The effect of wall leakage on the traditional duct flow equations based of the balance of mass, momentum and mechanical energy applied on a duct section is considered. Application of the momentum balance produces a Bernoulli equation type form, where the multiplier 1/2 in the dynamic pressure is however replaced by the value 1. Some relevant literature references are discussed. As an application, a nozzle duct flow problem is treated.
{"title":"Duct flow with leakage","authors":"Eero-Matti Salonen, R. Holopainen","doi":"10.23998/rm.137782","DOIUrl":"https://doi.org/10.23998/rm.137782","url":null,"abstract":"The effect of wall leakage on the traditional duct flow equations based of the balance of mass, momentum and mechanical energy applied on a duct section is considered. Application of the momentum balance produces a Bernoulli equation type form, where the multiplier 1/2 in the dynamic pressure is however replaced by the value 1. Some relevant literature references are discussed. As an application, a nozzle duct flow problem is treated.","PeriodicalId":52331,"journal":{"name":"Rakenteiden Mekaniikka","volume":"49 15","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139165915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ristiinliimatuista lautakerroksista koottu monikerroslevy, niin sanottu CLT-levy (Cross-Laminated Timber), on vakiinnuttanut paikkansa muiden insinööripuutuotteiden rinnalla teollisessa puurakentamisessa. CLT-levyä käytetään asuinkerrostaloissa, toimistoissa ja muissa julkisissa rakennuksissa etenkin seinien ja lattioiden kantavina rakenteina sekä osana koko rakennuksen jäykistysjärjestelmää. Lujuustekniseltä kannalta CLT-levyn tyypillisistä käyttökohteista ylivoimaisesti haastavimpia ovat lattiarakenteet, joissa levyn kerroksellisuus yhdistettynä puun ortotrooppisuuteen tekee rakenteen siirtymien ja jännitysten laskennasta monimutkaista. Tässä artikkelissa käydään läpi tällaisten lapetaivutettujen CLT-rakenteiden yleisimpien analyysimenetelmien teoreettisia perusteita sekä vertaillaan menetelmien etuja sekä niiden käyttöön vaikuttavia ominaisuuksia.
{"title":"Lapetaivutetun CLT-rakenteen lujuuslaskentamenetelmät","authors":"Sami Pajunen, Essi Lääveri, Markku Heinisuo","doi":"10.23998/rm.128483","DOIUrl":"https://doi.org/10.23998/rm.128483","url":null,"abstract":"Ristiinliimatuista lautakerroksista koottu monikerroslevy, niin sanottu CLT-levy (Cross-Laminated Timber), on vakiinnuttanut paikkansa muiden insinööripuutuotteiden rinnalla teollisessa puurakentamisessa. CLT-levyä käytetään asuinkerrostaloissa, toimistoissa ja muissa julkisissa rakennuksissa etenkin seinien ja lattioiden kantavina rakenteina sekä osana koko rakennuksen jäykistysjärjestelmää. Lujuustekniseltä kannalta CLT-levyn tyypillisistä käyttökohteista ylivoimaisesti haastavimpia ovat lattiarakenteet, joissa levyn kerroksellisuus yhdistettynä puun ortotrooppisuuteen tekee rakenteen siirtymien ja jännitysten laskennasta monimutkaista. Tässä artikkelissa käydään läpi tällaisten lapetaivutettujen CLT-rakenteiden yleisimpien analyysimenetelmien teoreettisia perusteita sekä vertaillaan menetelmien etuja sekä niiden käyttöön vaikuttavia ominaisuuksia.","PeriodicalId":52331,"journal":{"name":"Rakenteiden Mekaniikka","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47773926","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Esivalmistettujen kattoelementtien käyttö puurunkoisten hallien rakentamisessa on nykyään hyvin sujuvaa ja kustannustehokasta. Tyypillisesti kattoelementit suunnitellaan siten, että ne toimivat myös stabiliteettitukina pääkannattimille. Tässä tutkimuksessa käsitellään suunnittelumenetelmää, jossa kattoelementit suunniteltaisiin siten, että ne toimisivat osana koko rakennuksen jäykistysjärjestelmää perinteisten mastopilarien rinnalla. Vastaavaa suunnittelumenetelmää on käytetty jo pitkään teräsrunkoisissa hallirakennuksissa, ja tässä artikkelissa menetelmää muokataan puurakentamisen erityispiirteet huomioiden soveltumaan myös puurunkoisille hallirakennuksille. Artikkelissa tarkastellaan puuhallin pitkää sivua vastaan kohdistuvaa vaakakuormaa, jota voidaan pitää jäykistyslaskelmien perustapauksena. Katon levyjäykistys toteutetaan puurunkojen jäykistyksessä yleisesti käytetyllä kipsilevyllä, joka on ruuvattu puurunkoon. Saaduista tuloksista nähdään, että katon levyvaikutuksella on suuri vaikutus pilarien vaakakuormiin sekä katon vaakasiirtymiin. Pilareiden vaakakuormitukset ja nurjahduspituudet pienenevät huomattavasti verrattuna tapaukseen, jossa mastopilarit yksin ottaisivat vastaan rakennukseen kohdistuvat vaakakuormat. Kun katon levyjäykistys otetaan mitoituksessa huomioon, kehäpilareiden nurjahduspituudet pienenevät jopa 47 prosenttia verrattuna pelkkään mastojäykistykseen. Tulokset ovat vastaavia kuin on saatu teräsrunkoisten hallien laskelmissa. Esitetty menetelmä antaa perusteet puurunkoisten hallien kehittyneempään ja todellisuutta paremmin vastaavaan taloudelliseen mitoitukseen jopa ilman lisäkustannuksia verrattuna nykyiseen käytäntöön.
{"title":"Esivalmistettujen kattoelementtien hyödyntäminen osana puurakenteisten hallien jäykistystä","authors":"Sami Pajunen, Markku Heinisuo","doi":"10.23998/rm.130630","DOIUrl":"https://doi.org/10.23998/rm.130630","url":null,"abstract":"Esivalmistettujen kattoelementtien käyttö puurunkoisten hallien rakentamisessa on nykyään hyvin sujuvaa ja kustannustehokasta. Tyypillisesti kattoelementit suunnitellaan siten, että ne toimivat myös stabiliteettitukina pääkannattimille. Tässä tutkimuksessa käsitellään suunnittelumenetelmää, jossa kattoelementit suunniteltaisiin siten, että ne toimisivat osana koko rakennuksen jäykistysjärjestelmää perinteisten mastopilarien rinnalla. Vastaavaa suunnittelumenetelmää on käytetty jo pitkään teräsrunkoisissa hallirakennuksissa, ja tässä artikkelissa menetelmää muokataan puurakentamisen erityispiirteet huomioiden soveltumaan myös puurunkoisille hallirakennuksille. Artikkelissa tarkastellaan puuhallin pitkää sivua vastaan kohdistuvaa vaakakuormaa, jota voidaan pitää jäykistyslaskelmien perustapauksena. Katon levyjäykistys toteutetaan puurunkojen jäykistyksessä yleisesti käytetyllä kipsilevyllä, joka on ruuvattu puurunkoon. Saaduista tuloksista nähdään, että katon levyvaikutuksella on suuri vaikutus pilarien vaakakuormiin sekä katon vaakasiirtymiin. Pilareiden vaakakuormitukset ja nurjahduspituudet pienenevät huomattavasti verrattuna tapaukseen, jossa mastopilarit yksin ottaisivat vastaan rakennukseen kohdistuvat vaakakuormat. Kun katon levyjäykistys otetaan mitoituksessa huomioon, kehäpilareiden nurjahduspituudet pienenevät jopa 47 prosenttia verrattuna pelkkään mastojäykistykseen. Tulokset ovat vastaavia kuin on saatu teräsrunkoisten hallien laskelmissa. Esitetty menetelmä antaa perusteet puurunkoisten hallien kehittyneempään ja todellisuutta paremmin vastaavaan taloudelliseen mitoitukseen jopa ilman lisäkustannuksia verrattuna nykyiseen käytäntöön.","PeriodicalId":52331,"journal":{"name":"Rakenteiden Mekaniikka","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43885137","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Silas Z. Gebrehiwot, Leonardo Espinosa-Leal, H. Remes, Marinus Vermunt
Surface roughness is one of the key surface integrity factors affecting the strength and fatigue life of components. Stress concentrations occur due to the randomness of the surface profiles. The presence of a dominant valley, a complex geometry and interacting effects exasperate the severity of the stress concentrations. To estimate the theoretical stress concentration factor (SCF) at the valley, the notch root radius should be estimated carefully. We propose an effective method for estimating the root radius of the deepest valley using numerical derivative techniques. The surface roughness of a carefully sanded Alumec 89 block was measured using SJ-400 tester. The 1-D roughness data was used first to evaluate the root radius of the deepest valleys and then, estimate the SCF using analytical and computational methods. We used 2-D finite element (FE) models under uniaxial tension for the computational analyses. The validity of our method is based on determining the SCF using different theoretical methods and comparing the results to the FE calculations. The theoeritical estimations are made using the Neuber, Inglis and Arola-Ramulu approaches, whereas COMSOL Multiphysics is used for the FE analyses. Comparing the theoeritical methods with the FE calculations, the Arola-Ramulu approach was better, with a maximum of error. The minimum deviations can be explained by the model containing parameters such as , and which are inherent to the roughness profile of the material.
{"title":"Characterising the notch root radii and analyses of stress concentration factors near the dominant valleys of rough surface profiles","authors":"Silas Z. Gebrehiwot, Leonardo Espinosa-Leal, H. Remes, Marinus Vermunt","doi":"10.23998/rm.124815","DOIUrl":"https://doi.org/10.23998/rm.124815","url":null,"abstract":"Surface roughness is one of the key surface integrity factors affecting the strength and fatigue life of components. Stress concentrations occur due to the randomness of the surface profiles. The presence of a dominant valley, a complex geometry and interacting effects exasperate the severity of the stress concentrations. To estimate the theoretical stress concentration factor (SCF) at the valley, the notch root radius should be estimated carefully. We propose an effective method for estimating the root radius of the deepest valley using numerical derivative techniques. The surface roughness of a carefully sanded Alumec 89 block was measured using SJ-400 tester. The 1-D roughness data was used first to evaluate the root radius of the deepest valleys and then, estimate the SCF using analytical and computational methods. We used 2-D finite element (FE) models under uniaxial tension for the computational analyses. The validity of our method is based on determining the SCF using different theoretical methods and comparing the results to the FE calculations. The theoeritical estimations are made using the Neuber, Inglis and Arola-Ramulu approaches, whereas COMSOL Multiphysics is used for the FE analyses. Comparing the theoeritical methods with the FE calculations, the Arola-Ramulu approach was better, with a maximum of error. The minimum deviations can be explained by the model containing parameters such as , and which are inherent to the roughness profile of the material.","PeriodicalId":52331,"journal":{"name":"Rakenteiden Mekaniikka","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47610910","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study indicates the analysis of functionally graded carbon nanotube reinforced composite (FG-CNTRC) plates using a four-node quadrilateral element related to the C0-type of Reddy’s third-order shear deformation theory (C0 HSDT) and cell-based smoothed strains (CS) strategy. Reddy’s theory is surely taking the advantages and desirable properties of the third-order shear deformation theory. Besides, FG-CNTRC plates with advanced material properties are changed from the bottom to top surface with four kinds of carbon nanotube (CNTs). Numerical results and comparison with other reference solutions suggest that the benefits of the present element are accuracy and efficiency in analysis of FG-CNTRC plates.
{"title":"Four-node quadrilateral C 0-element based on cell-based smoothed strains strategy and third-order shear deformation theory for functionally graded carbon nanotube reinforced composite plates","authors":"Lan Hoang Ton That","doi":"10.23998/rm.119608","DOIUrl":"https://doi.org/10.23998/rm.119608","url":null,"abstract":"This study indicates the analysis of functionally graded carbon nanotube reinforced composite (FG-CNTRC) plates using a four-node quadrilateral element related to the C0-type of Reddy’s third-order shear deformation theory (C0 HSDT) and cell-based smoothed strains (CS) strategy. Reddy’s theory is surely taking the advantages and desirable properties of the third-order shear deformation theory. Besides, FG-CNTRC plates with advanced material properties are changed from the bottom to top surface with four kinds of carbon nanotube (CNTs). Numerical results and comparison with other reference solutions suggest that the benefits of the present element are accuracy and efficiency in analysis of FG-CNTRC plates.","PeriodicalId":52331,"journal":{"name":"Rakenteiden Mekaniikka","volume":"23 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41293638","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Welding is a commonly applied joining method in many applications in arctic and marine conditions, e.g., in ship and offshore structures, and energy production equipment. Such applications are usually subjected to fluctuating load conditions, and during a decades-long service, they may experience millions of load cycles. Consequently, fatigue strength design and acceptable flaw sizes in the welded details of these structures are among the most important design criteria. Multiple fatigue strength assessment approaches exist for assessing the fatigue strength of a welded detail. The present study introduces a numerical and analytical fatigue strength assessment, conducted on a non-load-carrying X-joint, which is a representative joint type used in many steel constructions. Fatigue analyses are carried out following the DNVGL-RP-C203 and BS7910:2013 fatigue design guidelines for offshore steel structures. The stress intensity factors (SIFs) for linear elastic fracture mechanics (LEFM) analyses were obtained using three different methods: the weight function approach, the analytical equations provided in the IIW Recommendations, and by conducting numerical crack propagation analysis using the Franc2D software. All three methods had a good agreement particularly for short crack depths, indicating the applicability of the analytical approaches for the fatigue analyses. The results showed that the consideration of degree of bending at the welded detail is crucial due to the distinguishing notch stress factors of membrane and bending loading, and different stress distributions in the through-thickness direction. In addition, it was found that the LEFM-based fatigue life assessments are significantly more conservative than the life predictions obtained using the structural hot-spot and effective notch stress approaches.
{"title":"Fatigue strength assessment of welded joints in the marine environment","authors":"A. Ahola, Timo Björk","doi":"10.23998/rm.124670","DOIUrl":"https://doi.org/10.23998/rm.124670","url":null,"abstract":"Welding is a commonly applied joining method in many applications in arctic and marine conditions, e.g., in ship and offshore structures, and energy production equipment. Such applications are usually subjected to fluctuating load conditions, and during a decades-long service, they may experience millions of load cycles. Consequently, fatigue strength design and acceptable flaw sizes in the welded details of these structures are among the most important design criteria. Multiple fatigue strength assessment approaches exist for assessing the fatigue strength of a welded detail. The present study introduces a numerical and analytical fatigue strength assessment, conducted on a non-load-carrying X-joint, which is a representative joint type used in many steel constructions. Fatigue analyses are carried out following the DNVGL-RP-C203 and BS7910:2013 fatigue design guidelines for offshore steel structures. The stress intensity factors (SIFs) for linear elastic fracture mechanics (LEFM) analyses were obtained using three different methods: the weight function approach, the analytical equations provided in the IIW Recommendations, and by conducting numerical crack propagation analysis using the Franc2D software. All three methods had a good agreement particularly for short crack depths, indicating the applicability of the analytical approaches for the fatigue analyses. The results showed that the consideration of degree of bending at the welded detail is crucial due to the distinguishing notch stress factors of membrane and bending loading, and different stress distributions in the through-thickness direction. In addition, it was found that the LEFM-based fatigue life assessments are significantly more conservative than the life predictions obtained using the structural hot-spot and effective notch stress approaches.","PeriodicalId":52331,"journal":{"name":"Rakenteiden Mekaniikka","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44627363","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pauli Hakala, O. Orell, E. Sarlin, E. Pääkkönen, Lauri Jutila, M. Kanerva
In this study, alternative core materials to commercial cork were searched for. Additionally, aging of new core materials was studied. Bio-based materials in sandwich structures can be useful for sports equipment, transportation, and furniture with much less impact on the environment in comparison with their synthetic counterparts. In this paper, sandwich panels made of fiber-reinforced polymer (FRP) skins and various sustainable core materials with a core thickness of 6 mm were studied. The core materials were: cork, expanded polystyrene (EPS), cellulose foam, and 3D-printed polylactic acid (PLA) honeycomb lattice. FRP composites made of flax fibre reinforcement and bio-based epoxy resin (30% bio-content) were used to manufacture the skins to compete the glass fibre reinforced rival composite. The experimental analysis of the panel performance focused on the out-of-plane behavior and aging due to conditioning in an ultraviolet (UV) irradiation-rain cabinet. The results showed that under mechanical and environmental loading, the sandwich composite with cellulose foam had comparable or even better mechanical performance under shearing load, including UV-rain effects, than structures with EPS cores. Failure localization was studied using digital image correlation (DIC). The 3D-printed PLA honeycomb sandwich structures had a high absolute flatwise tensile strength and shear strength but also greatest degradation by the UV-rain aging.
{"title":"Durability of sandwich structures with a maximized natural raw material basis: comparison of expanded polystyrene, cellulose foam and polylactic acid subjected to UV-rain aging","authors":"Pauli Hakala, O. Orell, E. Sarlin, E. Pääkkönen, Lauri Jutila, M. Kanerva","doi":"10.23998/rm.120756","DOIUrl":"https://doi.org/10.23998/rm.120756","url":null,"abstract":"In this study, alternative core materials to commercial cork were searched for. Additionally, aging of new core materials was studied. Bio-based materials in sandwich structures can be useful for sports equipment, transportation, and furniture with much less impact on the environment in comparison with their synthetic counterparts. In this paper, sandwich panels made of fiber-reinforced polymer (FRP) skins and various sustainable core materials with a core thickness of 6 mm were studied. The core materials were: cork, expanded polystyrene (EPS), cellulose foam, and 3D-printed polylactic acid (PLA) honeycomb lattice. FRP composites made of flax fibre reinforcement and bio-based epoxy resin (30% bio-content) were used to manufacture the skins to compete the glass fibre reinforced rival composite. The experimental analysis of the panel performance focused on the out-of-plane behavior and aging due to conditioning in an ultraviolet (UV) irradiation-rain cabinet. The results showed that under mechanical and environmental loading, the sandwich composite with cellulose foam had comparable or even better mechanical performance under shearing load, including UV-rain effects, than structures with EPS cores. Failure localization was studied using digital image correlation (DIC). The 3D-printed PLA honeycomb sandwich structures had a high absolute flatwise tensile strength and shear strength but also greatest degradation by the UV-rain aging.","PeriodicalId":52331,"journal":{"name":"Rakenteiden Mekaniikka","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49651696","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Miro-Tommi Tuutijärvi, A. Mahmoudzadeh Andwari, Ville Pirnes, Jonne Untinen
This study presents developing of a tyre testing trailer for heavy commercial vehicle tyres at the University of Oulu together with introducing the design of the trailer with different design aspects of the trailer systems. Processes regarding running of the tyre measurements with the trailer as well as the data preparation are performed. The first measurement results are conducted on both snow and wet asphalt conditions. Furthermore, current state and further development plans for the measurement trailer are discussed.
{"title":"Heavy vehicle tyre testing in natural environments","authors":"Miro-Tommi Tuutijärvi, A. Mahmoudzadeh Andwari, Ville Pirnes, Jonne Untinen","doi":"10.23998/rm.120702","DOIUrl":"https://doi.org/10.23998/rm.120702","url":null,"abstract":"This study presents developing of a tyre testing trailer for heavy commercial vehicle tyres at the University of Oulu together with introducing the design of the trailer with different design aspects of the trailer systems. Processes regarding running of the tyre measurements with the trailer as well as the data preparation are performed. The first measurement results are conducted on both snow and wet asphalt conditions. Furthermore, current state and further development plans for the measurement trailer are discussed.","PeriodicalId":52331,"journal":{"name":"Rakenteiden Mekaniikka","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48108235","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In order to get detailed information about deformations of structures efficiently, it may be necessary to use finite element models which combine three-dimensional discretizations of solidswith approximations of two-dimensional models for shells. Here we show how the idea of conjugate approximations can be used as a means to obtain a formulation of mixed-dimensional coupling between shells and solids. Our method is consistent with respect to the principle of virtual workand does not depend on additional computational parameters, an augmentation of a potential-energy functional by introducing new unknowns, or computations over auxiliary meshes.
{"title":"The coupling of solids and shells by conjugate approximations","authors":"M. Malinen, P. Råback","doi":"10.23998/rm.120470","DOIUrl":"https://doi.org/10.23998/rm.120470","url":null,"abstract":"In order to get detailed information about deformations of structures efficiently, it may be necessary to use finite element models which combine three-dimensional discretizations of solidswith approximations of two-dimensional models for shells. Here we show how the idea of conjugate approximations can be used as a means to obtain a formulation of mixed-dimensional coupling between shells and solids. Our method is consistent with respect to the principle of virtual workand does not depend on additional computational parameters, an augmentation of a potential-energy functional by introducing new unknowns, or computations over auxiliary meshes.","PeriodicalId":52331,"journal":{"name":"Rakenteiden Mekaniikka","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45528022","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
E. Immonen, Dennis Bengs, Mikael Manngård, Johan Westö
This article introduces a methodology for automatic generation of geometries and meshes for kilometer-scale Atmospheric Boundary Layer (ABL) flow simulations, with topography and elevation. The proposed programmatic (hence automatable) emph{template morphing approach} facilitates interpolation of scattered point cloud terrain data on a template geometry domain, morphing a high-quality quadrilateral template mesh for the interpolated geometry, and setup as well as execution of Computational Fluid Dynamics (CFD) flow simulation. The proposed method specifically addresses the previously reported problems of sustaining an ABL structure across the simulation domain by imposing the velocity and turbulence properties on all vertical surfaces. We present a validation study for the proposed method on an artificial Gaussian hill terrain. A real-world localized wind forecast application from the Turku Archipelago, Finland, is also presented, using open terrain data from National Land Survey of Finland. Such localized wind forecasts aim to assist ships in autonomous navigation and maneuvering in complex port or fairway environments, which is the motivation for this study.
{"title":"Automated geometry and hexahedral mesh generation for kilometer-scale atmospheric flow simulations","authors":"E. Immonen, Dennis Bengs, Mikael Manngård, Johan Westö","doi":"10.23998/rm.119848","DOIUrl":"https://doi.org/10.23998/rm.119848","url":null,"abstract":"This article introduces a methodology for automatic generation of geometries and meshes for kilometer-scale Atmospheric Boundary Layer (ABL) flow simulations, with topography and elevation. The proposed programmatic (hence automatable) emph{template morphing approach} facilitates interpolation of scattered point cloud terrain data on a template geometry domain, morphing a high-quality quadrilateral template mesh for the interpolated geometry, and setup as well as execution of Computational Fluid Dynamics (CFD) flow simulation. The proposed method specifically addresses the previously reported problems of sustaining an ABL structure across the simulation domain by imposing the velocity and turbulence properties on all vertical surfaces. We present a validation study for the proposed method on an artificial Gaussian hill terrain. A real-world localized wind forecast application from the Turku Archipelago, Finland, is also presented, using open terrain data from National Land Survey of Finland. Such localized wind forecasts aim to assist ships in autonomous navigation and maneuvering in complex port or fairway environments, which is the motivation for this study.","PeriodicalId":52331,"journal":{"name":"Rakenteiden Mekaniikka","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44701422","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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