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Papers by Hakan Wirdelius

A European consortium consisting of four major steel manufacturers and ten academic technology in... more A European consortium consisting of four major steel manufacturers and ten academic technology institutes has conducted a research and development project, called “Product Uniformity Control“ (PUC) in the period 2013 to 2017. This project aimed to develop and improve non-destructive (inline) measurement techniques to characterise the (uniformity of the) microstructure of steel strip products. In this project, a multitude of strip steel samples from various stages of production have been collected from the four participating steel manufacturers. The samples have been characterised in various ways, namely on their (1) non-destructive measurement parameters using different techniques suited for inline evaluation, (2) fundamental ultrasonic and electromagnetic properties (wave speed, ultrasonic attenuation, magnetisation loops, coercive field), (3) tensile properties (stress-strain curves) and (4) microstructure (by optical micrographs and EBSD images). The correlations between these di...

To reduce costs of production and increase economic sustainability it is necessary to introduce q... more To reduce costs of production and increase economic sustainability it is necessary to introduce quality assessment in an early stage in the manufacturing process. In an ongoing European project (Product Uniformity Control – PUC), the intention is to use ultrasonic information to assess microstructure parameters that are related to macroscale qualities such as mechanical properties. Laser induced ultrasonic technique (LUS) requires no media and can generate and detect ultrasonic information at some distance from the component. This technique is therefore addressed within this project as a solution to measure ultrasonic properties in an industrial environment. Mathematical modelling of the ultrasonic wave propagation problem has been used in order to get a deeper understanding of the physics and to identify ultrasonic properties that can be used as an indirect measurement of grain size. The use of both analytical and numerical models enabled extensive parametric studies together with ...

Ultrasonics, 2020

New manufacturing technologies such as additive manufacturing facilitate flexible and complex des... more New manufacturing technologies such as additive manufacturing facilitate flexible and complex designs and production of components. However, these new techniques should not compromise the safety aspect, which imposes higher demands on the integrity insurance and inspection methods. Phased array ultrasonic testing (PAUT) provides advanced inspection and evaluation processes, whereas qualification is still needed when applied together with new manufacturing techniques. Numerical modeling, as one of the potential qualification methods, has been developed for decades and should be validated before practical applications. This paper presents an experimental validation work of the phased array probe model implemented in a software, simSUNDT, by comparing the maximum echo amplitudes between the physical experiments and simulations. Two test specimens with side-drilled holes (SDHs) and different materials are considered for validation and practical purposes. An experimental platform with a mechanized gantry system, which enables stabilized inspection procedure, is built and applied during the validation work. Good correlations can be seen from the comparisons and this model is concluded as an acceptable alternative to the corresponding experimental work. The relation between depth and beam angle is also noticed and investigated, which is essential to guarantee an accurate inspection.

MATEC Web of Conferences, 2014

Laser welding of thin titanium components, a critical component of many gas turbine engines, has ... more Laser welding of thin titanium components, a critical component of many gas turbine engines, has demonstrated a tendency of generating pores in clusters with a prescribed orientation. These pores, also known as chain porosities, are often of harmless sizes (of 50-100 micrometer) as individuals. Though the cluster as such, depending on the distances and orientations in between the pores, may have an impact on the structural integrity. A recently developed algorithm for 3-D positioning of small pore defects in planar geometries using digital X-ray inspection aims at providing 3-D positions of the defects. This could then be used in-line to assess the welding quality in the manufacturing process. This presentation describes the development of a methodology that aims to incorporate nondestructive evaluation with, in this case, structural integrity.

MATEC Web of Conferences, 2014

The initial step towards a non-destructive technique that estimates grain orientation in an aniso... more The initial step towards a non-destructive technique that estimates grain orientation in an anisotropic weld is presented in this paper. The purpose is to aid future forward simulations of ultrasonic NDT of this kind of weld to achieve a better result. A forward model that consists of a weld model, a transmitter model, a receiver model and a 2D ray tracing algorithm is introduced. An inversion based on a multi-objective genetic algorithm is also presented. Experiments are conducted for both P and SV waves in order to collect enough data used in the inversion. Calculation is conducted to fulfil the estimation with both the synthetic data and the experimental data. Concluding remarks are presented at the end of the paper.

Journal of Applied Physics, 2013

An integral equation method for solving the eddy-current nondestructive evaluation problem for a ... more An integral equation method for solving the eddy-current nondestructive evaluation problem for a flat, tilted, and surface-breaking crack in a conducting half-space is presented. The method involves use of a half-space Green's tensor and the Bowler potential. This potential describes the jump in the electric field over the crack and is expanded in basis functions related to the Chebyshev polynomials, being a more analytical approach than the commonly used boundary element method. In the method, the scatterer defines a transformation operator to be applied on the incoming field. This is practical in simulations of the eddy-current inspection where this operator is independent of the position of the probe. The numerical calculations of the change in impedance due to the crack are compared to a Finite Element model of the problem and good agreement is found. V

SKI Project Number 98267 This report concerns a study which has been conducted for the Swedish Nu... more SKI Project Number 98267 This report concerns a study which has been conducted for the Swedish Nuclear Power Inspectorate (SKI). The conclusions and viewpoints presented in the report are those of the authors and do not necessarily coincide with those of the SKI. This paper presents results from a literature review of defect characteristics essential for non-destructive testing (NDT). Most of the major NDT methods are included in the study- ultrasonic testing (UT), radiography (RT) and eddy current testing (ET). The study was performed by means of searching in scientific databases, technical journals, conference proceedings etc. Mainly, the following databases were used: CHANS

IOP Conference Series: Materials Science and Engineering

Ultrasonic nondestructive testing (NDT) is commonly used for in-service inspection in different a... more Ultrasonic nondestructive testing (NDT) is commonly used for in-service inspection in different areas. But reliability of NDT method is highly dependent on the equipment and crack features. Although, it is possible to use thoroughly validated mathematical models to avoid complicated and costly experimental work, when it is necessary to qualify new procedures. Finite Element Model (FEM) is a powerful tool, which is commonly used for such cases. In this paper three mathematical models of three well defined cases will be compared with each other.

This paper presents results from a literature review of defect characteristics essential for non-... more This paper presents results from a literature review of defect characteristics essential for non-destructive testing (NDT). Most of the major NDT methods are included in the study ultrasonic testing (UT), radiography (RT) and eddy current testing (ET). The study was performed by means of searching in scientific databases, technical journals, conference proceedings etc. Mainly, the following databases were used: CHANS (Chalmers database), INSPEC, NTIS, Ei Compendex, World Surface Coating Abs, METADEX, JICST-Eplus, Aerospace database, Pascal, Eng Materials, SciSearch and Weldasearch. It is concluded that for eddy current testing, the defect geometry, the defect size and the defect orientation influence the outcome signal. A number of investigations address the relationships between the defect parameters like defect depth, length and width and the outcome signal parameters like amplitude, phase and signal shape. Also the phenomena of the electrical contacts between the defect surfaces ...

AIP Conference Proceedings, 2010

The simSUNDT software is based on a previous developed program (SUNDT). The latest version has be... more The simSUNDT software is based on a previous developed program (SUNDT). The latest version has been customized in order to generate realistic synthetic data (including a grain noise model), compatible with a number of off-line analysis software. The software consists of a Windows®-based preprocessor and postprocessor together with a mathematical kernel (UTDefect), dealing with the actual mathematical modeling. The model employs various integral transforms and integral equation and enables simulations of the entire ultrasonic testing situation. The model is completely three-dimensional though the simulated component is two-dimensional, bounded by the scanning surface and a planar back surface as an option. It is of great importance that inspection methods that are applied are proper validated and that their capability of detection of cracks and defects are quantified. In order to achieve this, statistical methods such as Probability of Detection (POD) often are applied, with the ambition to estimate the detectability as a function of defect size. Despite the fact that the proposed procedure with the utilization of test pieces is very expensive, it also tends to introduce a number of possible misalignments between the actual NDT situation that is to be performed and the proposed experimental simulation. The presentation will describe the developed model that will enable simulation of a phased array NDT inspection and the ambition to use this simulation software to generate POD information. The paper also includes the most recent developments of the model including some initial experimental validation of the phased array probe model.

Annals of Nuclear Energy, 2015

ABSTRACT A new approach to provide a long-term safeguards identification of spent nuclear fuel co... more ABSTRACT A new approach to provide a long-term safeguards identification of spent nuclear fuel containers, in particular copper canisters, is presented in this paper. The approach proposes the use of a tungsten insert marked with a binary code and placed inside the container. The insert is read with a combination of two independent techniques, radiation and ultrasonic measurements, in order to get a unique identification of the cask. Passive and active versions of the tag are considered. The passive version makes use of the radiation coming from the spent nuclear fuel itself. The active version of the tag is based on the use of an artificially introduced mixture of α-emitting isotopes, such as 241Am with materials, 11B and 23Na, which easily undergo α-induced reactions with emission of specific γ-lines, 2313 keV and 1809 keV, respectively. The paper discusses results of the radiation and ultrasonic measurements and Monte-Carlo evaluations as the first proof of the concept. The results of the investigations show the strong potential for this concept to maintain the continuity of knowledge of spent nuclear fuel copper canisters for a time scale up to a few thousands years without compromising the environmental safety of the casks.

A European consortium consisting of four major steel manufacturers and ten academic technology in... more A European consortium consisting of four major steel manufacturers and ten academic technology institutes has conducted a research and development project, called “Product Uniformity Control“ (PUC) in the period 2013 to 2017. This project aimed to develop and improve non-destructive (inline) measurement techniques to characterise the (uniformity of the) microstructure of steel strip products. In this project, a multitude of strip steel samples from various stages of production have been collected from the four participating steel manufacturers. The samples have been characterised in various ways, namely on their (1) non-destructive measurement parameters using different techniques suited for inline evaluation, (2) fundamental ultrasonic and electromagnetic properties (wave speed, ultrasonic attenuation, magnetisation loops, coercive field), (3) tensile properties (stress-strain curves) and (4) microstructure (by optical micrographs and EBSD images). The correlations between these di...

To reduce costs of production and increase economic sustainability it is necessary to introduce q... more To reduce costs of production and increase economic sustainability it is necessary to introduce quality assessment in an early stage in the manufacturing process. In an ongoing European project (Product Uniformity Control – PUC), the intention is to use ultrasonic information to assess microstructure parameters that are related to macroscale qualities such as mechanical properties. Laser induced ultrasonic technique (LUS) requires no media and can generate and detect ultrasonic information at some distance from the component. This technique is therefore addressed within this project as a solution to measure ultrasonic properties in an industrial environment. Mathematical modelling of the ultrasonic wave propagation problem has been used in order to get a deeper understanding of the physics and to identify ultrasonic properties that can be used as an indirect measurement of grain size. The use of both analytical and numerical models enabled extensive parametric studies together with ...

Ultrasonics, 2020

New manufacturing technologies such as additive manufacturing facilitate flexible and complex des... more New manufacturing technologies such as additive manufacturing facilitate flexible and complex designs and production of components. However, these new techniques should not compromise the safety aspect, which imposes higher demands on the integrity insurance and inspection methods. Phased array ultrasonic testing (PAUT) provides advanced inspection and evaluation processes, whereas qualification is still needed when applied together with new manufacturing techniques. Numerical modeling, as one of the potential qualification methods, has been developed for decades and should be validated before practical applications. This paper presents an experimental validation work of the phased array probe model implemented in a software, simSUNDT, by comparing the maximum echo amplitudes between the physical experiments and simulations. Two test specimens with side-drilled holes (SDHs) and different materials are considered for validation and practical purposes. An experimental platform with a mechanized gantry system, which enables stabilized inspection procedure, is built and applied during the validation work. Good correlations can be seen from the comparisons and this model is concluded as an acceptable alternative to the corresponding experimental work. The relation between depth and beam angle is also noticed and investigated, which is essential to guarantee an accurate inspection.

MATEC Web of Conferences, 2014

Laser welding of thin titanium components, a critical component of many gas turbine engines, has ... more Laser welding of thin titanium components, a critical component of many gas turbine engines, has demonstrated a tendency of generating pores in clusters with a prescribed orientation. These pores, also known as chain porosities, are often of harmless sizes (of 50-100 micrometer) as individuals. Though the cluster as such, depending on the distances and orientations in between the pores, may have an impact on the structural integrity. A recently developed algorithm for 3-D positioning of small pore defects in planar geometries using digital X-ray inspection aims at providing 3-D positions of the defects. This could then be used in-line to assess the welding quality in the manufacturing process. This presentation describes the development of a methodology that aims to incorporate nondestructive evaluation with, in this case, structural integrity.

MATEC Web of Conferences, 2014

The initial step towards a non-destructive technique that estimates grain orientation in an aniso... more The initial step towards a non-destructive technique that estimates grain orientation in an anisotropic weld is presented in this paper. The purpose is to aid future forward simulations of ultrasonic NDT of this kind of weld to achieve a better result. A forward model that consists of a weld model, a transmitter model, a receiver model and a 2D ray tracing algorithm is introduced. An inversion based on a multi-objective genetic algorithm is also presented. Experiments are conducted for both P and SV waves in order to collect enough data used in the inversion. Calculation is conducted to fulfil the estimation with both the synthetic data and the experimental data. Concluding remarks are presented at the end of the paper.

Journal of Applied Physics, 2013

An integral equation method for solving the eddy-current nondestructive evaluation problem for a ... more An integral equation method for solving the eddy-current nondestructive evaluation problem for a flat, tilted, and surface-breaking crack in a conducting half-space is presented. The method involves use of a half-space Green's tensor and the Bowler potential. This potential describes the jump in the electric field over the crack and is expanded in basis functions related to the Chebyshev polynomials, being a more analytical approach than the commonly used boundary element method. In the method, the scatterer defines a transformation operator to be applied on the incoming field. This is practical in simulations of the eddy-current inspection where this operator is independent of the position of the probe. The numerical calculations of the change in impedance due to the crack are compared to a Finite Element model of the problem and good agreement is found. V

SKI Project Number 98267 This report concerns a study which has been conducted for the Swedish Nu... more SKI Project Number 98267 This report concerns a study which has been conducted for the Swedish Nuclear Power Inspectorate (SKI). The conclusions and viewpoints presented in the report are those of the authors and do not necessarily coincide with those of the SKI. This paper presents results from a literature review of defect characteristics essential for non-destructive testing (NDT). Most of the major NDT methods are included in the study- ultrasonic testing (UT), radiography (RT) and eddy current testing (ET). The study was performed by means of searching in scientific databases, technical journals, conference proceedings etc. Mainly, the following databases were used: CHANS

IOP Conference Series: Materials Science and Engineering

Ultrasonic nondestructive testing (NDT) is commonly used for in-service inspection in different a... more Ultrasonic nondestructive testing (NDT) is commonly used for in-service inspection in different areas. But reliability of NDT method is highly dependent on the equipment and crack features. Although, it is possible to use thoroughly validated mathematical models to avoid complicated and costly experimental work, when it is necessary to qualify new procedures. Finite Element Model (FEM) is a powerful tool, which is commonly used for such cases. In this paper three mathematical models of three well defined cases will be compared with each other.

This paper presents results from a literature review of defect characteristics essential for non-... more This paper presents results from a literature review of defect characteristics essential for non-destructive testing (NDT). Most of the major NDT methods are included in the study ultrasonic testing (UT), radiography (RT) and eddy current testing (ET). The study was performed by means of searching in scientific databases, technical journals, conference proceedings etc. Mainly, the following databases were used: CHANS (Chalmers database), INSPEC, NTIS, Ei Compendex, World Surface Coating Abs, METADEX, JICST-Eplus, Aerospace database, Pascal, Eng Materials, SciSearch and Weldasearch. It is concluded that for eddy current testing, the defect geometry, the defect size and the defect orientation influence the outcome signal. A number of investigations address the relationships between the defect parameters like defect depth, length and width and the outcome signal parameters like amplitude, phase and signal shape. Also the phenomena of the electrical contacts between the defect surfaces ...

AIP Conference Proceedings, 2010

The simSUNDT software is based on a previous developed program (SUNDT). The latest version has be... more The simSUNDT software is based on a previous developed program (SUNDT). The latest version has been customized in order to generate realistic synthetic data (including a grain noise model), compatible with a number of off-line analysis software. The software consists of a Windows®-based preprocessor and postprocessor together with a mathematical kernel (UTDefect), dealing with the actual mathematical modeling. The model employs various integral transforms and integral equation and enables simulations of the entire ultrasonic testing situation. The model is completely three-dimensional though the simulated component is two-dimensional, bounded by the scanning surface and a planar back surface as an option. It is of great importance that inspection methods that are applied are proper validated and that their capability of detection of cracks and defects are quantified. In order to achieve this, statistical methods such as Probability of Detection (POD) often are applied, with the ambition to estimate the detectability as a function of defect size. Despite the fact that the proposed procedure with the utilization of test pieces is very expensive, it also tends to introduce a number of possible misalignments between the actual NDT situation that is to be performed and the proposed experimental simulation. The presentation will describe the developed model that will enable simulation of a phased array NDT inspection and the ambition to use this simulation software to generate POD information. The paper also includes the most recent developments of the model including some initial experimental validation of the phased array probe model.

Annals of Nuclear Energy, 2015

ABSTRACT A new approach to provide a long-term safeguards identification of spent nuclear fuel co... more ABSTRACT A new approach to provide a long-term safeguards identification of spent nuclear fuel containers, in particular copper canisters, is presented in this paper. The approach proposes the use of a tungsten insert marked with a binary code and placed inside the container. The insert is read with a combination of two independent techniques, radiation and ultrasonic measurements, in order to get a unique identification of the cask. Passive and active versions of the tag are considered. The passive version makes use of the radiation coming from the spent nuclear fuel itself. The active version of the tag is based on the use of an artificially introduced mixture of α-emitting isotopes, such as 241Am with materials, 11B and 23Na, which easily undergo α-induced reactions with emission of specific γ-lines, 2313 keV and 1809 keV, respectively. The paper discusses results of the radiation and ultrasonic measurements and Monte-Carlo evaluations as the first proof of the concept. The results of the investigations show the strong potential for this concept to maintain the continuity of knowledge of spent nuclear fuel copper canisters for a time scale up to a few thousands years without compromising the environmental safety of the casks.