Pub Date : 1900-01-01DOI: 10.23967/wccm-apcom.2022.064
E. Smotrova, S. Li, V. Silberschmidt
. Adaptation is the process, with which bone responds to changes in loading environment and modifies its properties and organisation to meet the mechanical demands. Trabecular bone undergoes significant adaptation when subjected to external forces, accomplished through resorption of old and fractured bone and formation of a new bone material. These processes are assumed to be driven by mechanical stimuli of bone-matrix deformation sensed by bone mechanosensory cells. Although numerous in vivo and in vitro experimental evidence of trabecular bone morphology adaptation was obtained, the exact nature of mechanical stimuli triggering biological responses (i.e., osteoclastic resorption and osteoblastic formation) is still debated. This study aims to compare different mechanical stimuli with regard to their ability to initiate the load-induced adaptation in trabecular bone. For this purpose, a 2D model of two trabeculae, connected at their basement, with bone marrow in the intertrabecular space was developed. The finite-element method was implemented for the model loaded in compression to calculate magnitudes of several candidates of the bone-adaptation stimuli. A user material subroutine was developed to relate a magnitude of each candidate to changes in the shape of trabeculae.
{"title":"Mechanical Stimuli in Prediction of Trabecular Bone Adaptation: Numerical Comparison","authors":"E. Smotrova, S. Li, V. Silberschmidt","doi":"10.23967/wccm-apcom.2022.064","DOIUrl":"https://doi.org/10.23967/wccm-apcom.2022.064","url":null,"abstract":". Adaptation is the process, with which bone responds to changes in loading environment and modifies its properties and organisation to meet the mechanical demands. Trabecular bone undergoes significant adaptation when subjected to external forces, accomplished through resorption of old and fractured bone and formation of a new bone material. These processes are assumed to be driven by mechanical stimuli of bone-matrix deformation sensed by bone mechanosensory cells. Although numerous in vivo and in vitro experimental evidence of trabecular bone morphology adaptation was obtained, the exact nature of mechanical stimuli triggering biological responses (i.e., osteoclastic resorption and osteoblastic formation) is still debated. This study aims to compare different mechanical stimuli with regard to their ability to initiate the load-induced adaptation in trabecular bone. For this purpose, a 2D model of two trabeculae, connected at their basement, with bone marrow in the intertrabecular space was developed. The finite-element method was implemented for the model loaded in compression to calculate magnitudes of several candidates of the bone-adaptation stimuli. A user material subroutine was developed to relate a magnitude of each candidate to changes in the shape of trabeculae.","PeriodicalId":429847,"journal":{"name":"15th World Congress on Computational Mechanics (WCCM-XV) and 8th Asian Pacific Congress on Computational Mechanics (APCOM-VIII)","volume":"100 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117191947","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}
Pub Date : 1900-01-01DOI: 10.23967/wccm-apcom.2022.072
I. Li, E. Wong, E. Sze
. The volume and mobility of a debris flow could increase with distance travelled as it has the potential to entrain a substantial amount of channel-bed material along its travel path. This entrainment effect renders the debris flow more devastating to downslope populations and facilities. Over the past two decades, the Geotechnical Engineering Office (GEO) of Hong Kong has expended considerable effort to develop debris mobility modelling tools for use in routine engineering practice for forward prediction purposes. Recently, GEO has completed a study to enhance an in-house debris mobility code. Physical parameters which can be estimated from the field by engineers or geologists are incorporated in the code to predict entrainment effects in a simple and rational manner. This allows the modelling of varying entrainment potential along a debris flow path. The code has been checked against simplified analytical solutions and validated against field observations in a major historical landslide event involving high-mobility debris flows in Hong Kong. The numerical modelling results indicated that simulated entrainment volume and mobility characteristics are broadly consistent with geological field mapping records.
{"title":"Modelling landslide debris flow with entrainment: development and validation","authors":"I. Li, E. Wong, E. Sze","doi":"10.23967/wccm-apcom.2022.072","DOIUrl":"https://doi.org/10.23967/wccm-apcom.2022.072","url":null,"abstract":". The volume and mobility of a debris flow could increase with distance travelled as it has the potential to entrain a substantial amount of channel-bed material along its travel path. This entrainment effect renders the debris flow more devastating to downslope populations and facilities. Over the past two decades, the Geotechnical Engineering Office (GEO) of Hong Kong has expended considerable effort to develop debris mobility modelling tools for use in routine engineering practice for forward prediction purposes. Recently, GEO has completed a study to enhance an in-house debris mobility code. Physical parameters which can be estimated from the field by engineers or geologists are incorporated in the code to predict entrainment effects in a simple and rational manner. This allows the modelling of varying entrainment potential along a debris flow path. The code has been checked against simplified analytical solutions and validated against field observations in a major historical landslide event involving high-mobility debris flows in Hong Kong. The numerical modelling results indicated that simulated entrainment volume and mobility characteristics are broadly consistent with geological field mapping records.","PeriodicalId":429847,"journal":{"name":"15th World Congress on Computational Mechanics (WCCM-XV) and 8th Asian Pacific Congress on Computational Mechanics (APCOM-VIII)","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116097361","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}
Pub Date : 1900-01-01DOI: 10.23967/wccm-apcom.2022.032
M. Yokoyama, A. Takei, R. Yoshidome, G. Yagawa
{"title":"Coupled simulation of vibration and sound radiation of violin in large space","authors":"M. Yokoyama, A. Takei, R. Yoshidome, G. Yagawa","doi":"10.23967/wccm-apcom.2022.032","DOIUrl":"https://doi.org/10.23967/wccm-apcom.2022.032","url":null,"abstract":"","PeriodicalId":429847,"journal":{"name":"15th World Congress on Computational Mechanics (WCCM-XV) and 8th Asian Pacific Congress on Computational Mechanics (APCOM-VIII)","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115356416","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}
Pub Date : 1900-01-01DOI: 10.23967/wccm-apcom.2022.110
F. Cruzeiro, L. Campos
. The accuracy of the numerical solution obtained by the Boundary Element Method (BEM) is directly affected by the type of interpolation function used. Meanwhile, interpolation by radial basis function augmented with polynomials has been shown to be more accurate than Lagrange interpolation for a range of different functions. Therefore, this paper is concerned with the application of such functions as the interpolation functions for all boundary values in the boundary element method for the numerical solution of two-dimensional heat transfer problems. Numerical examples with different geometries and temperature distributions are presented and comparisons with both isogeometric and classical formulation are made to demonstrate the accuracy of the proposed method.
{"title":"Testing the use of radial basis function augmented with polynomials as basis functions in the boundary element method for heat transfer problems","authors":"F. Cruzeiro, L. Campos","doi":"10.23967/wccm-apcom.2022.110","DOIUrl":"https://doi.org/10.23967/wccm-apcom.2022.110","url":null,"abstract":". The accuracy of the numerical solution obtained by the Boundary Element Method (BEM) is directly affected by the type of interpolation function used. Meanwhile, interpolation by radial basis function augmented with polynomials has been shown to be more accurate than Lagrange interpolation for a range of different functions. Therefore, this paper is concerned with the application of such functions as the interpolation functions for all boundary values in the boundary element method for the numerical solution of two-dimensional heat transfer problems. Numerical examples with different geometries and temperature distributions are presented and comparisons with both isogeometric and classical formulation are made to demonstrate the accuracy of the proposed method.","PeriodicalId":429847,"journal":{"name":"15th World Congress on Computational Mechanics (WCCM-XV) and 8th Asian Pacific Congress on Computational Mechanics (APCOM-VIII)","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121754663","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}
Pub Date : 1900-01-01DOI: 10.23967/wccm-apcom.2022.038
B. Rodenberg
{"title":"Design and evaluation of a waveform iteration–based approach for coupling heterogeneous time stepping methods via preCICE","authors":"B. Rodenberg","doi":"10.23967/wccm-apcom.2022.038","DOIUrl":"https://doi.org/10.23967/wccm-apcom.2022.038","url":null,"abstract":"","PeriodicalId":429847,"journal":{"name":"15th World Congress on Computational Mechanics (WCCM-XV) and 8th Asian Pacific Congress on Computational Mechanics (APCOM-VIII)","volume":"97 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124073506","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}
Pub Date : 1900-01-01DOI: 10.23967/wccm-apcom.2022.085
I. Riku, K. Mimura
. In this study, we at first employ a nonaffine polymer chains network model to account for the irreversible structural change during the deformation of DN gels. And then, a finite element model of the DN gels under simple tension is constructed. On the other hand, neck propagation is one kind of localized instability and there will be a local transfer of strain energy from one part of the model to neighboring parts. To solve such unstable quasi-static problem, an automatic mechanism provided by Abaqus/Standard is employed. The simulation results show that the nonaffine polymer chains network model together with the stablization algorithm for localized transformation of strain energy can be employed to reproduce the phenomenon of neck propagation in DN gels very well.
{"title":"Numerical Simulation of Neck Propagation in Double Network Hydrogel","authors":"I. Riku, K. Mimura","doi":"10.23967/wccm-apcom.2022.085","DOIUrl":"https://doi.org/10.23967/wccm-apcom.2022.085","url":null,"abstract":". In this study, we at first employ a nonaffine polymer chains network model to account for the irreversible structural change during the deformation of DN gels. And then, a finite element model of the DN gels under simple tension is constructed. On the other hand, neck propagation is one kind of localized instability and there will be a local transfer of strain energy from one part of the model to neighboring parts. To solve such unstable quasi-static problem, an automatic mechanism provided by Abaqus/Standard is employed. The simulation results show that the nonaffine polymer chains network model together with the stablization algorithm for localized transformation of strain energy can be employed to reproduce the phenomenon of neck propagation in DN gels very well.","PeriodicalId":429847,"journal":{"name":"15th World Congress on Computational Mechanics (WCCM-XV) and 8th Asian Pacific Congress on Computational Mechanics (APCOM-VIII)","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123392989","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}
Pub Date : 1900-01-01DOI: 10.23967/wccm-apcom.2022.095
K. Kida, Y. Wada
. The prediction of fracture behavior under extremely low cycle fatigue due to excessive loading is necessary for the life assessment of structures. This study evaluates the validity of the crack propagation criterion proposed in a previous study by performing generation phase and application phase analysis based on the results of fracture tests on a 1.5T-CT specimen (SGV410). The analysis show that the crack propagation criterion in the previous study predicted the experimental behavior well, however crack shape was incomplete in reproducing the crack shape.
{"title":"Proposal of Crack Propagation Criterion Considered Constraint Effect under Extremely Low Cycle Fatigue; Evaluation by 1.5T-CT Specimen","authors":"K. Kida, Y. Wada","doi":"10.23967/wccm-apcom.2022.095","DOIUrl":"https://doi.org/10.23967/wccm-apcom.2022.095","url":null,"abstract":". The prediction of fracture behavior under extremely low cycle fatigue due to excessive loading is necessary for the life assessment of structures. This study evaluates the validity of the crack propagation criterion proposed in a previous study by performing generation phase and application phase analysis based on the results of fracture tests on a 1.5T-CT specimen (SGV410). The analysis show that the crack propagation criterion in the previous study predicted the experimental behavior well, however crack shape was incomplete in reproducing the crack shape.","PeriodicalId":429847,"journal":{"name":"15th World Congress on Computational Mechanics (WCCM-XV) and 8th Asian Pacific Congress on Computational Mechanics (APCOM-VIII)","volume":"110 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124103270","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}
Pub Date : 1900-01-01DOI: 10.23967/wccm-apcom.2022.126
D. Magisano, L. Leonetti, G. Garcea
. This work presents a numerical framework for long dynamic simulations of structures made of multiple thin shells undergoing large deformations. The C1-continuity requirement of the Kirchhoff-Love theory is met in the interior of patches by cubic NURBS approximation functions with membrane locking avoided by patch-wise reduced integration. A simple penalty approach for coupling adjacent patches, applicable also to non-smooth interfaces and non-matching discretization is adopted to impose translational and rotational continuity. A time-stepping scheme is proposed to achieve energy conservation and unconditional stability for general nonlinear strain measures and penalty coupling terms, like the nonlinear rotational one for thin shells. The method is a modified mid-point rule with the internal forces evaluated using the average value of the stress at the step end-points and an integral mean of the strain-displacement tangent operator over the step computed by time integration points.
{"title":"Unconditionally stable dynamic analysis of multi-patch Kirchhoff-Love shells in large deformations","authors":"D. Magisano, L. Leonetti, G. Garcea","doi":"10.23967/wccm-apcom.2022.126","DOIUrl":"https://doi.org/10.23967/wccm-apcom.2022.126","url":null,"abstract":". This work presents a numerical framework for long dynamic simulations of structures made of multiple thin shells undergoing large deformations. The C1-continuity requirement of the Kirchhoff-Love theory is met in the interior of patches by cubic NURBS approximation functions with membrane locking avoided by patch-wise reduced integration. A simple penalty approach for coupling adjacent patches, applicable also to non-smooth interfaces and non-matching discretization is adopted to impose translational and rotational continuity. A time-stepping scheme is proposed to achieve energy conservation and unconditional stability for general nonlinear strain measures and penalty coupling terms, like the nonlinear rotational one for thin shells. The method is a modified mid-point rule with the internal forces evaluated using the average value of the stress at the step end-points and an integral mean of the strain-displacement tangent operator over the step computed by time integration points.","PeriodicalId":429847,"journal":{"name":"15th World Congress on Computational Mechanics (WCCM-XV) and 8th Asian Pacific Congress on Computational Mechanics (APCOM-VIII)","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123779504","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}
Pub Date : 1900-01-01DOI: 10.23967/wccm-apcom.2022.127
U. Ali, M. Kikumoto, M. Ciantia, Y. Cui
. Validation and/or calibration of distinct element method (DEM) models is usually performed by comparing element test simulation results with the corresponding stress-strain relationships observed in the laboratory [1] . However, such a validation procedure performed at the macroscopic level does not ensure capturing the microscopic particle-level motion [2] . Thus, the reliability of the DEM model may be limited to some stress paths and may not hold when the material response becomes non-uniform for example when shear bands develop. In this study, the validity of the DEM is assessed by comparing the numerical result with experimental data considering both particle-scale behavior (including particle rotations) and macroscopic stress-strain characteristics observed in shearing tests on granular media. Biaxial shearing tests were conducted on bi-disperse granular assemblies composed of around 2700 circular particles under different confining pressures. Particle-level motions were detected by a novel image analysis technique. Particle rotations are observed to be a key mechanism for the deformation of granular materials. The results from this study suggest that to properly calibrate DEM models able to capture the mechanical behavior in a more realistic way particle scale motions observed in laboratory experiments along with macroscopic response are necessary.
{"title":"Validation of DEM using macroscopic stress-strain behavior and microscopic particle motion in sheared granular assemblies","authors":"U. Ali, M. Kikumoto, M. Ciantia, Y. Cui","doi":"10.23967/wccm-apcom.2022.127","DOIUrl":"https://doi.org/10.23967/wccm-apcom.2022.127","url":null,"abstract":". Validation and/or calibration of distinct element method (DEM) models is usually performed by comparing element test simulation results with the corresponding stress-strain relationships observed in the laboratory [1] . However, such a validation procedure performed at the macroscopic level does not ensure capturing the microscopic particle-level motion [2] . Thus, the reliability of the DEM model may be limited to some stress paths and may not hold when the material response becomes non-uniform for example when shear bands develop. In this study, the validity of the DEM is assessed by comparing the numerical result with experimental data considering both particle-scale behavior (including particle rotations) and macroscopic stress-strain characteristics observed in shearing tests on granular media. Biaxial shearing tests were conducted on bi-disperse granular assemblies composed of around 2700 circular particles under different confining pressures. Particle-level motions were detected by a novel image analysis technique. Particle rotations are observed to be a key mechanism for the deformation of granular materials. The results from this study suggest that to properly calibrate DEM models able to capture the mechanical behavior in a more realistic way particle scale motions observed in laboratory experiments along with macroscopic response are necessary.","PeriodicalId":429847,"journal":{"name":"15th World Congress on Computational Mechanics (WCCM-XV) and 8th Asian Pacific Congress on Computational Mechanics (APCOM-VIII)","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129873401","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}
Pub Date : 1900-01-01DOI: 10.23967/wccm-apcom.2022.044
N. Yamagata, M. Ichimiya
. Die-casting is a casting method suitable for mass production because it can accurately form complicated shapes. However, when the mold is filled with the molten metal, casting cavities (gas porosity) are generated due to air entrainment, and the strength of the product varies. In this study, the mold filling process considering air entrainment in the die cast are simulated using the two-phase flow SPH method. And then, the behavior of air entrainment due to the filling of molten metal (Aluminum alloy), especially the efect of injection speeds are investigated. In concluson, it is possible to investigate the air entrainment behavior at the time of filling the molten metal and the flow behavior due to different filling speeds. In addition, to speed up the two-phase flow program by SPH method, a parallel algorithm using OpenMP is implemented.
{"title":"Development of Mold Filling Process Simulation considering Air Entrainment using SPH Method","authors":"N. Yamagata, M. Ichimiya","doi":"10.23967/wccm-apcom.2022.044","DOIUrl":"https://doi.org/10.23967/wccm-apcom.2022.044","url":null,"abstract":". Die-casting is a casting method suitable for mass production because it can accurately form complicated shapes. However, when the mold is filled with the molten metal, casting cavities (gas porosity) are generated due to air entrainment, and the strength of the product varies. In this study, the mold filling process considering air entrainment in the die cast are simulated using the two-phase flow SPH method. And then, the behavior of air entrainment due to the filling of molten metal (Aluminum alloy), especially the efect of injection speeds are investigated. In concluson, it is possible to investigate the air entrainment behavior at the time of filling the molten metal and the flow behavior due to different filling speeds. In addition, to speed up the two-phase flow program by SPH method, a parallel algorithm using OpenMP is implemented.","PeriodicalId":429847,"journal":{"name":"15th World Congress on Computational Mechanics (WCCM-XV) and 8th Asian Pacific Congress on Computational Mechanics (APCOM-VIII)","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129803070","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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