KR101324632B1 - Method for simulation of buckling for structure - Google Patents

Abstract

A buckling simulation method of a structure is disclosed. According to an embodiment of the present invention, in the pre-processing step of generating modeling data for at least two structures to be welded, and welding seam data for the mutual welding of the modeling data of each structure, in the modeling data generated in the pre-processing step, Enter the physical properties according to the metal and filler materials of each structure to be welded and the amount of heat input to the weld heat affected zone by welding, and based on the input data, buckling by expansion and contraction according to the welding heat of the structure There is provided a buckling simulation method of a structure comprising a post-processing step comprising a main processing step of calculating a and a buckling amount determining step of determining whether the buckling amount of the structure calculated in the main processing step is within an allowable value.

Description

Method for simulation of buckling for structure

The present invention relates to a buckling simulation method of the structure, and more particularly, to a buckling simulation method of the structure that can determine whether the buckling by welding before the actual fabrication of the structure by simulation.

In general, in the production of structures such as ships, members such as steel plates or beams are used.

The members are joined together to form a structure, mainly by welding.

By the way, welding is a work to integrate the two members by applying heat, inevitably apply heat to the work area, which can cause thermal deformation to the member is a work.

The thermal deformation may include thermal expansion due to heating during welding and deformation due to thermal contraction during cooling, and may be classified into in-plane deformation and out-of-plane deformation.

In particular, as shown in Figure 1, due to the large thermal deformation may cause deformation such as buckling in the member related to the stability of the structure, in this case may cause a big problem in the stability of the structure, in order to solve this reconstruction or Correction is made through the method of bending, etc., but the cost and time are excessive and the correction work was also unsatisfactory.

Recently, as a new paradigm such as eco-friendly and fuel saving is proposed to the shipbuilding industry, the use of thin thin sheets, which were not used much in the past, is increasing.

By the way, the thin plate is also assembled by welding, in the case of thin plate is effective in weight reduction but vulnerable to buckling deformation, there is a problem that buckling frequently occurs during the production of the actual structure.

Korean Patent Publication No. 2010-0083484

The present invention is to solve the above problems, the present invention simulates whether or not the buckling occurs in each member of the structure by welding before the actual production of the structure of the structure that can determine whether the buckling in advance It is a subject to provide a buckling simulation method.

In order to solve the above problems, according to an embodiment of the present invention, generating the modeling data for the structure formed by welding at least two members, and weld line data is welded to the modeling data of the structure A pretreatment step including a step of generating, inputting a property value according to the material of each member to the modeling data, inputting a heat input amount applied by welding, and based on the input property values and the heat input amount Buckling simulation of the structure comprising a main processing step including the step of calculating the buckling amount by the expansion and contraction of the structure and a post-treatment step comprising determining whether the buckling amount of the structure is within the allowable value. A method is provided.

The generating of the weld seam data may include designating to the modeling data which side of the structure the weld seam is generated.

The step of calculating the buckling amount may be a step of calculating by substituting an imaginary stress causing a deformation amount as much as the inherent deformation amount remaining in the heat affected zone by the heat input amount.

The calculating of the buckling amount may include a natural strain calculation step of calculating the natural strain amount, and an equivalent stress calculation step of calculating an equivalent virtual stress causing the natural strain amount.

The post-processing step may further include a recalculation step of re-running the main processing step by reinforcing the modeling data when the buckling amount of the structure exceeds the allowable value in the buckling amount determining step.

According to the buckling simulation method of the structure according to an embodiment of the present invention, it is possible to determine whether or not the structure buckling before the actual fabrication, it is possible to reinforce before fabrication to minimize the buckling of the structure generated by welding when the actual ship is drying As a result, it is possible to shorten the air by minimizing post-processing as well as improving the quality of the preparation.

1 is a photograph showing an example of a site where buckling occurs by welding;
2 is a flow chart showing an example of a buckling simulation method of the structure of the present invention;
3 is a diagram illustrating an example of modeling data generated in a modeling data step according to an embodiment of the present invention;
4 is a view illustrating an example of modeling data in which a weld line is generated, which is generated in a weld line data generation step according to an embodiment of the present invention;
5 and 6 are views showing a buckled state of the structure calculated in the buckling amount calculation step according to an embodiment of the present invention;
7 is a view showing a buckling amount of modeling data of a reinforced structure as an example in the recalculation step according to an embodiment of the present invention;
8 is a view showing the buckling amount of the modeling data of the structure reinforced by another example in the recalculation step according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. In describing the present embodiment, the same designations and the same reference numerals are used for the same components, and further description thereof will be omitted.

Figure 2 is a flow chart showing an embodiment in a buckling simulation method of the structure of the present invention.

Prior to explaining the present embodiment, the buckling simulation method of the structure according to the present embodiment can be realized by being mounted and recorded in a computer processing apparatus such as a computer and executed by a program of CAD or finite element (FEA).

In addition, the buckling simulation method according to an embodiment of the present invention described below can be generated by a variety of known programs, the configuration is also various module units, units, etc. according to the specific functions and / or functions described below It can be implemented as In addition, an apparatus and / or an apparatus for performing the buckling simulation method may be referred to as a buckling simulation apparatus.

Hereinafter, in describing the buckling simulation method according to an embodiment of the present invention, it is assumed that the buckling simulation apparatus is the main body. Of course, in describing the specific function, it can be mainly described by the configuration unit or the specific object.

Buckling simulation method of the structure according to the present embodiment may be composed of a pre-treatment step (S100), the main processing step (S200), and a post-treatment step (S300).

The preprocessing step (S100) is a step of generating modeling data regarding the shape and geometric conditions of the structure and a weld line in the modeling data for analysis of the structure.

The preprocessing step (S100) as described above may include a modeling data generation step (S110) and a welding line data generation step (S120).

The modeling data generation step (S110) is a step of generating modeling data for at least two structures or members to be welded to each other, as shown in FIG. 3.

Hereinafter, the base unit constituting the structure is referred to as a member, it will be described as the member is connected or combined with each other to form a structure. Further, in the following description, unless otherwise stated, the structure may be used to include a member.

Recently, modeling data for structures to be manufactured can be obtained by widely using computer-aided design (CAD) for designing ships, but such general modeling data is inputted for welding of each member of the structure. It may not be made, it may be formed of a structure connected to each member. However, since the buckling simulation method of the structure of the present embodiment relates to welding of two separated structures or members, the modeling data generated in the present modeling data generation step S110 is welded to each other, as shown in FIG. 3. At least two structures or members to be made may be divided or modeling data in which the dividing line 10 is formed.

The welding line data generation step (S120) is a step of generating a welding line element 20 at a portion to which the two structures to be welded to each other are welded to each other. The weld line elements may be created along the nodes 22 of the welded points of each structure, as shown in FIG. 4.

In addition, the welding line data generation step (S120) may include information on whether the welding line 20 is formed on the top surface, the bottom surface, or on either side of the structure. That is, generally, the welding operation is performed on any one surface of the member, and the shape in which the structure or the member is deformed may also vary according to the surface on which the welding is performed.

Therefore, in the welding line data generating step (S120), as shown in FIG. 4, information on which side of the modeling data is welded (for example, whether the welding is made from an upper surface or a lower surface). Can be entered. In FIG. 4, it is indicated as T _Top or T _Bottom .

Meanwhile, the main processing step S200 may include a property value input step S210, a heat input amount step S220, and a buckling amount calculation step S230.

In the physical property value input step (S210), the data according to the behavior in the elastic region and the plastic region according to the stress of the metal material forming the structure to be welded to the property modeling data generated in the pre-processing step (S100) and the plastic zone to be heated or cooled Various physical properties may be input, such as data on how much it expands and contracts or data on changes in physical properties according to temperature conditions, and data on state changes according to metal properties by heating and cooling. In addition to the data on the material of the structure, data such as various physical properties of the filler metal may be input.

The heat input amount input step (S220) is a step of inputting a heat input amount applied to a heat affected zone (HAZ: Heat Affected Zone) of the welding portion by welding the structure and the filler metal.

The amount of heat input as described above may vary depending on the welding speed and welding thickness, the welding method or the material and thickness of the structure to be welded, and the type of filler metal.

The buckling amount calculation step (S230) is a step of calculating the buckling amount of the structure as the physical property value and the heat input amount of the structure and the filler material input in the property value input step S210 and the heat input amount input step S220.

That is, the structure expands when heat is applied during welding, and contracts when cooling. In the buckling amount calculation step, the modeling is performed based on the data input in the property value input step S210 and the heat input amount step S220. When the calorific value input in the heat input amount input step (S220) is applied to the welding line of the modeling data generated in the data generation step (S110) and the physical property value input step (S210), the amount of any portion of the structure is how much It calculates whether it expands and contracts, and calculates the amount of buckling.

On the other hand, in the present embodiment, when calculating the buckling amount due to the welding heat input in the buckling amount calculation step (S230), the inherent strain remaining in the heat affected zone due to expansion and contraction by the welding heat input Equivalent virtual stresses may be calculated instead of acting on the corresponding part of the structure or member.

The inherent strain refers to the amount of residual strain in which the elastic strain is excluded from the total strain, and may vary according to heat input and steel type, and the inherent strain calculated in relation to the conventional equivalent load method has been accumulated over the last ten years. Many studies on the results can be used in this embodiment as it is to calculate the natural strain.

Of course, when using the inherent strain, as described above, the buckling amount calculation step (S230), the inherent strain calculation step of calculating the inherent strain amount and the equivalent stress to calculate the equivalent virtual stress causing the deformation by the inherent strain amount The stress calculation step may be further included.

In more detail, the inherent strain diagram refers to the residual strain in which the elastic strain is excluded from the total strain, and in the buckling calculation step, the virtual equivalent stress causing the strain as much as the inherent strain is used instead of the welding heat input. Instead of acting on the structure, it calculates the buckling amount of the structure.

The result calculated in the buckling amount calculation step S230 may be output as shown in FIG. 5.

The post-processing step S300 may include a buckling amount determining step S310 and a recalculating step S320.

The buckling amount determination step (S310), it is determined whether the buckling amount calculated in the main processing step (S200) is within the design allowance, if the buckling amount of the structure is within the allowable value to determine the modeling design drawings to be applied to the actual production If the buckling amount exceeds the allowable value, a recalculation step (S320) to be described below may be performed.

In the recalculation step S320, when it is determined that the buckling amount of the structure exceeds the allowable value in the buckling amount determining step S310, the reprocessing step S200 is performed by reinforcing the modeling data.

In more detail, in the buckling amount calculation step (S230), as shown in FIG. 6, a maximum buckling amount between the long papers is generated by 13 mm, so that the buckling amount generated as described above in the buckling amount determination step (S310) is allowed. If it is determined that exceeds, as shown in Figures 7 and 8 in the recalculation step (S320), it is possible to reinforce the modeling of the structure.

That is, it is possible to reinforce the modeling of the structure, such as increasing the thickness of the thin plate or the thick plate constituting the structure, or adjusting the spacing between the longage to reinforce the thin plate or thick plate.

For example, as shown in FIG. 6, when the buckling amount between the longines is 13 mm, as shown in FIG. 6, as shown in FIG. 7, the thickness of the thick plate 110 is doubled and then recalculated again. It can be seen that the amount of buckling between the 120 and the amount of deflection between the longines is 8 mm.

Alternatively, as shown in FIG. 6, when the buckling amount between the longines is 13 mm as shown in FIG. 6, as shown in FIG. 8, the reinforcement is added by adjusting the distance d of the longines 120 in a narrowing direction. Buckling can be effectively reduced.

After reinforcing the modeling of the structure as described above, the property value input step (S210) to the heat input step (S220) and the buckling amount calculation step (S230) of the main processing step can be performed again to predict the buckling amount of the structure again. will be.

In addition, if the result of the recalculation step (S320) results in the buckling amount due to welding within the design allowance, the modeled design drawing may be determined and applied to actual production, and the buckling amount may be designed despite the recalculation step (S320). If the allowable value is exceeded, the recalculation step S320 may be performed again.

Therefore, before the actual fabrication, the amount of buckling generated by welding can be predicted, thereby minimizing the case of buckling after the actual fabrication, thus improving the quality of the product and minimizing post-fabrication after fabrication to shorten the air. have.

It will be apparent to those skilled in the art that the present invention can be embodied in other specific forms without departing from the spirit or scope of the invention as defined in the appended claims. It is obvious to them. Therefore, the above-described embodiments should be regarded as illustrative rather than restrictive, and thus, the present invention is not limited to the above description and may be modified within the scope of the appended claims and their equivalents.

S100: preprocessing step S110: modeling data generation step
S120: welding seam data generation step S200: main processing step
S210: Input step of physical properties S220: Input step of heat input
S230: Buckling amount calculation step S300: Post processing step
S310: Buckling amount determination step S320: Recalculation step

Claims (5)

Generating modeling data for a structure formed by welding at least two members, and generating weld line data in which welding is made to the modeling data of the structure;
In the modeling data, the step of inputting the physical properties according to the material of each member, the input of the amount of heat applied by welding, and based on the input material properties and the amount of heat input remaining in the heat affected by the heat input Calculating an inherent strain amount, calculating a virtual stress equivalent to the inherent strain amount, and calculating a buckling amount when the calculated equivalent stress is applied to the structure; And
A post-processing step including a buckling amount determining step of determining whether the buckling amount of the structure is within an allowable value;
Buckling simulation method of the structure comprising a. The method of claim 1,
The generating of the welding line data may include:
A buckling simulation method for a structure that specifies in which modeling data the weld line is generated on which side of the structure. delete delete The method of claim 1,
The post-
If the buckling amount of the structure exceeds the allowable value in the step of determining the buckling, re-calculation step of reconstructing the modeling data to perform the main processing step further comprises a buckling simulation method of the structure.

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