temperature control assembly, comprising electric heating tubes, a control system, and a data acquisition system. The electric heating tubes, recommended for 6 to 12, heat the left, right, and rear sides of the furnace. The control system utilizes a working temperature controller with at least 30 program segments, PID automatic adjustment, and over-temperature or deviation alarms. The data acquisition system records the test temperature within the furnace and the temperature of the specimens, with a recording interval of 1 second.

[0024] Furthermore, the thermocouple in the furnace body adopts a nickel-chromium-nickel-silicon (K-type) thermocouple with a wire diameter of 0.75mm to 2.30mm, which is covered with a heat-resistant stainless steel sleeve or a heat-resistant porcelain sleeve, and filled with heat-resistant material in the middle. The length of the heat pipe extending out of the sleeve is not less than 25mm.

[0025] Furthermore, the specimen back temperature or core thermocouple adopts nickel-chromium-nickel-silicon (K-type) thermocouple, and the thermocouple wire with a diameter of 0.5 mm is welded on a round copper sheet with a thickness of 0.2 mm and a diameter of 12 mm.

[0026] Furthermore, it also includes a fire-bearing coupled test method for ship-bearing composite materials, and the test method includes a fire-bearing test method for specimens using a combustion furnace and a side pressure test method for specimens.

[0027] The test method of the present invention combines fire protection and mechanical tests, and can comprehensively evaluate the safety and reliability of materials.

[0028] Furthermore, the test specimen lateral pressure test method is that the test specimen is installed on a lateral pressure fixture, and the lateral pressure fixture is installed on a mechanical testing machine for testing, specifically comprising the following steps:

[0029] The first step is to install the specimen on the lateral pressure fixture at the center of the lateral pressure fixture, and stick an axial strain gauge or set a displacement meter on the surface of the specimen;

[0030] In the second step, the initial load is applied, the strain value is checked, and the fixture is adjusted to ensure uniform axial stress transmission. The specimen is loaded at a rate of 2 mm / min until the maximum load is reached. The test is terminated when the load drops by 30% of the maximum load.

[0031] The third step is to record the load and strain values during the test. After the test, the maximum load and compressive strength are summarized and analyzed to determine the residual strength of the specimen after fire damage.

[0032] Compared with the prior art, the fire-bearing coupling test device for ship load-bearing composite materials described in the present invention has the following advantages:

[0033] 1) The present invention is equipped with two sets of sample frames, which can realize fire resistance testing of horizontal and vertical specimens, with high device utilization and low cost. The test method of the present invention combines fire protection and mechanical testing, which can comprehensively evaluate the safety and reliability of materials. The side pressure fixture supports the specimen and transmits the load. The top plate, bottom plate, side plates and sliding plate jointly restrain the specimen. The fixture is adjustable to accommodate different specimen sizes. The load is transmitted to the specimen through the top plate and bottom plate.

[0034] 2) The test device of the present invention can be used to test the fire resistance of small-scale composite components and conduct rapid screening tests on the fire resistance of large-scale composite components. It can also simultaneously monitor the load-bearing capacity of composite materials when exposed to fire, thereby achieving simultaneous testing of the fire resistance and mechanical properties of composite materials.

[0035] 3) The experimental device of the present invention is used to test the residual strength of the composite material after being damaged by fire, and the mechanical strength of the composite material after being damaged by fire can be evaluated. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a structural diagram of a fire-bearing coupling test device (vertical test) for ship load-bearing composite materials of the present invention without a test piece installed;

[0037] Figure 2 This is a structural diagram of a fire-bearing coupling test device (vertical test) for ship load-bearing composite materials of the present invention;

[0038] Figure 3 This is a structural diagram of a fire-bearing coupling test device (horizontal test) for ship load-bearing composite materials of the present invention without a test piece installed;

[0039] Figure 4 This is a structural diagram of a fire-bearing coupling test device (horizontal test) for ship load-bearing composite materials of the present invention;

[0040] Figure 5 This is a schematic diagram of the structure of the test piece of the present invention using a lateral pressure test mechanics tool to apply load;

[0041] Figure 6 An exploded view of the test piece and the lateral pressure test mechanics tooling of the present invention;

[0042] Figure 7 It is a schematic diagram of the overall structure of the test piece and the lateral pressure test mechanics tooling of the present invention;

[0043] Figure 8 It is a structural schematic diagram of the clamping rod, the top plate and the top sliding plate of the present invention;

[0044] Figure 9 It is a schematic structural diagram of the angle plate and the lateral sliding plate of the present invention;

[0045] Figure 10 This is a schematic structural diagram of the angle plate, bottom sliding plate, and bottom plate of the present invention;

[0046] Figure 11 This is a temperature rise curve diagram of Example 1 of the present invention;

[0047] Figure 12 It is a comparison chart of the fire resistance test results of the present invention.

[0048] Description of reference numerals:

[0049] 1-furnace body, 2-first sample frame, 3-first closing frame, 4-second sample frame, 5-second closing frame, 6-loading assembly, 7-electric heating tube, 8-clamping rod, 81-threaded column, 9-top plate, 91-first threaded hole, 92-first bolt limiting hole, 10-top sliding plate, 101-second threaded hole, 11-lateral sliding plate, 111-third threaded hole, 12-angle plate, 121-second bolt limiting hole, 122-third bolt limiting hole, 13-bottom sliding plate, 131-fourth bolt limiting hole, 14-bottom plate, 141-fourth threaded hole, 15-test piece. DETAILED DESCRIPTION

[0050] To make the above-mentioned objects, features, and advantages of the present invention more clearly understood, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. In addition, a brief explanation is provided regarding the directions or positional relationships involved in the following specific embodiments: The directions or positional relationships indicated by "up," "down," "left," and "right" mentioned in the embodiments refer to the directions or positional relationships shown in the accompanying drawings.

[0051] like Figures 1 to 12As shown, the present invention proposes a fire-bearing coupling test device for ship load-bearing composite materials, including a combustion furnace, the combustion furnace including a furnace body 1, a first sample frame 2, a first closed frame 3, a second sample frame 4, a second closed frame 5, and a loading assembly 6, the first sample frame 2 and the first closed frame 3 are perpendicular to each other, the second sample frame 4 and the second closed frame 5 are perpendicular to each other, and the loading assembly 6 is arranged above the specimen 15; when the specimen is subjected to a horizontal fire resistance test, the first sample frame 2 and the first closed frame 3 are used, the first sample frame 2 and the first closed frame 3 are respectively located at the upper end and the side end of the furnace body 1, and the specimen is arranged in the first sample frame 2; when the specimen is subjected to a vertical fire resistance test, the second sample frame 4 and the second closed frame 5 are used, the second sample frame 4 and the second closed frame 5 are respectively located at the side end and the upper end of the furnace body 1, and the specimen is arranged in the second sample frame 4.

[0052] Specifically, the test piece is cut from the composite material plate to be tested, and a combination of fireproof materials is installed for testing according to the actual use scenario, wherein the fireproof material is the fire-exposed surface.

[0053] Specifically, it also includes a side pressure fixture of a mechanical testing machine, which tests the side pressure strength of the specimen before and after fire. After the fire test, the specimen can be subjected to a side pressure test on the mechanical testing machine to evaluate its residual strength. The side pressure fixture is non-standard and includes a clamping rod 8, a top plate 9, a top sliding plate 10, a lateral sliding plate 11, an angle plate 12, a bottom sliding plate 13, and a bottom plate 14. During the test, the specimen is placed inside the fixture, and the upper end of the specimen is sequentially set to the top sliding plate 10, the top plate 9, and the clamping rod 8, wherein the top sliding plate 10 contacts the specimen, and the lower end of the specimen is sequentially set to the bottom sliding plate 13 and the bottom plate 14, wherein the bottom sliding plate 13 contacts the specimen, and the left and right ends of the specimen are both set to angle plates 12 and lateral sliding plates 11, wherein the lateral sliding plate 11 contacts the specimen; by adjusting the side plates and the sliding plates, it can be ensured that the specimen is perpendicular to the bottom plate, and at the same time, it plays a role in suppressing buckling in the early stage of the test.

[0054] Specifically, the top sliding plate 10, the top plate 9, and the clamping rod 8 are connected to each other by bolts, the bottom sliding plate 13 and the bottom plate 14 are connected to each other by bolts, and the angle plate 12 and the side sliding plate 11 are connected to each other by bolts.

[0055] Specifically, a threaded column 81 is opened at the bottom of the clamping rod 8, and a first threaded hole 91 is opened on the top plate 9. The first threaded hole is located at the center of the top plate. The clamping rod is connected to the first threaded hole on the top plate through the threaded column to complete the assembly of the clamping rod and the top plate.

[0056] Specifically, two top sliding plates 10 and two bottom sliding plates 13 are provided, and the two top sliding plates and the two bottom sliding plates each form a clamping section, and the test piece is provided in the clamping section.

[0057] Specifically, a first bolt limiting hole 92 is provided on the top plate 9, and a second threaded hole 101 is provided on the top sliding plate 10. The top plate and the top sliding plate are connected by a capped bolt, and the capped bolt passes through the first bolt limiting hole and is connected to the second threaded hole in the top sliding plate. The first bolt limiting hole can ensure that the top sliding plate can be adjusted forward and backward according to the different thicknesses of the sample, and at the same time, the top sliding plate is fixed through the tightening contact of the bolt.

[0058] Specifically, four lateral sliding plates 11 are provided, two at each of the left and right ends of the specimen, and two adjacent lateral sliding plates form a clamping area to limit the specimen.

[0059] Specifically, the lateral sliding plate 11 is provided with a third threaded hole 111, and the angle plate 12 is provided with a second bolt retaining hole 121, located at the side end of the angle plate. The angle plate and the lateral sliding plate are connected using capped bolts, which pass through the second bolt retaining holes and connect with the third threaded holes in the lateral sliding plate. The second bolt retaining holes ensure that the lateral sliding plate can be adjusted forward and backward according to the thickness of the specimen. At the same time, when tightened with the capped bolts, they serve to secure the lateral sliding plate. The angled side of the lateral sliding plate contacts the specimen, restricting its forward and backward movement without restricting its rotation.

[0060] Specifically, a third bolt limiting hole 122 is provided on the angle plate 12, and the third bolt limiting hole is located at the bottom end of the angle plate. A fourth threaded hole 141 is provided on the base plate 14. The angle plate and the base plate are connected with capped bolts, and the capped bolts pass through the third bolt limiting hole and are connected with the fourth threaded hole of the base plate. The third threaded limiting hole in the angle plate can ensure that the angle plate can be adjusted left and right according to different sample widths.

[0061] Specifically, a fourth bolt limiting hole 131 is provided on the bottom sliding plate 13, and the bottom plate and the bottom sliding plate are connected with a capped bolt, and the capped bolt passes through the fourth bolt limiting hole on the bottom sliding plate and is connected with the fourth threaded hole of the bottom plate. The fourth threaded limiting hole on the bottom sliding plate can ensure that the bottom sliding plate can be adjusted forward and backward according to different sample thicknesses, and the capped bolt is tightened to contact with the limiting hole on the bottom sliding plate to play a fixing role.

[0062] Preferably, the side pressure tooling can accommodate a test piece with a size of (600-800) mm × (600-800) mm to carry out a side pressure test.

[0063] Specifically, the opening size of the first sample frame 2 is (600-800) mm×(600-800) mm, and the size of the first closed frame 3 is (500-900) mm×(500-900) mm.

[0064] Specifically, the opening size of the second sample frame 4 is (600-800) mm×(600-800) mm, and the size of the second closing frame 5 is (500-900) mm×(500-900) mm.

[0065] Specifically, the furnace body is composed of a steel structure and refractory materials, wherein the refractory materials play a role in heat preservation and insulation, and the outside of the furnace body is coated with anti-corrosion and high-temperature resistant paint.

[0066] Specifically, the first sample frame and the first closing frame are connected to the furnace body, and the second sample frame and the second closing frame are connected to the furnace body by tightening bolts.

[0067] Specifically, calcium silicate boards with a thickness of not less than 50 mm are arranged around the first sample frame and the test piece, as well as around the second sample frame and the test piece, so as to weaken the heat conduction effect of the steel plate.

[0068] Specifically, the device also includes a temperature control assembly, which includes electric heating tubes 7, a control system, and a data acquisition system. The electric heating tubes heat the left, right, and rear sides of the furnace body 1, with a total of 6 to 12 tubes. The control system uses a working temperature controller with at least 30 program segments, PID automatic adjustment, and an over-temperature or deviation alarm function. The data acquisition system records the test temperature at an interval of 1 second. The control system and data acquisition system are both existing technologies and will not be described in detail here.

[0069] Specifically, the loading assembly 6 is a cement casting test block or a hydraulic loading device. During vertical testing, the width of the loading assembly is consistent with or slightly smaller than the width of the specimen. During horizontal testing, the loading assembly is evenly distributed on the surface of the specimen.

[0070] Specifically, the loading test is configured with a deformation measuring instrument to monitor the deformation amount and deformation rate of the sample in real time.

[0071] Specifically, the test piece should be paved with a combination of fireproof materials for testing, wherein the fireproof material is the fire-exposed surface.

[0072] Specifically, the control system can realize standard heating curves such as ISO 834, ASTM E119, GB / T 9978 through customized settings, and the furnace temperature can reach up to 1200°C.

[0073] Specifically, a plurality of thermocouples are provided in the furnace body to detect the temperature in the furnace. The thermocouples should use a maximum measuring temperature of not less than 1450°C and a temperature measurement accuracy of ≤±10°C. The thermocouples are nickel-chromium-nickel-silicon (K-type) thermocouples with a wire diameter of 0.75mm to 2.30mm, and are covered with a heat-resistant stainless steel sleeve or a heat-resistant porcelain sleeve, with heat-resistant material filled in the middle. The length of the heat pipe extending from the sleeve is not less than 25mm. During vertical testing, the thermocouple extends from the rear furnace panel, is located at 1 / 2 to 3 / 4 of the height, and is 100mm away from the fire surface of the specimen. During horizontal testing, the thermocouple is arranged on the second closed frame, below the center of the fire surface of the specimen, and 100mm away from the fire surface of the specimen.

[0074] Specifically, the thermocouples in the furnace body should be sealed and filled during installation.

[0075] Specifically, the specimen back temperature or core thermocouples are set at the 1 / 4 position and the center position of the specimen, and the number is variable, but the installation of the thermocouples must not affect the performance of the specimen and normal testing.

[0076] Specifically, the fire exposure time of the specimen can be controlled according to the test design, and the maximum test time is not less than 2 hours.

[0077] Specifically, it also includes a coupled test method for fire bearing of ship-bearing composite materials, and the test method includes a test method for fire bearing of specimens using a combustion furnace and a test method for lateral pressure of specimens.

[0078] Specifically, the combustion furnace conducts a test method for the specimen under fire bearing, taking the horizontal test as an example. The specimen is installed in the second sample frame, and the frame supports both ends of the specimen. The second sample frame is hoisted above the furnace body by an overhead crane, and the second closed frame is moved to the front side of the furnace body by an overhead crane and a slide rail. The second sample frame and the second closed frame are tightly connected to the furnace body by tightening bolts. Thermocouples are arranged on the back of the specimen and confirmed to be connected to the data acquisition system. If a bearing test is required, the loading assembly is evenly arranged above the specimen using an overhead crane and a cloth bag 15 minutes before the start of the test, and a deformation measuring instrument is set to monitor the deformation amount and deformation rate of the specimen. Set the heating curve in the temperature control system and start the test.

[0079] Specifically, the vertical test method is similar to the horizontal test. The specimen is installed in the first sample frame. If a load-bearing test is required, a loading assembly is placed on top of the specimen and ensured to be securely fixed. Steel bars or other similar rigid materials can be used for auxiliary fixing. The first sample frame is moved to the front of the furnace body. An overhead crane is used to hoist the first enclosing frame above the furnace body, securely connecting it to the furnace body with compression bolts. A thermocouple is placed on the backside of the specimen and ensured to be connected to the data acquisition system. A heating curve is set in the temperature control system, and the test begins.

[0080] Specifically, the specimen lateral pressure test method is to compare the lateral pressure strength of the specimen after being exposed to fire with that of the specimen without being exposed to fire, so as to assess the residual strength of the specimen after being exposed to fire. Taking the specimen after being exposed to fire as an example, the fireproof material is removed and the specimen is installed on the lateral pressure fixture so that the end of the specimen is flush with the top plate of the fixture. The specimen is supported by the side plate sliding plate connected to the angle plate and the bottom plate sliding plate connected to the bottom plate. The specimen is centered by adjusting the side plate sliding plate and the top sliding plate of the bottom plate (the angle plate and the bottom sliding plate can slide relative to each other) to ensure that the specimen is perpendicular to the bottom plate. The bolts of the angle plate and the side plate sliding plate are tightened by hand to ensure the lateral support of the specimen. The top plate is placed on the specimen, and the top plate sliding plate is adjusted so that it is in parallel contact with the specimen, and the bolts are tightened.

[0081] Specifically, place the side pressure fixture on the testing machine to ensure that the load of the testing machine can be vertically transferred to the fixture, such as Figure 5 As shown, attach axial strain gauges or set displacement meters to the specimen surface, apply an initial load, check the strain value, and adjust the fixture to ensure uniform axial stress transmission. Load the specimen at a rate of 2 mm / min or another set rate until the maximum load is reached. Terminate the test when the load drops by approximately 30% of the maximum load. Record load, strain, and other values throughout the test. After the test, summarize and analyze the maximum load and compressive strength to determine the residual strength of the specimen after fire damage.

[0082] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention.

[0083] Example 1

[0084] In this example, a rapid screening test of the fire resistance of composite materials was conducted.

[0085] The test specimen is made of a carbon fiber-reinforced resin-based composite material with a 16mm thick PVC foam core, measuring 700mm x 700mm x 20mm, and covered with two layers of 30mm thick ceramic wool fireproofing. Five thermocouples were installed at the interface between the composite and the fireproofing material, as well as on the side of the composite facing away from the fire. The thermocouples were located at the quarter and center positions of the specimen to monitor the temperature rise during the test. The specimen was tested vertically, with a second enclosing frame installed at the top of the furnace. The specimen was mounted in this second sample frame, with the fire-exposed side being the side covered with the fireproofing material.

[0086] Adopt ISO 834 standard heating curve T=345log 10 (8t+1)+20 to conduct heating test (see the heating curve Figure 11 ), the temperature rise curve of the device of the present invention is in good agreement with the standard temperature rise curve, and the two curves are basically overlapped 5 minutes after the start of the test.

[0087] The test lasted 30 minutes. The temperature rise of the back-fired surface of the structural component, the interface temperature rise, and the specimen integrity were analyzed after the test. The test results are shown in Table 1. Because factors such as the fireproofing material coating, the layout of the studs, and the position of the thermocouples during the specimen preparation process can affect the test results, three specimens (specimens 1 to 3) were prepared under the same process conditions to comprehensively compare the parallelism of the tests.

[0088] To further verify the credibility of this method, two sets of 60 mm thick ceramic wool fireproof material coated composite test specimens (specimens 4-5) were prepared using the same preparation process, and standard size (2.44 m × 2.5 m) fire resistance tests were carried out.

[0089] The test time of specimens 1 to 4 was 30 minutes, and the test time of specimen 5 was 60 minutes. The temperature rise data and specimen status at 30 minutes were compared with the test conditions of this method. The results are shown in Table 1.

[0090] Table 1 Comparison results of fire resistance test between the test method of the present invention and standard size

[0091]

[0092] Through Table 1 and Figure 7 The test results show that when the device of the present invention is subjected to a fire resistance test, the temperature rise of the back-fire surface is basically consistent with the test result of the standard method; the interface temperature rise is slightly higher than the test result of the standard method; the maximum deviation of the average value of the interface temperature rise is 9.0°C, which is within the acceptable range of the test results (the standard requires that the average temperature rise of the back-fire surface is ≤140°C and the maximum temperature rise of the back-fire surface is ≤180°C).

[0093] The present invention reduces material costs by over 90% (the specimen area is 8.0% of the full-size structural component of the standard method), significantly shortens sample preparation cycles, and significantly reduces time and labor costs. Therefore, the test device of the present invention can be used for fire resistance testing of small-scale composite specimens and for rapid screening and verification of fireproofing materials before fire resistance testing of large-scale composite components.

[0094] Example 2

[0095] In this embodiment, a load-bearing capacity test of a load-bearing composite material under fire is conducted.

[0096] The carbon-glass hybrid sandwich composite material has a core material of 24mm thick PVC foam, a total size of 600mm×600mm×30mm, and is covered with 80mm thick ceramic wool fireproof material. Five thermocouples are installed at the interface between the composite material and the fireproof material and the back-fire side of the composite material. The thermocouples are located at the 1 / 4 position and the center position of the specimen.

[0097] The specimen is tested vertically with a second sample frame, a second closed frame is used on the top of the test device, and the fire-exposed surface is the side covered with fireproof material.

[0098] 15 minutes before the test, a uniformly distributed load of about 200 kg was applied to the top of the specimen, and a deformation measuring device was set at the center of the back-fire surface to monitor the axial compression deformation and axial compression deformation rate of the specimen in real time.

[0099] Adopt ISO 834 standard heating curve T=345log 10 The temperature rise test was carried out at (8t+1)+20, and the test time was 60 min. The temperature rise and deformation results are shown in Table 2.

[0100] Table 2 Test results of load-bearing capacity of composite materials under fire

[0101]

[0102] The present invention can test the load-bearing capacity of composite fireproof structures under fire conditions. It is a scaled version of standard test methods (such as Part 11 of the 2010 FTP Rules and GB / T 9978). While reducing testing costs, it can conduct a preliminary assessment of the fireproofing and load-bearing performance of composite fireproof structures to verify the feasibility of fire protection designs.

[0103] Example 3

[0104] In this embodiment, a residual strength test of the composite material after fire damage is conducted.

[0105] The composite material specimens after the fire test of Example 1 were subjected to a residual strength test, and a comparative test was conducted with unfired specimens having the same preparation process, specimen dimensions, and other conditions.

[0106] The specimens measured 700 mm × 700 mm × 20 mm. To ensure comparability and test accuracy, the fireproofing material on the surface of the fire-exposed specimens was removed, and the unexposed specimens were kept in the same condition as the fire-exposed specimens. The specimens were conditioned for at least 24 hours in an environment with a temperature of (23 ± 2)°C and a relative humidity of (45-55)%.

[0107] Axial strain gauges are affixed back-to-back to the specimen surface. The specimen is mounted in the test fixture with the damaged area centered in the fixture. An initial load is applied, the strain gauge values are checked, and the fixture is adjusted to ensure uniform axial stress transfer.

[0108] The specimens were loaded at a rate of 2 mm / min until they reached their maximum load. The test was terminated when the load dropped by approximately 30% of the maximum load. Load, strain, and other values were recorded during the test. After the test, the maximum load and compressive strength were summarized and analyzed to determine the residual strength of the specimens after fire damage. The test results are shown in Table 3.

[0109] Table 3 Test results of residual strength of composite materials after fire damage

[0110] test piece Maximum load, kN Compression strength, MPa Not affected by fire 412.18 26.42 After the fire 130.81 9.51 Retention rate, % 31.7 36.0

[0111] The present invention can perform residual strength tests on test pieces after being exposed to fire, and can be used to evaluate the damage and residual strength of composite materials after being exposed to fire, reflect the overall structural mechanical properties of the test pieces, and lay the foundation for the comprehensive evaluation of the fire safety and structural reliability of composite materials.

[0112] In summary, the experimental device of the present invention can effectively shorten the fireproofing design and verification cycle for marine composite materials, and assess the load-bearing and fire-resistance performance of composite components under fire through rapid screening tests. The method of use of this test device closely matches the temperature rise results of standard fire resistance tests, with the maximum deviation from the average interface temperature rise being 9.0°C. The material cost of a single test can be reduced by over 90% compared to standard fire resistance tests. It can be used for fire resistance testing of small-scale composite components and for rapid screening and verification of fireproofing materials before fire resistance testing of large-scale composite components. Furthermore, the test device of the present invention can be used to evaluate the load-bearing capacity and residual strength of ship-bearing composite materials under fire, achieving a comprehensive assessment of the fireproofing and mechanical properties of composite structures during and after fire, and comprehensively evaluating the fire safety and structural reliability of composite materials.

[0113] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the scope defined by the claims.

Claims

1. A fire-bearing coupling test device for ship-bearing composite materials, comprising a combustion furnace, characterized in that: The combustion furnace comprises a furnace body (1), a first sample frame (2), a first closed frame (3), a second sample frame (4), a second closed frame (5), and a loading assembly (6). The first sample frame (2) and the first closed frame (3) are perpendicular to each other, the second sample frame (4) and the second closed frame (5) are perpendicular to each other, and the loading assembly (6) is arranged above the test piece (15); when the test piece (15) is subjected to a horizontal fire resistance test, the first sample frame (2) and the first closed frame (3) are used, the first sample frame (2) and the first closed frame (3) are respectively located at the upper end and the side end of the furnace body (1), and the test piece (15) is arranged in the first sample frame (2); when the test piece (15) is subjected to a vertical fire resistance test, the second sample frame (4) and the second closed frame (5) are used, the second sample frame (4) and the second closed frame (5) are respectively located at the side end and the upper end of the furnace body (1), and the test piece (15) is arranged in the second sample frame (4).

2. The test device according to claim 1, characterized in that The opening size of the first sample frame (2) is (600-800) mm×(600-800) mm, the size of the first closed frame (3) is (500-900) mm×(500-900) mm, the opening size of the second sample frame (4) is (600-800) mm×(600-800) mm, and the size of the second closed frame (5) is (500-900) mm×(500-900) mm.

3. The test device according to claim 1, characterized in that The first sample frame (2) and the first closing frame (3) are connected to the furnace body (1), and the second sample frame (4) and the second closing frame (5) are connected to the furnace body (1) via compression bolts.

4. The test device according to claim 1, characterized in that The invention also includes a side pressure fixture of a mechanical testing machine, which is used to test the side pressure strength of a specimen (15) before and after being subjected to fire. The side pressure fixture of the mechanical testing machine includes a clamping rod (8), a top plate (9), a top sliding plate (10), a lateral sliding plate (11), an angle plate (12), a bottom sliding plate (13), and a bottom plate (14). During the test, the specimen (15) is placed inside the fixture. The upper end of the specimen (15) is sequentially arranged as the top sliding plate (10), the top plate (9), and the clamping rod (8), wherein the top sliding plate (10) contacts the specimen (15). The lower end of the specimen (15) is sequentially arranged as the bottom sliding plate (13) and the bottom plate (14), wherein the bottom sliding plate (13) contacts the specimen (15). The left and right ends of the specimen (15) are both arranged as angle plates (12) and lateral sliding plates (11), wherein the lateral sliding plates (11) contact the specimen (15).

5. The test device according to claim 4, characterized in that A threaded column (81) is provided at the bottom of the clamping rod (8), and a first threaded hole (91) is provided on the top plate (9). The clamping rod (8) is connected to the first threaded hole (91) on the top plate (9) through the threaded column (81).

6. The test device according to claim 4, characterized in that The top plate (9) is provided with a first bolt limiting hole (92), and the top sliding plate (10) is provided with a second threaded hole (101). The top plate (9) and the top sliding plate (10) are connected by a cap bolt, and the cap bolt passes through the first bolt limiting hole (92) and is connected to the second threaded hole (101) in the top sliding plate (10).

7. The test device according to claim 4, characterized in that The lateral sliding plate (11) is provided with a third threaded hole (111), and the angle plate (12) is provided with a second bolt limiting hole (121), the second bolt limiting hole (121) is located at the side end of the angle plate (12), the angle plate (12) and the lateral sliding plate (11) are connected by a capped bolt, and the capped bolt passes through the second bolt limiting hole (121) and is connected to the third threaded hole (111) in the lateral sliding plate (11).

8. The test device according to claim 4, characterized in that A third bolt limiting hole (122) is provided on the angle plate (12), and the third bolt limiting hole (122) is located at the bottom end of the angle plate (12). A fourth threaded hole (141) is provided on the bottom plate (14). The angle plate (12) and the bottom plate (14) are connected by a capped bolt, and the capped bolt passes through the third bolt limiting hole (122) and is connected to the fourth threaded hole (141) of the bottom plate.

9. The test device according to claim 4, characterized in that It also includes a fire-bearing coupled test method for ship-bearing composite materials, which includes a fire-bearing test method for specimens using a combustion furnace and a side pressure test method for specimens.

10. The test device according to claim 9, characterized in that The test specimen lateral pressure test method is to install the specimen on a lateral pressure fixture, which is installed on a mechanical testing machine for testing, and specifically includes the following steps: The first step is to install the specimen on the lateral pressure fixture at the center of the lateral pressure fixture, and stick an axial strain gauge or set a displacement meter on the surface of the specimen; In the second step, the initial load is applied, the strain value is checked, and the fixture is adjusted to ensure uniform axial stress transmission. The specimen is loaded at a rate of 2 mm / min until the maximum load is reached. The test is terminated when the load drops by 30% of the maximum load. The third step is to record the load and strain values during the test. After the test, the maximum load and compression strength are summarized and analyzed to determine the residual strength of the specimen after fire damage.

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