Departament de Resistència dels Materials i Estructures en Enginyeria (fins octubre 2015)
http://hdl.handle.net/2117/4001
2017-10-19T11:15:14ZDamage analysis of masonry structures subjected to rockfalls
http://hdl.handle.net/2117/108810
Damage analysis of masonry structures subjected to rockfalls
Mavrouli, Olga Christina; Giannopoulos, P. G.; Carbonell Puigbó, Josep Maria; Syrmakezis, Costas
Masonry structures present substantial vulnerability to rockfalls. The methodologies for the damage quantification of masonry structures subjected to rockfalls are scarce. An analytical procedure for the damage assessment of masonry structures is presented. The procedure comprises three stages: (1) determination of the rockfall impact actions which are applied to a masonry structure, in terms of external forces, using the particle finite element method (PFEM), (2) evaluation of the mechanical properties, modelling of the masonry structure, and calculation of the internal stresses, using the finite element method (FEM), (3) assessment of the damage due to the rockfall actions, applying a failure criterion adapted to masonries, and calculation of the damage in terms of the percentage of the damaged wall surface. Three real rockfall events and their impact on buildings are analysed. A sensitivity analysis of the proposed procedure is then used to identify the variables that mostly affect the extent of the wall damage, which are the masonry width, the tensile strength, the block diameter and lastly, velocity.
2017-10-18T15:08:11ZMavrouli, Olga ChristinaGiannopoulos, P. G.Carbonell Puigbó, Josep MariaSyrmakezis, CostasMasonry structures present substantial vulnerability to rockfalls. The methodologies for the damage quantification of masonry structures subjected to rockfalls are scarce. An analytical procedure for the damage assessment of masonry structures is presented. The procedure comprises three stages: (1) determination of the rockfall impact actions which are applied to a masonry structure, in terms of external forces, using the particle finite element method (PFEM), (2) evaluation of the mechanical properties, modelling of the masonry structure, and calculation of the internal stresses, using the finite element method (FEM), (3) assessment of the damage due to the rockfall actions, applying a failure criterion adapted to masonries, and calculation of the damage in terms of the percentage of the damaged wall surface. Three real rockfall events and their impact on buildings are analysed. A sensitivity analysis of the proposed procedure is then used to identify the variables that mostly affect the extent of the wall damage, which are the masonry width, the tensile strength, the block diameter and lastly, velocity.Comparison of production strategies and degree of postponement when incorporating additive manufacturing to product supply chains
http://hdl.handle.net/2117/108718
Comparison of production strategies and degree of postponement when incorporating additive manufacturing to product supply chains
Minguella Canela, Joaquim; Muguruza Blanco, Asier; Bonada Bo, Jordi; Ramón Lumbierres, Daniel Jacobo; Heredia, F.-Javier (Francisco Javier); Gimeno Feu, Robert; Guo, Ping; Hamilton, Mary; Shastry, Kiron; Webb, Sunny
The best-selling products manufactured nowadays are made in long series along rigid product value chains. Product repetition and continuous/stable manufacturing is seen as a chance for achieving economies of scale. Nevertheless, these speculative strategies fail to meet special customer demands, thus reducing the effective market share of a product in a range. Additive Manufacturing technologies open promising product customization opportunities; however, to achieve it, it is necessary to delay the production operations in order to incorporate the customer’s inputs in the product materialization. The study offered in the present paper compares different possible production strategies for a product (via conventional technologies and Additive Manufacturing) and assesses the degree of postponement that it would be recommended in order to meet a certain demand distribution. The problem solving is calculated by a program containing a stochastic mathematical model which incorporates extensive information on costs and lead times for the required manufacturing operations.
2017-10-16T11:33:58ZMinguella Canela, JoaquimMuguruza Blanco, AsierBonada Bo, JordiRamón Lumbierres, Daniel JacoboHeredia, F.-Javier (Francisco Javier)Gimeno Feu, RobertGuo, PingHamilton, MaryShastry, KironWebb, SunnyThe best-selling products manufactured nowadays are made in long series along rigid product value chains. Product repetition and continuous/stable manufacturing is seen as a chance for achieving economies of scale. Nevertheless, these speculative strategies fail to meet special customer demands, thus reducing the effective market share of a product in a range. Additive Manufacturing technologies open promising product customization opportunities; however, to achieve it, it is necessary to delay the production operations in order to incorporate the customer’s inputs in the product materialization. The study offered in the present paper compares different possible production strategies for a product (via conventional technologies and Additive Manufacturing) and assesses the degree of postponement that it would be recommended in order to meet a certain demand distribution. The problem solving is calculated by a program containing a stochastic mathematical model which incorporates extensive information on costs and lead times for the required manufacturing operations.Influence of exposure time on mechanical properties and photocuring conversion ratios for photosensitive materials used in Additive Manufacturing
http://hdl.handle.net/2117/108631
Influence of exposure time on mechanical properties and photocuring conversion ratios for photosensitive materials used in Additive Manufacturing
Bonada Bo, Jordi; Muguruza Blanco, Asier; Fernández-Francos, Xavier; Ramis Juan, Xavier
The influence of UV post-curing process on mechanical propertie s as well as photocuring conversion ratios is presented. An analytical model to determ inate the conversion ratio for frontal polymerization is used to define 3D printing parameters in ord er to obtain a conversion profile as homogenous as possible. The mechanical properties of 3D printed coupons with and without UV post-curing process were obtained through experimental tensile and bending tests. Furthermore, the experimental conversion ratios of printed samples were obtained by means of FTIR spect rometry analysis. It was observed that conversion ratios and some mechanical properties increase because of UV post-curing trea tment, enabling the chance to optimize the whole manufacturing process in function of the 3D printed part requirements
2017-10-11T07:41:38ZBonada Bo, JordiMuguruza Blanco, AsierFernández-Francos, XavierRamis Juan, XavierThe influence of UV post-curing process on mechanical propertie s as well as photocuring conversion ratios is presented. An analytical model to determ inate the conversion ratio for frontal polymerization is used to define 3D printing parameters in ord er to obtain a conversion profile as homogenous as possible. The mechanical properties of 3D printed coupons with and without UV post-curing process were obtained through experimental tensile and bending tests. Furthermore, the experimental conversion ratios of printed samples were obtained by means of FTIR spect rometry analysis. It was observed that conversion ratios and some mechanical properties increase because of UV post-curing trea tment, enabling the chance to optimize the whole manufacturing process in function of the 3D printed part requirementsDevelopment of a multi-material additive manufacturing process for electronic devices
http://hdl.handle.net/2117/108630
Development of a multi-material additive manufacturing process for electronic devices
Muguruza Blanco, Asier; Bonada Bo, Jordi; Gómez, Agustin; Minguella Canela, Joaquim; Fernandes, Joana; Ramos, Francisco; Xuriguera Martin, Elena; Varea Espelt, Aida; Cirera Hernandez, Albert
In order to increas e the versatility of additive manufacturing multimaterial processes, a hybrid system has been developed, which is capable of combining 3D printing technology by DLP (Digital Light Processing) with a two -dimensional Drop- on-Demand Inkjet printing system. Through DLP technology based on digital micromirror devices (DMDs) it is possible to build up 3D geometries layer -by-layer using polymerization of photosensitive resins. Concurrently, while the construction process is performed, the InkJet printing system is used to deposit tiny drops of conductive inks on the substrate generated, which will thus constitute an electric circuit em bedded within the three dimensional structure. On the other hand, photosensitive resins have been filled with Low Temperature Co- firing Ceramic (LTCC) particles, in order to modify the basis properties of the part by using sinterizable slurries. Finally the challenges in the sintering process for a chieving functional parts are discussed and a few prototypes have been built in order to validate this technology
2017-10-11T07:05:19ZMuguruza Blanco, AsierBonada Bo, JordiGómez, AgustinMinguella Canela, JoaquimFernandes, JoanaRamos, FranciscoXuriguera Martin, ElenaVarea Espelt, AidaCirera Hernandez, AlbertIn order to increas e the versatility of additive manufacturing multimaterial processes, a hybrid system has been developed, which is capable of combining 3D printing technology by DLP (Digital Light Processing) with a two -dimensional Drop- on-Demand Inkjet printing system. Through DLP technology based on digital micromirror devices (DMDs) it is possible to build up 3D geometries layer -by-layer using polymerization of photosensitive resins. Concurrently, while the construction process is performed, the InkJet printing system is used to deposit tiny drops of conductive inks on the substrate generated, which will thus constitute an electric circuit em bedded within the three dimensional structure. On the other hand, photosensitive resins have been filled with Low Temperature Co- firing Ceramic (LTCC) particles, in order to modify the basis properties of the part by using sinterizable slurries. Finally the challenges in the sintering process for a chieving functional parts are discussed and a few prototypes have been built in order to validate this technologyDevelopment of a multimaterial additive manufacturing process for electronic devices
http://hdl.handle.net/2117/107550
Development of a multimaterial additive manufacturing process for electronic devices
Muguruza Blanco, Asier; Bonada Bo, Jordi; Gómez Fernández, Agustín; Minguella Canela, Joaquim; fernandes, joana; Ramos, Francisco; Xuriguera Martin, Elena; Varea Espelt, Aida; Cirera Hernandez, Albert
In order to increase the versatility of additive manufacturing multimaterial processes, a hybrid system has been developed, which is capable of combin ing 3D printing technology by DLP (Digital Light Processing) with a two - dimensional Drop - on - Demand Inkjet printing system. Through DLP technology based on digital micromirror devices (DMDs) it is possible to build up 3D geometries layer - by - layer using polyme rization of photo sensitive resins. Concurrently, while the construction process is performed, the I nk J et printing system is used to deposit tiny drops of conductive inks on the substrate generated, which will thus constitute an electric circuit embedded within the three dimensional structure. On the other hand, photo sensitive resins have been filled with Low Te mperature Co - f iring Ceramic (LT CC) particles , in order to modify the basis properties of the part by using sinterizable slurries. Finally the challenges in the sintering process for achieving functional parts are discussed and a few prototypes have been built in order t o validate this technology
2017-09-12T10:46:57ZMuguruza Blanco, AsierBonada Bo, JordiGómez Fernández, AgustínMinguella Canela, Joaquimfernandes, joanaRamos, FranciscoXuriguera Martin, ElenaVarea Espelt, AidaCirera Hernandez, AlbertIn order to increase the versatility of additive manufacturing multimaterial processes, a hybrid system has been developed, which is capable of combin ing 3D printing technology by DLP (Digital Light Processing) with a two - dimensional Drop - on - Demand Inkjet printing system. Through DLP technology based on digital micromirror devices (DMDs) it is possible to build up 3D geometries layer - by - layer using polyme rization of photo sensitive resins. Concurrently, while the construction process is performed, the I nk J et printing system is used to deposit tiny drops of conductive inks on the substrate generated, which will thus constitute an electric circuit embedded within the three dimensional structure. On the other hand, photo sensitive resins have been filled with Low Te mperature Co - f iring Ceramic (LT CC) particles , in order to modify the basis properties of the part by using sinterizable slurries. Finally the challenges in the sintering process for achieving functional parts are discussed and a few prototypes have been built in order t o validate this technologyInfluence of exposure time on mechanical properties and photocuring conversion ratios for photosensitive materials used in additive manufacturing
http://hdl.handle.net/2117/107548
Influence of exposure time on mechanical properties and photocuring conversion ratios for photosensitive materials used in additive manufacturing
Bonada Bo, Jordi; Muguruza Blanco, Asier; Fernández Francos, Xavier; Ramis Juan, Xavier
The influence of UV post - curing process on mechanical properties as well as photocuring conversion ratios is presented. An analytical model to determinate the conversion ratio for frontal polymerization is used t o define 3D printing parameters in order to obtain a conversion profile as homogeno us as possible. The mechanical properties of 3D p rinted coupons with and without UV post - curing process were obtained through experimental tensile and bending tests. Furthermore, the experimental conversion ratios of printed samples were obtained by means of FTIR spectrometry analysis. It was observed that conversion ratios and some mechanical properties increase because of UV post - curing treatment, enabling the chance to optimize the whole manufacturing process in function of the 3D printed part requiremen ts.
2017-09-12T10:18:37ZBonada Bo, JordiMuguruza Blanco, AsierFernández Francos, XavierRamis Juan, XavierThe influence of UV post - curing process on mechanical properties as well as photocuring conversion ratios is presented. An analytical model to determinate the conversion ratio for frontal polymerization is used t o define 3D printing parameters in order to obtain a conversion profile as homogeno us as possible. The mechanical properties of 3D p rinted coupons with and without UV post - curing process were obtained through experimental tensile and bending tests. Furthermore, the experimental conversion ratios of printed samples were obtained by means of FTIR spectrometry analysis. It was observed that conversion ratios and some mechanical properties increase because of UV post - curing treatment, enabling the chance to optimize the whole manufacturing process in function of the 3D printed part requiremen ts.Diseño y primeros resultados de tres ensayos de lanzamiento de bloques de roca para el estudio de la fragmentación
http://hdl.handle.net/2117/106107
Diseño y primeros resultados de tres ensayos de lanzamiento de bloques de roca para el estudio de la fragmentación
Gili Ripoll, José Antonio; Matas Casado, Gerard; Corominas Dulcet, Jordi; Núñez Andrés, María Amparo; Lantada Zarzosa, Maria de Las Nieves; Ruiz Carulla, Roger; Mavrouli, Olga; Buill Pozuelo, Felipe; Moya Sánchez, José; Prades Valls, Albert; Puig i Polo, Càrol; Martínez Bofill, Joan; Salo Salgado, Lluis
RESUMENLa caída de bloques de roca sobre infraestructuras y zonas urbanizadas causa elevados daños y alguna víctima cada año en nuestro país. Los modelos de propagación existentes no tienen en cuenta la fragmentación durante la caída, hecho que influye significativamente en las trayectorias, número de fragmentos y alcance y energía de los mismos. En este artículo presentamos los resultados de tres ensayos a escala real, enfocados a la caracterización de la fragmentación, llevados a cabo con tres litologías distintas. Los resultados de los ensayos han sido usados para construir y calibrar modelos de propagación que incluyen la fragmentación. En los ensayos se han lanzado un total de 100 bloques entre 0,2 y 4,8 m3 desde alturas entre 16 y 27,5 m. Antes de los lanzamientos, los bloques fueron caracterizados geométricamente (fotogrametría masiva envolvente) y geomecánicamente (esclerómetro Schmidt L). Las trayectorias se han seguido mediante 3 cámaras de alta velocidad. También se han tomado imágenes aéreas mediante un dron. Un 43% de los bloques calizos, un 27% de los bloques de dacitas y un 17% de los bloques graníticos se han fragmentado de manera significativa durante los lanzamientos. Se ha obtenido nula correlación entre el rebote del martillo L de Schmidt y la fragmentación de los bloques. Tras cada rotura, se han inventariado las dimensiones de los fragmentos finales, lo que ha permitido comprobar que su distribución (RBSD) puede ajustarse mediante modelos tipo
2017-07-03T12:29:53ZGili Ripoll, José AntonioMatas Casado, GerardCorominas Dulcet, JordiNúñez Andrés, María AmparoLantada Zarzosa, Maria de Las NievesRuiz Carulla, RogerMavrouli, OlgaBuill Pozuelo, FelipeMoya Sánchez, JoséPrades Valls, AlbertPuig i Polo, CàrolMartínez Bofill, JoanSalo Salgado, LluisRESUMENLa caída de bloques de roca sobre infraestructuras y zonas urbanizadas causa elevados daños y alguna víctima cada año en nuestro país. Los modelos de propagación existentes no tienen en cuenta la fragmentación durante la caída, hecho que influye significativamente en las trayectorias, número de fragmentos y alcance y energía de los mismos. En este artículo presentamos los resultados de tres ensayos a escala real, enfocados a la caracterización de la fragmentación, llevados a cabo con tres litologías distintas. Los resultados de los ensayos han sido usados para construir y calibrar modelos de propagación que incluyen la fragmentación. En los ensayos se han lanzado un total de 100 bloques entre 0,2 y 4,8 m3 desde alturas entre 16 y 27,5 m. Antes de los lanzamientos, los bloques fueron caracterizados geométricamente (fotogrametría masiva envolvente) y geomecánicamente (esclerómetro Schmidt L). Las trayectorias se han seguido mediante 3 cámaras de alta velocidad. También se han tomado imágenes aéreas mediante un dron. Un 43% de los bloques calizos, un 27% de los bloques de dacitas y un 17% de los bloques graníticos se han fragmentado de manera significativa durante los lanzamientos. Se ha obtenido nula correlación entre el rebote del martillo L de Schmidt y la fragmentación de los bloques. Tras cada rotura, se han inventariado las dimensiones de los fragmentos finales, lo que ha permitido comprobar que su distribución (RBSD) puede ajustarse mediante modelos tipoSeismic damage assessment of URM buildings: a comparison of non-linear static procedures
http://hdl.handle.net/2117/105901
Seismic damage assessment of URM buildings: a comparison of non-linear static procedures
González Drigo, José Ramón; Ávila Haro, Jorge Arturo; Pujades Beneit, Lluís; Barbat Barbat, Horia Alejandro
In the scientific literature, a significant number of non-linear procedures are proposed in order to evaluate the seismic vulnerability of a building. In this work, and in the context of the Risk-UE methodology, a complete comparison of six representative nonlinear procedures, applied to an unreinforced building, has been performed. The incremental dynamic analysis has been considered in order to provide a reference for comparisons. Additionally, the evaluation of the applicability and reliability of the nonlinear static procedures has been performed and, some simple modifications, oriented to improve their use, have been proposed. The seismic demand has been conveniently defined applying the conditional spectrum approach procedure. Two different methodologies were used in order to define the fragility curves. Accordingly, a complete comparison of the calculated damage indices and the damage curves, corresponding to the different considered peak ground acceleration values,
has been undertaken. The comparison results let know that the damage curves obtained by performing the non-linear procedures and by applying the Risk-UE methodology tend to overestimate the damage corresponding to low values of the PGA while the damage related to higher values of the PGA is underestimated.
2017-06-27T13:57:34ZGonzález Drigo, José RamónÁvila Haro, Jorge ArturoPujades Beneit, LluísBarbat Barbat, Horia AlejandroIn the scientific literature, a significant number of non-linear procedures are proposed in order to evaluate the seismic vulnerability of a building. In this work, and in the context of the Risk-UE methodology, a complete comparison of six representative nonlinear procedures, applied to an unreinforced building, has been performed. The incremental dynamic analysis has been considered in order to provide a reference for comparisons. Additionally, the evaluation of the applicability and reliability of the nonlinear static procedures has been performed and, some simple modifications, oriented to improve their use, have been proposed. The seismic demand has been conveniently defined applying the conditional spectrum approach procedure. Two different methodologies were used in order to define the fragility curves. Accordingly, a complete comparison of the calculated damage indices and the damage curves, corresponding to the different considered peak ground acceleration values,
has been undertaken. The comparison results let know that the damage curves obtained by performing the non-linear procedures and by applying the Risk-UE methodology tend to overestimate the damage corresponding to low values of the PGA while the damage related to higher values of the PGA is underestimated.New parametric model for capacity curves and a new capacity based damage index
http://hdl.handle.net/2117/105898
New parametric model for capacity curves and a new capacity based damage index
Pujades Beneit, Lluís; Vargas Alzate, Yeudy Felipe; Barbat Barbat, Horia Alejandro; González Drigo, José Ramón; Díaz-Alvarado, S.A.; Hidalgo-Leiva, D.A.
A recently proposed parametric model re-conceptualizes capacity curves as composed by linear and non-linear parts. The normalized non-linear capacity curve can be modelled by a cumulative lognormal function. While the linear part is defined by the initial stiffness, the non-linear part keeps the information about the physical degradation of the structure for increasing drifts. Besides, the non-linear part of capacity curves allows defining new curves related to energy loss and to tangent and secant stiffness degradation. It has been shown that an adequate combination of the energy loss and secant stiffness degradation functions leads to a good pointer of physical damage and, therefore, it can be used as a new damage index. This new damage index can be calibrated in such a way that it is equivalent to the well-known Park and Ang damage index, which, in turn, can be obtained from incremental dynamic analyses. In this paper the theoretical formulation of the parametric model and the one of the new damage index are reviewed first. Then the relation between the degradation of the building and the increase of its fundamental period of response is investigated, showing that the increase of the period can be also a good damage forecaster.
2017-06-27T13:33:06ZPujades Beneit, LluísVargas Alzate, Yeudy FelipeBarbat Barbat, Horia AlejandroGonzález Drigo, José RamónDíaz-Alvarado, S.A.Hidalgo-Leiva, D.A.A recently proposed parametric model re-conceptualizes capacity curves as composed by linear and non-linear parts. The normalized non-linear capacity curve can be modelled by a cumulative lognormal function. While the linear part is defined by the initial stiffness, the non-linear part keeps the information about the physical degradation of the structure for increasing drifts. Besides, the non-linear part of capacity curves allows defining new curves related to energy loss and to tangent and secant stiffness degradation. It has been shown that an adequate combination of the energy loss and secant stiffness degradation functions leads to a good pointer of physical damage and, therefore, it can be used as a new damage index. This new damage index can be calibrated in such a way that it is equivalent to the well-known Park and Ang damage index, which, in turn, can be obtained from incremental dynamic analyses. In this paper the theoretical formulation of the parametric model and the one of the new damage index are reviewed first. Then the relation between the degradation of the building and the increase of its fundamental period of response is investigated, showing that the increase of the period can be also a good damage forecaster.Seismic assessment of high-rise URM buildings: a probabilistic approach
http://hdl.handle.net/2117/105897
Seismic assessment of high-rise URM buildings: a probabilistic approach
Ávila Haro, Jorge Arturo; González Drigo, José Ramón; Pujades Beneit, Lluís; Barbat Barbat, Horia Alejandro
The definition of the seismic demand and the correct characterization of the mechanical properties of the materials are two of the major difficulties in the seismic damage assessment of unreinforced masonry buildings due to the large uncertainties and variability that they present. A seven-story unreinforced masonry building in Barcelona, Spain, is taken as a case-study and modeled as an isolated solid clay structure with unidirectional iron beams-brick vaults slabs and load-bearing walls. In order to overcome the material definition shortcomings, the compressive strength, Young modulus, shear modulus and shear strength are modeled as random variables. On the other hand, the seismic demand variability is addressed through a set of different ground motions selected with the conditional spectrum method and subsequently scaled to different levels of demand (pga) as the incremental dynamic analysis methodology suggests. Due to computational and time limitations, a sufficiently representative sample is selected firstly from the population of mechanical properties, and secondly from the population of dynamics analyses for each direction of analysis. The obtained results show the correlation and different grades of influence for each of the selected random variables and levels of seismic demand (pga).
2017-06-27T13:16:22ZÁvila Haro, Jorge ArturoGonzález Drigo, José RamónPujades Beneit, LluísBarbat Barbat, Horia AlejandroThe definition of the seismic demand and the correct characterization of the mechanical properties of the materials are two of the major difficulties in the seismic damage assessment of unreinforced masonry buildings due to the large uncertainties and variability that they present. A seven-story unreinforced masonry building in Barcelona, Spain, is taken as a case-study and modeled as an isolated solid clay structure with unidirectional iron beams-brick vaults slabs and load-bearing walls. In order to overcome the material definition shortcomings, the compressive strength, Young modulus, shear modulus and shear strength are modeled as random variables. On the other hand, the seismic demand variability is addressed through a set of different ground motions selected with the conditional spectrum method and subsequently scaled to different levels of demand (pga) as the incremental dynamic analysis methodology suggests. Due to computational and time limitations, a sufficiently representative sample is selected firstly from the population of mechanical properties, and secondly from the population of dynamics analyses for each direction of analysis. The obtained results show the correlation and different grades of influence for each of the selected random variables and levels of seismic demand (pga).