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Bahaloohoreh, HassanORCID iD iconorcid.org/0000-0001-6231-8944
Alternative names
Publications (10 of 17) Show all publications
Bahaloo, H., Gren, P., Casselgren, J., Forsberg, F. & Sjödahl, M. (2024). Capillary Bridge in Contact with Ice Particles Can Be Related to the Thin Liquid Film on Ice. Journal of cold regions engineering, 38(1), Article ID 04023021.
Open this publication in new window or tab >>Capillary Bridge in Contact with Ice Particles Can Be Related to the Thin Liquid Film on Ice
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2024 (English)In: Journal of cold regions engineering, ISSN 0887-381X, E-ISSN 1943-5495, Vol. 38, no 1, article id 04023021Article in journal (Refereed) Published
Abstract [en]

We experimentally demonstrate the presence of a capillary bridge in the contact between an ice particle and a smooth aluminum surface at a relative humidity of approximately 50% and temperatures below the melting point. We conduct the experiments in a freezer with a controlled temperature and consider the mechanical instability of the bridge upon separation of the ice particle from the aluminum surface at a constant speed. We observe that a liquid bridge forms, and this formation becomes more pronounced as the temperature approaches the melting point. We also show that the separation distance is proportional to the cube root of the volume of the bridge. We hypothesize that the volume of the liquid bridge can be used to provide a rough estimate of the thickness of the liquid layer on the ice particle since in the absence of other driving mechanisms, some of the liquid on the surface must have been pulled to the bridge area. We show that the estimated value lies within the range previously reported in the literature. With these assumptions, the estimated thickness of the liquid layer decreases from nearly 56 nm at T = −1.7°C to 0.2 nm at T = −12.7°C. The dependence can be approximated with a power law, proportional to (TM − T)−β, where β < 2.6 and TM is the melting temperature. We further observe that for a rough surface, the capillary bridge formation in the considered experimental conditions vanishes.

Place, publisher, year, edition, pages
American Society of Civil Engineers (ASCE), 2024
National Category
Infrastructure Engineering
Research subject
Experimental Mechanics
Identifiers
urn:nbn:se:ltu:diva-102441 (URN)10.1061/JCRGEI.CRENG-738 (DOI)001143507100005 ()2-s2.0-85175442634 (Scopus ID)
Note

Validerad;2023;Nivå 2;2023-11-15 (sofila);

Full text license: CC BY

Available from: 2023-11-13 Created: 2023-11-13 Last updated: 2024-05-06Bibliographically approved
Bahaloo, H., Forsberg, F., Casselgren, J., Lycksam, H. & Sjödahl, M. (2024). Mapping of density-dependent material properties of dry manufactured snow using μCT. Applied Physics A: Materials Science & Processing, 130, Article ID 16.
Open this publication in new window or tab >>Mapping of density-dependent material properties of dry manufactured snow using μCT
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2024 (English)In: Applied Physics A: Materials Science & Processing, ISSN 0947-8396, E-ISSN 1432-0630, Vol. 130, article id 16Article in journal (Refereed) Published
Abstract [en]

Despite the significance of snow in various cryospheric, polar, and construction contexts, more comprehensive studies are required on its mechanical properties. In recent years, the utilization of μ CT has yielded valuable insights into snow analysis. Our objective is to establish a methodology for mapping density-dependent material properties for dry manufactured snow within the density range of 400–600 kg/m 3 utilizing μ CT imaging and step-wise, quasi-static, mechanical loading. We also aim to investigate the variations in the structural parameters of snow during loading. The three-dimensional (3D) structure of snow is captured using μ CT with 801 projections at the beginning of the experiments and at the end of each loading step. The sample is compressed at a temperature of − 18 o C using a constant rate of deformation (0.2 mm/min) in multiple steps. The relative density of the snow is determined at each load step using binary image segmentation. It varies from 0.44 in the beginning to nearly 0.65 at the end of the loading, which corresponds to a density range of 400–600 kg/m 3 . The estimated modulus and viscosity terms, obtained from the Burger’s model, show an increasing trend with density. The values of the Maxwell and Kelvin–Voigt moduli were found to range from 60 to 320 MPa and from 6 to 40 MPa, respectively. Meanwhile, the viscosity values for the Maxwell and Kelvin–Voigt models varied from 0.4 to 3.5 GPa-s, and 0.3–3.2 GPa-s, respectively, within the considered density range. In addition, Digital Volume Correlation (DVC) was used to calculate the full-field strain distribution in the specimen at each load step. The image analysis results show that, the particle size and specific surface area (SSA) do not change significantly within the studied range of loading and densities, while the sphericity of the particles is increased. The grain diameter ranges from approximately 100 μ m to nearly 400 μ m, with a mode of nearly 200 μ m. The methodology presented in this study opens up a path for an extensive statistical analysis of the material properties by experimenting more snow samples.

Place, publisher, year, edition, pages
Springer Nature, 2024
Keywords
Micro tomography, Material modeling, Stress-strain response, Digital volume correlation, Image analysis, Snow
National Category
Other Materials Engineering
Research subject
Experimental Mechanics; Fluid Mechanics
Identifiers
urn:nbn:se:ltu:diva-103511 (URN)10.1007/s00339-023-07167-y (DOI)001123446400001 ()2-s2.0-85179360802 (Scopus ID)
Note

Validerad;2024;Nivå 2;2024-02-26 (signyg);

Full text license: CC BY

Available from: 2024-01-08 Created: 2024-01-08 Last updated: 2024-05-06Bibliographically approved
Bahaloohoreh, H., Forsberg, F., Lycksam, H., Casselgren, J. & Sjödahl, M. (2024). Material mapping strategy to identify the density-dependent properties of dry natural snow. Applied Physics A: Materials Science & Processing, 130(2), Article ID 141.
Open this publication in new window or tab >>Material mapping strategy to identify the density-dependent properties of dry natural snow
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2024 (English)In: Applied Physics A: Materials Science & Processing, ISSN 0947-8396, E-ISSN 1432-0630, Vol. 130, no 2, article id 141Article in journal (Refereed) Published
Abstract [en]

The mechanical properties of natural snow play a crucial role in understanding glaciers, avalanches, polar regions, and snow-related constructions. Research has concentrated on how the mechanical properties of snow vary, primarily with its density; the integration of cutting-edge techniques like micro-tomography with traditional loading methods can enhance our comprehension of these properties in natural snow. This study employs CT imaging and uniaxial compression tests, along with the Digital Volume Correlation (DVC) to investigate the density-dependent material properties of natural snow. The data from two snow samples, one initially non-compressed (test 1) and the other initially compressed (test 2), were fed into Burger’s viscoelastic model to estimate the material properties. CT imaging with 801 projections captures the three-dimensional structure of the snow initially and after each loading step at -18C, using a constant deformation rate (0.2 mm/min). The relative density of the snow, ranging from 0.175 to 0.39 (equivalent to 160–360 kg/m), is determined at each load step through binary image segmentation. Modulus and viscosity terms, estimated from Burger’s model, exhibit a density-dependent increase. Maxwell and Kelvin–Voigt moduli range from 0.5 to 14 MPa and 0.1 to 0.8 MPa, respectively. Viscosity values for the Maxwell and Kelvin–Voigt models vary from 0.2 to 2.9 GPa-s and 0.2 to 2.3 GPa-s within the considered density range, showing an exponent between 3 and 4 when represented as power functions. Initial grain characteristics for tests 1 and 2, obtained through image segmentation, reveal an average Specific Surface Area (SSA) of around 55 1/mm and 40 1/mm, respectively. The full-field strain distribution in the specimen at each load step is calculated using the DVC, highlighting strong strain localization indicative of non-homogeneous behavior in natural snow. These findings not only contribute to our understanding of natural snow mechanics but also hold implications for applications in fields such as glacier dynamics and avalanche prediction.

Place, publisher, year, edition, pages
Springer Nature, 2024
Keywords
Material mapping, Micro tomography, Compression test, Digital volume correlation, Snow and ice
National Category
Other Materials Engineering
Research subject
Experimental Mechanics; Fluid Mechanics
Identifiers
urn:nbn:se:ltu:diva-104236 (URN)10.1007/s00339-024-07288-y (DOI)001153419300002 ()2-s2.0-85183678465 (Scopus ID)
Note

Validerad;2024;Nivå 2;2024-02-12 (joosat);

CC BY Full text license

Available from: 2024-02-12 Created: 2024-02-12 Last updated: 2024-05-06Bibliographically approved
Bahaloo, H. (2024). Mechanics of Ice and Snow as a Granular Material. (Doctoral dissertation). Luleå: Luleå University of Technology
Open this publication in new window or tab >>Mechanics of Ice and Snow as a Granular Material
2024 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

In this thesis, the mechanical properties of ice and dry snow as a class of granular materials are investigated through a series of experiments, analyses, and simulations. The primary focus is on understanding the intricate details of ice sintering, capillary bridge formation, and the behavior of snow under varying conditions.

The investigation into ice sintering reveals a formulation of the sintering force, considering temperature, pressing force, contact duration, and particle size during the primary sintering stage. The results indicate a nearly linear increase in sintering force with external pressing force, while dependency on contact duration and particle size follows a nonlinear power-law relationship. The temperature dependence of the sintering force is nonlinear, aligning with the Arrhenius equation. The ultimate tensile strength of ice and the axial stress concentration factor are identified as crucial factors in determining the sintering force. Additionally, observations near the melting point reveal the formation of a liquid bridge between contacted ice particles.

Moving on to capillary bridge formation, the experiments demonstrate the presence of a liquid bridge between an ice particle and a smooth (or rough) aluminum surface at controlled temperature conditions. The separation distance is found to be proportional to the cube root of the bridge volume, which decreases with decreasing temperature. Notably, for a rough surface, capillary bridge formation diminishes under the considered experimental conditions.

The significance of snow in various contexts prompts an exploration of its mechanical properties. Utilizing micro-computed tomography imaging and quasi-static mechanical loading, a methodology for mapping the density-dependent material properties of manufactured snow is established. The study investigates structural parameter variations during loading, revealing insights into the three-dimensional structure, relative density, and mechanical behavior of snow. Results from Burger’s model show an increasing trend in modulus and viscosity terms with density. Digital volume correlation aids in calculating full-field strain distribution, highlighting particle characteristics and changes in specific surface areas during loading.

Expanding the scope to natural snow, cutting-edge techniques like micro-tomography are integrated with traditional loading methods. Employing CT imaging and uniaxial compression tests, along with digital volume correlation, density-dependent material properties are analyzed. The study incorporates two snow samples, revealing density-dependent trends in modulus and viscosity terms. The results provide valuable insights into the non-homogeneous behavior of natural snow and contribute to fields such as glacier dynamics and avalanche prediction.

Finally, the discrete element method with a variable bond model is used to simulate the behavior of granular materials, specifically focusing on snow. The model incorporates temperature dependent cohesion and effectively captures the angle of repose and stress-strain behavior of snow.

In summary, this thesis presents an investigation into the mechanical properties of ice, capillary bridge formation, manufactured snow, natural snow, and granular materials, providing insights and contributing to the understanding of ice and snow in various environmental and engineering contexts.

Place, publisher, year, edition, pages
Luleå: Luleå University of Technology, 2024
Series
Doctoral thesis / Luleå University of Technology 1 jan 1997 → …, ISSN 1402-1544
Keywords
micro tomography, mechanics, ice and snow, sintering force, thin liquid layer, discrete element method
National Category
Geotechnical Engineering
Research subject
Experimental Mechanics
Identifiers
urn:nbn:se:ltu:diva-105285 (URN)978-91-8048-558-6 (ISBN)978-91-8048-559-3 (ISBN)
Public defence
2024-06-12, E632, Luleå University of Technology, Luleå, 10:00 (English)
Opponent
Supervisors
Available from: 2024-04-29 Created: 2024-04-29 Last updated: 2024-05-22Bibliographically approved
Bahaloohoreh, H., Gren, P., Casselgren, J., Forsberg, F. & Sjödahl, M. (2023). Capillary bridge in contact of ice particles reveals the thin liquid film on ice.
Open this publication in new window or tab >>Capillary bridge in contact of ice particles reveals the thin liquid film on ice
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2023 (English)Manuscript (preprint) (Other academic)
National Category
Other Engineering and Technologies not elsewhere specified
Research subject
Experimental Mechanics
Identifiers
urn:nbn:se:ltu:diva-94783 (URN)
Available from: 2022-12-08 Created: 2022-12-08 Last updated: 2022-12-09
Bahaloohoreh, H. (2023). Experiments and simulations on the mechanics of ice and snow. (Licentiate dissertation). Luleå: Luleå University of Technology
Open this publication in new window or tab >>Experiments and simulations on the mechanics of ice and snow
2023 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

In this study, experiments and simulations were conducted to investigate ice and snow. The ice sintering force as a function of temperature, pressing force (contact load), contact duration, and particle size during the primary stage of sintering was formulated using experimental methods along with an approximate, semi-analytic, close-form solution. It was shown that the ice sintering force increases nearly linear with increasing external pressing force but best approximated as a power law for dependency on both contact duration and particle size. Moreover, the exponent of the power law for size dependence is around the value predicted by general sintering theory. The temperature dependence of the sintering force is highly nonlinear and follows the Arrhenius equation. It was observed that at temperatures closer to the melting point, a liquid bridge is observed upon these paration of the contacted ice particles. The ratio of ultimate tensile strength of ice to the axial stress concentration factor in tension is found as an important factor in determining the sintering force, and a value of nearly 1.1 MPa was estimated to best catch the sintering force of ice in different conditions. From the temperature dependency, the activation energy is calculated to be around 41.4 kJ/mol, which is close to the previously reported value. Also, the results for the sintering force suggest that smaller particles are “stickier” than larger particles. Moreover, cavitation and surface cracking is observed during the formation of the ice particles and these can be one of the sources for the variations observed in the measured ice sintering force values.

The presence of a capillary bridge in contact between an ice particle and a "smooth" (or rough) Aluminum surface at relative humidity around 50% and temperatures below the melting point was experimentally demonstrated. Experiments were conducted under controlled temperature conditions and the mechanical instability of the bridge upon separation of the ice particle from the Aluminum surface with a constant speed was considered. It was observed that a liquid bridge with a more pronounced volume at temperatures near the melting point is formed. It was showen that the separation distance is proportional to the cube root of the volume of the bridge. The volume of the liquidbridge is used to estimate the thickness of the liquid layer on the ice particle and the estimated value was shown to be within the range reported in the literature. The thickness of the liquid layer decreases from nearly 56 nm at -1.7◦C to 0.2 nm at -12.7◦C. The dependence can be approximated with a power law, proportional to (TM − T)−β, where β < 2.6. We further observe that for a rough surface, the capillary bridge formation in the considered experimental conditions vanishes.

The Discrete Element Method (DEM) was employed to simulate the filling behavior of dry snow. Snow as a heterogeneous, hot material which is constituted from spherical ice particles which can form bonds. The bonding behavior of ice particles is important in determining the macroscopic behavior of snow. The bond diameter of ice-ice contacts as a function of time, compressive load, and strain rate is used and a DEM for dry snow was developed and programmed in MATLAB. A beam element with implemented damage model was used in the simulation. The simulated parameters were macroscopic angle of repose, packing density, and surface conditions as a function of temperature and fillingrate. The DEM results were able to verify the existing published experimental data. The simulation results showed that angle of repose of snow decreased with decreasing the temperature, the surface became irregular due to particles rotation and re-arrangement for lower falling speeds of particles, and density increased with depth of deposition.

Place, publisher, year, edition, pages
Luleå: Luleå University of Technology, 2023
Series
Licentiate thesis / Luleå University of Technology, ISSN 1402-1757
Keywords
Experiments, Sintering force, Capillar bridge, liquid film, Discrete Element Method, Particles
National Category
Applied Mechanics
Research subject
Experimental Mechanics
Identifiers
urn:nbn:se:ltu:diva-94782 (URN)978-91-8048-234-9 (ISBN)978-91-8048-235-6 (ISBN)
Presentation
2023-02-20, E632, Luleå tekniska universitet, Luleå, 13:00 (English)
Opponent
Supervisors
Available from: 2022-12-08 Created: 2022-12-08 Last updated: 2023-02-01Bibliographically approved
Bahaloo, H., Eidevåg, T., Gren, P., Casselgren, J., Forsberg, F., Abrahamsson, P. & Sjödahl, M. (2022). Ice Sintering: Dependence of Sintering Force on Temperature, Load, Duration, and Particle Size. In: Pär Jonsén; Lars-Göran Westerberg; Simon Larsson; Erik Olsson (Ed.), Svenska Mekanikdagar 2022: . Paper presented at Svenska Mekanikdagarna 2022, Luleå, Sweden, June 15-16, 2022 . Luleå tekniska universitet
Open this publication in new window or tab >>Ice Sintering: Dependence of Sintering Force on Temperature, Load, Duration, and Particle Size
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2022 (English)In: Svenska Mekanikdagar 2022 / [ed] Pär Jonsén; Lars-Göran Westerberg; Simon Larsson; Erik Olsson, Luleå tekniska universitet, 2022Conference paper, Oral presentation with published abstract (Refereed)
Place, publisher, year, edition, pages
Luleå tekniska universitet, 2022
National Category
Applied Mechanics
Research subject
Experimental Mechanics
Identifiers
urn:nbn:se:ltu:diva-95068 (URN)
Conference
Svenska Mekanikdagarna 2022, Luleå, Sweden, June 15-16, 2022 
Note

Presentation of an earlier published article with DOI: 10.1063/5.0073824

Available from: 2022-12-29 Created: 2022-12-29 Last updated: 2024-02-12Bibliographically approved
Bahaloohoreh, H., Eidevåg, T., Gren, P., Casselgren, J., Forsberg, F., Abrahamsson, P. & Sjödahl, M. (2022). Ice sintering: Dependence of sintering force on temperature, load, duration, and particle size. Journal of Applied Physics, 131(2), Article ID 025109.
Open this publication in new window or tab >>Ice sintering: Dependence of sintering force on temperature, load, duration, and particle size
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2022 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 131, no 2, article id 025109Article in journal (Refereed) Published
Abstract [en]

We present experiments along with an approximate, semi-analytic, close-form solution to predict ice sintering force as a function of temperature, contact load, contact duration, and particle size during the primary stage of sintering. The ice sintering force increases nearly linear with increasing contact load but nonlinear with both contact duration and particle size in the form of a power law. The exponent of the power law for size dependence is around the value predicted by general sintering theory. The temperature dependence of the sintering force is also nonlinear and follows the Arrhenius equation. At temperatures closer to the melting point, a liquid bridge is observed upon the separation of the contacted ice particles. We also find that the ratio of ultimate tensile strength of ice to the axial stress concentration factor in tension is an important factor in determining the sintering force, and a value of nearly 1.1 MPa can best catch the sintering force of ice in different conditions. We find that the activation energy is around 41.4KJ/mol41.4KJ/mol, which is close to the previously reported data. Also, our results suggest that smaller particles are “stickier” than larger particles. Moreover, during the formation of the ice particles, cavitation and surface cracking is observed which can be one of the sources for the variations observed in the measured ice sintering force.

Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2022
National Category
Applied Mechanics
Research subject
Experimental Mechanics
Identifiers
urn:nbn:se:ltu:diva-88792 (URN)10.1063/5.0073824 (DOI)000746515900007 ()2-s2.0-85123639304 (Scopus ID)
Note

Validerad;2022;Nivå 2;2022-01-17 (johcin)

Available from: 2022-01-17 Created: 2022-01-17 Last updated: 2024-05-06Bibliographically approved
Bahaloo, H., Casselgren, J., Forsberg, F. & Sjödahl, M. (2021). Discrete element simulation of dry snow using the developed analytic bond model. In: IOP Conference Series: Materials Science and Engineering: . Paper presented at World Symposium on Mechanical-Materials Engineering & Science (WMMES 2021), 9th-11th September 2021, Prague, Czech Republic. Institute of Physics (IOP), 1190, Article ID 012015.
Open this publication in new window or tab >>Discrete element simulation of dry snow using the developed analytic bond model
2021 (English)In: IOP Conference Series: Materials Science and Engineering, Institute of Physics (IOP), 2021, Vol. 1190, article id 012015Conference paper, Published paper (Refereed)
Abstract [en]

Snow is a heterogenous, hot material which is constituted from ice particles. The bonding behavior of ice particles is an important parameter determining the macroscopic behavior of snow. Discrete Element Method (DEM) is usually used as a tool to model dry snow. The most important input data required into the DEM is bonding behavior of ice particles since ice particles can adhere to form bonds when they brought into contact. This study had two aims: first, an analytical formulation was derived to predict the bond diameter of ice-ice contacts as a function of time, compressive load, and strain rate. Using the previously published data for strain rate of ice, a solution method was developed. The results of bond diameter development with time were compared to experimental data and a good agreement was found. Second, a DEM for dry snow was developed and programmed in MATLAB and the developed bond model was employed in the simulation to study the deposition behavior of snow in a container under gravity acceleration. A specific beam element with implemented damage model was developed in implemented in the simulation using the bond data obtained from the analytical approach. The simulated parameters were macroscopic angle of repose, packing density, and surface conditions as a function of temperature and filling rate. The results showed that discrete element simulations were able to verify the existing published experimental data. Specifically, the simulation results showed that angle of repose of snow decreased rapidly with decreasing the temperature, the surface became very irregular due to the particles rotation and re-arrangement for lower falling speeds of particles, and density increased with depth of deposition. These findings were all matched with experimental observations.

Place, publisher, year, edition, pages
Institute of Physics (IOP), 2021
Series
IOP Conference Series: Materials Science and Engineering, ISSN 1757-8981, E-ISSN 1757-899X ; 1190
National Category
Fluid Mechanics and Acoustics
Research subject
Experimental Mechanics
Identifiers
urn:nbn:se:ltu:diva-88235 (URN)10.1088/1757-899X/1190/1/012015 (DOI)
Conference
World Symposium on Mechanical-Materials Engineering & Science (WMMES 2021), 9th-11th September 2021, Prague, Czech Republic
Available from: 2021-12-07 Created: 2021-12-07 Last updated: 2023-09-05Bibliographically approved
Enns-Bray, W. S., Bahaloo, H., Fleps, I., Pauchard, Y., Taghizadeh, E., Sigurdsson, S., . . . Helgason, B. (2019). Biofidelic finite element models for accurately classifying hip fracture in a retrospective clinical study of elderly women from the AGES Reykjavik cohort. Bone, 120, 25-37
Open this publication in new window or tab >>Biofidelic finite element models for accurately classifying hip fracture in a retrospective clinical study of elderly women from the AGES Reykjavik cohort
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2019 (English)In: Bone, ISSN 8756-3282, E-ISSN 1873-2763, Vol. 120, p. 25-37Article in journal (Refereed) Published
National Category
Orthopaedics
Identifiers
urn:nbn:se:ltu:diva-78057 (URN)10.1016/j.bone.2018.09.014 (DOI)000458471700004 ()30240961 (PubMedID)2-s2.0-85054160890 (Scopus ID)
Available from: 2020-03-13 Created: 2020-03-13 Last updated: 2023-09-05Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0001-6231-8944

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