CN115358115A - Analysis method of temperature field based on measured welding temperature field combined with finite element - Google Patents

Abstract

This application provides a temperature field analysis method based on the measured welding temperature field combined with finite elements, including: setting temperature detection points on the surface of the weldment; sorting the actual temperature field of each temperature detection point into the form of number and time; Establish the same weldment model as the weldment in the finite element analysis software, and define the thermodynamic material parameters of the weldment model as the form of temperature; and use the finite element analysis element to solve the simulated temperature field on the surface of the weldment model; compare the simulation If the temperature difference between the temperature field and the actual temperature field does not exceed the predetermined value at the same time, it proves that the simulated temperature field is valid; if the temperature difference between the two is greater than the predetermined value at the same time, adjust the output thermal efficiency in the heat source formula, and Adjust the thermodynamic material parameters of the weldment model until the temperature difference between the two at the same time does not exceed the predetermined value. The method of the present application can accurately simulate the complex welding process and the change of temperature field in the whole process of complex welded components.

Description

Analysis method of temperature field based on measured welding temperature field combined with finite element

technical field

The present application relates to the technical field of welding temperature field analysis, and in particular, relates to a temperature field analysis method based on actual measurement of welding temperature field combined with finite elements.

Background technique

Existing analysis methods for welding temperature field oversimplify the actual situation, resulting in the temperature field conforming to the actual situation only at a few points, and it is difficult to evaluate the change of the overall weldment temperature field. For example, the following simplified situations: the obtained temperature field is only the temperature value of a certain point in a certain period of time; in the finite element modeling, the welding process of the weld bead is greatly simplified, regardless of the welding direction of each layer of weld bead or even the The multi-layer weld bead is merged into one layer of weld bead for modeling; the parameters of the heat source subroutine are simplified, and the current and voltage are applied according to a certain value, ignoring the change of the two with respect to time.

The existing temperature field analysis methods are more suitable for the welding of simple components, such as the welding of flat butt joints and flat T-joints, but it is difficult to weld some complex structures, such as the welding of intersecting nodes. Using traditional methods to obtain the corresponding temperature field changes will lead to inaccurate analysis of subsequent residual stress.

Contents of the invention

The main purpose of this application is to provide a temperature field analysis method based on the measured welding temperature field combined with finite elements, which can accurately simulate complex welding processes and temperature field changes in the whole process of complex welding components.

In order to achieve the above purpose, this application provides a temperature field analysis method based on the measured welding temperature field combined with finite elements, including:

Step S1: setting temperature detection points on the surface of the weldment, numbering the temperature detection points on the weldment, and marking them as an integer n in turn, where n≥1;

Step S2: Weld the weldment, organize the actual temperature field T ₀ (n, t) of each temperature detection point into the form of number n and time t, and record the welding direction M ( t), welding layer number N(t), welding current A(t) and welding voltage V(t) are all sorted into the form of time t;

Step S3: Establishing the same weldment model as the weldment in the finite element analysis software, and defining the thermodynamic material parameters of the weldment model in the form of temperature T in the finite element analysis software;

Step S4: Compile the heat source formula about the welding current A(t), the welding voltage V(t) and the welding direction M(t) of the weldment, and use the finite element analysis element to solve The simulated temperature field T ₁ (x, y, z, t) of the surface of the weldment model;

Step S5: In the simulated temperature field T ₁ (x, y, z, t), find the actual temperature field T ₀ (n, t) corresponding to the detection point according to the x, y, z coordinates , compare the simulated temperature field T ₁ (x, y, z, t) with the actual temperature field T ₀ (n, t), if the temperature difference between the two does not exceed a predetermined value at the same time, it proves that the simulation The temperature field T ₁ (x, y, z, t) is valid; if the temperature difference between the simulated temperature field T ₁ (x, y, z, t) and the actual temperature field T ₀ (n, t) at the same time is greater than the predetermined value, then adjust the output heat efficiency in the heat source formula to control the temperature, and at the same time adjust the thermodynamic material parameters of the weldment model in the finite element analysis software to control the rate of temperature change , until the temperature difference between the simulated temperature field T ₁ (x, y, z, t) and the temperature field T ₀ (n, t) at the same moment does not exceed the predetermined value.

Further, in the step S1, the temperature detection points are three rows, the temperature detection points of the three rows are all parallel to the weld seam on the welding, and the temperature detection points of the three rows are along the line away from the weld seam. The directions of the directions are arranged at intervals in sequence, and each row of the temperature detection points includes a plurality of the temperature detection points arranged at intervals.

Further, the three rows of temperature detection points include the first row of temperature detection points, the second row of temperature detection points and the third row of temperature detection points,

Wherein, the distance between the first row of temperature detection points and the weld seam on the weldment is 3cm to 5cm;

The distance between the second row of temperature detection points and the weld seam on the weldment is 6cm to 8cm;

The distance between the second row of temperature detection points and the weld seam on the weldment is 9cm to 11cm.

Further, in the step S3, the thermodynamic material parameters include conductivity, specific heat, heat transfer coefficient and heat radiation rate.

Further, in the step S3, when the weldment model is established in the finite element analysis software, the model of the weld area on the weldment model is based on the welding direction M(t) of the actual welding and the number of welding layers N(t) to establish and activate the birth and death unit.

Further, the activation direction of the life-death unit is consistent with the welding direction M(t), and the activation sequence and time of the life-death unit are determined according to the welding layer number N(t).

Further, when activating the life-death units, the ones with a smaller number of layers are activated first, and the ones with a larger number of layers are activated later, and the activation time of the life-death units of each layer corresponds to the welding start time of each layer.

Further, in the step S4, the heat source formula is compiled by using the moving heat source subroutine.

Further, the moving mode of the moving heat source of the moving heat source subroutine is consistent with the welding direction M(t).

Further, the predetermined value is 10°C.

Applying the technical solution of the present application, the temperature field analysis method based on the actual measurement of the welding temperature field combined with the finite element method of the present invention obtains the change of the temperature field in the whole process of the weldment through the temperature acquisition instrument, and organizes the temperature field into a spatial and temporal analysis method. form, and then organize the recorded welding sequence, number of welding layers, welding current and welding voltage into the form of time, and put them into the finite element analysis software to obtain the transient temperature field by moving heat source method, and compare the two temperature fields Comparison, if the difference is not large, it can prove that the numerical simulation temperature field is valid. If the difference is large, the parameters of the moving heat source and the heat transfer coefficient of the base metal can be adjusted appropriately to approach the measured temperature field until the error of the two is within the allowable range , then the adjusted numerical simulation temperature field is also accurate and effective. That is to say, the present invention can use the temperature acquisition instrument to obtain the temperature field of the actual weldment, and then use the method of finite element numerical simulation to approach the actual temperature field, and then use the method of finite element analysis software simulation to study different structures under different welding methods The distribution law of the temperature field of the formal weldment.

Description of drawings

The accompanying drawings constituting a part of the present application are used to provide further understanding of the present application, and the schematic embodiments and descriptions of the present application are used to explain the present application, and do not constitute improper limitations to the present application. In the attached picture:

Fig. 1 is the front view of the intersecting joint weldment disclosed in the embodiment of the present application;

Fig. 2 is a side view of the intersecting joint weldment disclosed in the embodiment of the present application;

Fig. 3 is a flow chart of the temperature field analysis method based on the actually measured welding temperature field combined with finite elements disclosed in the embodiment of the present application.

Wherein, the above-mentioned accompanying drawings include the following reference signs:

10. Weldment; 11. Weld seam; 12. Temperature detection point.

Detailed ways

It should be noted that, in the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and embodiments.

It should be noted that the terminology used here is only for describing specific implementations, and is not intended to limit the exemplary implementations according to the present application. As used herein, unless the context clearly dictates otherwise, the singular is intended to include the plural, and it should also be understood that when the terms "comprising" and/or "comprising" are used in this specification, they mean There are features, steps, operations, means, components and/or combinations thereof.

The relative arrangements of components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present application unless specifically stated otherwise. At the same time, it should be understood that, for the convenience of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. Techniques, methods and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such techniques, methods and devices should be considered part of the Authorized Specification. In all examples shown and discussed herein, any specific values should be construed as illustrative only, and not as limiting. Therefore, other examples of the exemplary embodiment may have different values. It should be noted that similar numbers and letters denote similar items in the following figures, therefore, once an item is defined in one figure, it does not require further discussion in subsequent figures.

Referring to Figures 1 to 3, according to an embodiment of the present invention, a temperature field analysis method based on the measured welding temperature field combined with finite elements is provided, hereinafter referred to as the temperature field analysis method, and the temperature field analysis method includes five Steps, each step of the temperature field analysis method will be described in detail below.

Step S1: setting temperature detection points 12 on the surface of the weldment 10, numbering the temperature detection points 12 on the weldment 10, and marking them as an integer n in turn, where n≥1.

In this step, the temperature detection parts 12 arranged on the surface of the weldment 10 are three rows, and the temperature detection points 12 of the three rows are all parallel to the weld seam 11 on the welding, and the temperature detection points 12 of the three rows are far away from the weldment 10. The direction of the weld seam 11 is sequentially arranged at intervals, and each row of temperature detection points 12 includes a plurality of temperature detection points 12 arranged at intervals, so that the change of the temperature field near the weld seam 11 can be detected to the greatest extent.

Specifically, in order to detect the temperature at the temperature detection point 12, a temperature detection element is provided on the surface of the weldment 10, and the temperature detection element is electrically connected to the temperature acquisition instrument, so as to transfer the collected temperature to the temperature acquisition instrument. Optionally, the temperature detecting element described in this implementation may be, for example, a temperature sensor.

Referring to Fig. 1 and shown in Fig. 2, the three rows of temperature detection points 12 described in this embodiment include the first row of temperature detection points 12, the second row of temperature detection points 12 and the third row of temperature detection points 12, as shown in Fig. 1 As shown in FIG. 2 , the first row of temperature detection points 12 , the second row of temperature detection points 12 and the third row of temperature detection points 12 are sequentially arranged at intervals along the direction away from the weld seam 11 . Wherein, the distance a between the first row of temperature detection points 12 and the weld 11 is 3cm to 5cm, such as 3cm, 4cm, 5cm, etc.; the distance b between the second row of temperature detection points 12 and the weld 11 is 6cm to 8cm, such as 7cm , 7cm, or 8cm, etc.; the distance between the second row of temperature detection points 12 and c weld 11 is 9cm to 11cm, such as 9cm, 10cm, or 11cm, etc. In the temperature detection points 12 of the same row, two adjacent temperature The distance between the detection points 12 is 5cm to 10cm, such as 5cm, 6cm, 7cm, 8cm, 9cm or 10cm. With such an arrangement, the change of the temperature field near the weld seam 11 can be further detected to the greatest extent.

Step S2: Weld the weldment 10, organize the actual temperature field T ₀ (n, t) of each temperature detection point 12 into the form of number n and time t, and record the welding direction M(t) during the welding process , welding layer number N(t), welding current A(t) and welding voltage V(t) are all sorted into the form of time t.

Specifically, the temperature detection points 12 are numbered and marked in the form of 1, 2, 3, 4... integers.

The temperature field T ₀ (n, t) of each detection point acquired by the temperature acquisition instrument is sorted into the form of number n and time t.

T ₀ (n, t) =

When the welding direction M(t), welding layer number N(t), welding current A(t) and welding voltage V(t) are all sorted into the form of time t:

M(t)=

N(t)=

A(t)=

V(t)=

Step S3: Establish the same weldment model as the weldment 10 in the finite element analysis software, and define the thermodynamic material parameters of the weldment model in the form of temperature T in the finite element analysis software.

When establishing the same weldment model as the weldment 10 in the finite element analysis software, in addition to making the basic size of the weldment model the same as the actual weldment 10, the groove angle and weld interval of the model weldment should also be the same as the actual weldment. The dimensions of the piece 10 are kept strictly consistent.

Optionally, the thermodynamic material parameters described herein include conductivity, specific heat, heat transfer coefficient, and thermal emissivity. Because the thermodynamic material parameters of the actual weldment 10 change with the change of temperature, therefore, in the finite element analysis software, the thermodynamic material parameters of the weldment model are defined as the form of temperature T, which can improve the temperature field analysis in this application. The analytical precision of the method.

When the weldment model is established in the finite element analysis software, the model of the weld area on the weldment model is established and activated according to the actual welding welding direction M(t) and the number of welding layers N(t).

The activation direction of the life-death unit is consistent with the welding direction M(t), and the activation sequence and time of the life-death unit are determined according to the number of welding layers N(t). When activating the life-death unit, the one with the smaller number of layers is activated first, and the one with the larger number of layers is activated later. The activation time of the life-death unit of each layer corresponds to the welding start time of each layer.

Step S4: Write the heat source formulas for the welding current A(t), welding voltage V(t) and welding direction M(t) of the weldment 10, and use the finite element analysis element to solve the simulated temperature field T on the surface of the weldment model ₁ (x, y, z, t).

In this step, the heat source formula is compiled using the moving heat source subroutine. The moving mode of the moving heat source of the moving heat source subroutine is consistent with the welding direction M(t).

Step S5: In the simulated temperature field T ₁ (x, y, z, t), find the actual temperature field T ₀ (n, t) corresponding to the detection point according to the x, y, z coordinates, and compare the simulated temperature field T ₁ (x, y, z, t) and the actual temperature field T ₀ (n, t), if the temperature difference between the two does not exceed the predetermined value at the same time, it proves that the simulated temperature field T ₁ (x, y, z, t) is valid; if the temperature difference between the two is greater than the predetermined value at the same time, adjust the output heat efficiency in the heat source formula to control the temperature, and at the same time adjust the thermodynamic material parameters (heat transfer coefficient) of the weldment model in the finite element analysis software To control the rate of temperature change until the temperature difference between the simulated temperature field T ₁ (x, y, z, t) and the temperature field T ₀ (n, t) at the same time does not exceed the predetermined value. Optionally, the predetermined value is 10°C. In this way, complex welding processes and temperature field changes in the whole process of complex welded components can be accurately simulated.

From the above description, it can be seen that the above-mentioned embodiments of the present application have achieved the following technical effects: The temperature field analysis method based on the actual measurement of the welding temperature field and combined with the finite element method of the present invention obtains the temperature field of the weldment in the whole process through the temperature acquisition instrument The change of the temperature field, and organize the temperature field into the form of space and time, and then organize the recorded welding sequence, number of welding layers, welding current and welding voltage into the form of time, and substitute it into the finite element analysis software. The moving heat source method obtains the transient temperature field, and compares the two temperature fields. If the difference is not large, it can prove that the numerical simulation temperature field is effective. If the difference is large, the parameters of the moving heat source and the heat transfer coefficient of the base material can be adjusted appropriately. To approach the measured temperature field until the error of the two is within the allowable range, then the adjusted numerical simulation temperature field is also accurate and effective. Use the temperature acquisition instrument to obtain the temperature field of the actual weldment, and then use the finite element numerical simulation method to approach the actual temperature field, and then use the finite element analysis software simulation method to study the distribution of the temperature field of the weldment with different structural forms under different welding methods .

For the convenience of description, spatially relative terms may be used here, such as "on ...", "over ...", "on the surface of ...", "above", etc., to describe the The spatial positional relationship between one device or feature shown and other devices or features. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, devices described as "above" or "above" other devices or configurations would then be oriented "beneath" or "above" the other devices or configurations. under other devices or configurations". Thus, the exemplary term "above" can encompass both an orientation of "above" and "beneath". The device may be oriented differently (rotated 90 degrees or at other orientations) and the spatially relative descriptions used herein interpreted accordingly.

In addition, it should be noted that the use of words such as "first" and "second" to define components is only for the convenience of distinguishing corresponding components. To limit the protection scope of this application.

The above descriptions are only preferred embodiments of the present application, and are not intended to limit the present application. For those skilled in the art, various modifications and changes may be made to the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of this application shall be included within the protection scope of this application.

Claims (9)

1. A temperature field analysis method based on actual measurement welding temperature field and in conjunction with finite element, it is characterized in that, comprising: Step S1: setting temperature detection points (12) on the surface of the weldment (10), numbering the temperature detection points (12) on the weldment (10), and marking them as an integer n in turn, where n≥1 ; Step S2: Weld the weldment (10), organize the actual temperature field T ₀ (n, t) of each temperature detection point (12) into the form of number n and time t, and record the welding process The welding direction M(t), number of welding layers N(t), welding current A(t) and welding voltage V(t) are all arranged in the form of time t; Step S3: establishing the same weldment model as the weldment (10) in the finite element analysis software, and defining the thermodynamic material parameters of the weldment model in the form of temperature T in the finite element analysis software; Step S4: writing heat source formulas for the welding current A(t), the welding voltage V(t) and the welding direction M(t) of the weldment (10), and using the finite element analysis The component solves the simulated temperature field T ₁ (x, y, z, t) on the surface of the weldment model; Step S5: In the simulated temperature field T ₁ (x, y, z, t), find out the actual temperature field T ₀ (n, t) corresponding to the temperature detection point according to the x, y, z coordinates ), compare the simulated temperature field T ₁ (x, y, z, t) with the actual temperature field T ₀ (n, t), if the temperature difference between the two does not exceed the predetermined value at the same time, it proves that the The simulated temperature field T ₁ (x, y, z, t) is valid; if at the same time the simulated temperature field T ₁ (x, y, z, t) and the actual temperature field T ₀ (n, t) If the temperature difference is greater than the predetermined value, then adjust the output thermal efficiency in the heat source formula to control the temperature, and at the same time adjust the thermodynamic material parameters of the weldment model in the finite element analysis software to control the rate of temperature change until the temperature difference between the simulated temperature field T ₁ (x, y, z, t) and the temperature field T ₀ (n, t) at the same time does not exceed the predetermined value; In the step S1, the temperature detection points (12) are three rows, and the temperature detection points (12) of the three rows are all parallel to the weld seam (11) on the welding, and the temperature detection points of the three rows (12) The temperature detection points (12) in each row include a plurality of temperature detection points (12) arranged at intervals along the direction away from the weld seam (11). 2. The temperature field analysis method based on the actual measured welding temperature field combined with finite elements according to claim 1, characterized in that the temperature detection points (12) in the three rows include the first row of temperature detection points (12), the second The second row of temperature detection points (12) and the third row of temperature detection points (12), Wherein, the distance between the first row of temperature detection points (12) and the weld seam (11) on the weldment (10) is 3cm to 5cm; The distance between the second row of temperature detection points (12) and the weld seam (11) on the weldment (10) is 6cm to 8cm; The distance between the second row of temperature detection points (12) and the weld seam (11) on the weldment (10) is 9cm to 11cm; The distance between two adjacent temperature detection points ( 12 ) on each row of the temperature detection points ( 12 ) is 5 cm to 10 cm. 3. The temperature field analysis method based on the actual measured welding temperature field combined with finite elements according to claim 1, characterized in that, in the step S3, the thermodynamic material parameters include conductivity, specific heat, and heat transfer coefficient and thermal emissivity. 4. The temperature field analysis method based on the measured welding temperature field and finite element according to claim 1, characterized in that, in the step S3, when the weldment model is established in the finite element analysis software , the model of the weld area on the weldment model is established and activated according to the actual welding direction M(t) and the number of welding layers N(t). 5. The temperature field analysis method based on the measured welding temperature field combined with finite elements according to claim 4, characterized in that the activation direction of the life-death unit is consistent with the welding direction M(t), and the life-death unit The activation sequence and time are determined according to the number of welding layers N (t). 6. The temperature field analysis method based on the actually measured welding temperature field combined with finite elements according to claim 5, characterized in that, when activating the life-death unit, the one with a small number of layers is activated first, and the one with a large number of layers is activated later. The activation time of the life-death unit of a layer is in one-to-one correspondence with the welding start time of each layer. 7. The temperature field analysis method based on the measured welding temperature field combined with finite elements according to claim 1, characterized in that, in the step S4, the heat source formula is obtained by using a moving heat source subroutine. 8. The temperature field analysis method based on the measured welding temperature field combined with finite elements according to claim 7, characterized in that the moving mode of the moving heat source in the moving heat source subroutine is consistent with the welding direction M(t) . 9. The temperature field analysis method based on the actually measured welding temperature field combined with finite elements according to any one of claims 1 to 8, wherein the predetermined value is 10°C.

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