kSIST FprEN ISO 18166:2025

SLOVENSKI STANDARD
oSIST prEN ISO 18166:2025
01-marec-2025
Numerična simulacija varjenja - Izvedba in dokumentacija (ISO/DIS 18166:2025)
Numerical welding simulation - Execution and documentation (ISO/DIS 18166:2025)
Numerische Schweißsimulation - Ausführung und Dokumentation (ISO/DIS 18166:2025)
Simulation numérique de soudage - Exécution et documentation (ISO/DIS 18166:2025)
Ta slovenski standard je istoveten z: prEN ISO 18166
ICS:
25.160.01 Varjenje, trdo in mehko Welding, brazing and
spajkanje na splošno soldering in general
oSIST prEN ISO 18166:2025 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

oSIST prEN ISO 18166:2025
oSIST prEN ISO 18166:2025
DRAFT
International
Standard
ISO/DIS 18166
ISO/TC 44
Numerical welding simulation —
Secretariat: AFNOR
Execution and documentation
Voting begins on:
Simulation numérique de soudage — Exécution et documentation
2025-01-03
Voting terminates on:
ICS: 35.240.50; 25.160.01
2025-03-28
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
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NOTIFICATION OF ANY RELEVANT PATENT
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PROVIDE SUPPORTING DOCUMENTATION.
Reference number
ISO/DIS 18166:2025(en)
oSIST prEN ISO 18166:2025
ISO/DIS 18166:2025(en)
© ISO 2025
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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Published in Switzerland
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Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms. 3
5 Principle . 3
6 Scientific Computation Tools (SCTs) . 3
7 Required data for simulation . 4
8 Formulation of the problem and establishing the simulation strategy . 5
9 Establishment of the input parameters . 7
9.1 Input data .7
9.2 Simulation template .7
10 Geometry and mesh . 8
10.1 Geometry and meshing of welded joint .8
10.2 Mesh size .8
10.3 Type of elements .8
10.4 Modelling of the filler material .8
11 Performing the simulation . 9
11.1 Code verification .9
11.2 Thermal and metallurgical computations .10
11.2.1 General .10
11.2.2 Focus on metallurgical transformations .10
11.2.3 Modelling of heat source.10
11.2.4 Boundary and initial thermal conditions .10
11.3 Thermomechanical computation for residual stresses prediction .10
11.3.1 General .10
11.3.2 Model parameters adjustments .11
11.3.3 Materials with phase transformations .11
11.3.4 Boundary conditions .11
11.4 Monitoring the solution during computation.11
12 Simulation post-processing .12
12.1 General . 12
12.2 Cross-section of fusion zone . 12
12.3 Transient evolution of temperatures . 12
12.4 Phases and residual stresses distributions . 12
13 Comparing/challenging the results.13
13.1 General . 13
13.2 Calculation verification . 13
13.3 Validation .14
13.3.1 General .14
13.3.2 Validation process .14
13.3.3 Lack of knowledge . . 15
13.3.4 Validation experiment guidelines . 15
13.3.5 Additional validation activities . 15
14 Uncertainty quantification .15
15 Reporting/display of results .16
15.1 General .16

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15.2 Objective of welding simulation .16
15.3 Material properties and input data .16
15.4 Geometry and mesh .17
15.5 Numerical model parameters .17
15.6 Analysis of results .17
Annex A (informative) Technical specification of Scientific Computation Tools (SCTs) for
numerical welding simulation / computational weld mechanics .18
Annex B (informative) Documentation template.20
Annex C (informative) Heat source modelling and calibration .25
Annex D (informative) Guidelines for validation experiment .34
Annex E (informative) Characterizing, tracing, and managing uncertainty in computational
weld mechanics and real world systems .36
Bibliography .38

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Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent
rights identified during the development of the document will be in the Introduction and/or on the ISO list of
patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document has been prepared by Technical Committee ISO/TC 44, Welding and allied processes, working
group 5, in collaboration with the European Committee for Standardization (CEN) Technical Committee
CEN/TC 121, Welding and allied processes, in accordance with the Agreement on technical cooperation
between ISO and CEN (Vienna Agreement).
This first edition cancels and replaces the Technical Specification ISO/TS 18166:2016 which has been
technically revised.
Any feedback or questions on this document should be directed to the user’s
national standards body. A complete listing of these bodies can be found at
www.iso.org/members.html. Official interpretations of TC 44 documents, where they exist, are available
from this page: https://committee.iso.org/sites/tc44/home/interpretation.html.

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Introduction
This document is not intended for use in a specific industry or with a specific software. Commercial tools
are not excluded. This document is beneficial for the design and assessment of a wide range of components
if the physical phenomena, software and numerical methods meet the specifications of the scientific
computational tools (SCTs) defined in Annex A.
This document can be used by industrial bodies or companies to define their requirements for specific
applications of computational welding mechanics (CWM).

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oSIST prEN ISO 18166:2025
DRAFT International Standard ISO/DIS 18166:2025(en)
Numerical welding simulation — Execution and
documentation
1 Scope
This document specifies the execution, validation, verification and documentation of a numerical welding
simulation within the field of computational welding mechanics (CWM) and performed with a Scientific
Computational Tool (SCT).
This document is applicable to the thermal and mechanical finite element analysis (FEA) of arc, laser and
electron beam welding processes for the purpose of calculating the effects of welding processes, and in
particular residual stresses and distortion, in support of structural integrity assessment.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/TR 25901-1:2016 and the
following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
calculation scheme
set of modelling choices to perform a numerical simulation
Note 1 to entry: A calculation scheme defines the choice of physical models and of the coupling physics between
models, the correlations, the discretization both spatial (meshing) and temporal (time step), the calculation options.
3.2
calibration
process of adjusting modelling parameter values of the scientific computing tool
Note 1 to entry: Calibration improves agreement between the calculated values and the reference values.
3.3
greedy algorithm
algorithm that follows the problem-solving heuristic of making the locally optimal choice at each stage
Note 1 to entry: In many cases, a greedy strategy does not produce an optimal solution, but a greedy heuristic can
yield locally optimal solutions that approximate a globally optimal solution in a reasonable amount of time.
3.4
heat flux
rate at which thermal energy is transferred through a unit area of surface

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3.5
heat source (numerical)
spatial and temporal numerical distribution of the thermal energy transferred to the weldment by the
welding process
3.6
numerical simulation
implementation of one or more SCTs, with calculation schemes and input data, to produce numerical results
describing the evolution of a physical situation
3.8
power density
amount of thermal power absorbed or generated per unit volume
3.9
scientific computing tool (SCT)
software for numerical simulation of physical phenomena
Note 1 to entry: An SCT can consist of one or more solvers and include pre- and post-processors
Note 2 to entry: SCTs use computational methods to solve science and engineering problems.
Note 3 to entry: Refer to Annex A for technical specifications of SCTs.
3.10
reference scientific computing tool
scientific computing tool (SCT) for which the predictive performance is considered to be superior to that
expected of the scientific computing tool to be validated
3.11
scope of utilization
situations and scenarios studied using the SCT for CWM
3.12
spatial discretization
distribution and type of the geometric units for subdividing the geometric model
3.13
temporal discretization
step size and number of time units for subdividing the duration being modelled
3.14
validation case
data set considered to be pertinent and selected for carrying out separate effects or integral validation of an SCT
Note 1 to entry: Data set can be experimental test, operating experience feedback, simulation using a reference
scientific computing tool, analytical solution, etc.
3.15
validation experiment
experiment designed to validate the simulation results taking into account all relevant data and their
uncertainty
3.16
validation file
document in which all the results of the validation of an SCT are inventoried
3.17
verification file
document in which all the results of the verification of an SCT are inventoried

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4 Symbols and abbreviated terms
For the purposes of this document, the symbols and abbreviated terms given in Table 1 apply.
Table 1 — Symbols and abbreviated terms
Symbol or Definition
abbreviated
term
2D two dimensional
3D three dimensional
CTE coefficient of thermal expansion
CWM computational weld mechanics
EBW electron beam welding
FEA finite element analysis
GMAW gas metal arc welding
GTAW gas tungsten arc welding
HAZ heat-affected zone
PIRT phenomena identification ranking table
PWHT post weld heat treatment
QI quantities of interest
SAW submerged arc welding
SCT scientific computation tool
SMAW shielded metal arc welding
TIG tungsten inert gas
WPS welding procedure specification
WPQR welding procedure qualification record
5 Principle
The thermomechanical numerical simulation of welding is mainly based on the finite element method. It
consists of a WPS implemented in an SCT for CWM, pre- and post-processing tools, and verification and
validation methods (see [18] and [19]).
The CWM problem is generally defined as a three-dimensional solid element model employing a moving heat
source with simultaneous calculation of temperature, microstructure, displacement and stresses, utilizing
time dependent elastoplastic constitutive law based on material properties ranging from room temperature
up to the melting temperature.
It requires the geometric modelling of the part to be joined in the form of a mesh, the modelling of the
initial and boundary conditions and the definition of materials behaviors. From the spatial and temporal
discretization, the SCT allows the resolution of a heat transfer problem with transient heat source, with
possibly the determination of metallurgical transformations and the thermomechanical calculation of
residual stresses and distortions. The pre- and post-processing tools may be different from the SCT.
However, it is the set of tools used for the intended studies that is the subject of the recommendations of this
document.
6 Scientific Computation Tools (SCTs)
A SCT for numerical welding simulation has specific capabilities compared to conventional FEA software.
The SCT shall enable the calculation of the quantities of interest for the intended scope of utilization with
uncertainty values appropriate to the needs of the studies for intended use. The SCT shall enable the
implementation solution of a CWM problem following all the recommendations of this document.

oSIST prEN ISO 18166:2025
ISO/DIS 18166:2025(en)
In order to follow all the recommendations of this document the SCT shall:
— create 2D and 3D meshes of single and multi-pass welded joints;
— visualize and export the quantities of interest;
— define and verify the heat source according to space and time coordinates;
— access to solver parameters of accuracy, convergence, numerical schemes in order to be able to carry out
a spatial and temporal convergence study;
— simulate the spatio-temporal evolution of the temperature;
— simulate the phase transformations if any;
— couple thermomechanics with metallurgical effects, simulation of residual stresses.
The SCT should:
— simulate the addition of filler metal;
— activate and deactivate elements during a simulation;
— consider viscous and creep effects especially when PWHT is of concern;
— simulate the temperature and the cyclic behaviour of the materials, recovery effects, and transformation
induced plasticity.
The SCT should use and have a library of:
— validated and verified material data;
— cases for verification and validation.
The user can also add their own data.
7 Required data for simulation
In order to ensure a representative modelling, the user shall have enough information on the way the
welding was carried out that may be obtained from a welding book, from the description and qualification of
the welding procedures specifications (WPS) or production report.
The user shall have access to the following:
— fabrication procedure records, detailing how the structure was constructed;
— design / construction drawings defining the nominal component geometry and dimensions;
— weld groove geometry (from drawings or WPS);
— weld procedure information, type of process, heat input per unit length of weld (welding voltage, current
and welding speed, deposit flow rate, type of cover gas, filler metal, welding position, number and
arrangement of passes, their trajectory, their sequence as well as the requirements for finishing and
root passes, and buttering. The characteristics of external clamping devices, interpass and pre and post
temperatures requirements;
— applied mechanical restraint;
— basic materials data from test certificates (or specifications);
— plant survey data characterising the constructed weldment geometry and dimensions (actual dimensions,
distortion effects, root penetration, presence of cap etc.);

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ISO/DIS 18166:2025(en)
— an etched macrograph showing a cross section of the weldment normal to the welding direction which
may be used to define the local geometry, number of weld passes, weld pass sequence and possibly the
weld heat input, hardness, metallography;
— construction records – photographs, weld dressing, inspection certificates (radiographs, etc.), repairs,
PWHT conditions, proof test conditions.
If any of this information is not available, the user may use data from a similar WPS or obtained from expert
advice, that shall be justified.
8 Formulation of the problem and establishing the simulation strategy
This Clause gives the user a method regarding the quantities of interest, to select the predominant physical
phenomena, identifying the levels of uncertainty, and deducing the appropriate assumptions and modelling
strategies.
The selection of physical phenomena results from a whole process, which depends on the problem and the
objectives of calculation, and that shall be justified by the user.
By identifying the physical phenomena, prioritizing them, specifying the state of knowledge, the available
data, the uncertainties, the maturity of the models and codes, the user should find the appropriate
assumptions and modelling strategies. To do this, the following questions should be answered:
— What is the objective of the welding simulation?
— How the results will be used and what level of conservatism and confidence is required?
— What are the quantities of interest?
— What are the physical phenomena involved? Are they separable?
— What are their effects on the quantities of interest?
— Are tests to observe them available? What kind of tests, with separable or integral variables?
— Is the method to model them known? What is the state of the computational codes?
— How does the model capabilities of modelling and lack of knowledge, impact the capacity to simulate the
dominant physical phenomena?
— Do the materials exhibit phase transformations? Have they been heat treated before welding? Are viscous
phenomena to be taken into account? How precisely should the process be modelled?
— What are the time and space scales, what physical phenomena are steady-state, transient, spatial 2D, 3D,
axisymmetric, and what are the appropriate modelling details?
[15] [16] [17]
To answer these questions, users should use Table 2 and Table 3 (source , , :) below with the help of
other experts in the same field. A three-level scale is used to rank:
— the effects of phenomena, model parameters on quantities of interest;
— the level of knowledge regarding the availability of data and models.

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Table 2 — Impact level of physical phenomena on quantities of interest
Rank Weight Definition – Effect Implication
The phenomenon has a significant or The phenomenon should be explicitly considered
High (H) 1 dominant impact on any of the evalua- in experimental programs and modelled with
tion criteria. high accuracy in computational tools.
The phenomenon has only a moderate Experimental studies and modelling are required,
Medium (M) 0,5
impact on the evaluation criteria. but the scope and accuracy may be compromised.
The phenomenon should be exhibited experi-
The phenomenon has small or no impact
Low (L) 0 mentally and considered in computational tools.
on the evaluation criteria.
However, almost any model is sufficient.
Table 3 — Level of knowledge regarding availability of data and models
Rank Weight Availability of data Availability of models
The phenomenon is well understood.
Data obtained for the welding configu- Models that are validated for application to weld-
Adequate (A) 1
ration are available in sufficient range, ing configuration are available.
quantity and quality.
The phenomenon is understood. Data
obtained for the welding configuration The phenomenon can be can only be modelled
are available, but not in sufficient range, with moderate uncertainty or approximately
Some (S) 0,5 quantity or quality. Alternatively, data modelled, e.g. by lower order models or models
pertinent to other conditions exist and for similar phenomena that can be extrapolated to
can be extrapolated to the welding con- the welding configuration.
figuration.
No validated models exist. Modelling the phenom-
The phenomenon is not well understood.
None (N) 0 enon is currently either not possible or is possible
No relevant data exist,
only with large uncertainty.
The user, with the help of other experts regarding the quantities of interest of the welding configuration,
identifies the physical phenomena, and ranks them in terms of impact on the evaluation criteria on QI. The
user identifies the model and data, and ranks them in terms of availability and level of knowledge. Based
on the importance ranking and knowledge level, the user determines the phenomena that need further
consideration and the simulation strategy.
As shown in Figure 1, a graphical representation (IL (Importance Level) vs KL (Knowledge Level)) is useful.

oSIST prEN ISO 18166:2025
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Figure 1 — Graphical representation (IL (Importance Level) vs KL (Knowledge Level))
For example, for phenomena with high impact on the QI but with no relevant data or model, the user should
then supplement the data to reduce uncertainties or modify his model by ensuring a conservative approach.
Another example, the heat source power per unit volume distribution modelling has a high importance level
on residual stresses, and an adequate level of knowledge of mechanical behavior as a function of temperature
is required to achieve best-estimate simulations (see Annex C).
9 Establishment of the input parameters
9.1 Input data
From the data of the physical problem to be simulated, in particular the configuration and the simulation
strategy, the user establishes the material data to be considered (thermo-physical, thermo-mechanical, and
thermo-metallurgical material properties across the temperatures of interest), the parameters of the model
and the solver, the applicable boundary conditions, the geometrical modelling and the simulation domain.
9.2 Simulation template
The user should link the input data in a preparation frame for the simulation data. The user should
summarise the objective of the simulation (by specifying the quantities of interest), the hypotheses and
choices of modelling and simulation, the verifications and validations carried out and the results obtained.
The user may use the form given as example in Annex B.
In addition, the user can make full or partial use of a subroutine automating preprocessing operations in the SCT
such as data setting from the template in Annex B, thus limiting user related copying and interpretation errors.

oSIST prEN ISO 18166:2025
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10 Geometry and mesh
10.1 Geometry and meshing of welded joint
The user shall represent the geometry of the weld and the size of the passes.
The user should use a three-dimensional (3D) geometric model. However, depending on the configuration, the
user may assume a two-dimensional (2D) plane strain state perpendicular to the weld or 2D axisymmetric
modelling. The user should then justify these assumptions and assess the related uncertainties and the
impact on the quantities of interest.
10.2 Mesh size
The weld and adjacent HAZ regions require a sufficient degree of mesh refinement to model the gradients of
temperature that occur during welding and to resolve the evolution of residual stresses.
Outside of the weld and HAZ region it is prudent to coarsen the mesh in order to contain the model size,
while ensuring the mesh is sufficiently refined in the areas of structural concern, which may not necessarily
be local to the weld.
The user may perform preliminary mesh refinement studies to optimise the analysis requirements. Spatial
discretization shall be considered with the evolution of physical phenomena and QI over time and space.
10.3 Type of elements
First order finite elements should be used for thermal simulation. In thermomechanical simulation, finite
elements suitable for materials with elastoplastic behavior according to the Von-Mises criterion shall be
used. For example, the user may use sub-integrated second order elements or selectively integrated first
order elements.
The mesh for thermomechanical simulation may be a different mesh than one used for thermal simulation.
The temperature fields of the thermal simulation are then transferred to the mesh for thermomechanical
simulation. The transfer method shall ensure the integrity of transferred field and the user should perform
sensitivity analyses to evaluate the impact on the quantities of interest. Similarly, the user may choose a
thermal simulation mesh different from the one used during heat source fitting such as described in
Annex C. The user should then ensure that changing size of the mesh does not significantly affect the thermal
predictions or the power transmitted to the weldment.
10.4 Modelling of the filler material
A method of activating and deactivating the bead elements should be used to simulate the weld material
deposition. Deactivation may be realized by reducing the Young's modulus value by three orders of
magnitude from its ambient temperature value, or by choosing a Young's modulus value that is close to
its melting temperature value. Activation may be accomplished by assigning the elements their original
properties and behavior. As passes are added, the beads of which the elements have been deactivated
are sequentially added back to the model. The user may use activation/deactivation with both imposed
temperature or imposed heat flux.
In addition, the user should:
— ensure that the volume of the deposited material is consistent with a macrograph of the weldment cross-
section;
— activate elements when they’re bellow the solidus temperature;
— assign properties to non-activated elements that do not significantly impact the heat transfer and
mechanical rigidity of the structure.

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11 Performing the simulation
11.1 Code verification
Verification is a formalized process to determine if equations are resolved correctly. The user should carry
out verification test(s) and should not entirely rely on the verifications carried out by the SCT supplier but on
global or elementary tests (are in terms of size of the problem or the number of physical phenomena):
— results from other SCTs or previous version of the SCT;
— results from analytical solution;
— results from manufactured solution.
During verification, the user should also pay attention to the following:
— the conformance of the modelling with the physical problem, operating parameters (geometry, position,
welding axis, sequence of material passes, etc.), with the boundary conditions (clamping, interpass
temperature) and loads;
— a correct and adapted numerical resolution regarding convergence in mesh and time;
— verification of material behaviour using a single element model;
— the control of local or global results consistent with forces and moments equilibrium conditions.
The framework shown in Annex B provides a template file that summarises the CWM input data making it
possible for the user to ensure that all necessary data are available and that the validity of these data has
been verified before starting any simulation. A good practice is that any item contributing to the verification
should be recorded in a verification folder. The template in Annex B provides a means of recording, the
analysis of the problem, the modelling choices and the mesh. The user should check the conformity of the
modelling, the boundary conditions and loadings with the operating configuration, and the simulation
strategy listed in the simulation template.
For boundary conditions and loadings, the user shall check that:
— the interpass temperature, pre and post heating protocols are correctly simulated;
— the mechanical clamping, heat source, convection and radiation models are applied to the right areas.
The user should ensure that the choices of time step and spatial discretization for the mesh, are consistent
with the evolution of the physical phenomena and the quantities of interest.
Testing of the numerical model should also be performed, with a coarser mesh, time steps variations, change
of convergence criteria or lower loadings. The user should also check the appropriate application of the heat
source (power transmitted to the weldment and the trajectory) and the realistic phase fraction evolution
during simulation.
Secondly, the user should plot the evolution of the parameters of the material laws as a function of
temperature and phases and compare them on the same chart with similar data from literature or previous
analyses.
The user should control the correct numerical implementation of models, especially the thermomechanical
behavior. The user should simulate four thermal cycles, one at the center of the pass, one at its border
(L/2), one at a distance L and the last at 3L/2 (where L is the width of the pass). Then, after extraction
and verification of the temperature cycles are realistic, the user should simulate a blocked dilatometry test
[13]
(Satoh test ) using each thermal cycle as thermal loading. The user should determine the consistency of
the transient stresses over the thermal cycle and the sensitivity of the results to the time step resolution.

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11.2 Thermal and metallurgical computations
11.2.1 General
The spatial and temporal evolution of the temperature in the part and the distribution of metallurgical
phases precede the stress calculations.
11.2.2 Focus on metallurgical transformations
In case that metallurgical solid-state transformations (phase or precipitation) impact the thermophysical
properties, the user shall choose one of the following calculation schemes:
— simulate phase transformations after thermal simulation, that is to say post-processing;
— or during thermal simulation iterations, introduce weak or strong coupling.
In the latter case, the user shall take into account the evolution of the thermophysical properties as a
function of the metallurgical state (i.e. the nature of the formed phases or the precipitation state). In this
case the heat source should be fitted with the same calculation scheme (iterations and mesh), otherwise an
evaluation of the impact on the quantities of interest should be done.
11.2.3 Modelling of heat source
The power transmitted to the part should be modelled with a spatio-temporal distribution called a heat
source. This modelling requires a calibration of the heat source parameters which should be done with
measurements on a validation case representative of the operating conditions. If experimental data are not
available, the user may rely on representative process data (such as Welding Procedure Qualification Record
(WPQR)). Through sensitivity analyses on heat source parameters, the user evaluates the impact of the lack
of experimental data on the quantities of interest. The user shall ensure:
— that the heat-source accurately represents the power transmitted to the weldment by the process,
according to the experimental data available;
— the constancy of power through all iterations of the thermal simulation, even if the mesh is modified
during the calculation scheme. To do so, the user may apply a correction factor to respect the power
transmitted to the part at each iteration.
The user may use the calibration methodology for power density heat source described in Annex C. An
alternative to the moving heat source approach for simulating heat input is to apply a thermal cycle using
a prescribed temperature to the domain subject to heat input. This approach also require recalibration to
determine the duration of application of the cycle and the area of application, based on experimental data or
simulations, while respecting the energy balance: the energy transmitted to the part can’t be greater than
the energy supplied by the welding process.
11.2.4 Boundary and initial thermal conditions
The user shall model the initial thermal and boundary conditions of the welding operations. These concern
the room temperature, the interpass temperature, convective exchanges with the outside, as well as
radiative transfers.
11.3 Thermomechanical computation for residual stresses prediction
11.3.1 General
After the thermal or thermometallurgical simulation, the thermomechani
...