Simulation of the Laser welding on a pipe using Dflux Subroutine Abaqus

Project Overview

In this example, the laser welding process on a pipe is simulated using the DFLUX subroutine in the Abaqus software.

A volumetric heat flux is used to simulate the welding process. The Cylindrical Involution Normal (CIN) heat source model is used to define the volumetric heat flux, and the DFLUX subroutine is implemented to define the CIN heat source model.

The DFLUX subroutine is used to define a nonuniform heat flux that moves along the welding path on the pipe.

CIN Heat Source Model

The Cylindrical Involution Normal (CIN) heat source model is adopted to calculate the volumetric heat flux distribution around the welding pool.

The equation of the CIN heat source model is defined as a function of position and time, together with a number of heat source parameters.

The DFLUX subroutine is used to implement this heat source model and define the nonuniform heat flux during the welding process.

Circular Welding Path

Unlike a welding process on a flat plate, the welding torch in this simulation moves around the pipe in a circular path.

Therefore, the welding speed must be defined in terms of angular velocity, using the unit radian/second.

The radius of the pipe is 0.06 m and the linear welding velocity is 0.06 m/s. The angular velocity is therefore calculated from:

ω = V / R = 0.06 / 0.06 = 1 rad/s

With an angular velocity of 1 rad/s, the welding torch completes one complete revolution around the pipe in approximately 6.283 seconds.

Welding and Cooling Process

The analysis is performed in two steps.

In the first step, the welding process is simulated for a duration of 6.283 seconds. During this step, the welding torch moves around the pipe and the moving volumetric heat flux is applied using the DFLUX subroutine.

In the second step, the cooling process is simulated for a duration of 1000 seconds after the welding process has been completed.

Thermal-Mechanical Analysis

Two Coupled Temperature-Displacement steps are defined to simulate the thermal and mechanical behavior of the pipe during the welding and cooling processes.

This approach allows the temperature field and the corresponding mechanical response of the pipe to be considered simultaneously throughout the analysis.

Material Properties

The pipe is made of Stainless Steel SA240. The material properties are defined as temperature-dependent properties.

The following material properties depend on temperature:

• Density
• Thermal conductivity
• Specific heat
• Thermal expansion
• Elastic properties
• Plastic properties

What You Will Learn

• How to simulate laser welding on a pipe in Abaqus.
• How to use the DFLUX subroutine for laser welding.
• How to define a volumetric heat flux.
• How to implement the CIN heat source model.
• How to define a nonuniform heat flux using DFLUX.
• How to simulate a welding torch moving around a pipe.
• How to define a circular welding path.
• How to convert linear welding velocity into angular velocity.
• How to define the angular velocity in rad/s.
• How to simulate a welding speed of 0.06 m/s.
• How to simulate a pipe with a radius of 0.06 m.
• How to calculate an angular velocity of 1 rad/s.
• How to simulate the 6.283-second welding process.
• How to simulate the 1000-second cooling process.
• How to define two Coupled Temperature-Displacement steps.
• How to define temperature-dependent material properties.
• How to implement a Fortran DFLUX subroutine in Abaqus.

Key Features

• Laser welding simulation on a pipe.
• DFLUX Fortran subroutine.
• Volumetric heat flux.
• Cylindrical Involution Normal (CIN) heat source model.
• Nonuniform heat flux distribution.
• Circular welding path around the pipe.
• Pipe radius: 0.06 m.
• Linear welding velocity: 0.06 m/s.
• Angular velocity: 1 rad/s.
• 6.283-second welding stage.
• 1000-second cooling stage.
• Two Coupled Temperature-Displacement steps.
• Temperature-dependent material properties.
• Stainless Steel SA240.
• Research article included.