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Publications (10 of 153) Show all publications
Dittes, N., Sjödahl, M., Pettersson, A. & Lang, D. (2019). Automated Dielectric Thermoscopy Characterization of Water Contaminated Grease. Tribology Transactions, 62(5), 859-867
Open this publication in new window or tab >>Automated Dielectric Thermoscopy Characterization of Water Contaminated Grease
2019 (English)In: Tribology Transactions, ISSN 1040-2004, E-ISSN 1547-397X, Vol. 62, no 5, p. 859-867Article in journal (Refereed) Published
Abstract [en]

Machine maintenance is important for improving machine uptime, reliability, and reducing costs. Grease is used in most rolling element bearings, and one common failure criterion is water contamination, so developing a sensor which can detect water content automatically without human input could be a useful endeavor. The temperature dependence on the dielectric properties of water-contaminated grease is investigated in this paper with computer logged instrumentation. This method has been termed Dielectric Thermoscopy (DT). Several off the shelf (two lithium, one lithium complex, and two calcium sulphonate complex) and one unadditivized lithium grease are tested with varying amounts of water contamination from 0% to approximately 5%. Another grease is tested with small increments of added water from 0% to 0.97% to test the resolution of the measurement. The purpose is to use the capacitance temperature slope (termed dielectric thermoscopy) to show correlations to the water content of the grease sample and investigate if any grease types will pose problems in the measurement. A small, custom made fringe field capacitance sensor with an integrated temperature sensor has been used for this characterization and data is logged automatically with laboratory equipment and a PC. A useable and positive correlation to water content and the DT measurement of roughly 0.5 pF per 10 °C and percentage of water is found, although it was found that some greases have different behavior than others.

Place, publisher, year, edition, pages
Taylor & Francis, 2019
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear) Applied Mechanics
Research subject
Machine Elements; Experimental Mechanics
Identifiers
urn:nbn:se:ltu:diva-75141 (URN)10.1080/10402004.2019.1629051 (DOI)
Note

Validerad;2019;Nivå 2;2019-08-22 (johcin)

Available from: 2019-06-28 Created: 2019-06-28 Last updated: 2019-08-22Bibliographically approved
Sjödahl, M. (2019). Gradient Correlation Functions in Digital Image Correlation. Applied Sciences, 9(10), Article ID 2127.
Open this publication in new window or tab >>Gradient Correlation Functions in Digital Image Correlation
2019 (English)In: Applied Sciences, E-ISSN 2076-3417, Vol. 9, no 10, article id 2127Article in journal (Refereed) Published
Abstract [en]

The performance of seven different correlation functions applied in Digital Image Correlation has been investigated using simulated and experimentally acquired laser speckle patterns. The correlation functions were constructed as combinations of the pure intensity correlation function, the gradient correlation function and the Hessian correlation function, respectively. It was found that the correlation function that was constructed as the product of all three pure correlation functions performed best for the small speckle sizes and large correlation values, respectively. The difference between the different functions disappeared as the speckle size increased and the correlation value dropped. On average, the random error of the combined correlation function was half that of the traditional intensity correlation function within the optimum region.

Place, publisher, year, edition, pages
MDPI, 2019
Keywords
image correlation, gradient correlation functions, laser speckles
National Category
Applied Mechanics
Research subject
Experimental Mechanics
Identifiers
urn:nbn:se:ltu:diva-75069 (URN)10.3390/app9102127 (DOI)000473748100162 ()2-s2.0-85066461522 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-06-27 (johcin)

Available from: 2019-06-27 Created: 2019-06-27 Last updated: 2019-08-16Bibliographically approved
Lindström, J., Lejon, E., Kyösti, P., Mecella, M., Heutelbeck, D., Hemmje, M., . . . Gunnarsson, B. (2019). Towards intelligent and sustainable production systems with a zero-defect manufacturing approach in an Industry4.0 context. In: Edited by Peter Butala, Edvard Govekar, Rok Vrabič (Ed.), Procedia CIRP, vol 81: . Paper presented at 52nd CIRP Conference on Manufacturing Systems (CMS), Ljubljana, Slovenia, June 12-14, 2019 (pp. 880-885). Elsevier, 81
Open this publication in new window or tab >>Towards intelligent and sustainable production systems with a zero-defect manufacturing approach in an Industry4.0 context
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2019 (English)In: Procedia CIRP, vol 81 / [ed] Edited by Peter Butala, Edvard Govekar, Rok Vrabič, Elsevier, 2019, Vol. 81, p. 880-885Conference paper, Published paper (Refereed)
Abstract [en]

The paper addresses intelligent and sustainable production achieved through combination and integration of online predictive maintenance, monitoring of process parameters and continuous quality control of both input materials and output from the process. This enables production systems, within both manufacturing and process industries, to move towards zero-defect manufacturing. Such a zero-defect manufacturing approach allows for earlier identification of problems or issues, which will or already negatively affect the output. The paper outlines the first part of the second cycle of an action research effort at Gestamp HardTech AB in Sweden, whose objective is to keep its position as a world-leading provider of press-hardened vehicle parts. In order to fully implement the zero-defect manufacturing approach, 4-6 action research cycles are expected to be needed in order to iteratively refine the approach. During the first cycle, various methods and solutions for some of the individual issues/problems have been conceptualized, realized and initially tested. The selected design criteria for the action research efforts were: simplicity, low cost, robustness, high-quality output and future-proofing. The result from the research in the second cycle so far is an action plan for the technical change and a set of challenges/problems which need additional investigation.

Place, publisher, year, edition, pages
Elsevier, 2019
Series
Procedia CIRP, vol 81, ISSN 2212-8271
Keywords
continuous quality controlI, Industry4.0, intelligent, online predictive maintenance, production, sustainable, zero-defect manufacturing
National Category
Engineering and Technology Information Systems, Social aspects Control Engineering Applied Mechanics
Research subject
Information systems; Experimental Mechanics; Control Engineering
Identifiers
urn:nbn:se:ltu:diva-75114 (URN)10.1016/j.procir.2019.03.218 (DOI)
Conference
52nd CIRP Conference on Manufacturing Systems (CMS), Ljubljana, Slovenia, June 12-14, 2019
Available from: 2019-06-28 Created: 2019-06-28 Last updated: 2019-07-08Bibliographically approved
Wahl, J., Gren, P., Bergström, P., Lindbäck, T., Magnusson, M., Domeij, K. & Sjödahl, M. (2018). Comparison between process simulation and deformation measured by defocused speckle photography. In: M. Kujawińska ; L. R. Jaroszewicz (Ed.), Speckle 2018: VII International Conference On Speckle Metrology. Paper presented at SPECKLE 2018: VII International Conference on Speckle Metrology, 9-12 September 2018, Janów Podlaski, Poland.. SPIE - International Society for Optical Engineering, 10834, Article ID 108341K.
Open this publication in new window or tab >>Comparison between process simulation and deformation measured by defocused speckle photography
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2018 (English)In: Speckle 2018: VII International Conference On Speckle Metrology / [ed] M. Kujawińska ; L. R. Jaroszewicz, SPIE - International Society for Optical Engineering, 2018, Vol. 10834, article id 108341KConference paper, Published paper (Refereed)
Abstract [en]

Defocused laser speckle photography is used as a tool to measure the heat responses in a titanium component during laser heating. The evolution of the response is compared with a set of preprocessed Finite Element Simulations of the corresponding process with the aim to verify the simulation model and to find the simulation settings that best resemble the experimental results. The titanium component consists of a 300 x 100 mm2 substrate of thickness 3.2 mm on which a 200 x 30 x 11 mm3 ridge is built up using the laser metal deposition by wire process. The component is heated on the top of the ridge by a 300 W laser for 10 s and the deformation of the subtrate is followed throughout the heating-cooling cycle. The simulated deformation gradient is shown to resemble the measured response, and the magnitude of the response indicates that about 70 % of the laser power transferres into heat in the metal.

Place, publisher, year, edition, pages
SPIE - International Society for Optical Engineering, 2018
Series
Proceedings of SPIE - the International Society for Optical Engineering, ISSN 0277-786X ; 10834
Keywords
Laser speckle, deformation, in-process measurement
National Category
Applied Mechanics Other Mechanical Engineering
Research subject
Experimental Mechanics; Computer Aided Design
Identifiers
urn:nbn:se:ltu:diva-71895 (URN)10.1117/12.2319384 (DOI)000455052600052 ()2-s2.0-85058383509 (Scopus ID)9781510622975 (ISBN)
Conference
SPECKLE 2018: VII International Conference on Speckle Metrology, 9-12 September 2018, Janów Podlaski, Poland.
Funder
VINNOVA
Available from: 2018-12-05 Created: 2018-12-05 Last updated: 2019-01-28Bibliographically approved
Amer, E., Gren, P., Ramser, K. & Sjödahl, M. (2018). Measurement of selective species concentration using spectroscopic holography. In: M. Kujawińska ; L. R. Jaroszewicz (Ed.), Speckle 2018: VII International Conference on Speckle Metrology. Paper presented at Speckle 2018: VII International Conference On Speckle Metrology 9-12 September 2018 Janów Podlaski, Poland. SPIE - International Society for Optical Engineering, 10834, Article ID 108340P.
Open this publication in new window or tab >>Measurement of selective species concentration using spectroscopic holography
2018 (English)In: Speckle 2018: VII International Conference on Speckle Metrology / [ed] M. Kujawińska ; L. R. Jaroszewicz, SPIE - International Society for Optical Engineering, 2018, Vol. 10834, article id 108340PConference paper, Published paper (Refereed)
Abstract [en]

Spectroscopic holography refers to techniques in which the detected hologram contains information about specific species in the medium under study. In general, at least two lasers are required with wavelengths chosen carefully to fit the interaction process utilized. In this process, energy from the shorter wavelength laser beam is transferred to the longer wavelength coherently through the process of stimulated emission. Two interaction mechanisms are considered; Stimulated Laser Induced Fluorescence (LIF) and Stimulated Raman Scattering (SRS), which both are species specific with the ability of coherent interaction. In this paper, the fundamental properties of spectroscopic holography is presented and demonstrated with a few idealized experiments. These validation experiments are performed in a gas chamber in which different gases may be blended and the gas pressure changed between 1-12 bars. In addition, two examples of applications are presented. In the first set of experiments, LIF holography is used to image light absorption and laser heating in a dye simultaneously. The second set of experiments is performed in a ow of methane gas. It is demonstrated that the combination of holographic phase measurements and SRS gain images may be used for calibration. This calibration may further be used to measure absolute concentration in a burning flame.

Place, publisher, year, edition, pages
SPIE - International Society for Optical Engineering, 2018
Series
Proceedings of SPIE - the International Society for Optical Engineering, ISSN 0277-786X ; 10834
National Category
Applied Mechanics
Research subject
Experimental Mechanics
Identifiers
urn:nbn:se:ltu:diva-72430 (URN)10.1117/12.2319386 (DOI)000455052600021 ()2-s2.0-85058412906 (Scopus ID)9781510622975 (ISBN)
Conference
Speckle 2018: VII International Conference On Speckle Metrology 9-12 September 2018 Janów Podlaski, Poland
Available from: 2019-01-03 Created: 2019-01-03 Last updated: 2019-01-28Bibliographically approved
Dittes, N., Pettersson, A., Sjödahl, M., Casselgren, J., Marklund, P. & Lugt, P. M. (2018). Optical Attenuation Characterization of Water Contaminated Lubricating Grease. Tribology Transactions, 61(4), 726-732
Open this publication in new window or tab >>Optical Attenuation Characterization of Water Contaminated Lubricating Grease
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2018 (English)In: Tribology Transactions, ISSN 1040-2004, E-ISSN 1547-397X, Vol. 61, no 4, p. 726-732Article in journal (Refereed) Published
Abstract [en]

Water-contaminated grease samples are investigated with attenuation spectra in the visible and near-infrared (NIR) regions in this article. The purpose of this investigation was to identify a model with optical attenuation spectra such that the water content of grease samples could be characterized with a simple measurement setup using common methodology from the field of instrumental chemistry. The ratio between two chosen wavelengths of light appears to approximate the water content of grease samples with an acceptable coefficient of determination using a methodology to show what can potentially be done to develop condition monitoring tools. To illustrate the outlined method, a prestudy of grease aging and oxidation levels is also investigated to show that other variables do not significantly change the measurement.

Place, publisher, year, edition, pages
Taylor & Francis, 2018
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear) Applied Mechanics
Research subject
Machine Elements; Experimental Mechanics
Identifiers
urn:nbn:se:ltu:diva-67205 (URN)10.1080/10402004.2017.1404175 (DOI)000438157400015 ()2-s2.0-85044094152 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-08-09 (rokbeg)

Available from: 2018-01-09 Created: 2018-01-09 Last updated: 2018-12-14Bibliographically approved
Sjödahl, M. & Amer, E. (2018). Quantitative measurement of thin phase objects: comparison of speckle deflectometry and defocus-variant lateral shear interferometry. Applied Optics, 57(14), 3645-3652
Open this publication in new window or tab >>Quantitative measurement of thin phase objects: comparison of speckle deflectometry and defocus-variant lateral shear interferometry
2018 (English)In: Applied Optics, ISSN 1559-128X, E-ISSN 2155-3165, Vol. 57, no 14, p. 3645-3652Article in journal (Refereed) Published
Abstract [en]

The two techniques of lateral shear interferometry and speckle deflectometry are analyzed in a common optical system for their ability to measure phase gradient fields of a thin phase object. The optical system is designed to introduce a shear in the frequency domain of a telecentric imaging system that gives a sensitivity of both techniques in proportion to the defocus introduced. In this implementation, both techniques successfully measure the horizontal component of the phase gradient field. The response of both techniques scales linearly with the defocus distance, and the precision is comparative, with a random error in the order of a few rad/mm. It is further concluded that the precision of the two techniques relates to the transverse speckle size in opposite ways. While a large spatial coherence width, and correspondingly a large lateral speckle size, makes lateral shear interferometry less susceptible to defocus, a large lateral speckle size is detrimental for speckle correlation. The susceptibility for the magnitude of the defocus is larger for the lateral shear interferometry technique as compared to the speckle deflectometry technique. The two techniques provide the same type of information; however, there are a few fundamental differences. Lateral shear interferometry relies on a special hardware configuration in which the shear angle is intrinsically integrated into the system. The design of a system sensitive to both in-plane phase gradient components requires a more complex configuration and is not considered in this paper. Speckle deflectometry, on the other hand, requires no special hardware, and both components of the phase gradient field are given directly from the measured speckle deformation field.

Place, publisher, year, edition, pages
Optical Society of America, 2018
National Category
Fluid Mechanics and Acoustics
Research subject
Fluid Mechanics
Identifiers
urn:nbn:se:ltu:diva-68878 (URN)10.1364/AO.57.003645 (DOI)000431880000003 ()2-s2.0-85046971352 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-05-24 (andbra)

Available from: 2018-05-24 Created: 2018-05-24 Last updated: 2018-08-21Bibliographically approved
Bergström, P., Michael, F. & Sjödahl, M. (2018). Virtual projective shape matching in targetless CAD-based close-range photogrammetry for efficient estimation of specific deviations. Optical Engineering: The Journal of SPIE, 57(5), Article ID 053110.
Open this publication in new window or tab >>Virtual projective shape matching in targetless CAD-based close-range photogrammetry for efficient estimation of specific deviations
2018 (English)In: Optical Engineering: The Journal of SPIE, ISSN 0091-3286, E-ISSN 1560-2303, Vol. 57, no 5, article id 053110Article in journal (Refereed) Published
Abstract [en]

A concept for targetless, computer-aided design (CAD)-based, close-range photogrammetry for online shape inspection is introduced. The shape of an object, which is arbitrarily located on a conveyor belt, is to be measured and compared with its nominal shape as defined by a CAD model. For most manufactured objects, deviations are only measured at a few given comparison points. These deviations can be estimated using local photogrammetry based on a priori geometrical information given by the CAD model and the comparison points. Our method results in faster output with higher precision, because we do not generate a shape representation of the entire measured object using typical photogrammetric methods. Images depicting the object from convergent angles are captured by an array of cameras in a precalibrated network, and the CAD model is matched and aligned, within the projective geometry of the camera network, to the depicted object in the images without the use of targets. An algorithm for solving this virtual projective targetless shape matching problem is presented.

Place, publisher, year, edition, pages
SPIE - International Society for Optical Engineering, 2018
Keywords
computer-aided design, close-range, matching, online, photogrammetry, shape
National Category
Reliability and Maintenance Applied Mechanics
Research subject
Experimental Mechanics
Identifiers
urn:nbn:se:ltu:diva-68856 (URN)10.1117/1.OE.57.5.053110 (DOI)000435435300019 ()2-s2.0-85047752202 (Scopus ID)
Projects
SIVPRO
Note

Validerad;2018;Nivå 2;2018-05-28 (andbra)

Available from: 2018-05-22 Created: 2018-05-22 Last updated: 2018-12-14Bibliographically approved
Öhman, J. & Sjödahl, M. (2017). Axial Particle Positioning by Wavefront Parameterization using Chebyshev Polynomials and Off-axis Digital Holography. In: Digital Holography and Three-Dimensional Imaging: . Paper presented at Digital Holography and Three-Dimensional Imaging 2017, JeJu Island, South Korea, 29 May–1 June 2017. Washington: The Optical Society, Article ID M4A.3.
Open this publication in new window or tab >>Axial Particle Positioning by Wavefront Parameterization using Chebyshev Polynomials and Off-axis Digital Holography
2017 (English)In: Digital Holography and Three-Dimensional Imaging, Washington: The Optical Society , 2017, article id M4A.3Conference paper, Published paper (Refereed)
Abstract [en]

A particle can be axially positioned where its scattered light has a plane wavefront. The phase anomaly compared to a plane wave is fitted to 3D Chebyshev polynomial, where coefficients correspond to the axial position.

Place, publisher, year, edition, pages
Washington: The Optical Society, 2017
Series
Digital Holography and Three-Dimensional Imaging
Keywords
Particle Scattering, Digital Holography
National Category
Atom and Molecular Physics and Optics Applied Mechanics
Research subject
Experimental Mechanics
Identifiers
urn:nbn:se:ltu:diva-64069 (URN)10.1364/DH.2017.M4A.3 (DOI)2-s2.0-85026326255 (Scopus ID)978-1-943580-28-6 (ISBN)
Conference
Digital Holography and Three-Dimensional Imaging 2017, JeJu Island, South Korea, 29 May–1 June 2017
Funder
Swedish Research Council, 621-2014-4906
Available from: 2017-06-15 Created: 2017-06-15 Last updated: 2018-04-16Bibliographically approved
Eppanapelli, L. K., Casselgren, J., Wåhlin, J. & Sjödahl, M. (2017). Investigation of snow single scattering properties of snow based on first order Legendre phase function. Optics and lasers in engineering, 91, 151-159
Open this publication in new window or tab >>Investigation of snow single scattering properties of snow based on first order Legendre phase function
2017 (English)In: Optics and lasers in engineering, ISSN 0143-8166, E-ISSN 1873-0302, Vol. 91, p. 151-159Article in journal (Refereed) Published
Abstract [en]

Angularly resolved bidirectional reflectance measurements were modelled by ap- proximating a first order Legendre expanded phase function to retrieve single scattering properties of snow. The measurements from 10 different snow types with known density and specific surface area (SSA) were investigated. A near infrared (NIR) spectrometer was used to measure reflected light above the snow surface over the hemisphere in the wavelength region 900 nm to 1650 nm. A solver based on discrete ordinate radiative transfer (DISORT) model was used to retrieve the estimated Legendre coefficients of the phase function and a cor- relation between the coefficients and physical properties of different snow types is investigated. Results of this study suggest that the first two coefficients of the first order Legendre phase function provide sufficient information about the physical properties of snow where the latter captures the anisotropic behaviour of snow and the former provides a relative estimate of the single scattering albedo of snow. The coefficients of the first order phase function were com- pared with the experimental data and observed that both the coefficients are in good agreement with the experimental data. These findings suggest that our approach can be applied as a qualitative tool to investigate physical properties of snow and also to classify different snow types.

Place, publisher, year, edition, pages
Elsevier, 2017
Keywords
Radiative transfer model, Scattering phase function, Snow, SSA, Reflectance spectrum, NIR spectrometer
National Category
Applied Mechanics
Research subject
Experimental Mechanics
Identifiers
urn:nbn:se:ltu:diva-60532 (URN)10.1016/j.optlaseng.2016.11.013 (DOI)000393264300016 ()2-s2.0-84998694302 (Scopus ID)
Note

Validerad; 2017; Nivå 2; 2016-12-19 (andbra)

Available from: 2016-11-18 Created: 2016-11-18 Last updated: 2018-09-13Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-4879-8261

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