METHOD AND APPARATUS FOR PROVIDING A SIMULATION OF A WELDING PROCESS USING INTEGRATED MODELS

PROCEDE ET APPAREIL DE SIMULATION D'UN PROCESSUS DE SOUDAGE AU MOYEN DE MODELES INTEGRES

English Abstract

A method and apparatus for providing a simulation of a welding process using
integrated models (100) which are interconnected by an interconnection tool
(114) to determine stresses and distortions of a material being welded. The
method and apparatus includes determining a model of a geometry of a set of
materials to be welded, defining a set of coordinates of elements and nodes of
the geometry model (102) for a finite element analysis mesh, delivering the
finite element analysis mesh coordinates to a thermal analysis model (106),
the thermal analysis model (106) including an analytical solution model (108)
and a finite element analysis model (110), and determining a thermal analysis
of the welding process, the thermal analysis responsively providing a thermal
history of the welding process. The method and apparatus further includes
delivering the thermal history of the welding process to a structural analysis
model (112), and providing a structural analysis of the welding process as a
function of the thermal history.

French Abstract

L'invention concerne un procédé et un appareil de simulation d'un processus de soudage au moyen de modèles intégrés (100) interconnectés par un outil (114) d'interconnexion afin de déterminer les contraintes et les déformations d'une matière soumise à un processus de soudage. Le procédé et l'utilisation de l'appareil consistent à définir un modèle géométrique d'un ensemble de matières à souder, à définir un ensemble de coordonnées d'éléments et de noeuds du modèle géométrique (102) pour une maille d'analyse par éléments finis, à délivrer les coordonnées de la maille d'analyse par éléments finis à un modèle (106) d'analyse thermique, le modèle (106) d'analyse thermique comprenant un modèle (108) de solution analytique et un modèle (110) d'analyse par éléments finis, et à déterminer une analyse thermique du processus de soudage, l'analyse thermique générant en réponse un historique thermique du procédé de soudage. Le procédé et l'utilisation de l'appareil consistent également à délivrer l'historique thermique du processus de soudage à un modèle (110) d'analyse structurelle, et à générer une analyse structurelle du processus de soudage en fonction de l'historique thermique.

Claims

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Claims
1. A method for providing a simulation of
a welding process using integrated models (100), the
integrated models (100) being interconnected by an
interconnection tool (114) to determine stresses and
distortions of a material being welded, including the
steps of:
determining a model of a geometry of the
material;
defining a set of coordinates of elements
and nodes of the geometry model (102) for a finite
element analysis mesh;
delivering the finite element analysis mesh
coordinates to a thermal analysis model (106), the
thermal analysis model (100) including an analytical
solution model (108) and a finite element analysis
model (110);
determining a thermal analysis of the
welding process as a function of at least one of the
analytical solution model (108) and the finite element
analysis model (110), the analytical solution model
(108) being adapted to provide a thermal history of
the welding process for a global distortion analysis,
and the finite element analysis model (110) being
adapted to provide a thermal history of the welding
process for a detailed residual stress analysis;
delivering the thermal history of the
welding process to a structural analysis model (112);
and

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providing a structural analysis of the
welding process as a function of the thermal history.
2. A method, as set forth in claim 1,
wherein providing a thermal history of the welding
process for a detailed residual stress analysis
includes the step of providing a thermal history of
the welding process for a specific portion of the
welding process.
3. A method, as set forth in claim 1,
wherein providing a structural analysis of the welding
process includes the step of modeling a set of
characteristics of the materials being welded during
the welding process.
4. A method, as set forth in claim 3,
wherein characteristics of the materials include
residual stresses and distortions.
5. A method, as set forth in claim 1,
wherein determining a thermal analysis of the welding
process as a function of the analytical solution model
(108) includes the steps of:
determining a set of adiabatic boundary
conditions of the material being welded;
determining a set of reflected heat sources
as a function of the adiabatic boundary conditions;
determining a set of point heat sources as a
function of the reflected heat sources; and

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determining a total analytical solution from
superposition of the point heat sources.
6. A method, as set forth in claim 1,
wherein determining a thermal analysis of the welding
process as a function of the finite element analysis
model (110) includes the step of determining a set of
numerical computations of conditions at each desired
node and element coordinate of the finite element
analysis mesh.
7. A method, as set forth in claim 1,
wherein delivering the thermal history of the welding
process to a structural analysis model (112) includes
the step of delivering the thermal history by way of
an interface module (116).
8. An apparatus for providing a simulation
of a welding process using integrated models (100),
the integrated models (100) being interconnected by an
interconnection tool (114) to determine stresses and
distortions of a material being welded, comprising:
a geometry modeler (102) adapted to
determine a model of a geometry of the material;
a meshing tool (104) adapted to define a set
of coordinates of elements and nodes of the geometry
model (102) for a finite element analysis mesh;
a thermal analysis model (106) adapted to
receive the finite element analysis mesh, determine a
thermal analysis of the welding process, and

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responsively provide a thermal history of the welding
process, wherein the thermal analysis model (106)
includes:
an analytical solution model (108) adapted
to provide a thermal history of the welding process
for a global distortion analysis; and
a finite element analysis model (110)
adapted to provide a thermal history of the welding
process for a detailed residual stress analysis; and
a structural analysis model (112) adapted to
provide a structural analysis of the welding process
as a function of the thermal history.
9. An apparatus, as set forth in claim 8,
wherein the interconnection tool (114) is a graphical
user interface.

Description

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Description
METHOD AND APPARATUS FOR PROVIDING A SIMULATION OF A
WELDING PROCESS USING INTEGRATED MODELS
Technical Field
This invention relates generally to a method
and apparatus for modeling a welding process and, more
particularly, to a method and apparatus for
integrating models for a welding process to perform a
thermal and structural analysis of the process.
Background Art
The process of welding materials has some
amount of detrimental effect on the materials being
welded. For example, materials being welded are
subjected to residual stresses and distortions due to
the extreme heat caused by the weld process.
In the past, attempts have been made to
analyze and determine the effects of heat on materials
from the welding process. One method in particular,
the finite element method (FEM), uses finite element
analysis to model the weld process, and has been
widely used to analyze the thermal effects of welding.
However, FEM can be extremely cumbersome to implement
and very costly.
Another method used to determine the effects
of heat on materials from the welding process
incorporates an analytical solution to determine the
thermal history of the welding process. For example,

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analytical solutions have been developed which use the
superposition of point heat source solutions. These
methods generally do not require the extremely
cumbersome finite element analysis techniques
previously used, and therefore provide a much more
rapid analytical solution procedure. However,
analytical methods do not account for such features as
weld joint geometry. Furthermore, it may be desired
to use both types of thermal models for some
applications. For example, an analytical based model
may be used for providing rapid, global solutions, and
the FEM may be used to provide accurate temperature
models for local areas of concern.
The present invention is directed to
overcoming one or more of the problems as set forth
above.
Disclosure of the Invention
In one aspect of the present invention a
method for providing a simulation of a welding process
using integrated models is disclosed. The method
includes the steps of determining a model of a
geometry of a set of materials to be welded, defining
a set of coordinates of elements and nodes of the
geometry model for a finite element analysis mesh,
delivering the finite element analysis mesh
coordinates to a thermal analysis model, the thermal
analysis model including an analytical solution model
and a finite element analysis model, and determining a
thermal analysis of the welding process, the thermal

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analysis responsively providing a thermal history of
the welding process. The method further includes the
steps of delivering the thermal history of the welding
process to a structural analysis model, and providing
a structural analysis of the welding process as a
function of the thermal history.
Brief Description of the Drawings
Fig. 1 is a block diagram illustrating a
preferred embodiment of the present invention; and
Fig. 2 is a flow diagram illustrating a
preferred method of the present invention.
Best Mode for Carrying Out the Invention
Referring to Fig. 1, a block diagram
illustrating a preferred embodiment of a set of
integrated models 100 for performing a simulation
analysis of a welding process is shown. The
integrated models 100 work together to determine
stresses and distortions of a material which is welded
in the welding process. The stresses and distortions
have an adverse effect on the strengths and
characteristics of the material. Therefore, it is
desired to model the stresses and distortions, and use
the information from the models to determine methods
which may minimize the adverse effects of welding.
In the preferred embodiment, an
interconnection tool 114, such as a graphical user
interface (GUI), interconnects the models into an
integrated network of working models to determine

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stresses and distortions of the material. The
interconnection tool 114 is preferably computer-based
and may be configured to operate autonomously, through
manual intervention, or some combination of the two
modes. For example, the interconnection tool 114 may
coordinate the modeling functions while displaying the
status and results to a human, who may override the
system or input additional information at any desired
time.
A geometry modeler 102 determines the
geometry model for the materials to be welded.
Preferably, the geometry modeler 102 simplifies the
geometry by removing unnecessary features of the
materials from the model. Examples of such features
include, but are not limited to, chamfers, holes,
slight irregularities, and the like.
The geometry model data is then delivered to
a meshing tool 104. The meshing tool 104 is used to
generate a finite element analysis mesh, preferably by
defining coordinates for elements and nodes which
constitute the mesh. Finite element analysis
techniques which use mesh coordinates are well known
in the art and will not be described further.
A thermal analysis model 106 is used to
perform a thermal analysis of the materials during the
welding process. In the preferred embodiment, the
thermal analysis model 106 includes at least two
models: An analytical solution model 108 provides a
rapid analytical solution of the thermal process,
i.e., welding process, for a global solution of

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distortions caused by the welding process. A finite
element analysis model 110 provides local detailed
analysis of residual stress from the welding process.
In the preferred embodiment, the analytical
solution model 108 determines solutions of point heat
sources, the point heat sources being obtained from
heat input based on welding processes and reflected
heat sources determined from adiabatic boundary
conditions of the material. The total analytical
solution is determined from superposition of all the
point heat sources. The principle of obtaining
reflected heat sources from adiabatic boundary
conditions is well known in the art and will not be
discussed further. The analytical solution model 108
provides a rapid solution for the complete welding
process. However, the solution is not highly
detailed. Therefore, the analytical solution model
108 is typically used when a fast, global solution is
desired, and a high degree of detail is not needed.
The finite element analysis model 110
employs numerical computations of conditions at each
of the desired node and element coordinates of the
finite element analysis mesh. The finite element
analysis model tends to be computationally lengthy and
intensive. Therefore, the finite element analysis
model 110 is generally used only when a detailed
analysis of a specific portion of the model is
desired.
The information from the thermal analysis
model 106 is compiled into a thermal history and

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delivered to a structural analysis model 112. In
addition, the finite element mesh provided by the
meshing tool 104 is delivered to the structural
analysis model 112. The interconnection is
automatically established in the interconnection tool
114. In the preferred embodiment, the thermal history
is delivered from the thermal analysis model 106 to
the structural analysis model 112 by way of an
interface module 116. Preferably, the interface
module 116 is automated from the interconnection tool
114 and is adapted to seamlessly connect the thermal
solution from the analytical solution model 108, the
finite element analysis model 110, or both, to the
structural analysis model 112.
The structural analysis model 112 provides
further analysis of the materials during the welding
process. Typically, the behavior of the material
during welding is analyzed and modeled. Examples of
features analyzed include, but are not limited to,
melting and remelting of the material, phase
transformation of the material, cyclic effects of
multiple weld passes, and the like. The stresses and
distortions of the material are determined by the
structural analysis model. Preferably, the determined
stresses and distortions may be further analyzed and
subsequently used to modify the welding process to
reduce the adverse effects of the extreme heat
associated with welding.

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Industrial Applicabilit
As an example of an application of the
present invention, reference is made to Fig. 2, a flow
diagram illustrating a preferred method of the present
invention.
In a first control block 202, a model of the
geometry of a set of materials to be welded is
determined. In a second control block 204, a set of
coordinates of elements and nodes of the geometry
model is defined for a finite element analysis mesh.
In a third control block 206, the finite element
analysis mesh coordinates are delivered to a thermal
analysis model 106. In the preferred embodiment, the
thermal analysis model 106 includes an analytical
solution model 108 and a finite element analysis model
110.
In a fourth control block 208, a thermal
analysis of the welding process is determined as a
function of at least one of the analytical solution
model 108 and the finite element analysis model 110.
The thermal analysis preferably provides a thermal
history of the welding process. In a fifth control
block 210, the thermal history of the welding process
is delivered to a structural analysis model 112. In a
sixth control block 212, a structural analysis of the
welding process as a function of the thermal history
is provided. Preferably, the structural analysis
includes information related to stresses and
distortions caused by the welding process. This
information may be used to develop methods and

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techniques to modify the welding process to minimize
the stresses and distortions produced during
subsequent welds.
Other aspects, objects, and features of the
present invention can be obtained from a study of the
drawings, the disclosure, and the appended claims.

Representative Drawing