KR20110098668A - Method for evaluating fatigue property of t-joint portion at t-type welding joint structure - Google Patents

Abstract

An object of the present invention is to provide a method for easily and quickly evaluating the fatigue characteristics of a T joint portion in a T-shaped weld joint structure without performing a complicated fatigue test.
When the weld joint edge radius of curvature of the T joint part is ρ (mm), the uniform elongation (%) of the weld heat affected part of the T joint part is UE _HAZ , and the yield stress (MPa) of the weld heat affected part of the T joint part is YP _HAZ . It is a method of evaluating the fatigue characteristic of a T-type welded joint structure by using the weld edge deformation evaluation parameter represented by Formula (1).
[Equation 1]

Description

Fatigue characteristics evaluation method of T joint part in T type weld joint structure {METHOD FOR EVALUATING FATIGUE PROPERTY OF T-JOINT PORTION AT T-TYPE WELDING JOINT STRUCTURE}

The present invention relates to a method for easily and quickly evaluating (predicting, estimating) the fatigue characteristics of a T joint part in a T-type welded joint structure without actually producing a welded joint and performing a fatigue test. The evaluation method of the present invention is applicable to various fields to which T-type welded joint structures, such as shipbuilding, offshore structures, low temperature tanks, line pipes, civil engineering and architectural structures, are applied.

Most of the breakage of the welded structure in which the thick steel plate is used, such as a ship or a machine, is caused by the occurrence of fatigue cracking, and most of the fatigue crack occurs from the weld joint portion. It is because the fatigue strength of a weld joint part is remarkably low compared with a base material.

It is known that the fatigue characteristic in a weld joint part has a big influence of the shape (especially the edge part radius) of the weld toe part of the base material side. Therefore, conventionally, in order to improve the fatigue characteristic of a weld joint part, the method of reducing a stress concentration by making a weld edge part grind | polish smooth or grind | polish (flattening the shape of a weld part), for example, Nonpatent literature 1 is performed. Reference).

On the other hand, the influence of the material properties (mechanical properties) on the fatigue properties of the weld joint part is not clear, and little studies have been made so far. Therefore, in evaluating (predicting) the fatigue characteristics of a weld joint part, it is a fact that it is determined by statistically processing the fatigue test result of many weld joints. Specifically, the weld joint structure test body which changes the conditions of a weld joint part, reflects each condition, is produced, the fatigue test is carried out, and enormous cost and time are taken, and it is unrealistic.

Therefore, Patent Document 1 discloses a test method for easily and quickly evaluating fatigue fracture susceptibility in a weld heat affected zone of steel without actually welding. Here, the fatigue crack is generated from the welded edge portion where stress concentration is the most intense and propagates, but the position where the fatigue crack is most likely to occur is focused on the point of the weld heat affected zone (HAZ), and the predetermined thermal history and notch processing are given. Fatigue fracture susceptibility of HAZ was evaluated using the test piece which attached. However, since the method of the said patent document 1 was not examined from the material characteristic of a weld joint part, the provision of the material design guide useful for the fatigue characteristic evaluation of a weld joint part is desired.

Japanese Patent Application Laid-open No. Hei 7-103871

Fatigue Design Manual, Japanese Society of Materials Research, Yang Hyundang, January 1995

This invention is made | formed in view of the said situation, The objective is to evaluate (predict and estimate) easily and quickly the fatigue characteristic of the T joint part in a T-type welded joint structure, without performing a complicated fatigue test. To provide a way to do this.

The evaluation method of this invention which could solve the said subject is a method of evaluating the fatigue characteristic of the T joint part in a T-type welded joint structure, The welding joint edge curvature radius of the said T joint part is (rho) (mm), and the said T joint When the uniform elongation (%) of the negative weld heat affected _zone is set to UE _HAZ and the yield stress (MPa) of the weld heat affected _zone of the T joint section is YP _HAZ , the weld edge deformation evaluation parameter represented by the following equation (1) The purpose of this is to evaluate the fatigue characteristics of the T-type welded joint structure.

Moreover, another evaluation method of this invention which could solve the said subject is a method of evaluating the fatigue characteristic of the T joint part in a T-type welded joint structure, The radius of curvature of the weld edge of the said T joint part is (ρ), The uniform elongation (%) after 10000 plastic deformation load of the welded heat affected _{zone of} the T joint part is UE _{HAZ, cycle} , and the yield stress (MPa) after 10000 plastic deformation load of the welded heat affected _{zone of} the T joint part is converted into YP _{HAZ, cycle} . When it does, it has a summary in evaluating the fatigue characteristic of a T-type weld joint structure by using the weld toe part deformation evaluation parameter (2) shown by following formula (2).

The parameters of the equations (1) and (2) defined in the present invention are useful as an alternative evaluation parameter of the weld edge fatigue properties of the T joint part in the T-type welded joint structure, and do not actually perform a weld test by producing a weld joint. Even if it is, the fatigue characteristic of a T joint part can be evaluated (predicted and estimated). The fatigue characteristic evaluation method of the T joint part according to the present invention can be applied not only to the case where local plastic deformation occurs at the weld end portion but also to the case where the local plastic deformation is repeatedly loaded at the weld end portion. Uses the parameters of Equation 1, and in the latter case, the fatigue characteristics of the T joint portion can be evaluated by using the parameters of Equation 2.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows a state in which a fatigue crack generate | occur | produces by local plastic deformation which locally generate | occur | produces in a weld toe part.
Fig. 2 shows uniform uniform elongation (UE _HAZ ) of welding heat affected portion (UE _HAZ ) = 5% of T-joint and yield stress (YP _HAZ ) = 500 _MPa of welded heat-affected portion of T-joint, and changes only the weld edge curvature radius p. A graph showing the effect on the localized plastic deformation of the weld edge at the time of application.
FIG. 3 shows that the weld-edge curvature radius ρ = 0.5 mm and the yield stress (YP _HAZ ) of the welded heat affected _zone of the T joint portion are constant at 500 _MPa , and only the uniform elongation (UE _HAZ ) of the welded heat affected _zone of the T joint portion is changed. A graph showing the effect on the localized plastic deformation of the weld edge at the time of application.
Fig. 4 shows that the weld edge portion radius of curvature ρ = 0.5 mm and the uniform elongation (UE _HAZ ) of the welded heat affected _zone of the T joint part are constant at 5%, and only the yield stress (YP _HAZ ) of the welded heat affected part of the T joint part is changed. A graph showing the effect on the localized plastic deformation of the weld edge at the time of application.
FIG. 5 is a diagram schematically showing a situation in which plastic deformation occurs locally when a fatigue test is performed using the micronotched test piece used in the example. FIG.
FIG. 6 is a graph showing a relationship between a weld end portion deformation evaluation parameter (1) defined in the present invention and a stress range Δσ / TS corresponding to 10 ⁵ fatigue fatigue crack generation lifetimes in Examples.
FIG. 7 is a graph showing the relationship between the weld edge deformation evaluation parameter (2) defined in the present invention and the stress range Δσ / TS corresponding to fatigue crack generation life 10 ⁵ times in Examples.

MEANS TO SOLVE THE PROBLEM The present inventors examined, in order to provide the method of evaluating (predicting and estimating) the fatigue characteristic of a T joint part in a T-type welded joint structure from a material design point of view, without performing a complicated fatigue test. . As a result, by using the weld toe end deformation evaluation parameter (1) represented by the following formula (1) or the weld toe end deformation evaluation parameter (2) represented by the following formula (2), the fatigue characteristics of the T joint portion can be easily and quickly. The present invention was completed by finding that can be easily evaluated. Among them, the weld edge deformation evaluation parameter (1) is useful for the evaluation of the fatigue characteristics when local plastic deformation occurs in the weld edge, and the weld edge deformation evaluation parameter (2) is local to the weld edge. It is useful for evaluating the fatigue characteristics when the plastic deformation is repeatedly loaded.

[Equation 1]

Where p is the radius of curvature of the weld end (mm)

UE _HAZ is the uniform elongation (%) of the weld heat affected _zone of a T joint part.

YP _HAZ means the yield stress (MPa) of the weld heat affected part of a T joint part.

[Equation 2]

Where p is the radius of curvature of the weld end (mm)

UE _{HAZ, cycle} is the uniform elongation (%) after 10000 times plastic deformation load of the welding heat affected _{zone of a} T joint part,

YP _{HAZ, cycle} means yield stress (MPa) after 10000 plastic deformation loads of the weld heat affected _{zone of a} T joint part.

Hereinafter, the process which reached | attained this invention is demonstrated, referring FIG.

In the present invention, among the weld joint shapes, in order to make the relationship between the fatigue properties and the material properties of the T joint parts clarified by simulation, the T-joint shape (T joint part), which is widely used in welding structures, is used as the following basis. The experiment was performed. Here, the T-type welded joint structure formed by joining the vertical member which butt-welded high strength steel plate and the horizontal member which butt-weld high strength steel plate by welding was used. The plate | board thickness of the horizontal member and the vertical member used for the basic experiment was 60 mm, and the nominal stress (corresponding to YP of a base material) of the horizontal member was 490 Mpa.

In the examination, attention was paid not only to the weld edge edge curvature radius [rho (mm)] in which a close relationship with the fatigue characteristic was known, but also to the material elongation factor (UE) and the yield stress (YP). This is because the amount of local plastic deformation occurring in the weld end portion is a dominant factor of the fatigue characteristics (see Fig. 1), and the UE and YP are related to plastic deformation. In addition, fatigue cracks are generated and propagated from the welded edge portion where strain concentration is most severe, and the edge portion is a weld heat affected zone (HAZ), and therefore, in the present invention, attention is paid to the UE and the yield stress of the HAZ portion. In this invention, the uniform elongation (%) of _HAZ of a T joint part is made into UE _HAZ , and the yield stress (MPa) of the welding heat affected part of a T joint part is made into YP _HAZ .

In addition, when the conditions (ρ, UE _HAZ and YP _HAZ ) of the T joint part were examined on the plastic deformation of the weld end portion, the results of FIGS. 2 to 4 were obtained.

Fig. 2 is a graph showing the effect on the welded edge localized plastic deformation amount when only ρ is changed when UE _HAZ = 5% and YP _HAZ = 500 _MPa .

As shown in FIG. 2, when conditions other than p are made constant, the weld branch part local plastic deformation amount also decreases exponentially as p becomes large. This result is consistent with conventional knowledge. As described above, it is known that the weld tip radius affects the strain concentration. As the tip radius increases, the stress concentration decreases, so that the local plastic deformation also decreases. From the result of FIG. 2, the following equation 1A is derived.

[Equation 1A]

p is a weld edge radius of curvature (mm), and the uniform elongation UE _HAZ (%) of the weld heat affected portion of the T joint portion and the yield stress YP _HAZ (MPa) of the weld heat affected portion of the T joint portion are constant.

Fig. 3 is a graph showing the influence on the localized plastic deformation amount of the weld end portion when only p = 0.5 mm and YP _HAZ = 500 _MPa and UE _HAZ is changed.

From Figure 3, it can be seen that this is local plastic deformation behavior greatly changed by the change of the UE _HAZ, the _HAZ becomes small UE decreases even local plastic deformation amount welding Gdansk unit. From the result of FIG. 3, the following equation 1B is derived.

[Equation 1B]

UE _HAZ is the uniform elongation (%) of the weld heat affected _zone of the T joint part, and the weld edge end curvature radius (mm) and the yield stress YP _HAZ (MPa) of the weld heat affected part of the T joint part are constant.

4 is a graph showing the effect on the localized end plastic deformation amount when only YP _HAZ is changed, while ρ = 0.5 mm and UE _HAZ = 5%. From Figure 4, a local plastic deformation occurs and behavior greatly changed by the change in the _HAZ YP, YP greater the _HAZ can be seen that also become small local plastic deformation amount weld Gdansk. The yield stress of the weld heat affected zone has a great influence on the deformation behavior of the edge portion under fatigue load, and thus, the influence on the localized plastic deformation of the edge portion may be considered to be large. From the result of FIG. 4, the following equation 1C is derived.

[Equation 1C]

YP _HAZ is the yield stress (MPa) of the weld heat affected _zone of the T joint portion, the weld edge edge curvature radius (mm) and the uniform elongation UE _HAZ (%) of the weld heat affected _zone of the T joint portion are constant.

Based on the results of the above basic experiments, the effects of the above requirements (ρ, UE _HAZ and YP _HAZ ) on the local plastic deformation amount of the weld end portion were examined in detail. As a result, in the case where it is assumed that the conditions other than the above requirements (for example, the plate thickness of the horizontal member and the vertical member, the welding method, etc.) are the same conditions without changing, the above formulas 1A, 1B and 1C It was found that the multiplied weld edge portion local plastic deformation amount, that is, the parameter (1) represented by the above formula (1) had a good correlation with the fatigue property of the weld edge portion, and completed the present invention. The smaller the value of the parameter calculated by the above expression (1), the larger the local plastic deformation amount of the weld end portion is, indicating that the fatigue characteristics are excellent (see FIG. 6 to be described later).

Moreover, the said parameter was useful also in the evaluation of the fatigue characteristic at the time of the local plastic deformation repeated loading in a weld toe part, and it turned out that the evaluation parameter of said Formula (2) should just be used in this case. That is, depending on the type of steel, the yield stress and the uniform elongation may change due to the repeated loading of the stress exceeding the yield stress, and in that case, the local plastic deformation is repeatedly loaded also in the weld edge, so that HAZ The negative yield stress and the uniform elongation change, which greatly affects the fatigue life of the weld end portion. By using Equation 2, the fatigue life when the yield stress and the uniform elongation are changed by the cyclic load can be evaluated with high accuracy.

In Equation 2, in Equation 1, UE _HAZ (uniform elongation at the welded heat affected _zone of the T joint part) is represented by UE _{HAZ, cycle} (uniform elongation after 10000 plastic deformation loads at the welded heat affected _zone of the T joint part). , YP _HAZ (yield stress at the weld heat affected _zone of the T-joint part) to YP _{HAZ, cycle} (yield stress after 10000 plastic deformation loads at the weld heat affected _zone of the T-joint part), respectively, same.

In addition, in Formula (2), the number of repetitions is set to 10000 times, taking into account the rule of thumb that the change in yield stress and uniform elongation after repeated loads varies greatly up to 1000 to 5000 repeated loads, but becomes substantially constant thereafter. As a representative value of the yield stress and the uniform elongation of the HAZ part after 5000 times, each value in 10000 times (0.5% deformation) is selected.

As described above, the present invention finds that the weld end portion deformation evaluation parameter represented by Equation (1) or (2) is useful as an alternative evaluation parameter of the fatigue property of the T joint portion in the T-type welded joint structure. There is a characteristic. According to the present invention, it is possible to evaluate the fatigue characteristics of the T joint portion without creating a welded joint and performing a fatigue test in a conventional manner.

In the present invention, the above-described equation (1) or (2) is derived on the premise that a condition not included in the evaluation parameter is constant and local plastic deformation occurs at the weld end portion. As the preconditions for applying the method of the present invention, the following matters are mentioned.

First, in order to generate local plastic deformation in the weld toe portion, the range of the nominal stress of the horizontal member (base material) is approximately 300 to 500 MPa. If the nominal stress of the horizontal member is less than 300 MPa, there is a possibility that the plastic strain is not locally deformed, while if it is more than 500 MPa, the entire steel plate surface may be plastically deformed. Similarly, the tensile strength of the horizontal member and the weld heat affected zone HAZ is approximately 400 to 700 MPa.

In addition, the permissible range of p, UE _HAZ and YP _HAZ to which Equation 1 is applied is not particularly limited, but from the viewpoint of generating local plastic deformation at the weld end portion, approximately p: 0.1 mm or more and 2.0 mm Hereinafter, it is preferable to exist in UE _HAZ : 5% or more and 20% or less, and YP _HAZ : 300 Mpa or more and 650 Mpa or less.

In addition, the permissible range of ρ, UE _{HAZ, cycle} and YP _{HAZ, cycle} to which Equation 2 is applied is not particularly limited, but from the viewpoint of generating local plastic deformation at the weld edge, approximately p: 0.1 It is preferable to exist in the range of mm or more and 2.0 mm or less, UE _{HAZ, cycle} : 5% or more and 20% or less, YP _{HAZ, cycle} : 300 MPa or more and 650 MPa or less.

The plate | board thickness of the horizontal member which comprises the welding structure made into object by this invention is about 50-80 mm, considering the influence on the stress concentration coefficient of a weld toe part. Also about a vertical member, it is preferable that it is about 50-80 mm similarly to the above.

Other than the above requirements, the present invention is not particularly limited. For example, the welding method for joining a vertical member and a horizontal member is not specifically limited, For example, a submerged arc welding method and a carbon dioxide arc welding method are mentioned.

Moreover, the kind of steel plate which comprises a vertical member and a horizontal member is not specifically limited, either, The steel plate normally used for a welded structure can be applied as long as the requirements, such as said tensile strength, are satisfied. It is preferable that the kind of steel plate which comprises a vertical member and a horizontal member is the same.

The weld edge deformation evaluation parameter represented by Equation 1 or Equation 2 may include at least one of a weld edge radius ρ and material properties UE _HAZ and YP _HAZ or UE _{HAZ, cycle} and YP _{HAZ cycle} . Is suitably used to compare and examine the fatigue characteristics of different T joint portions. The numerical values calculated on the basis of these equations serve as an index for determining the superiority (fatigue characteristic design guide) of the fatigue characteristics between two or more types of T joint portions. It is not an indicator for estimating.

Specifically, as a representative application example of the present invention, when several T-type welded joints in which the combination of the plate thickness of the horizontal member and the vertical member have the same test are fabricated, p is not required for each joint even if a complicated fatigue test is not performed. A simple curvature investigation for calculating and a tensile test for calculating the material properties (eg, UE _HAZ and YP _HAZ ) are performed to calculate and compare the values of the evaluation parameters represented by Equation 1 or Equation 2. It is mentioned to determine the weld joint which is excellent in a fatigue characteristic by this. The smaller the value, the better the fatigue characteristic, so that the T joint having the best fatigue characteristic can be selected.

In addition, if the relationship between the evaluation parameter represented by the above formula and the required fatigue characteristics is databased in advance, the material design guideline, welding conditions, and the like of the T joint portion having excellent fatigue characteristics can also be determined. Where ρ changes the type of welding material (in particular, the welding wire forming the weld metal), while the material properties of the uniform elongation and yield stress (eg, UE _HAZ and YP _HAZ ) Since it is possible to change all by changing the heat quantity J, the relationship of a welding condition and a material characteristic can be made into a database.

Hereinafter, although an Example is given and this invention is demonstrated further more concretely, this invention is not restrict | limited by the following example, It is also possible to change suitably and to implement in the range suitable for the said and later meaning, and they are all this invention. It is included in the technical scope.

First embodiment

In this embodiment, a micronotched test piece is produced as a test piece simulating a welded joint, and the fatigue characteristics when the fatigue test is performed using the test piece, and the weld toe portion represented by the above formula (1) or (2). The relationship between the modification evaluation parameter (1) or (2) was examined.

In detail, the smooth-plate notch test piece (the test piece without discontinuous shape, such as a weld part, 65 mm in length x 16 mm in width x 4 mm in thickness) shown in FIG. 5 was prepared. When this test piece is used, deformation is concentrated on the notch portion and local plastic deformation occurs, so that the deformation state of the welded edge portion of the T joint can be reproduced.

The fatigue property (fatigue crack life) of the smooth test piece shown in FIG. 5 is a value obtained by dividing the load stress range Δσ (the difference between the repetitive maximum stress S ₁ and the repetitive minimum stress S ₂ acting in the fatigue test) by the tensile strength TS of the test piece. (Δσ / TS). In the present Example, the fatigue test was done with the following method, and the stress range (DELTA) (s) / TS corresponding to 10 ⁵ times of fatigue crack initiation lifetime was computed.

(Fatigue test)

The test piece was mounted on a hydraulic fatigue tester so that a tensile load was applied in the axial direction (arrow direction in FIG. 5) to the test piece, and a repeated load was applied under conditions in which S ₁ and S ₂ were constant. S ₁ and S ₂ were measured by a strain gauge attached to a position sufficiently separated from the notch of the test piece. In addition, three identical specimens were prepared (n = 3), and the stress load conditions were tested under conditions in which the fatigue crack generation life was in the range of about 10 ⁴ to 10 ⁶ , and the relationship between the stress range and the fatigue crack generation life was performed. The stress range was calculated by formulating the stress range as a function of the fatigue crack initiation life and calculating the stress range when the fatigue crack initiation life was 10 ⁵ . Similarly, repeated plastic deformation 10000 cycle (0.5% strain) after the load to obtain a relationship between stress range and fatigue crack initiation life was calculated as the stress range in the fatigue hayeoteul a crack initiation life = 10 ^5.

Specifically, the fatigue test described above was conducted using Test Pieces 1 to 8 in Table 1 in which the yield stress (YP), uniform elongation (UE), and notch curvature (R) were different, and Δσ / TS was obtained by the method described above. Measured. Moreover, the weld toe part strain evaluation parameters (1) and (2) were computed about the said test pieces 1-8, respectively. Here, the notch curvature R of the test piece corresponds to the weld end portion curvature radius ρ of the T joint, and the yield stress YP and the uniform elongation UE of the test piece are the yield stress YP _HAZ or YP _HAZ of the HAZ part of the T joint part, respectively _{, cycle} and uniform elongation correspond to UE _HAZ or UE _{HAZ, cycle} .

These results are written together in Table 1. 6, the relationship between the weld end edge deformation evaluation parameter (1) and (DELTA) / TS is shown by graphing, and the relationship between the weld end edge deformation evaluation parameter (2) and (DELTA) / TS is shown by graphing.

From Table 1 and FIG. 6 and FIG. 7, it can consider as follows.

As mentioned above, although the numerical value of evaluation parameter (1) or (2) is small, it shows that the fatigue characteristic tends to be high, but the result of FIG. 6 and FIG. 7 is almost in agreement with this tendency. For example, referring to FIG. 6, the specimens 2 and 4 with the smallest numerical value of the evaluation parameter (1) among the specimens 1-8 were large (DELTA) σ / TS compared with the other specimen, and the fatigue characteristic improved. The same tendency as in FIG. 6 was also seen in FIG.

Specifically, for example, when the test pieces 1 and 3 (all notch curvature R = 0.8 mm) and the test pieces 2 and 4 (all notch curvature R = 1.6 mm) of Table 1 are compared, the notch curvature is compared with the test pieces 1 and 3, for example. Although the specimens 2 and 4 with large (R) have large Δσ / TS and the numerical values of the evaluation parameters (1) and (2) are small (see Fig. 6), these results are known in the prior art (welding edge radius of curvature). (ρ) is larger, fatigue characteristic is improved].

On the other hand, even if the notch curvature R is the same, a fatigue characteristic may differ with a material characteristic. Specifically, Test Pieces 2 and 4 having a notch curvature R of 1.6 mm differ in the YP and the UE (corresponding to the YP _HAZ and the uniform elongation UE _HAZ of the T-joint part) of the test piece, so that the evaluation parameters (1) and (2) Although the numerical value of is another example, the test piece 2 whose numerical value of said evaluation parameter (1) and (2) is smaller than the test piece 4 is excellent in a fatigue characteristic. Similarly, the test pieces 1 and 3 having the notch curvature R = 0.8 mm have different values of the evaluation parameters (1) and (2) because the test pieces YP and UE (corresponding to the YP _HAZ and the uniform elongation UE _HAZ of the T-joint part) differ. As another example, the test piece 1 having a smaller value of the evaluation parameters (1) and (2) than the test piece 3 has excellent fatigue characteristics.

These results are derived only by using the said parameter prescribed | regulated by this invention, and according to this invention, since the fatigue characteristic of the test pieces resulting from the material characteristic which cannot be discriminated conventionally was also evaluated, it is very useful.

Claims (2)

It is a method of evaluating the fatigue characteristics of a T joint part in a T-type welded joint structure,
The radius of curvature of the weld joint edge of the T joint part is ρ (mm), the uniform elongation (%) of the weld heat affected _zone of the T joint part is UE _HAZ , and the yield stress (MPa) of the weld heat affected _zone of the T joint part is YP _HAZ . When the fatigue property of the T-type welded joint structure is evaluated by using the weld toe end deformation evaluation parameter (1) represented by Equation 1 below, the fatigue property evaluation method of the T joint part.
[Equation 1]

It is a method of evaluating the fatigue characteristics of a T joint part in a T-type welded joint structure,
The radius of curvature of the weld joint edge of the T joint part is ρ (mm), and the uniform elongation (%) after plastic deformation load of 10000 times of the weld heat affected _{zone of} the T joint part is UE _{HAZ, cycle} , and 10000 times the weld heat affected part of the T joint part. When the yield stress (MPa) after the plastic deformation load is YP _{HAZ, cycle} , the fatigue property of the T-type welded joint structure is evaluated by using the weld edge deformation evaluation parameter (2) represented by Equation 2 below. The fatigue characteristic evaluation method of T joint part.
[Equation 2]

Images