A prediction method for impact energy of ESSO crack arrest test based on dynamic tearing energy

Abstract

The present invention provides a prediction method for the impact energy of an ESSO crack arrest test based on dynamic tearing energy. Through the test parameters of the dynamic tearing test, a correlation equation between the dynamic tearing energy and the temperature is established. Then, the tip temperature of the notch in the gradient temperature type ESSO test is detected to obtain the dynamic tearing energy corresponding to the temperature. According to the correlation model of the impact cracking energy and the dynamic tearing energy of the ESSO test, the lower limit value of the impact cracking energy of the ESSO test is obtained. According to the lower limit value of the impact cracking energy, corresponding impact device parameters are set to perform the test. The test result has high accuracy, effectively reduces the discrete degree of the test result, improves the test detection accuracy, and provides strong technical support for the accurate evaluation of the crack arrest performance of high-strength thick plates for ships.

Description

Technical Field

[0001] The invention relates to the technical field of testing the fracture resistance of metal materials, and in particular to a method for predicting the impact energy of an ESSO crack arrest test based on dynamic tearing energy. Background Art

[0002] In order to effectively ensure the structural safety of ultra-large container ships, the International Association of Classification Societies (IACS) requires that the high-strength steel thick plates used in the upper deck side plates, side strakes and other parts must have crack arresting ability. In its unified requirements UR W31 "YP47 thick plates and brittle crack arresting plates", a large-scale test method for crack arresting performance is given, mainly including the ESSO test method and the double tensile test method, and it is believed that the measurement results of these two methods are equivalent. For the ESSO test method, a fast-growing brittle crack is formed by impacting the prefabricated notch at the edge of the specimen, and the crack arresting performance of the material is evaluated based on the crack expansion and stopping characteristics in the specimen. Due to the impact process in the test, the impact energy may affect the stress distribution in the specimen, thereby causing the discreteness of the test results. Therefore, in UR W31, the upper limit of the impact energy is specified, as shown in formula (1).

[0003] (1)

[0004] Among them, E i is the impact energy, t is the specimen thickness, and σ is the principal tensile stress. In UR W31, the basis for determining formula (1) is not explained, and the lower limit of the impact energy and the deviation analysis of the results measured by the upper and lower limits are not given. In the literature "The Effect of Impact Energy on ESSO Test Results", researchers analyzed the effect of impact energy on the crack arrest toughness K measured in the ESSO test. ca The influence of the impact energy lower limit and the upper limit in UR W31 were found to be -10℃ K ca Value deviation up to 1000N·mm 3 / 2 This indicates that the existing specifications for impact energy are problematic. At the same time, the document also proposes that the crack arrest toughness K measured by the lower limit of impact energy ca The results are consistent with those of the double tensile test, and it is suggested that the impact energy should be taken as the lower limit in the ESSO test, but the specific calculation method of the lower limit is not given. In order to reduce the impact of the impact process on the discreteness of the ESSO test results, it is necessary to obtain an estimation method for the lower limit of the impact energy. At present, no work in this regard has been reported in China. Summary of the invention

[0005] In view of this, the present invention aims to propose a prediction method for the impact energy of the ESSO crack arrest test based on dynamic tearing energy. Starting from the gradient temperature type ESSO test mechanism, the correlation between the impact energy and the material's own toughness is clarified, and a prediction model for the lower limit of the ESSO impact energy based on dynamic tearing energy is proposed, which provides strong technical support for the accurate evaluation of the crack arrest performance of high-strength thick plates for ships with a thickness of ≥16 mm.

[0006] The present invention discloses a method for predicting the impact energy of an ESSO crack arrest test based on dynamic tearing energy, comprising the following steps:

[0007] Step S1: performing a dynamic tearing test at a series of temperatures on a steel plate to obtain dynamic tearing energy at corresponding temperatures;

[0008] Step S2: fitting the test data of step S1 to establish a correlation equation between dynamic tearing energy and temperature;

[0009] Step S3: Conduct a gradient temperature ESSO test on the same batch of steel plates as in step S1, establish a gradient temperature field in the ESSO specimen, and measure the notch tip temperature T after the temperature field is stable;

[0010] Step S4: Substituting the notch tip temperature T measured in step S3 into the correlation equation between dynamic tear energy and temperature obtained in step S2 to obtain the dynamic tear energy at temperature T;

[0011] Step S5: Substitute the dynamic tearing energy obtained in step S4 into the correlation model between the impact cracking energy and the dynamic tearing energy in the ESSO test, as shown in formula (7), to obtain the lower limit of the impact cracking energy in the ESSO test:

[0012] (7)

[0013] Among them, E i is the impact initiation energy of the ESSO specimen, DTE is the dynamic tearing energy corresponding to the notch tip temperature of the ESSO specimen, t is the specimen thickness, ρ1 is the curvature radius of the notch tip of the ESSO specimen, and ρ2 is the curvature radius of the notch tip of the dynamic tearing specimen.

[0014] Furthermore, the test data in step S2 at least includes dynamic tearing energy.

[0015] Furthermore, step S2 includes:

[0016] Step S21: The multiple groups of tests obtained in step S1 are fitted using the Boltzman formula to obtain the correlation equation between dynamic tearing energy and temperature, as shown in formula (8):

[0017] (8)

[0018] Among them, k1, k2, k3, and k4 are unknown coefficients.

[0019] Furthermore, the curvature radius of the notch tip of the ESSO specimen is 0.18 mm, and the curvature radius of the notch tip of the dynamic tearing specimen is 0.025 mm. The correlation model of the impact cracking energy and the dynamic tearing energy of the ESSO test in step S5 is: (9).

[0020] Furthermore, the thickness of the steel plate is greater than or equal to 16 mm.

[0021] Furthermore, the thickness of the steel plate is 60-90 mm.

[0022] Furthermore, the series temperature is between -100°C and 20°C.

[0023] Compared with the prior art, the prediction method of the ESSO crack arrest test impact energy based on dynamic tearing energy described in the present invention has the following advantages:

[0024] The present invention starts from the mechanism of ESSO test and dynamic tear test, and on the basis of comprehensive analysis of influencing factors such as impact velocity, ambient temperature, sample thickness, notch tip curvature radius, etc., clarifies the main influencing factors, and provides a correlation model. According to the test parameters in the dynamic tear test, the lower limit of the impact cracking energy of the ESSO test can be predicted more accurately. According to the lower limit of the impact cracking energy, the corresponding impact device parameters are set to conduct the test. The test results are highly accurate, the discrete degree of the test results is effectively reduced, and the test detection accuracy is improved. The correlation model provided by the present invention has the advantages of clear physical mechanism, concise equation form, high prediction accuracy, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 It is a schematic diagram of the structure of the temperature gradient ESSO specimen;

[0027] Figure 2 The crack arrest toughness K is measured according to the lower limit of the impact energy obtained by the prediction method provided in this application. ca , the crack arrest toughness K measured according to the upper limit of impact energy obtained by the prior art ca Compared with the crack arrest toughness K measured by double tensile testca Schematic diagram of the result comparison. DETAILED DESCRIPTION

[0028] In order to make the technical means, objectives and effects of the present invention easy to understand, the embodiments of the present invention are described in detail below with reference to specific drawings.

[0029] It should be noted that all the terms used in the present invention for directional and positional indications, such as "upper", "lower", "left", "right", "front", "back", "vertical", "horizontal", "inside", "outside", "top", "lower", "lateral", "longitudinal", "center", etc., are only used to explain the relative positional relationship and connection status between the components in a certain state (as shown in the accompanying drawings), and are only for the convenience of describing the present invention, rather than requiring the present invention to be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the descriptions of "first", "second", etc. in the present invention are only used for descriptive purposes, and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features.

[0030] In the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0032] The dynamic tear test is a commonly used test method for evaluating the impact toughness of metal materials. This method uses a pendulum test device to impact a specimen with a prefabricated notch (typical size is 16mm×40mm×180mm), and the material absorption energy measured during the impact process (defined as dynamic tear energy) is used as a characterization parameter of the material toughness performance. The specific test process can be found in GB / T 5482-2023 "Dynamic tear test method for metallic materials". Considering that there are certain similarities between the impact cracking process of the ESSO test and the dynamic tear test process, the present invention believes that there is a correlation between the dynamic tear energy and the lower limit of the ESSO impact energy, and a correlation model between the two can be established through analysis. It should be noted that since the thickness of the standard specimen for the dynamic tear test is 16mm, the target material of the present invention is high-strength steel with a thickness of ≥16mm. For steel plates with a thickness of <16mm, the lower limit of the ESSO impact energy will be predicted by other test methods.

[0033] In the research process of the present invention, the test method used is mainly the gradient temperature type ESSO test method, and its schematic diagram is as follows Figure 1 As shown, the edge of the specimen has a prefabricated notch. During the test, a gradient temperature field is established in the specimen (typical size is plate thickness × 500mm × 500mm). After the temperature field is stabilized, a tensile load is applied. After the stable loading time is not less than 10s, the impact device is started to impact the notch portion cooled to a low temperature. After the brittle crack starts from the notch tip, it expands and stops in the specimen. According to the crack arrest length and temperature gradient, the temperature T at the crack arrest point can be calculated. K , as shown in formula (2); according to the principal tensile stress and crack arrest length, the crack arrest toughness K can be calculated ca , as shown in formula (3); the measured multiple groups of T K and K ca Substituting the value into formula (4) can determine the values ​​of K0 and T0, and then the crack arrest toughness K at the corresponding temperature can be calculated. ca value.

[0034] T k =T i +aΔT (2)

[0035] (3)

[0036] (4)

[0037] Among them, T i is the cold end temperature, a is the crack arrest length, △T is the temperature gradient, σ is the main tensile stress, W s is the sample width, K0 is the temperature correlation coefficient, and T0 is the temperature correlation index.

[0038] like Figure 1-2 As shown, the present invention discloses a method for predicting the impact energy of an ESSO crack arrest test based on dynamic tearing energy, comprising the following steps:

[0039] Step S1: performing a dynamic tearing test at a series of temperatures on a steel plate to obtain dynamic tearing energy at corresponding temperatures;

[0040] Step S2: fitting the test data of step S1 to establish a correlation equation between dynamic tearing energy and temperature;

[0041] Step S3: Conduct a gradient temperature ESSO test on the same batch of steel plates as in step S1, establish a gradient temperature field in the ESSO specimen, and measure the notch tip temperature T after the temperature field is stable;

[0042] Step S4: Substituting the notch tip temperature T measured in step S3 into the correlation equation between dynamic tear energy and temperature obtained in step S2 to obtain the dynamic tear energy at temperature T;

[0043] Step S5: Substitute the dynamic tearing energy obtained in step S4 into the correlation model between the impact cracking energy and the dynamic tearing energy in the ESSO test, as shown in formula (7), to obtain the lower limit of the impact cracking energy in the ESSO test:

[0044] (7)

[0045] Among them, E i is the impact initiation energy of the ESSO specimen, DTE is the dynamic tearing energy corresponding to the notch tip temperature of the ESSO specimen, t is the specimen thickness, ρ1 is the curvature radius of the notch tip of the ESSO specimen, and ρ2 is the curvature radius of the notch tip of the dynamic tearing specimen.

[0046] During the impact process of the ESSO test, the energy required for the crack initiation process at the notch tip mainly depends on factors such as impact velocity, ambient temperature, specimen thickness, notch tip curvature radius and material toughness; in the dynamic tear test, the factors affecting the crack initiation energy at the notch tip are basically the same as those in the ESSO test. In order to study the correlation between the impact energy and dynamic tear energy in the ESSO test, it is necessary to determine the main factors affecting the difference between the two. The influencing factors are:

[0047] ① Impact velocity. The ESSO test uses a drop hammer or pneumatic impact method, and the dynamic tear test uses a pendulum impact method. The impact velocity during the two tests is at the same level, and there is no significant difference in the impact on the crack initiation energy;

[0048] ② Ambient temperature. UR W31 does not give a clear requirement value for the notch tip temperature in the ESSO test. In actual tests, after measuring the actual notch tip temperature, the dynamic tear energy corresponding to the notch tip temperature can be obtained based on the dynamic tear energy-temperature curve measured in the series of temperature dynamic tear tests. Therefore, the ambient temperature will not have a significant impact on the crack initiation energy of the two tests.

[0049] ③ Sample thickness. The sample used in the ESSO test is the original plate thickness sample, and the standard sample thickness used in the dynamic tear test is 16mm. Since the sample thickness will directly affect the stress state in the notch tip area, resulting in different cracking energies for samples of different thicknesses, thickness is an important influencing factor;

[0050] ④ Curvature radius of notch tip. The notch of ESSO specimen is a wire-cut notch, and its curvature radius is generally 0.18mm. The notch of dynamic tear specimen is a pressed notch, and its curvature radius is generally 0.025mm. The difference in curvature radius will lead to different degrees of difficulty of crack initiation at the notch tip, and then cause the difference in impact cracking energy, which is an important influencing factor.

[0051] ⑤ Material toughness. The crack initiation energy at the notch tip of the ESSO specimen is closely related to the toughness of the material itself, which can usually be characterized by the dynamic tear energy measured by the dynamic tear test. Therefore, the crack initiation energy of the ESSO specimen has a certain correlation with the dynamic tear energy.

[0052] Based on the above analysis, this embodiment provides a correlation model between ESSO impact energy and dynamic tearing energy. The specific establishment process is as follows:

[0053] (1) Analysis of specimen thickness effect. As the thickness increases, the impact cracking energy at the notch tip of the ESSO specimen increases. However, since the thickness affects the stress state at the notch tip (as the plate thickness increases, the stress state changes from a plane stress state to a plane strain state), the impact cracking energy does not increase linearly with increasing thickness. This also means that the impact cracking energy and dynamic tearing energy do not satisfy a simple linear relationship. The correlation can be characterized by equation (5):

[0054] (5)

[0055] Among them, E i is the impact cracking energy of ESSO specimen, DTE is the dynamic tearing energy corresponding to the notch tip temperature of ESSO specimen, and t is the specimen thickness.

[0056] (2) Analysis of the curvature radius of the notch tip. The smaller the curvature radius of the notch tip, the easier it is for the crack to initiate and the smaller the impact initiation energy. The correlation can be expressed by equation (6).

[0057] (6)

[0058] Among them, ρ1 is the curvature radius of the notch tip of the ESSO specimen, and ρ2 is the curvature radius of the notch tip of the dynamic tearing specimen.

[0059] (3) Establishment of prediction model. Taking into account the influence of specimen thickness and notch tip curvature radius, the correlation model between impact cracking energy and dynamic tearing energy in ESSO test can be characterized by formula (7):

[0060] (7)

[0061] Among them, E i is the impact initiation energy of the ESSO specimen, DTE is the dynamic tearing energy corresponding to the notch tip temperature of the ESSO specimen, t is the specimen thickness, ρ1 is the curvature radius of the notch tip of the ESSO specimen, and ρ2 is the curvature radius of the notch tip of the dynamic tearing specimen.

[0062] The test data in step S2 at least includes dynamic tearing energy.

[0063] As one embodiment, step S2 includes:

[0064] Step S21: The multiple groups of tests obtained in step S1 are fitted using the Boltzman formula to obtain the correlation equation between dynamic tearing energy and temperature, as shown in formula (8):

[0065] (8)

[0066] Among them, k1, k2, k3, and k4 are unknown coefficients.

[0067] k1, k2, k3, and k4 can be obtained by fitting multiple sets of test data using the Boltzman formula.

[0068] In general, the radius of curvature of the notch tip of the ESSO specimen is generally 0.18 mm, and the radius of curvature of the notch tip of the dynamic tearing specimen is generally 0.025 mm, so the value of formula (6) can generally be taken as 2.68. Then the correlation model of the impact cracking energy and dynamic tearing energy of the ESSO test is:

[0069] (9).

[0070] As one of the optional embodiments, the thickness of the steel plate is greater than or equal to 16 mm.

[0071] Furthermore, the thickness of the steel plate is 60-90 mm.

[0072] In this embodiment, the series temperature is between -100°C and 20°C.

[0073] In order to verify the accuracy of the prediction method provided in this embodiment, the following operations can be performed:

[0074] Step S6: Set the parameters of the impact device, adjust the energy therein to the lower limit of the impact cracking energy of the ESSO test obtained in step S5, start the device to impact the notch of the sample, measure the crack arrest length a, and substitute the corresponding parameters into formula (3) to calculate the crack arrest toughness K ca value;

[0075] Step S7: Performing ESSO test on the same batch of steel plates, the impact crack initiation energy takes the first preset value; measuring the corresponding crack arrest toughness K ca value;

[0076] Step S8: The crack arrest toughness K obtained in step S6 and step S7 is ca The values ​​were compared to verify the prediction accuracy of the lower limit of impact cracking energy in the ESSO test.

[0077] Example 1

[0078] This embodiment provides a method for predicting the impact energy of the ESSO crack arrest test based on dynamic tearing energy, which is specifically performed as follows:

[0079] 1. According to GB / T 5482-2023 “Dynamic tear test method for metallic materials”, a series of temperature dynamic tear tests were carried out on a typical batch of shipbuilding high-strength steel thick plates. The dynamic tear energy at each temperature was measured. The Boltzman formula was used to fit the test data to obtain the dynamic tear energy-temperature correlation equation. The results are shown in Table 1.

[0080] Table 1 Series of temperature dynamic tear test results and correlation equations

[0081]

[0082] 2. According to the provisions of UR W31, a gradient temperature type ESSO test is carried out on the same batch of steel plates. A gradient temperature field is established in the ESSO specimen. After the temperature field is stable, the notch tip temperature T is measured. The dynamic tear energy at the same temperature can be obtained by substituting the energy value into the correlation equation in Table 1. The lower limit of the impact cracking energy in the ESSO test can be obtained by substituting the energy value into equation (9). The results are shown in Table 2.

[0083] Table 2 ESSO impact cracking energy calculation results

[0084]

[0085] 3. Set the parameters of the impact device, adjust the energy to the value in Table 2, start the device to impact the notch of the sample, measure the crack arrest length, and substitute the relevant parameters into formula (3) to calculate the crack arrest toughness K ca Secondly, the second sample of the same batch of steel plates was subjected to ESSO test, and the impact cracking energy was (calculated value - 500 J). The test results are shown in Table 3. It can be seen from Table 3 that the lower limit of ESSO impact energy estimated by formula (9) is effective.

[0086] Table 3 Comparison of ESSO impact cracking energy calculation results

[0087]

[0088] 4. Repeat steps 1-3 for 4 different batches of steel plates, determine the corresponding ESSO impact energy lower limit according to formula (9), and carry out the gradient temperature ESSO test to measure the crack arrest toughness K ca At the same time, the upper limit of ESSO impact energy is determined according to formula (1), and the temperature gradient ESSO test is carried out to measure the crack arrest toughness K ca The two energy measured crack arrest toughness K ca The results are compared with those obtained by the double tensile test of the same material, and the results are shown in Table 4. As can be seen from Table 4, the crack arrest toughness K measured according to the lower limit of the impact energy ca The results are consistent with those obtained by the double tensile test, with the maximum deviation not exceeding 5%, indicating that the ESSO impact energy prediction model proposed in the present invention is effective.

[0089] Table 4 Comparison of ESSO test results and double tensile test results

[0090]

[0091] like Figure 2 As shown, the crack arrest toughness K measured by the impact energy lower limit value obtained by the prediction method provided in this embodiment ca Compared with the crack arrest toughness K measured by double tensile test ca The results are very close, and the crack arrest toughness K measured according to the upper limit of impact energy obtained by the prior art is ca Compared with the crack arrest toughness K measured by double tensile test ca The difference is large, which shows that the prediction method of the ESSO crack arrest test impact energy based on dynamic tearing energy provided in this embodiment can more accurately obtain the lower limit of the impact energy, and then predict the crack arrest toughness K ca It provides a basis for accurate detection and provides strong technical support for accurate evaluation of the crack arrest performance of high-strength thick plates for ships.

[0092] Through the above settings, in the process of evaluating the crack arrest performance of shipbuilding high-strength steel thick plates using the ESSO test method, firstly, dynamic tear tests are carried out on the steel plates at a series of temperatures to obtain the dynamic tear energy at the corresponding temperature. The dynamic tear energy-temperature equation is established using the Boltzman formula. Then, a gradient temperature field that meets the UR W31 requirements is established in the ESSO specimen. After the temperature field is stable, the root temperature of the notch of the ESSO specimen is measured. The corresponding dynamic tear energy is determined based on this temperature and the dynamic tear energy-temperature equation. Finally, the lower limit of the impact cracking energy of the ESSO specimen is calculated by formula (9). The parameters of the impact device are set according to this energy value, and the notch of the specimen is impacted and the test is completed. This can effectively reduce the discreteness of the test results and improve the measurement accuracy.

[0093] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for predicting the impact energy of an ESSO crack arrest test based on dynamic tearing energy, characterized in that: The following steps are involved: Step S1: performing a dynamic tearing test at a series of temperatures on a steel plate to obtain dynamic tearing energy at corresponding temperatures; Step S2: fitting the test data of step S1 to establish a correlation equation between dynamic tearing energy and temperature; Step S3: Conduct a gradient temperature ESSO test on the same batch of steel plates as in step S1, establish a gradient temperature field in the ESSO specimen, and measure the notch tip temperature T after the temperature field is stable; Step S4: Substituting the notch tip temperature T measured in step S3 into the correlation equation between dynamic tear energy and temperature obtained in step S2 to obtain the dynamic tear energy at temperature T; Step S5: Substitute the dynamic tearing energy obtained in step S4 into the correlation model between the impact cracking energy and the dynamic tearing energy in the ESSO test, as shown in formula (7), to obtain the lower limit of the impact cracking energy in the ESSO test: （7） Among them, E i is the impact initiation energy of the ESSO specimen, DTE is the dynamic tearing energy corresponding to the notch tip temperature of the ESSO specimen, t is the specimen thickness, ρ1 is the curvature radius of the notch tip of the ESSO specimen, and ρ2 is the curvature radius of the notch tip of the dynamic tearing specimen.

2. The prediction method of ESSO crack arrest test impact energy based on dynamic tearing energy according to claim 1, characterized in that: The test data in step S2 at least includes dynamic tearing energy.

3. The prediction method of ESSO crack arrest test impact energy based on dynamic tearing energy according to claim 1, characterized in that: Step S2 includes: Step S21: The multiple groups of tests obtained in step S1 are fitted using the Boltzman formula to obtain the correlation equation between dynamic tearing energy and temperature, as shown in formula (8): （8） Among them, k1, k2, k3, and k4 are unknown coefficients.

4. The prediction method of ESSO crack arrest test impact energy based on dynamic tearing energy according to claim 1, characterized in that: The curvature radius of the notch tip of the ESSO specimen is 0.18 mm, and the curvature radius of the notch tip of the dynamic tearing specimen is 0.025 mm. The correlation model of the impact cracking energy and the dynamic tearing energy of the ESSO test in step S5 is: （9）。 5. The method for predicting the impact energy of the ESSO crack arrest test based on dynamic tearing energy according to claim 1, characterized in that: The thickness of the steel plate is greater than or equal to 16 mm.

6. The method for predicting the impact energy of the ESSO crack arrest test based on dynamic tearing energy according to claim 5, characterized in that: The thickness of the steel plate is 60-90 mm.

7. The method for predicting the impact energy of the ESSO crack arrest test based on dynamic tearing energy according to claim 1, characterized in that: The temperature of the series is between -100°C and 20°C.

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