Pub Date : 2021-06-17DOI: 10.2495/CMEM-V9-N2-117-125
F. Concli, Concli Gorla
Gearboxes are widely used in several applications ranging from the automotive to the industrial and robotic sectors. A planetary gearbox is a special kinematic gear arrangement that, taking advantage of a planet carrier, ensures high reduction ratios together with a very small design. Therefore, they are widely employed for transmissions which require a high power density. There are several fields of applications including, but not limited to, mechatronic, automation and wind power generation. To improve the design of new solutions, for performing monitoring activities on actual gearboxes and for the definition of maintenance schedules, the availability of physical models able to accurately describe the behavior of the system, both in healthy and damaged conditions, would represent a great support. Experimental and numerical studies of the behavior of gearboxes are already available in the literature. Nevertheless, while the experimental approaches are valid only for the specific configuration tested, the numerical techniques show limitations related to the computational effort required. This paper presents an innovative approach for the characterization of the behavior of two different geared transmissions. It is based on a hybrid approach that combines finite elements (FE) with analytical formulations. In detail, the solver computes separately the macro deformation of the bodies (numerical solution based on a coarse grid) and the contacts (solved analytically avoiding the need of mesh refinements). The computational effort is reduced significantly without affecting the accuracy of the results significantly. This approach was used to investigate and understand the vibro-dynamical behavior of a back-to-back test rig (typically used for the characterization of the surface fatigue strength of gears) and of an indus- trial planetary gearbox. The results obtained for the healthy – not damaged – gearboxes were compared with experimental measurements for both configurations in order to validate the hybrid approach. Once the models were validated, the same methodology was eventually used to study the effects of typical gear failures and in specifically surface fatigue (pitting), on the vibrational response. The capability to reproduce the effect of damages with the model of a gearbox represents the first indispensable step of a Structural Health Monitoring strategy. State-of-art and challenges are analyzed and discussed in the paper.
{"title":"Dynamic modeling of gears: An innovative hybrid FEM–analytical approach","authors":"F. Concli, Concli Gorla","doi":"10.2495/CMEM-V9-N2-117-125","DOIUrl":"https://doi.org/10.2495/CMEM-V9-N2-117-125","url":null,"abstract":"Gearboxes are widely used in several applications ranging from the automotive to the industrial and robotic sectors. A planetary gearbox is a special kinematic gear arrangement that, taking advantage of a planet carrier, ensures high reduction ratios together with a very small design. Therefore, they are widely employed for transmissions which require a high power density. There are several fields of applications including, but not limited to, mechatronic, automation and wind power generation. To improve the design of new solutions, for performing monitoring activities on actual gearboxes and for the definition of maintenance schedules, the availability of physical models able to accurately describe the behavior of the system, both in healthy and damaged conditions, would represent a great support. Experimental and numerical studies of the behavior of gearboxes are already available in the literature. Nevertheless, while the experimental approaches are valid only for the specific configuration tested, the numerical techniques show limitations related to the computational effort required. This paper presents an innovative approach for the characterization of the behavior of two different geared transmissions. It is based on a hybrid approach that combines finite elements (FE) with analytical formulations. In detail, the solver computes separately the macro deformation of the bodies (numerical solution based on a coarse grid) and the contacts (solved analytically avoiding the need of mesh refinements). The computational effort is reduced significantly without affecting the accuracy of the results significantly. This approach was used to investigate and understand the vibro-dynamical behavior of a back-to-back test rig (typically used for the characterization of the surface fatigue strength of gears) and of an indus- trial planetary gearbox. The results obtained for the healthy – not damaged – gearboxes were compared with experimental measurements for both configurations in order to validate the hybrid approach. Once the models were validated, the same methodology was eventually used to study the effects of typical gear failures and in specifically surface fatigue (pitting), on the vibrational response. The capability to reproduce the effect of damages with the model of a gearbox represents the first indispensable step of a Structural Health Monitoring strategy. State-of-art and challenges are analyzed and discussed in the paper.","PeriodicalId":36958,"journal":{"name":"International Journal of Computational Methods and Experimental Measurements","volume":"61 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88779247","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 : 2021-03-04DOI: 10.2495/CMEM-V9-N1-28-37
S. Koley, K. Panduranga
In wave–structure interaction problems, energy balance relations are often derived and used to check the accuracy of the computational results obtained using numerical methods. These energy identities are also used to get qualitative information about various physical quantities of interest. It is well known that for rigid structures, the energy identity is K K r t 2 2 1 + = , where Kr and Kt are the reflection and transmission coefficients, respectively. Even if we take flexible barriers, then also the aforementioned energy identity will hold. Now, for wave past a thick porous structure, often a major portion of the incoming wave energy is dissipated due to the structural porosity. So, the aforementioned energy identity will be modified into K K K r t D 2 2 1 + + = , where KD takes into account the amount of dissipative wave energy. These energy identities are available in the literature for thin porous barriers. But derivation of the energy identity is complicated for thick porous structures due to complex momentum equation and boundary conditions. In the present paper, an appropriate energy identity will be derived for water waves past a thick rectangular porous structure. In this regard, Green’s second identity is used in multi-domain regions with the arguments velocity potential and its complex conjugate. With the help of complex function theory, the final form of the same is written in a compact form. Now, to compute each quantity associated with the energy identity, the associated boundary value problem is converted into a system of Fredholm integral equations. Finally, using the boundary element method, the components present in the energy identity are obtained and checked for validation.
在波-结构相互作用问题中，经常推导能量平衡关系，并用来检验数值方法计算结果的准确性。这些能量恒等式也被用来获得各种感兴趣的物理量的定性信息。众所周知，对于刚性结构，能量恒等式为K Kr t 2 2 1 + =，其中Kr和Kt分别为反射系数和透射系数。即使我们采取灵活的屏障，那么前面提到的能量同一性也会成立。现在，对于波浪通过厚多孔结构时，由于结构孔隙性，通常入射波能的大部分被耗散。因此，将上述能量恒等式修改为K K K r t D 2 21 1 + + =，其中KD考虑的是耗散波能的大小。这些能量恒等式在薄多孔势垒的文献中是可用的。但由于复杂的动量方程和边界条件，厚孔结构的能量恒等式推导比较复杂。本文将推导出水波通过厚矩形多孔结构时的能量恒等式。在这方面，格林的第二恒等式被用于多域区域，其参数是速度势及其复共轭。借助复变函数理论，将其最终形式写成紧化形式。现在，为了计算与能量恒等式相关的每一个量，相关的边值问题被转换成一个Fredholm积分方程系统。最后，利用边界元法，得到了能量恒等式中存在的分量，并进行了验证。
{"title":"Energy balance relations for flow through thick porous structures","authors":"S. Koley, K. Panduranga","doi":"10.2495/CMEM-V9-N1-28-37","DOIUrl":"https://doi.org/10.2495/CMEM-V9-N1-28-37","url":null,"abstract":"In wave–structure interaction problems, energy balance relations are often derived and used to check the accuracy of the computational results obtained using numerical methods. These energy identities are also used to get qualitative information about various physical quantities of interest. It is well known that for rigid structures, the energy identity is K K r t 2 2 1 + = , where Kr and Kt are the reflection and transmission coefficients, respectively. Even if we take flexible barriers, then also the aforementioned energy identity will hold. Now, for wave past a thick porous structure, often a major portion of the incoming wave energy is dissipated due to the structural porosity. So, the aforementioned energy identity will be modified into K K K r t D 2 2 1 + + = , where KD takes into account the amount of dissipative wave energy. These energy identities are available in the literature for thin porous barriers. But derivation of the energy identity is complicated for thick porous structures due to complex momentum equation and boundary conditions. In the present paper, an appropriate energy identity will be derived for water waves past a thick rectangular porous structure. In this regard, Green’s second identity is used in multi-domain regions with the arguments velocity potential and its complex conjugate. With the help of complex function theory, the final form of the same is written in a compact form. Now, to compute each quantity associated with the energy identity, the associated boundary value problem is converted into a system of Fredholm integral equations. Finally, using the boundary element method, the components present in the energy identity are obtained and checked for validation.","PeriodicalId":36958,"journal":{"name":"International Journal of Computational Methods and Experimental Measurements","volume":"181 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80251156","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 : 2021-01-01DOI: 10.2495/cmem-v9-n3-261-275
M. Pourghasemi, N. Fathi, P. Vorobieff, G. Ahmadi, Seyed Sobhan Aleyasin, L. Eça
An Eulerian–Lagrangian model is developed to investigate the solid particle migration in low Reynolds number shear flows between two parallel plates. A continuous kernel function with a predefined thickness is applied in the implemented numerical model to smooth the discontinuity at the interface between primary and secondary phases. At each time step, the solid particle’s rotation and displacement are calculated to directly capture the interaction between the solid particle and primary liquid phase without simplification. Solution verification is performed using the global deviation grid convergence index approach. The observed order of accuracy for the primary phase solver approaches 2, consistent with the formal order of accuracy of the applied discretization scheme. The obtained velocity profiles from the implemented numerical approach show a good agreement with the analytical solution, confirming the single-phase flow solver’s reliability. The obtained numerical results from the applied Eulerian–Lagrangian multiphase model are also compared with experimental data from a linear shear flow apparatus with suspended buoyant particles, and good agreement was found.
{"title":"Spherical particle migration evaluation in low reynolds number couette flow using smooth profile method","authors":"M. Pourghasemi, N. Fathi, P. Vorobieff, G. Ahmadi, Seyed Sobhan Aleyasin, L. Eça","doi":"10.2495/cmem-v9-n3-261-275","DOIUrl":"https://doi.org/10.2495/cmem-v9-n3-261-275","url":null,"abstract":"An Eulerian–Lagrangian model is developed to investigate the solid particle migration in low Reynolds number shear flows between two parallel plates. A continuous kernel function with a predefined thickness is applied in the implemented numerical model to smooth the discontinuity at the interface between primary and secondary phases. At each time step, the solid particle’s rotation and displacement are calculated to directly capture the interaction between the solid particle and primary liquid phase without simplification. Solution verification is performed using the global deviation grid convergence index approach. The observed order of accuracy for the primary phase solver approaches 2, consistent with the formal order of accuracy of the applied discretization scheme. The obtained velocity profiles from the implemented numerical approach show a good agreement with the analytical solution, confirming the single-phase flow solver’s reliability. The obtained numerical results from the applied Eulerian–Lagrangian multiphase model are also compared with experimental data from a linear shear flow apparatus with suspended buoyant particles, and good agreement was found.","PeriodicalId":36958,"journal":{"name":"International Journal of Computational Methods and Experimental Measurements","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81262863","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 : 2021-01-01DOI: 10.2495/cmem-v9-n3-213-225
Madhu Sudan Sapkota, E. Apeh, M. Hadfield, R. Haratian, R. Adey, J. Baynham
The validation of the operationality of models is considered a crucial step in the model development process. Recent developments in Digital Twinning (DT) enable the online availability of operational data from the physical asset required for operational validation. The benefits of DT in situations where operational validation has formed a basis for model adaptation has also been demonstrated. However, these benefits within DT have not been fully utilized due to the lack of an approach for benchmarking the required quantity, quality and diversity of validation data and performance metrics for online model validation and adaptation. Therefore, there is a need for a framework for benchmarking validation data and metrics requirements during model validation in different domains. An approach for benchmarking the required quantity, quality and variability of validation data and performance metric(s) for online model adaptation within DT is proposed. The approach is focused on addressing the problem of parameter(s) uncertainty of a predictive model within its uncertainty boundary. It involves generating virtual test models, a primary and another reference model for the performance evaluation of one compared to the another with the benchmarked validating data and metrics within DT. This process is repeated until the dataset and/or metric(s) are promising enough to validate primary model against the reference model. The proposed approach is demonstrated using BEASY – a simulator designed to predict protection provided by a cathodic protection system to an asset. In this case, a marine structure is the focus of the study, where the protection potentials to prevent corrosion are predicted over the life of the structure. The algorithm(s) for the approach are provided within a Scientific Software (MATLAB) and integrated to the simulator-based cathodic-protection model.
{"title":"An approac h for adaptive model performance validation within digital twinning","authors":"Madhu Sudan Sapkota, E. Apeh, M. Hadfield, R. Haratian, R. Adey, J. Baynham","doi":"10.2495/cmem-v9-n3-213-225","DOIUrl":"https://doi.org/10.2495/cmem-v9-n3-213-225","url":null,"abstract":"The validation of the operationality of models is considered a crucial step in the model development process. Recent developments in Digital Twinning (DT) enable the online availability of operational data from the physical asset required for operational validation. The benefits of DT in situations where operational validation has formed a basis for model adaptation has also been demonstrated. However, these benefits within DT have not been fully utilized due to the lack of an approach for benchmarking the required quantity, quality and diversity of validation data and performance metrics for online model validation and adaptation. Therefore, there is a need for a framework for benchmarking validation data and metrics requirements during model validation in different domains. An approach for benchmarking the required quantity, quality and variability of validation data and performance metric(s) for online model adaptation within DT is proposed. The approach is focused on addressing the problem of parameter(s) uncertainty of a predictive model within its uncertainty boundary. It involves generating virtual test models, a primary and another reference model for the performance evaluation of one compared to the another with the benchmarked validating data and metrics within DT. This process is repeated until the dataset and/or metric(s) are promising enough to validate primary model against the reference model. The proposed approach is demonstrated using BEASY – a simulator designed to predict protection provided by a cathodic protection system to an asset. In this case, a marine structure is the focus of the study, where the protection potentials to prevent corrosion are predicted over the life of the structure. The algorithm(s) for the approach are provided within a Scientific Software (MATLAB) and integrated to the simulator-based cathodic-protection model.","PeriodicalId":36958,"journal":{"name":"International Journal of Computational Methods and Experimental Measurements","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87427874","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 : 2021-01-01DOI: 10.2495/cmem-v9-n3-226-238
Simone Borrelli, A. Formaggio, Vittoria Civilini, A. Lugas
The study of the biomechanics of the human spine is not yet developed extensively. Recent developments in this field have heightened the need for observing the spine from a comprehensive perspective to understand the complex biomechanical patterns, which underlie the kinematic and dynamic responses of this multiple-joint column. Within this frame of exigence, a joint study embracing experimental tests and multibody modelling was designed. This study provides novel insights to the segmental contribution profiles in flexion and extension, analysing different forms of sagittal-plane angles. Moreover, the validation of the multibody model contributes to defining the key aspects for a consistent spine modelling as well as it introduces the basis for simulating pathological conditions and post-orthopaedic surgical outcomes.
{"title":"Phantom -based lumbar spine experimental investigation and validation of a multibody model","authors":"Simone Borrelli, A. Formaggio, Vittoria Civilini, A. Lugas","doi":"10.2495/cmem-v9-n3-226-238","DOIUrl":"https://doi.org/10.2495/cmem-v9-n3-226-238","url":null,"abstract":"The study of the biomechanics of the human spine is not yet developed extensively. Recent developments in this field have heightened the need for observing the spine from a comprehensive perspective to understand the complex biomechanical patterns, which underlie the kinematic and dynamic responses of this multiple-joint column. Within this frame of exigence, a joint study embracing experimental tests and multibody modelling was designed. This study provides novel insights to the segmental contribution profiles in flexion and extension, analysing different forms of sagittal-plane angles. Moreover, the validation of the multibody model contributes to defining the key aspects for a consistent spine modelling as well as it introduces the basis for simulating pathological conditions and post-orthopaedic surgical outcomes.","PeriodicalId":36958,"journal":{"name":"International Journal of Computational Methods and Experimental Measurements","volume":"85 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76259039","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 : 2021-01-01DOI: 10.2495/cmem-v9-n3-249-260
M. Mastrone, L. Fraccaroli, F. Concli
The correct prediction of ductile fracture of mechanical components requires the knowledge of physical quantities that are in the plastic field. This region is characterized by non-linearities, and the classical yield criteria cannot be applied since they work only in the elastic field. It has been observed that parameters such as stress triaxiality and plastic strain play a determinant role in failure mechanisms. Thanks to simulation software, it is possible to implement the virtual models capable of calculating these parameters numerically by solving partial differential equations. These parameters can then be used to describe the fracture locus of a material that, in turn, allows to predict failure of a component. In this work, the Rice and Tracey damage model was calibrated for an aluminum alloy and validated on a punch test exploiting Finite Element Analysis. Good agreement between experimental observations and numerical results was obtained, demonstrating the capability of the considered model to predict failure on a real test case.
{"title":"Ductile damage model of an alluminum alloy: experimental and numerical validation on a punch test","authors":"M. Mastrone, L. Fraccaroli, F. Concli","doi":"10.2495/cmem-v9-n3-249-260","DOIUrl":"https://doi.org/10.2495/cmem-v9-n3-249-260","url":null,"abstract":"The correct prediction of ductile fracture of mechanical components requires the knowledge of physical quantities that are in the plastic field. This region is characterized by non-linearities, and the classical yield criteria cannot be applied since they work only in the elastic field. It has been observed that parameters such as stress triaxiality and plastic strain play a determinant role in failure mechanisms. Thanks to simulation software, it is possible to implement the virtual models capable of calculating these parameters numerically by solving partial differential equations. These parameters can then be used to describe the fracture locus of a material that, in turn, allows to predict failure of a component. In this work, the Rice and Tracey damage model was calibrated for an aluminum alloy and validated on a punch test exploiting Finite Element Analysis. Good agreement between experimental observations and numerical results was obtained, demonstrating the capability of the considered model to predict failure on a real test case.","PeriodicalId":36958,"journal":{"name":"International Journal of Computational Methods and Experimental Measurements","volume":"56 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73361026","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 : 2021-01-01DOI: 10.2495/cmem-v9-n3-201-212
S. Martínez-Almajano, R. Castedo, Lina Ma López, Anastasio P. Santos, M. Chiquito, A. Alañón, C. Reifarth
This work deals with the response of eight reinforced concrete (RC) slabs, made at full-scale, some of them with the addition of externally bonded fibre reinforced polymer (FRP). The reinforcements were placed in all cases on the face opposite to the explosive detonation. Three scaled distances have been used from 0.83 m/kg1/3, in one test with no extra reinforcement; four tests were made with a scaled distance of 0.42 m/kg1/3: one without extra reinforcement, two with carbon fibre reinforcement (CFRP) and one with the E-glass fibre reinforcement (GFRP); finally, 0.21 m/kg1/3, in three trials, one without extra reinforcement, one with carbon fibre reinforcement and one with the E-GFRP. The first slab, used for calibration of the numerical models, was instrumented with pressure and acceleration sensors. For the validation of the other seven slabs, the damage surfaces on both sides of the slabs are used. In terms of numerical simulation performed with LS-DYNA, several models covering different solutions such as smooth particle hydrodynamics (SPH) or load blast enhanced have been performed for the description of the explosive, as well as the use of CSCM material models for concrete to analyse the best available solutions. The steel was modelled with the piecewise linear plasticity material, while the material laminated composite fabric was used for the FRP. Reinforcement with CFRP resulted in a generally reduced damage area on both surfaces. All models show a good correlation, including nonspherical charges made with SPH models, with the test results when comparing them with respect to acceleration and surface damage. SPH models work well for the high and medium scaled distance, but not so good for the shorter scaled distance.
{"title":"Field test and numerical modelling of RC slabs at different scaled distances with two types of external reinforcement","authors":"S. Martínez-Almajano, R. Castedo, Lina Ma López, Anastasio P. Santos, M. Chiquito, A. Alañón, C. Reifarth","doi":"10.2495/cmem-v9-n3-201-212","DOIUrl":"https://doi.org/10.2495/cmem-v9-n3-201-212","url":null,"abstract":"This work deals with the response of eight reinforced concrete (RC) slabs, made at full-scale, some of them with the addition of externally bonded fibre reinforced polymer (FRP). The reinforcements were placed in all cases on the face opposite to the explosive detonation. Three scaled distances have been used from 0.83 m/kg1/3, in one test with no extra reinforcement; four tests were made with a scaled distance of 0.42 m/kg1/3: one without extra reinforcement, two with carbon fibre reinforcement (CFRP) and one with the E-glass fibre reinforcement (GFRP); finally, 0.21 m/kg1/3, in three trials, one without extra reinforcement, one with carbon fibre reinforcement and one with the E-GFRP. The first slab, used for calibration of the numerical models, was instrumented with pressure and acceleration sensors. For the validation of the other seven slabs, the damage surfaces on both sides of the slabs are used. In terms of numerical simulation performed with LS-DYNA, several models covering different solutions such as smooth particle hydrodynamics (SPH) or load blast enhanced have been performed for the description of the explosive, as well as the use of CSCM material models for concrete to analyse the best available solutions. The steel was modelled with the piecewise linear plasticity material, while the material laminated composite fabric was used for the FRP. Reinforcement with CFRP resulted in a generally reduced damage area on both surfaces. All models show a good correlation, including nonspherical charges made with SPH models, with the test results when comparing them with respect to acceleration and surface damage. SPH models work well for the high and medium scaled distance, but not so good for the shorter scaled distance.","PeriodicalId":36958,"journal":{"name":"International Journal of Computational Methods and Experimental Measurements","volume":"257 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72401115","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 : 2021-01-01DOI: 10.2495/cmem-v9-n3-189-200
M. Šejnoha, J. Vorel, S. Valentová, G. Marseglia
This paper outlines the prediction of a macroscopic viscoelastic response of plain weave textile composites made either from basalt or carbon fiber tows impregnated by polymeric matrix. Owing to a natural orthotropic response at the level of yarns, the calibration of a simple meso-scale constitutive model from virtual laboratory tests is precluded and a fully coupled analysis is needed instead. One option is solving the problem in the framework of FE analysis when both the microand meso-scale problems are solved with the help of the finite element method. This requires formulation of a suitable computational model most often represented by a statistically equivalent periodic unit cell on both scales. However, such an approach may prove computationally expensive particularly at stages of initial design where a large parametric study is often needed to test various material and geometrical configurations. A suitable method of attack then arises from the application of computationally efficient classical micromechanical models such as the Mori-Tanaka (MT) method. This approach is examined in the present study. While the present work is mostly computational, it requires an extensive experimental program to tune the generalized Leonov constitutive model describing the behavior of the matrix phase. Additionally, a series of virtual laboratory tests is carried out at the level of yarns to improve the predictive capability of the MT method.
{"title":"Multiscale viscoelastic analysis of plain weave textile composites","authors":"M. Šejnoha, J. Vorel, S. Valentová, G. Marseglia","doi":"10.2495/cmem-v9-n3-189-200","DOIUrl":"https://doi.org/10.2495/cmem-v9-n3-189-200","url":null,"abstract":"This paper outlines the prediction of a macroscopic viscoelastic response of plain weave textile composites made either from basalt or carbon fiber tows impregnated by polymeric matrix. Owing to a natural orthotropic response at the level of yarns, the calibration of a simple meso-scale constitutive model from virtual laboratory tests is precluded and a fully coupled analysis is needed instead. One option is solving the problem in the framework of FE analysis when both the microand meso-scale problems are solved with the help of the finite element method. This requires formulation of a suitable computational model most often represented by a statistically equivalent periodic unit cell on both scales. However, such an approach may prove computationally expensive particularly at stages of initial design where a large parametric study is often needed to test various material and geometrical configurations. A suitable method of attack then arises from the application of computationally efficient classical micromechanical models such as the Mori-Tanaka (MT) method. This approach is examined in the present study. While the present work is mostly computational, it requires an extensive experimental program to tune the generalized Leonov constitutive model describing the behavior of the matrix phase. Additionally, a series of virtual laboratory tests is carried out at the level of yarns to improve the predictive capability of the MT method.","PeriodicalId":36958,"journal":{"name":"International Journal of Computational Methods and Experimental Measurements","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90064921","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 : 2020-01-01DOI: 10.2495/CMEM-V8-N1-13-26
A. Rudek, D. Muckenhaupt, T. Zitzmann, G. Russ, B. Duignan
A new defouling erosion model for Lagrangian particle tracking is used to predict defouling of amorphous, heterogeneous coatings such as those typically found in aircraft compressors. The main problem description, the mathematical formulation and the underpinning experiment of the model are presented in a previous communication by the authors. In this work, the Ansys CFX implementation of the model is described and an experiment is presented for the validation of the model. Air flows laden with a number of dry-ice particles are observed in an optically accessible stream channel containing a flat plate target. The defouling process of these particles is recorded with HSCs and the main parameters, such as indentation size in fouling layers, are processed and compared to corresponding numerical results. The model parameters considered are particle impact velocity and angle as well as particle and fouling material. Typical coatings which are relevant to commercial aircraft defouling processes are investigated. The target plate angle and the air velocity are varied and dry-ice particles of random size and shape are injected into the flow. The experiment is set up in a wind-tunnel test-rig and all recordings are made using two HSCs, a digital camera and Prandtl probe measurement. Experimental and numerical defouling results show good overall agreement for steep target angles but significant deviations for low target angles. Potential improvement to the defouling erosion model is discussed based on these results. The model as presented is used in large-scale compressor defouling simulations in the development process of on-wing aircraft maintenance systems.
{"title":"A validation study for a new erosion model to predict erosive airfoil defouling","authors":"A. Rudek, D. Muckenhaupt, T. Zitzmann, G. Russ, B. Duignan","doi":"10.2495/CMEM-V8-N1-13-26","DOIUrl":"https://doi.org/10.2495/CMEM-V8-N1-13-26","url":null,"abstract":"A new defouling erosion model for Lagrangian particle tracking is used to predict defouling of amorphous, heterogeneous coatings such as those typically found in aircraft compressors. The main problem description, the mathematical formulation and the underpinning experiment of the model are presented in a previous communication by the authors. In this work, the Ansys CFX implementation of the model is described and an experiment is presented for the validation of the model. Air flows laden with a number of dry-ice particles are observed in an optically accessible stream channel containing a flat plate target. The defouling process of these particles is recorded with HSCs and the main parameters, such as indentation size in fouling layers, are processed and compared to corresponding numerical results. The model parameters considered are particle impact velocity and angle as well as particle and fouling material. Typical coatings which are relevant to commercial aircraft defouling processes are investigated. The target plate angle and the air velocity are varied and dry-ice particles of random size and shape are injected into the flow. The experiment is set up in a wind-tunnel test-rig and all recordings are made using two HSCs, a digital camera and Prandtl probe measurement. Experimental and numerical defouling results show good overall agreement for steep target angles but significant deviations for low target angles. Potential improvement to the defouling erosion model is discussed based on these results. The model as presented is used in large-scale compressor defouling simulations in the development process of on-wing aircraft maintenance systems.","PeriodicalId":36958,"journal":{"name":"International Journal of Computational Methods and Experimental Measurements","volume":"14 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74098005","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 : 2019-10-01DOI: 10.2495/cmem-v7-n4-350-362
I. Roselli, G. Canio, M. Rossi, C. Calderini, S. Lagomarsino
The application of 3D motion capture systems to shaking table testing provides a unique tool for recording relative displacements of a large number of measurement points of the tested structure. The analysis of 3D relative displacements during dynamic tests allows us to evaluate the structure deformations and to monitor the cracks formation and evolution. The present paper focuses on the processing and analysis of 3D motion capture data to extract accurate displacements between markers positioned on a full-scale model of a masonry cross vault representing a vault of the mosque of Dey, Algiers, tested at the ENEA Casaccia Research Centre. The management and processing of the data acquired through 67 markers located on the vault are described, showing the potentialities of the methodology. Moreover, the possible formulation of damage indices based on the structure deformations and cracks aperture detected from markers relative displacements (MRDs) was explored. In particular, cracks could be counted and classifi ed as a function of the detected apertures, following damage thresholds indicated in the Italian regulations. Moreover, the failure mechanism could be easily visualized and analysed by monitoring the cumulative MRDs. In addition, in-plane and out-of-plane deformations of walls could be monitored during each seismic test, providing accurate information on the torsional and bending effects.
{"title":"Relative displacements of 3D optical markers for deformations and crack monitoring of a masonry structure under shaking table tests","authors":"I. Roselli, G. Canio, M. Rossi, C. Calderini, S. Lagomarsino","doi":"10.2495/cmem-v7-n4-350-362","DOIUrl":"https://doi.org/10.2495/cmem-v7-n4-350-362","url":null,"abstract":"The application of 3D motion capture systems to shaking table testing provides a unique tool for recording relative displacements of a large number of measurement points of the tested structure. The analysis of 3D relative displacements during dynamic tests allows us to evaluate the structure deformations and to monitor the cracks formation and evolution. The present paper focuses on the processing and analysis of 3D motion capture data to extract accurate displacements between markers positioned on a full-scale model of a masonry cross vault representing a vault of the mosque of Dey, Algiers, tested at the ENEA Casaccia Research Centre. The management and processing of the data acquired through 67 markers located on the vault are described, showing the potentialities of the methodology. Moreover, the possible formulation of damage indices based on the structure deformations and cracks aperture detected from markers relative displacements (MRDs) was explored. In particular, cracks could be counted and classifi ed as a function of the detected apertures, following damage thresholds indicated in the Italian regulations. Moreover, the failure mechanism could be easily visualized and analysed by monitoring the cumulative MRDs. In addition, in-plane and out-of-plane deformations of walls could be monitored during each seismic test, providing accurate information on the torsional and bending effects.","PeriodicalId":36958,"journal":{"name":"International Journal of Computational Methods and Experimental Measurements","volume":"28 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78185011","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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