Masonry is a composite material and can be considered anisotropic on a macroscopic scale, i.e., masonry exhibits different properties in different directions, both in the elastic and inelastic range. Like other quasi-brittle materials, masonry exhibits softening and hardening behavior after failure for compression and tension. In this paper a smeared continuum plasticity model of masonry is presented as well as it numerical implementation in an explicit finite element time integration scheme, as such a material model does not exist for a commercial explicit finite element solver. The implementation is done by writing a user-defined material model (VUMAT) as a Fortran subroutine in the commercial software ABAQUS Explicit. The material model is tested both in uniaxial and biaxial loading against similar tests from earlier research. The results show good agreement with earlier research.
{"title":"A plane-stress plasticity model for masonry for the explicit finite element time integration scheme","authors":"Oliver Lundqvist, M. Chauhan","doi":"10.23998/rm.76502","DOIUrl":"https://doi.org/10.23998/rm.76502","url":null,"abstract":"Masonry is a composite material and can be considered anisotropic on a macroscopic scale, i.e., masonry exhibits different properties in different directions, both in the elastic and inelastic range. Like other quasi-brittle materials, masonry exhibits softening and hardening behavior after failure for compression and tension. In this paper a smeared continuum plasticity model of masonry is presented as well as it numerical implementation in an explicit finite element time integration scheme, as such a material model does not exist for a commercial explicit finite element solver. The implementation is done by writing a user-defined material model (VUMAT) as a Fortran subroutine in the commercial software ABAQUS Explicit. The material model is tested both in uniaxial and biaxial loading against similar tests from earlier research. The results show good agreement with earlier research.","PeriodicalId":52331,"journal":{"name":"Rakenteiden Mekaniikka","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68797437","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}
The understanding and assessment of accidental crash scenarios on reinforced concrete structures is of high interest for safety issues. Although experimental research on this topic has already a long and successful history, there are many issues waiting to be solved as far as numerical simulations are concerned. In this article some particularities of the Abaqus Concrete Damaged Plasticity (CDP) model are investigated with the purpose of using efficiently the CDP model in impact loaded reinforced concrete structure simulations. In particular, the sensitivity of the simulation response with respect to model parameters and element size is studied. The simulation response is compared to measurements from benchmark impact tests on reinforced concrete plates.
{"title":"Using the Abaqus CDP model in impact simulations","authors":"Alexis Fedoroff, K. Calonius","doi":"10.23998/rm.79723","DOIUrl":"https://doi.org/10.23998/rm.79723","url":null,"abstract":"The understanding and assessment of accidental crash scenarios on reinforced concrete structures is of high interest for safety issues. Although experimental research on this topic has already a long and successful history, there are many issues waiting to be solved as far as numerical simulations are concerned. In this article some particularities of the Abaqus Concrete Damaged Plasticity (CDP) model are investigated with the purpose of using efficiently the CDP model in impact loaded reinforced concrete structure simulations. In particular, the sensitivity of the simulation response with respect to model parameters and element size is studied. The simulation response is compared to measurements from benchmark impact tests on reinforced concrete plates.","PeriodicalId":52331,"journal":{"name":"Rakenteiden Mekaniikka","volume":"53 1","pages":"180-207"},"PeriodicalIF":0.0,"publicationDate":"2020-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43366631","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}
The objective of COMPLETE project is to provide a decision-making optimization tool for controlling harmful invasive species spreading in the Baltic Sea region due to biofouling of ship hull structures. The tool includes several elements that consider the research problem, for example, from biological or toxicological points of view. In this paper, the methods used for defining towing resistances of ships is studied. The aim is to create a toolkit for the evaluation of the effect of biofouling on a single vessel level. Theoretical results are compared to the recorded values of empirical measurements performed during normal operation of the ship. The goal is to observe the impact of variables that are difficult to model (such as weather conditions) and assess the potential need for further development of the tool.
{"title":"Laivojen pohjien likaantumisen vaikutus kulkuvastukseen Itämerellä: teoreettinen viitekehys ja empiiriset mittaukset","authors":"Elias Altarriba","doi":"10.23998/rm.79336","DOIUrl":"https://doi.org/10.23998/rm.79336","url":null,"abstract":"The objective of COMPLETE project is to provide a decision-making optimization tool for controlling harmful invasive species spreading in the Baltic Sea region due to biofouling of ship hull structures. The tool includes several elements that consider the research problem, for example, from biological or toxicological points of view. In this paper, the methods used for defining towing resistances of ships is studied. The aim is to create a toolkit for the evaluation of the effect of biofouling on a single vessel level. Theoretical results are compared to the recorded values of empirical measurements performed during normal operation of the ship. The goal is to observe the impact of variables that are difficult to model (such as weather conditions) and assess the potential need for further development of the tool.","PeriodicalId":52331,"journal":{"name":"Rakenteiden Mekaniikka","volume":"53 1","pages":"208-239"},"PeriodicalIF":0.0,"publicationDate":"2020-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47624006","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 paper considers numerically the effect of pore-fluid on thermal spallation of granitic rock. For this end, a numerical model based on the embedded discontinuity finite element approach to rock fracture and an explicit scheme to solve the underlying thermo-mechanical problem is developed. In the present implementation, a displacement discontinuity (crack) is embedded perpendicular to the first principal direction in a linear triangle element upon violation of the Rankine criterion. In the thermo-mechanical problem, the heating due to mechanical dissipation is neglected as insignificant in comparison to the external heat flux. This leads to an uncoupled thermo-mechanical problem where the only input from the thermal part to the mechanical part is thermal strains. This problem is solved with explicit time marching using the mass scaling to speed up the solution. Finally, the fluid trapped into the micro-pores is modelled as a material that can bear only volumetric compressive stresses. A thermal spallation problem of a rock sample under axisymmetry is simulated as a numerical example.
{"title":"Numerical modelling of pore-fluid-enhanced thermal spallation in granitic rock","authors":"T. Saksala","doi":"10.23998/rm.77645","DOIUrl":"https://doi.org/10.23998/rm.77645","url":null,"abstract":"This paper considers numerically the effect of pore-fluid on thermal spallation of granitic rock. For this end, a numerical model based on the embedded discontinuity finite element approach to rock fracture and an explicit scheme to solve the underlying thermo-mechanical problem is developed. In the present implementation, a displacement discontinuity (crack) is embedded perpendicular to the first principal direction in a linear triangle element upon violation of the Rankine criterion. In the thermo-mechanical problem, the heating due to mechanical dissipation is neglected as insignificant in comparison to the external heat flux. This leads to an uncoupled thermo-mechanical problem where the only input from the thermal part to the mechanical part is thermal strains. This problem is solved with explicit time marching using the mass scaling to speed up the solution. Finally, the fluid trapped into the micro-pores is modelled as a material that can bear only volumetric compressive stresses. A thermal spallation problem of a rock sample under axisymmetry is simulated as a numerical example.","PeriodicalId":52331,"journal":{"name":"Rakenteiden Mekaniikka","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42482920","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}
H. Askes, J. Hartikainen, K. Kolari, R. Kouhia, T. Saksala, Jani Vilppo
In this paper two partially complementary formulations of the simple phenomenological Kachanov-Rabotnov continuum damage constitutive model are presented. The models are based on a consistent thermodynamic formulation using proper expressions for the Helmholtz free energy or its complementary form of the dissipation potential. Basic features of the models are discussed and the behaviour in tensile test and creep problems is demonstrated.
{"title":"On the Kachanov-Rabotnov continuum damage model","authors":"H. Askes, J. Hartikainen, K. Kolari, R. Kouhia, T. Saksala, Jani Vilppo","doi":"10.23998/rm.82528","DOIUrl":"https://doi.org/10.23998/rm.82528","url":null,"abstract":"In this paper two partially complementary formulations of the simple phenomenological Kachanov-Rabotnov continuum damage constitutive model are presented. The models are based on a consistent thermodynamic formulation using proper expressions for the Helmholtz free energy or its complementary form of the dissipation potential. Basic features of the models are discussed and the behaviour in tensile test and creep problems is demonstrated.","PeriodicalId":52331,"journal":{"name":"Rakenteiden Mekaniikka","volume":"53 1","pages":"125-144"},"PeriodicalIF":0.0,"publicationDate":"2020-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42488640","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 this paper, the celebrated theorem of G. Grioli is considered according to which the rotation factor in the polar decomposition of the deformation gradient minimizes Biot's strain tensor. The theorem is demonstrated by applications to some cases in large displacement theory: simple shear, plane deformation, Euler-Bernoulli and Timoshenko beam theories, and bar element in space. An interpretation could be that the material behaves economically: first occurs the part of deformation which does not induce any stresses and then the material starts to resist the deformation.
{"title":"Griolin teoreema: rotaatio, joka minimoi muodonmuutoksen","authors":"Martti Mikkola","doi":"10.23998/rm.77296","DOIUrl":"https://doi.org/10.23998/rm.77296","url":null,"abstract":"In this paper, the celebrated theorem of G. Grioli is considered according to which the rotation factor in the polar decomposition of the deformation gradient minimizes Biot's strain tensor. The theorem is demonstrated by applications to some cases in large displacement theory: simple shear, plane deformation, Euler-Bernoulli and Timoshenko beam theories, and bar element in space. An interpretation could be that the material behaves economically: first occurs the part of deformation which does not induce any stresses and then the material starts to resist the deformation.","PeriodicalId":52331,"journal":{"name":"Rakenteiden Mekaniikka","volume":"53 1","pages":"110-124"},"PeriodicalIF":0.0,"publicationDate":"2020-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45891961","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}
Artikkeli on täydennys tämän lehden aikaisempaan energiataseiden käyttöä koskevaan artikkeliin. Mekaanisen energian taseen periaatteessa kokoonpuristuvassa virtauksessa esiintyvä niin sanottu kokoonpuristumistermi otetaan mukaan tarkasteluun. Eräs havainnollistava esimerkkitapaus käydään yksityiskohtaisesti läpi. Lisäksi esitetään kritiikkiä virtauslaskennan esityksissä ilmeneviin epätäsmällisyyksiin, joita saattaa esiintyä energiatarkastelujen yhteydessä.
{"title":"Lisähuomioita energiataseiden käytöstä virtauslaskennassa","authors":"E-M. Salonen, Rauno Holopainen","doi":"10.23998/rm.82681","DOIUrl":"https://doi.org/10.23998/rm.82681","url":null,"abstract":"Artikkeli on täydennys tämän lehden aikaisempaan energiataseiden käyttöä koskevaan artikkeliin. Mekaanisen energian taseen periaatteessa kokoonpuristuvassa virtauksessa esiintyvä niin sanottu kokoonpuristumistermi otetaan mukaan tarkasteluun. Eräs havainnollistava esimerkkitapaus käydään yksityiskohtaisesti läpi. Lisäksi esitetään kritiikkiä virtauslaskennan esityksissä ilmeneviin epätäsmällisyyksiin, joita saattaa esiintyä energiatarkastelujen yhteydessä.","PeriodicalId":52331,"journal":{"name":"Rakenteiden Mekaniikka","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41802460","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}
Antti-Jussi Vuotikka, Marko Jokinen, Pasi Halla-aho, Jukka Aho, A. Mäntylä, T. Frondelius
It has been recently discovered that there is a periodical axial impact phenomenon in a running engine crankshaft. Bending of the shaft causes significant extension of the crankshaft and impact to the engine block through the axial thrust bearing. The aim of this work is to study impact-induced energy fluctuations in a complex-shaped Wartsila sixteen vee 32 engine crankshaft by using an explicit finite element method (FEM) during the first 25 ms after impact. Using the FEM allows us to study real components used in industry, and analyze their dynamics in the transient phase. In conclusion, we found interesting results that can be used as guidelines for a full-scale crankshaft measurement instrumentation plan. The full-scale measurements will be performed later in the Wartsila Oy facility at Vaasa, Finland. The main finding is that a substantive amount of energy is trapped in the head region and the first two crank pins of the crankshaft, which can affect crankshaft durability regarding high-cycle fatigue.
{"title":"Finite element method modeling of crankshaft axial impact measurements","authors":"Antti-Jussi Vuotikka, Marko Jokinen, Pasi Halla-aho, Jukka Aho, A. Mäntylä, T. Frondelius","doi":"10.23998/rm.80099","DOIUrl":"https://doi.org/10.23998/rm.80099","url":null,"abstract":"It has been recently discovered that there is a periodical axial impact phenomenon in a running engine crankshaft. Bending of the shaft causes significant extension of the crankshaft and impact to the engine block through the axial thrust bearing. The aim of this work is to study impact-induced energy fluctuations in a complex-shaped Wartsila sixteen vee 32 engine crankshaft by using an explicit finite element method (FEM) during the first 25 ms after impact. Using the FEM allows us to study real components used in industry, and analyze their dynamics in the transient phase. In conclusion, we found interesting results that can be used as guidelines for a full-scale crankshaft measurement instrumentation plan. The full-scale measurements will be performed later in the Wartsila Oy facility at Vaasa, Finland. The main finding is that a substantive amount of energy is trapped in the head region and the first two crank pins of the crankshaft, which can affect crankshaft durability regarding high-cycle fatigue.","PeriodicalId":52331,"journal":{"name":"Rakenteiden Mekaniikka","volume":"53 1","pages":"85-99"},"PeriodicalIF":0.0,"publicationDate":"2020-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48934284","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}
The article examines curvilinear coordinate systems generalized from rectangular linear coordinate systems and transformations theirbetween. The theory is based on the theory of linear coordinate systems. Unambigious definition of the base system of linear coordinate systems is considered a key feature of the generalization. The applications concern important coordinate systems applied in continuum mechanics, transformations between the coordinate systems, change of basis, the derivatives of changed bases, and the so-called Christoffel symbols needed in the derivatives. Also benefits of curvilinear coordinates and their transformations are discussed. The article is based on T. Salmi's unpublished written material.
{"title":"Käyräviivaiset koordinaatistot kontinuumimekaniikassa","authors":"Sami Holopainen","doi":"10.23998/rm.83338","DOIUrl":"https://doi.org/10.23998/rm.83338","url":null,"abstract":"The article examines curvilinear coordinate systems generalized from rectangular linear coordinate systems and transformations theirbetween. The theory is based on the theory of linear coordinate systems. Unambigious definition of the base system of linear coordinate systems is considered a key feature of the generalization. The applications concern important coordinate systems applied in continuum mechanics, transformations between the coordinate systems, change of basis, the derivatives of changed bases, and the so-called Christoffel symbols needed in the derivatives. Also benefits of curvilinear coordinates and their transformations are discussed. The article is based on T. Salmi's unpublished written material.","PeriodicalId":52331,"journal":{"name":"Rakenteiden Mekaniikka","volume":"53 1","pages":"53-66"},"PeriodicalIF":0.0,"publicationDate":"2020-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42652683","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：