Method for testing high-temperature tensile elastic modulus of fiber monofilament

Abstract

The invention discloses a method for testing the high-temperature tensile elastic modulus of a fiber monofilament, and belongs to the technical field of fiber stretching. The problem that the real tensile property of the fiber at the high temperature cannot be completely and truly reflected by the existing method is solved. Comprising the following steps: preparing a fiber monofilament tensile sample; clamping the fiber monofilament tensile sample to a clamping end of a testing device of a tensile testing machine; cutting off the two sides of the round hole in the end part of the sample lining; closing the short high-temperature furnace; the target temperature is set, heating is started, and in the heating process, the upper clamping end and the lower clamping end are placed at the room temperature; starting the tensile testing machine to carry out a tensile test, and recording a stress-strain curve to obtain an apparent tensile elastic modulus E (T1); and performing iterative calculation according to the following formula until E (T1) n obtained by the nth iteration is infinitely close to E (T1) n-1 obtained by the (n-1) th iteration, thereby obtaining the finally corrected tensile elastic modulus E (T1) n, the testing method for the high-temperature tensile elastic modulus of the fiber monofilament, disclosed by the invention, is high in accuracy.

Description

Technical Field

[0001] The invention belongs to the technical field of fiber tensile performance testing, and in particular relates to a method for testing the high-temperature tensile elastic modulus of a fiber monofilament. Background Art

[0002] Alumina fiber has a high melting point, low density, high strength, and excellent high temperature resistance. Its tensile elastic modulus in high temperature environment is one of its most important performance indicators. However, according to research, the high temperature tensile elastic modulus test of alumina fiber monofilaments is to heat treat the sample at high temperature, cool it to room temperature, and then perform the tensile test at room temperature. This method cannot fully reflect the true tensile performance of the fiber under high temperature conditions. There are currently no relevant standards, patents, and articles for the high temperature in-situ tensile elastic modulus test of fiber monofilaments.

[0003] The prior art provides a DMA method for testing the tensile elastic modulus of fibers at high temperatures. However, since DMA equipment is relatively precise, afraid of contamination, and complicated to operate, fiber debris and paper frame debris can easily contaminate the equipment during the high-temperature test. Therefore, the DMA method is not suitable for daily fiber high-temperature tensile elastic modulus testing. Summary of the invention

[0004] In view of the above analysis, the present invention aims to provide a method for testing the high-temperature tensile elastic modulus of a fiber monofilament, which can solve at least one of the following technical problems: (1) The existing DMA method is not suitable for testing the high-temperature tensile elastic modulus of daily fibers; (2) The existing method uses a method of heat treating the sample at high temperature, cooling it to room temperature, and then performing a tensile test at room temperature. This method cannot fully and truly reflect the actual tensile performance of the fiber under high temperature conditions.

[0005] The purpose of the present invention is mainly achieved through the following technical solutions:

[0006] In one aspect, the present invention provides a method for testing the high-temperature tensile elastic modulus of a fiber monofilament, comprising the following steps:

[0007] S1. Glue the fiber monofilament sample onto the sample liner to obtain the fiber monofilament tensile sample;

[0008] S2. Clamp the prepared fiber monofilament tensile specimen to the upper and lower clamping ends of the tensile testing machine test device; place the middle part of the fiber monofilament tensile specimen in a short high-temperature furnace;

[0009] S3. Cut off the two sides of the circular hole at the end of the sample lining of the fiber monofilament tensile test sample and remove the cut paper pieces;

[0010] S4. Close the short high-temperature furnace and block the furnace hole with a baffle;

[0011] S5. After setting the target temperature, start heating. During the heating process, the upper and lower clamping ends are placed at room temperature.

[0012] S6, when the holding time is up, start the tensile testing machine to perform a tensile test, record the stress-strain curve, and obtain the apparent tensile elastic modulus E(T1);

[0013] S7, iterate the calculation according to the following formula (1) until the E(T1) obtained in the nth iteration is n E(T1) obtained from the n-1th iteration n-1 Infinitely close, the final corrected tensile elastic modulus E(T1) is obtained n ;

[0014]

[0015] Wherein: L0 is the length of the uniform temperature zone of the fiber monofilament sample in the high temperature furnace, L1 is the length of the transition section of the clamping end of the fiber monofilament sample outside the uniform temperature zone, L is the length between the clamping ends of the fiber monofilament sample, T1 is the temperature of the uniform temperature zone in the short high temperature furnace, T2 is the temperature of the clamping end of the fiber monofilament tensile sample, E(T1) is the apparent tensile elastic modulus of the fiber monofilament tensile sample measured at temperature T1, E(T2) is the tensile elastic modulus of the fiber monofilament tensile sample measured at T2; n is the number of iterations, E(T1) n-1 and E(T1) n are the tensile elastic modulus obtained by iteration n-1 times and n times respectively.

[0016] Further, S1 includes the following steps:

[0017] Step 1: Use coordinate paper to punch a circular hole at each end of the length direction of the sample lining. The center lines of the two circular holes should coincide with a certain engraved line on the coordinate paper.

[0018] Step 2: Place the sample liner on a flat surface; drop quick-drying glue on the center line of the outer edges of the circular holes at both ends of the sample liner;

[0019] Step 3, placing the fiber monofilament sample on the sample liner, with the fiber monofilament sample coinciding with the center lines of the two end circular holes, and the two ends of the fiber monofilament sample passing through the quick-drying glue outside the two end circular holes;

[0020] Step 4: Cover the paper piece on the quick-drying glue and the fiber monofilament sample on the sample liner along the outer edges of the two end circular holes, and stick the fiber monofilament sample on the sample liner to obtain the fiber monofilament tensile sample.

[0021] Furthermore, in step 1, a plurality of circular holes may be provided on the sample between the two end circular holes.

[0022] Furthermore, in step 1, the width of the sample lining is controlled to be 8 to 13 mm.

[0023] Furthermore, in step 1, the diameter of the circular hole at the end is controlled to be 5 to 7 mm.

[0024] Furthermore, in S2, the sample liner is clamped at the upper and lower clamping ends of the testing machine, the two sides of the sample liner are parallel to the two sides of the clamping surface of the clamping end, and the sample liner is located in the transverse center of the two clamping surfaces.

[0025] Furthermore, the short high temperature furnace is kept at a distance from both clamping ends.

[0026] Furthermore, the distance between the outer side surface of the short high-temperature furnace and the nearest clamping end is 65 to 75 mm.

[0027] Furthermore, an observation window is provided in the middle of the short high-temperature furnace.

[0028] Furthermore, an upper baffle is provided on the upper side of the short high-temperature furnace, and a lower baffle is provided on the lower side of the short high-temperature furnace.

[0029] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0030] (1) In the test method for the high-temperature tensile elastic modulus of a fiber monofilament of the present invention, a cold clamping method is adopted to clamp the fiber monofilament tensile specimen, and the specimen is heated in a short high-temperature furnace. Before heating, the middle part of the specimen lining is cut off, and then the temperature is raised and the tensile test is performed to achieve the test of the high-temperature in-situ apparent tensile elastic modulus of the fiber monofilament; assuming that the temperature of the transition section of the fiber monofilament tensile specimen decreases linearly from the end of the sample uniform temperature section to the transition section, and the tensile elastic modulus of the fiber monofilament changes linearly from high temperature to room temperature, the true tensile elastic modulus value is finally calculated by formula derivation and iteration.

[0031] (2) During the preparation of the fiber monofilament tensile test specimen of the present invention, the fiber monofilament test specimen is adhered to the test specimen liner, and circular holes are punched in the test specimen liner by a puncher, which can effectively prevent the fiber monofilament from being damaged due to excessive length, and the fiber monofilament can be observed through the circular holes in the middle of the test specimen liner, thereby ensuring that the fiber is coaxial with the two circular holes during the sample preparation process.

[0032] (3) The relative deviation between the value of the high-temperature tensile elastic modulus of the fiber monofilament measured by the test method for the high-temperature tensile elastic modulus of the fiber monofilament of the present invention and the value measured by the DMA method is less than 0.15%, and the accuracy is high.

[0033] Other features and advantages of the present invention will be described in the following description, and part of them will become obvious from the description, or will be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings are only for the purpose of illustrating the particular invention and are not to be considered as limiting the invention. The same reference symbols denote the same components throughout the accompanying drawings.

[0035] Figure 1 Schematic diagram of preparation of fiber monofilament tensile specimen;

[0036] Figure 2 It is a structural schematic diagram of the tensile testing machine test device;

[0037] Figure 3 Schematic diagram of high-temperature stretching of fiber monofilament.

[0038] Reference numerals:

[0039] 1-fiber monofilament sample, 2-sample lining, 3-end round hole, 4-quick-drying glue, 5-paper, 6-upper clamping end, 7-lower clamping end, 8-short high-temperature furnace, 9-upper baffle, 10-lower baffle, 11-observation window. DETAILED DESCRIPTION

[0040] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention and are used to illustrate the principles of the present invention.

[0041] The present invention provides a method for testing the high-temperature tensile elastic modulus of a fiber monofilament, comprising the following steps:

[0042] S1, sticking the fiber monofilament sample 1 to the sample liner 2 to obtain the fiber monofilament tensile sample;

[0043] S2. Clamp the prepared fiber monofilament tensile specimen to the upper and lower clamping ends of the tensile testing machine test device; place the middle part of the fiber monofilament tensile specimen in a short high-temperature furnace;

[0044] S3, cutting off the two sides of the circular hole at the end of the sample liner 2 of the fiber monofilament tensile test sample, and removing the cut paper pieces;

[0045] S4. Close the short high-temperature furnace and block the furnace hole with a baffle;

[0046] S5. After setting the target temperature, start heating. During the heating process, the upper and lower clamping ends are placed at room temperature.

[0047] S6, when the holding time is up, start the tensile testing machine to perform a tensile test, record the stress-strain curve, and obtain the apparent tensile elastic modulus E(T1);

[0048] S7, iterate the calculation according to the following formula (1) until the E(T1) obtained in the nth iteration is nE(T1) obtained from the n-1th iteration n-1 Infinitely close (relative deviation is less than 0.5%), the final corrected tensile elastic modulus E(T1) is obtained. n ;

[0049]

[0050] Wherein, L0 is the length of the uniform temperature zone of the fiber monofilament sample in the high temperature furnace, L1 is the length of the transition section from the uniform temperature zone of the fiber monofilament sample to the clamping end of the fixture, and L is the length between the two clamping ends of the fiber monofilament sample; T1 is the temperature of the uniform temperature zone in the short high temperature furnace, T2 is the temperature of the clamping end of the fiber monofilament tensile sample (i.e., room temperature), E(T1) is the apparent tensile elastic modulus of the fiber monofilament tensile sample measured at temperature T1, and E(T2) is the tensile elastic modulus of the fiber monofilament tensile sample measured at temperature T2; n is the number of iterations, and when n=1, E(T1) n-1 E(T1)0 is the apparent elastic modulus E(T1) measured at temperature T1, E(T1) n-1 and E(T1) n are the tensile elastic modulus obtained by iteration n-1 times and n times respectively.

[0051] Specifically, the fiber monofilament may be an alumina fiber monofilament.

[0052] Specifically, S1 includes the following steps:

[0053] Step 1: Figure 1 As shown, the sample liner 2 uses coordinate paper, and a round hole 3 is punched at each end of the sample liner 2 in the length direction, and the center lines of the two round holes 3 coincide with a certain engraved line in the coordinate paper;

[0054] Step 2, place the sample liner 2 on a plane; drop quick-drying glue 4 on the center line of the outer edges of the two end circular holes 3 on the sample liner 2;

[0055] Step 3, placing the fiber monofilament sample 1 on the sample liner 2, the fiber monofilament sample 1 coincides with the center line of the two end circular holes 3, and the two ends of the fiber monofilament sample 1 pass through the quick-drying glue 4 outside the two end circular holes 3;

[0056] Step 4: Cover the paper piece 5 on the quick-drying glue 4 and the fiber monofilament sample 1 on the sample liner 2 along the outer edges of the two end circular holes 3, and stick the fiber monofilament sample 1 on the sample liner 2 to obtain the fiber monofilament tensile sample.

[0057] Specifically, in the above step 1, a plurality of circular holes can be provided on the sample lining 2 between the two end circular holes 3. Since the fiber monofilament sample 1 is usually transparent, the presence of the circular holes can be used as a contrast, so that the fiber monofilament sample can be seen more clearly during sample preparation; and the circular holes provided on the sample lining facilitate cutting the sample lining during testing.

[0058] Specifically, in the above step 1, considering that the width of the sample liner 2 is too large, the centering is difficult to control during clamping, and the matching performance with the clamping surface of the clamping end of the tensile testing machine is poor, therefore, the width of the sample liner 2 is controlled to be 8 to 13 mm.

[0059] Specifically, in the above step 1, the diameter of the circular hole 3 at the end is controlled to be 5 to 7 mm.

[0060] Specifically, in the above step 1, a hole puncher may be used to punch the circular hole.

[0061] Specifically, in the above step 1, the sample preparation method of the fiber monofilament tensile specimen of the present invention uses coordinate paper as the sample liner, and the fiber monofilament sample is pasted along the engraved lines of the coordinate paper, so that the fiber monofilament sample can be kept vertical, thereby ensuring the centering of the fiber monofilament sample during the test, and improving the accuracy of the test result;

[0062] Specifically, in the above step 2, quick-drying glue is dropped on the outside of the two circular holes of the sample liner, and then the fiber monofilament sample is placed at the center line of the two circular holes, and then the adhesive is covered with a paper piece of a suitable size. At this time, the prepared fiber monofilament sample has good alignment and the adhesive area is flat, and the accuracy of the test results will not be affected by the presence of hard glue points during the clamping test.

[0063] Specifically, in the above S2, if Figure 2 The figure shows a schematic diagram of the structure of a tensile testing machine test device, in which the prepared fiber monofilament tensile specimen is clamped to the upper clamping end 6 and the lower clamping end 7 of the tensile testing machine test device; a part of the fiber monofilament tensile specimen is placed in a short high-temperature furnace 8; an upper baffle 9 is provided on the upper side of the short high-temperature furnace 8, a lower baffle 10 is provided on the lower side of the short high-temperature furnace 8, and an observation window 11 is provided in the middle of the short high-temperature furnace 8.

[0064] Specifically, in the above S7, the schematic diagram of high temperature stretching of the fiber monofilament is as follows: Figure 3 L0 is the length of the uniform temperature zone of the fiber monofilament sample in the high temperature furnace, and L1 is the length of the transition section from the uniform temperature zone of the fiber monofilament sample to the clamping end of the fixture.

[0065] Specifically, in the above S2, the sample liner is clamped at the upper and lower clamping ends of the testing machine, and the two sides of the sample liner should be parallel to the two sides of the clamping surface of the clamping end. The sample liner is located in the transverse center of the two clamping surfaces, so that the fiber monofilament tensile sample can better maintain the centering during the test.

[0066] Specifically, in the above S2, the short high-temperature furnace 8 should maintain a certain distance from the two clamping ends to protect the clamping ends from being damaged by high-temperature radiation.

[0067] Specifically, in the above S2, the distance between the outer side surface of the short high-temperature furnace 8 and the nearest clamping end is 65-75 mm, for example, 66 mm, 67 mm, 68 mm, 69 mm, 70 mm, 71 mm, 72 mm, 73 mm, and 74 mm.

[0068] It should be noted that the test method of the present invention adopts a cold clamping method to perform in-situ tensile testing by heating in a short high-temperature furnace. Since the high-temperature test sample of this method is in the middle of a high-temperature heating furnace and both ends are outside the high-temperature heating device, the obtained high-temperature tensile elastic modulus is not accurate. The inventor has corrected the tensile elastic modulus data. The calculation method of the corrected tensile elastic modulus of S7 is derived by the inventor in the long-term in-depth research process: the inventor has tested a series of alumina fiber monofilaments that were subjected to tensile tests at room temperature after high-temperature treatment at different temperatures. A large number of experiments have verified that as the temperature increases, the tensile elastic modulus of the alumina fiber monofilament increases accordingly. After in-depth research, the inventor assumes that during the high-temperature in-situ tensile test of the alumina fiber monofilament using a cold clamping method, the tensile elastic modulus E changes linearly from high temperature to room temperature, that is: E(T)=a0+a1T

[0069] Then we have:

[0070] Get a0 and a1,

[0071] Assume that the temperature of the fiber monofilament in the transition section changes linearly, that is: T = b0 + b1x

[0072] Then we have:

[0073] Get b0 and b1,

[0074] Solve the total elongation ΔL during the stretching process of the fiber monofilament

[0075] Elongation in the uniform temperature section L0:

[0076] Take a microelement segment dx at x in the transition section of the fiber monofilament, where the temperature is T(x), and its deformation under the tensile stress of σ is δ(dx)

[0077] Then we have: T(x)=b0+b1x

[0078] E(x,T)=a0+a1T=a0+a1b0+a1b1x

[0079] And by

[0080]

[0081] have to

[0082]

[0083]

[0084] ∴The total deformation of the fiber is

[0085] ΔL=ΔL0+2ΔL1

[0086] Substituting (6) and (7) derived above into

[0087]

[0088] ∴The value of the tensile elastic modulus after iteration 1 is:

[0089]

[0090]

[0091] The tensile elastic modulus after iteration 2 is:

[0092]

[0093] …

[0094] The tensile elastic modulus after n iterations is:

[0095]

[0096] When E(T1) n and E(T1) n-1 Infinitely close (relative deviation is less than 0.5%), the final corrected tensile elastic modulus E(T1) is obtained. n .

[0097] Compared with the prior art, in the test method for the high-temperature tensile elastic modulus of the fiber monofilament of the present invention, the fiber monofilament tensile specimen is clamped in a cold clamping manner, and is heated in a short high-temperature furnace. Before heating, the middle part of the specimen lining is cut off, and then the temperature is increased and the tensile test is performed to achieve the test of the high-temperature in-situ apparent tensile elastic modulus of the fiber monofilament; assuming that the temperature of the transition section of the fiber monofilament tensile specimen decreases linearly from the end of the specimen at uniform temperature to the transition section, the tensile elastic modulus of the fiber monofilament changes linearly from high temperature to room temperature, and the true tensile elastic modulus value is finally calculated through formula derivation and iteration.

[0098] During the preparation of the fiber monofilament tensile test specimen of the present invention, the fiber monofilament test specimen is adhered to a test specimen liner, and circular holes are punched in the test specimen liner by a puncher, which can effectively prevent the fiber monofilament from being damaged due to excessive length, and the fiber monofilament can be observed through a plurality of circular holes in the middle of the test specimen liner, thereby ensuring that the fiber is coaxial with the two circular holes during the sample preparation process.

[0099] The relative deviation between the value of the fiber monofilament high temperature tensile elastic modulus measured by the fiber monofilament high temperature tensile elastic modulus testing method of the present invention and the value measured by the DMA method is less than 0.15%, and the accuracy is high.

[0100] Example 1

[0101] like Figure 1-3 As shown, this embodiment provides a method for testing the high-temperature tensile elastic modulus of a fiber monofilament, comprising the following steps:

[0102] S1, sticking the fiber monofilament sample 1 to the sample liner 2 to obtain the fiber monofilament tensile sample;

[0103] S2, clamping the prepared fiber monofilament tensile specimen to the upper and lower clamping ends of the tensile testing machine test device; placing a portion of the fiber monofilament tensile specimen in a short high-temperature furnace;

[0104] S3, cutting off the two sides of the circular hole at the end of the sample liner 2 of the fiber monofilament tensile test sample, and removing the cut paper pieces;

[0105] S4. Close the short high-temperature furnace and block the furnace hole with a baffle;

[0106] S5. After setting the target temperature T1, start heating. During the heating process, the upper and lower clamping ends are placed at room temperature.

[0107] S6, when the holding time is up, start the tensile testing machine to perform a tensile test, record the stress-strain curve, and obtain the apparent tensile elastic modulus E(T1);

[0108] S7, measuring the tensile elastic modulus E(T2) of the fiber monofilament tensile specimen at room temperature T2,

[0109] S8, iterate the calculation according to the following formula (1) until the E(T1) obtained in the nth iteration is n E(T1) obtained from the n-1th iteration n-1 Infinitely close (relative deviation is less than 0.5%), the final corrected tensile elastic modulus E(T1) is obtained. n ;

[0110]

[0111] In this embodiment:

[0112] T1 is the temperature of the uniform temperature section in the furnace, which is 600°C;

[0113] T2 is the temperature of the fiber clamping end, which is 23°C; E(T1) is the apparent tensile elastic modulus measured at temperature T1, which is 231 GPa; E(T2) is the tensile elastic modulus of the fiber measured at T2, which is 228 GPa; L0 is the length of the uniform temperature zone of the fiber monofilament sample in the high-temperature furnace, which is 20 mm; L1 is the length of the transition section from the outside of the uniform temperature zone of the fiber monofilament sample to the clamping end of the fixture, which is 115 mm; and L is the length between the two clamping ends of the fiber monofilament sample, which is 250 mm.

[0114] E(T1)1=229.66GPa obtained after one iteration;

[0115] Iterate twice to get E(T1)2 = 229.55 GPa;

[0116] E(T1)3=229.54GPa obtained by three iterations;

[0117] Since the data obtained in the third iteration are infinitely close to those obtained in the second iteration (relative deviation is less than 0.5%), the final corrected tensile elastic modulus E(T1) is n E(T1)3=229.54GPa.

[0118] Specifically, the fiber monofilament is an alumina fiber monofilament.

[0119] Specifically, S1 includes the following steps:

[0120] Step 1: Figure 1 As shown, the sample liner 2 uses coordinate paper, and a round hole 3 is punched at each end of the sample liner 2 in the length direction, and the center lines of the two round holes 3 coincide with a certain engraved line in the coordinate paper;

[0121] Step 2, place the sample liner 2 on a plane; drop quick-drying glue 4 on the center line of the outer edges of the two end circular holes 3 on the sample liner 2;

[0122] Step 3, placing the fiber monofilament sample 1 on the sample liner 2, the fiber monofilament sample 1 coincides with the center line of the two end circular holes 3, and the two ends of the fiber monofilament sample 1 pass through the quick-drying glue 4 outside the two end circular holes 3;

[0123] Step 4: Cover the paper piece 5 on the quick-drying glue 4 and the fiber monofilament sample 1 on the sample liner 2 along the outer edges of the two end circular holes 3, and stick the fiber monofilament sample 1 on the sample liner 2 to obtain the fiber monofilament tensile sample.

[0124] Specifically, in the above step 1, a plurality of circular holes may be provided on the sample liner 2 between the two end circular holes 3 .

[0125] Specifically, in the above step 1, the width of the sample lining 2 is controlled to be 10 mm.

[0126] Specifically, in the above step 1, the diameter of the circular hole 3 at the end is controlled to be 6 mm.

[0127] The distance between the outer side of the short high-temperature furnace 8 and the nearest clamping end is 70 mm.

[0128] The final corrected tensile elastic modulus E(T1) at T1 temperature measured in this embodiment is n It is 229.54GPa.

[0129] The inventors used the DMA method to measure the high-temperature tensile elastic modulus of the fiber monofilament at temperature T1, and found that it was 230.12 GPa.

[0130] It can be seen that the relative deviation between the value of the high-temperature tensile elastic modulus of the fiber monofilament measured by the method of the present invention and the value measured by the DMA method is 0.13%, and the accuracy is high.

[0131] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for testing the high-temperature tensile elastic modulus of a fiber monofilament, characterized in that: The following steps are involved: S1, sticking a fiber monofilament sample (1) onto a sample liner (2) to obtain a fiber monofilament tensile sample; S2, clamping the prepared fiber monofilament tensile specimen to the upper and lower clamping ends of the tensile testing machine test device; placing the middle part of the fiber monofilament tensile specimen in a short high-temperature furnace (8); S3, cutting off the two sides of the circular hole at the end of the sample liner (2) of the fiber monofilament tensile test sample, and removing the cut paper pieces; S4, closing the short high-temperature furnace (8) and blocking the furnace hole with a baffle; S5. After setting the target temperature, start heating. During the heating process, the upper and lower clamping ends are placed at room temperature. S6, when the holding time is up, start the tensile testing machine to perform a tensile test, record the stress-strain curve, and obtain the apparent tensile elastic modulus E(T1); S7, iterate the calculation according to the following formula (1) until the E(T1) obtained in the nth iteration is n E(T1) obtained from the n-1th iteration n-1 Infinitely close, the final corrected tensile elastic modulus E(T1) is obtained n ; Wherein: L0 is the length of the uniform temperature zone of the fiber monofilament sample in the high temperature furnace, L1 is the length of the transition section of the clamping end of the fiber monofilament sample outside the uniform temperature zone, L is the length between the clamping ends of the fiber monofilament sample, T1 is the temperature of the uniform temperature zone in the short high temperature furnace, T2 is the temperature of the clamping end of the fiber monofilament tensile sample, E(T1) is the apparent tensile elastic modulus of the fiber monofilament tensile sample measured at temperature T1, E(T2) is the tensile elastic modulus of the fiber monofilament tensile sample measured at T2; n is the number of iterations, E(T1) n-1 and E(T1) n are the tensile elastic modulus obtained by iteration n-1 times and n times respectively.

2. The method for testing the high-temperature tensile elastic modulus of a fiber monofilament according to claim 1, characterized in that: The S1 comprises the following steps: Step 1: Use coordinate paper to punch a circular hole (3) at each end of the sample liner (2) in the length direction, and the center lines of the two circular holes (3) coincide with a certain engraved line on the coordinate paper; Step 2, place the sample liner (2) on a flat surface; drop quick-drying glue (4) on the center line of the outer edges of the two end circular holes (3) on the sample liner (2); Step 3, placing the fiber monofilament sample (1) on the sample liner (2), with the fiber monofilament sample (1) coinciding with the center lines of the two end circular holes (3), and the two ends of the fiber monofilament sample (1) passing through the quick-drying glue (4) outside the two end circular holes (3); Step 4: Cover the paper sheet (5) along the outer edges of the two end circular holes (3) onto the quick-drying glue (4) and the fiber monofilament sample (1) on the sample liner (2), and stick the fiber monofilament sample (1) onto the sample liner (2) to obtain a fiber monofilament tensile sample.

3. The method for testing the high-temperature tensile elastic modulus of a fiber monofilament according to claim 2, characterized in that: In step 1, a plurality of circular holes may be provided on the sample between the two end circular holes.

4. The method for testing the high-temperature tensile elastic modulus of a fiber monofilament according to claim 2, characterized in that: In the step 1, the width of the sample lining (2) is controlled to be 8 to 13 mm.

5. The method for testing the high-temperature tensile elastic modulus of a fiber monofilament according to claim 2, characterized in that: In the step 1, the diameter of the circular hole (3) at the end is controlled to be 5 to 7 mm.

6. The method for testing the high-temperature tensile elastic modulus of a fiber monofilament according to claim 1, characterized in that: In S2, the sample liner is clamped at the upper and lower clamping ends of the testing machine, the two sides of the sample liner are parallel to the two sides of the clamping surface of the clamping end, and the sample liner is located in the transverse center of the two clamping surfaces.

7. The method for testing the high-temperature tensile elastic modulus of a fiber monofilament according to claim 1, characterized in that: The short high-temperature furnace (8) is kept at a distance from both clamping ends.

8. The method for testing the high-temperature tensile elastic modulus of a fiber monofilament according to claim 7, characterized in that: The distance between the outer side surface of the short high-temperature furnace (8) and the nearest clamping end is 65-75 mm.

9. The method for testing the high-temperature tensile elastic modulus of a fiber monofilament according to any one of claims 1 to 8, characterized in that: An observation window (11) is provided in the middle of the short high-temperature furnace (8).

10. The method for testing the high-temperature tensile elastic modulus of a fiber monofilament according to any one of claims 1 to 8, characterized in that: An upper baffle (9) is provided on the upper side of the short high-temperature furnace (8), and a lower baffle (10) is provided on the lower side of the short high-temperature furnace (8).

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