Rakenteiden Mekaniikka最新文献_第2页

Duct flow with leakage 有泄漏的管道流量

Rakenteiden Mekaniikka Pub Date : 2023-12-22 DOI: 10.23998/rm.137782

Eero-Matti Salonen, R. Holopainen

引用次数: 0

Lapetaivutetun CLT-rakenteen lujuuslaskentamenetelmät 翻领切丝CLT结构强度的计算方法

Rakenteiden Mekaniikka Pub Date : 2023-09-04 DOI: 10.23998/rm.128483

Sami Pajunen, Essi Lääveri, Markku Heinisuo

引用次数: 0

Esivalmistettujen kattoelementtien hyödyntäminen osana puurakenteisten hallien jäykistystä

Rakenteiden Mekaniikka Pub Date : 2023-08-28 DOI: 10.23998/rm.130630

Sami Pajunen, Markku Heinisuo

{"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}

引用次数: 0

Characterising the notch root radii and analyses of stress concentration factors near the dominant valleys of rough surface profiles 粗糙表面轮廓的缺口根半径表征及优势谷附近应力集中系数分析

Rakenteiden Mekaniikka Pub Date : 2023-06-12 DOI: 10.23998/rm.124815

Silas Z. Gebrehiwot, Leonardo Espinosa-Leal, H. Remes, Marinus Vermunt

{"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}

引用次数: 0

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 基于单元平滑应变策略和三阶剪切变形理论的功能梯度碳纳米管增强复合材料板四节点四边形C0单元

Rakenteiden Mekaniikka Pub Date : 2023-05-02 DOI: 10.23998/rm.119608

Lan Hoang Ton That

引用次数: 0

Fatigue strength assessment of welded joints in the marine environment 海洋环境下焊接接头疲劳强度评定

Rakenteiden Mekaniikka Pub Date : 2023-05-02 DOI: 10.23998/rm.124670

A. Ahola, Timo Björk

{"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}

引用次数: 0

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 以最大限度的天然原材料为基础的夹层结构的耐久性：发泡聚苯乙烯、纤维素泡沫和聚乳酸在紫外线雨老化下的比较

Rakenteiden Mekaniikka Pub Date : 2023-05-02 DOI: 10.23998/rm.120756

Pauli Hakala, O. Orell, E. Sarlin, E. Pääkkönen, Lauri Jutila, M. Kanerva

{"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}

引用次数: 0

Heavy vehicle tyre testing in natural environments 重型车辆轮胎在自然环境下的试验

Rakenteiden Mekaniikka Pub Date : 2023-03-16 DOI: 10.23998/rm.120702

Miro-Tommi Tuutijärvi, A. Mahmoudzadeh Andwari, Ville Pirnes, Jonne Untinen

引用次数: 0

The coupling of solids and shells by conjugate approximations 用共轭近似法研究固体与壳的耦合

Rakenteiden Mekaniikka Pub Date : 2023-02-13 DOI: 10.23998/rm.120470

M. Malinen, P. Råback

引用次数: 0

Automated geometry and hexahedral mesh generation for kilometer-scale atmospheric flow simulations 自动几何和六面体网格生成的公里尺度大气流动模拟

Rakenteiden Mekaniikka Pub Date : 2023-02-13 DOI: 10.23998/rm.119848

E. Immonen, Dennis Bengs, Mikael Manngård, Johan Westö

{"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}

引用次数: 0