Finite element based simulation method for microstructure evolution of electromagnetic pulse micro-welds

Abstract

The application relates to the field of electromagnetic pulse welding and provides a simulation method for microstructure evolution of an electromagnetic pulse micro-welding spot based on finite elements, which comprises the following steps: dividing time nodes and obtaining peripheral frame lines of the microstructure of the electromagnetic pulse micro-welding spot at the time of generation of the microstructure at each time node; obtaining a geometric model of the micro-welding spot at each time node and coupling the peripheral frame lines and the geometric model of the micro-welding spot to finite element software; obtaining micro-welding spot model parameters from the time of generation of the micro-welding spot to the time of completion of generation through the finite element software; re-dividing the time nodes based on the variation amplitude of the micro-welding spot model parameters and evolving the growth process of the microstructure of the micro-welding spot according to the re-divided time stages. According to the variation of the electromagnetic pulse micro-welding spot, the corresponding relationship between the time domain characteristics of the micro-welding spot and the peripheral frame lines, and the finite element theory, the microstructure evolution process of the electromagnetic pulse micro-welding spot can be simulated.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electromagnetic pulse welding, in particular to a simulation method for microstructure evolution of electromagnetic pulse micro-welding spot based on finite element. BACKGROUND

[0002] At present, with the increasing demand for high-precision welding scenarios, electromagnetic pulses are increasingly used in high-precision welding scenarios due to their non-heat generation and high welding precision.

[0003] During electromagnetic pulse welding, fine deformation occurs when the welding object is fused. However, to achieve higher precision welding requirements, the electromagnetic pulse micro-welding spot needs to be monitored in time for subsequent timely adjustment of the electromagnetic pulse equipment. However, there is no related simulation method for the microstructure evolution process of the electromagnetic pulse micro-welding spot. SUMMARY

[0004] The purpose of the present application is to provide a simulation method for microstructure evolution of electromagnetic pulse micro-welding spot based on finite element, which can simulate the microstructure evolution process of electromagnetic pulse micro-welding spot based on the time-domain characteristics of micro-welding spot changes and the corresponding relationship of the peripheral frame line, combined with finite element theory, according to the change of electromagnetic pulse micro-welding spot.

[0005] The present application solves the technical problem by adopting the following technical solution:

[0006] The simulation method for microstructure evolution of electromagnetic pulse micro-welding spot based on finite element includes the following steps:

[0007] Divide time nodes and obtain the peripheral frame line when the microstructure of the electromagnetic pulse micro-welding spot is generated at each time node;

[0008] Obtain the micro-welding spot geometric model at each time node, and couple the peripheral frame line and the geometric model of the micro-welding spot to the finite element software;

[0009] Obtain the micro-welding spot model parameters from the generation of the micro-welding spot to the completion of the generation by the finite element software;

[0010] Re-divide the time nodes based on the change amplitude of the micro-welding spot model parameters, and evolve the growth process of the microstructure of the micro-welding spot according to the re-divided time stages.

[0011] Further, the division of time nodes and the acquisition of the peripheral frame line when the microstructure of the electromagnetic pulse micro-welding spot is generated at each time node specifically includes the following steps:

[0012] Taking the electromagnetic pulse welding equipment starting and moving the energy output port to the specified position as the time starting point, taking the welding completion as the time ending point, and dividing the time nodes from the time starting point to the time ending point in units of 0.05 microseconds;

[0013] The electromagnetic pulse micro-welding point is defined as the energy stress point on the welding object closest to the energy output port of the electromagnetic pulse welding equipment.

[0014] According to the deformation properties of the welding object during electromagnetic pulse welding, the peripheral frame line during the generation of the electromagnetic pulse micro-welding point microstructure is obtained.

[0015] Further, the obtained peripheral frame line during the generation of the electromagnetic pulse micro-welding point microstructure surrounds the energy output range corresponding to the energy output port of the electromagnetic pulse welding equipment, and each edge of the peripheral frame line is 1-2 millimeters away from the energy output range.

[0016] Further, the micro-welding point model parameters from the generation of the micro-welding point to the completion of the generation are obtained by the finite element software, wherein the micro-welding point model parameters include: the time when the energy output by the energy output port of the electromagnetic pulse welding equipment acts on the welding object closest to it, the deformation start time of the micro-welding point on the welding object closest to the energy output port, the latest deformation start time of the welding object among all the welding objects, and the latest deformation end time of all the welding objects.

[0017] Further, the time nodes are re-divided based on the change amplitude of the micro-welding point model parameters, and the growth process of the micro-welding point microstructure is evolved according to the re-divided time stages, specifically:

[0018] When the time when the energy output by the energy output port of the electromagnetic pulse welding equipment acts on the welding object closest to it is less than or equal to the preset time, and the deformation start time of the micro-welding point on the welding object closest to the energy output port is greater than or equal to 0.5 microseconds, and the latest deformation time of the welding object among all the welding objects is greater than or equal to 1 microsecond, then when re-dividing the time nodes, the unit of the divided time nodes is increased.

[0019] Further, the preset time is 1 microsecond.

[0020] Further, when the unit of the divided time nodes is increased, the unit of the divided time nodes is increased to 0.1 microsecond.

[0021] The beneficial effects of the present application are: through the above-mentioned simulation method for microstructure evolution of electromagnetic pulse micro-welding spot based on finite element, firstly, time nodes are divided, and the peripheral frame line at the time of microstructure generation of the electromagnetic pulse micro-welding spot is obtained at each time node; secondly, the micro-welding spot geometric model at each time node is obtained, and the peripheral frame line and the geometric model of the micro-welding spot are coupled to the finite element software; then, the micro-welding spot model parameters from the generation of the micro-welding spot to the completion of the generation are obtained through the finite element software; finally, the time nodes are re-divided based on the change amplitude of the micro-welding spot model parameters, and the growth process of the microstructure of the micro-welding spot is evolved according to the re-divided time stages, which can simulate the microstructure evolution process of the electromagnetic pulse micro-welding spot according to the change of the electromagnetic pulse micro-welding spot, based on the corresponding relationship between the time domain characteristics of the micro-welding spot change and the peripheral frame line, and combined with the finite element theory. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 The flowchart of the simulation method for microstructure evolution of electromagnetic pulse micro-welding spot based on finite element of the present application. DETAILED DESCRIPTION

[0023] The technical solutions of the present application will be described in detail below with reference to the drawings.

[0024] The present application proposes a simulation method for microstructure evolution of electromagnetic pulse micro-welding spot based on finite element, and the flowchart is shown in Figure 1 The method comprises the following steps:

[0025] S1. Dividing time nodes, and obtaining the peripheral frame line at the time of microstructure generation of the electromagnetic pulse micro-welding spot at each time node;

[0026] S2. Obtaining the micro-welding spot geometric model at each time node, and coupling the peripheral frame line and the geometric model of the micro-welding spot to the finite element software;

[0027] S3. Obtaining the micro-welding spot model parameters from the generation of the micro-welding spot to the completion of the generation through the finite element software;

[0028] S4. Re-dividing the time nodes based on the change amplitude of the micro-welding spot model parameters, and evolving the growth process of the microstructure of the micro-welding spot according to the re-divided time stages.

[0029] In the above method, in order to combine the finite element theory, the time domain characteristics of the electromagnetic pulse welding process can be effectively bound with the microstructure of the micro-welding spot during welding, therefore, the welding time needs to be divided, here, the time nodes are divided, and the peripheral frame line at the time of microstructure generation of the electromagnetic pulse micro-welding spot is obtained at each time node, which specifically comprises the following steps:

[0030] S11. Taking the start of the electromagnetic pulse welding equipment and moving the energy output port to the designated position as the time starting point, and taking the completion of the welding as the time ending point, dividing the time nodes from the time starting point to the time ending point in units of 0.05 microseconds; here, since the total time of electromagnetic pulse welding is generally a few microseconds, in order to effectively monitor the microstructure of the micro-welding point at each time node, the time unit for division can be flexibly selected according to the type of the welded object.

[0031] S12. The electromagnetic pulse micro-welding point is the energy stress point on the closest welded object corresponding to the energy output range of the energy output port of the electromagnetic pulse welding equipment; compared to the principle of conventional welding by heating and fusion, electromagnetic pulse does not achieve welding of the welded object by heating principle, therefore, the electromagnetic pulse micro-welding point set here is essentially a collection of points on the surface of the closest welded object where the energy output port acts to produce deformation.

[0032] S13. According to the deformation properties of the welded object during electromagnetic pulse welding, the peripheral frame line of the electromagnetic pulse micro-welding point microstructure generation is obtained; since different metals and non-metals can be welded using electromagnetic pulse welding, different welded objects will deform to different degrees when stressed.

[0033] It should be noted that in this application, the peripheral frame line of the electromagnetic pulse micro-welding point microstructure generation is obtained, which surrounds the energy output range corresponding to the energy output port of the electromagnetic pulse welding equipment, and the distance between each edge of the peripheral frame line and the energy output range is 1-2 millimeters. Generally speaking, the distance between each edge of the peripheral frame line and the energy output range should not be too large, and can be flexibly set. In order to achieve the monitoring effect of the welding area and reduce the subsequent data processing pressure, 1-2 millimeters is selected in this application.

[0034] In actual application, the micro-welding point model parameters from the generation of the micro-welding point to the completion of the generation are obtained by finite element software, wherein the micro-welding point model parameters include: the time when the energy output by the energy output port of the electromagnetic pulse welding equipment acts on the closest welded object, the deformation start time of the micro-welding point on the closest welded object to the energy output port, the latest deformation start time of the welded object among all the welded objects, and the latest deformation end time of all the welded objects.

[0035] In addition, the time nodes are re-divided based on the change amplitude of the micro-welding point model parameters, and the growth process of the micro-welding point microstructure is evolved according to the re-divided time stages, which specifically refers to:

[0036] When the time for the energy output from the energy output port of the electromagnetic pulse welding equipment to act on the nearest weldment is less than or equal to the preset time, and the deformation start time of the micro-weld point on the weldment closest to the energy output port is greater than or equal to 0.5 microseconds, and the latest deformation time of the weldment among all weldments is greater than or equal to 1 microsecond, then when re-dividing the time nodes, the unit of the divided time node is increased.

[0037] In practical applications, since the entire electromagnetic pulse welding process typically lasts only a few microseconds, the time it takes for the energy output from the electromagnetic pulse welding equipment to act on the nearest workpiece is generally quite constant. If the time is excessively long, it may indicate a equipment malfunction. Therefore, timely inspection and repair are necessary in case of a malfunction. The normal energy application time, i.e., the preset time, is generally around 1 microsecond. Furthermore, when increasing the unit of measurement for time intervals, the unit can be increased to 0.1 microseconds.

Claims

1. A simulation method for the microstructure evolution of electromagnetic pulse micro-weld joints based on the finite element method, characterized in that, Includes the following steps: Divide the time nodes and obtain the outer border line of the electromagnetic pulse micro-weld joint microstructure generation at each time node; Obtain the geometric model of the micro-weld joint at each time point, and couple the outer boundary line of the micro-weld joint and the geometric model to the finite element software; The micro-weld joint model parameters are obtained from the time of micro-weld joint generation to the time of completion of generation using finite element software. The micro-weld joint model parameters include: the time when the energy output port of the electromagnetic pulse welding equipment acts on the closest weldment, the deformation start time of the micro-weld joint on the weldment closest to the energy output port, the latest deformation start time of all weldments, and the latest deformation end time of all weldments. The time nodes are redefined based on the variation range of the micro-weld joint model parameters. The growth process of the micro-organism of the micro-weld joint is then evolved according to the redefined time nodes. Specifically, when the energy output from the energy output port of the electromagnetic pulse welding equipment acts on the nearest weldment for a time less than or equal to a preset time, and the deformation start time of the micro-weld joint on the weldment closest to the energy output port is greater than or equal to 0.5 microseconds, and the latest deformation time of the weldment among all weldments is greater than or equal to 1 microsecond, then the unit of the redefined time node is increased.

2. The simulation method for the microstructure evolution of electromagnetic pulse micro-weld joints based on finite element method according to claim 1, characterized in that, The process of dividing time nodes and obtaining the outer boundary line of the electromagnetic pulse micro-weld joint microstructure at each time node specifically includes the following steps: The time starting point is defined as the start of the electromagnetic pulse welding equipment and the movement of the energy output port to the designated position, and the time ending point is defined as the completion of welding. The time nodes from the time starting point to the time ending point are divided in units of 0.05 microseconds. The point on the workpiece closest to the energy output port of the electromagnetic pulse welding equipment, corresponding to the energy output range of the electromagnetic pulse welding equipment, is the electromagnetic pulse micro-welding point. Based on the deformation properties of the workpiece during electromagnetic pulse welding, the outer boundary line of the electromagnetic pulse micro-weld joint microstructure is obtained.

3. The simulation method for the microstructure evolution of electromagnetic pulse micro-weld joints based on finite element method according to claim 2, characterized in that, The outer frame line of the obtained electromagnetic pulse micro-weld joint microstructure during generation surrounds the energy output range corresponding to the energy output port of the electromagnetic pulse welding equipment, and the distance between each side of the outer frame line and the energy output range is 1-2 mm.

4. The simulation method for the microstructure evolution of electromagnetic pulse micro-weld joints based on finite element method according to claim 1, characterized in that, The preset time is 1 microsecond.

5. The simulation method for the microstructure evolution of electromagnetic pulse micro-weld joints based on finite element method according to claim 1, characterized in that, When increasing the unit of the time node division, the unit of the time node division is increased to 0.1 microseconds.

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