1,721,010 research outputs found
Numerical Modeling of Masonry and Historical Structures: From Theory to Application
No full textNumerical Modeling of Masonry and Historical Structures: From Theory to Application provides detailed information on the theoretical background and practical guidelines for numerical modeling of unreinforced and reinforced (strengthened) masonry and historical structures. The book consists of four main sections, covering seismic vulnerability analysis of masonry and historical structures, numerical modeling of unreinforced masonry, numerical modeling of FRP-strengthened masonry, and numerical modeling of TRM-strengthened masonry. Each section reflects the theoretical background and current state-of-the art, providing practical guidelines for simulations and the use of input parameters
Numerical prediction of the mechanical behavior of TRM composites and TRM-strengthened masonry panels
Get PDFThe work concerns the detailed finite element modelling of multiscale experimental tests performed on glass-Textile Reinforced Mortars (TRM) with the aim of investigating the complex three-dimensional aspects associated with the TRM behavior and understanding what parameters are crucial for the correct simulation and prediction of the composite’s response at each scale. The investigation ranges from materials to structural scale. Each sample’s component and its interfaces are modeled individually. The results show that the 3D micro-modelling successfully replicates the experimental TRM response at different scales by using consistent materials parameters in all the simulation levels, proving a comprehensive understanding of the composite behavior and performance
Bond behaviour of FRP strengthening applied on curved masonry substrates: Numerical study
Get PDFAim of the present paper is to numerically investigate the bond behaviour of FRP strengthening systems externally applied on curved masonry specimens. In particular, considering the simple spring-model approach proposed by the authors in previous research, a new constitutive law derived from the work of Thorenfeld et al. (1987) is here proposed by also considering the coupled behaviour between shear and normal forces at the reinforcement/masonry interface. Numerical analyses are developed with reference to case studies deduced from the literature and consisting of shear lap bond tests of curved masonry specimens characterised by different values of the geometric curvature and different strengthening configurations. The obtained results show the ability of the proposed modelling approach in capturing some effects, such as the beneficial friction effect when compression normal stresses develop at the interface level
High strain rate effects in masonry structures under waterborne debris impacts
Get PDFMasonry buildings are vulnerable to extreme hydrodynamic events such as floods or tsunamis. Post-disaster surveys have shown that waterborne debris impacts can significantly damage masonry walls during these events. To simulate these actions, the current design or research practice is to compute the force–time diagram of the impact and then use it for dynamic analyses. Standing on the current knowledge, debris impacts are highly impulsive, but it is not clear if such loads are fast enough to activate the high strain rate effects in masonry, i.e. the strain rate dependency of material properties. The present study aims to answer this question, for the first time, following nonlinear Finite Element (FE) simulations. Simulations are conducted on a masonry wall, following a micro-modelling strategy, subjected to water flow and waterborne debris impact under different scenarios. It is found that the strain rates exceed the critical threshold after which strain rate effects are considerable. Such a finding, initially obtained using the minimum design demand for log-type debris imposed by ASCE/SEI 7-22, is further extended to a range of impact force–time diagrams different in impact duration and peak force (corresponding to different debris properties or flow velocity). It is also shown that the impact location (i.e. midspan or close to the boundary) affects the strain rate magnitude because of the changes in the impact stiffness and the activated failure mechanisms. Furthermore, it is found that the dynamic tensile post-elastic behaviour of the materials is the most influencing parameter in the structural response. These results open a new area in the field of assessment and design of masonry structures to waterborne debris and guide the development of future experiments, numerical simulations or design relations
Fast discrete homogenization approach for the analysis under out-of-plane loads of unenforced and TRM reinforced masonry panels
No full textA novel discretized homogenization strategy has been developed in order to deal with the analysis of masonry structures. In particular, unenforced and TRM reinforced masonry panels have been simulated under out-of-plane-loads The proposed method provides several advantages when compared with the already existing homogenization approaches. Bricks and mortar have been substituted by elastic cells linked by homogenized interfaces where the non-linear properties are lumped. Such interfaces are modeled as 8-noded 3D bricks along with a Concrete Damage Plasticity model, already available in Abaqus. In fact, the implementation at a structural level of the homogemzed properties results faster and easier. leading to major competitiveness and even ensuring the coupling of the in-plane and out-of-plane actions. The proposed strategy has been tested and validated by comparison with experimental references available in the literature and numerical references, provided by the authors, based on a micro-modeling approach. The results are highly satisfactory in the prediction of the damage pattern and of the global behavior of me analyzed masonry panels
A fast modeling approach for numerical analysis of unreinforced and FRCM reinforced masonry walls under out-of-plane loading
Get PDFA new discretized homogenization approach is proposed in this study in order to predict the behavior of unreinforced and FRCM reinforced masonry structures. The proposed approach allows overcoming the common disadvantages of the existing homogenization approaches: (a) being difficult to implement and (b) not allowing to couple the in-plane and out-of-plane actions. Reference experimental results and detailed numerical modeling are used for validation of the proposed modeling strategy. In the proposed model, the elastic cells are linked by homogenized interfaces. The mechanical properties coming from the homogenization procedures are lumped at the interfaces by means of the generic Concrete Damage Plasticity model, allowing easy implementation and avoiding computational issues peculiar to other approaches available in the literature. The new approach shows accurate results in predicting the global behavior and the damage pattern for both unreinforced and FRCM strengthened masonry walls. The results are promising also with a view to be applied for more complex reinforced applications as double curvature masonry structures
Non-linear homogenized and heterogeneous Fe models for FRCM reinforced masonry walls out-of-plane loaded
No full textTwo distinct non-linear FE modeling techniques are compared to have an insight into the efficacy of FRCM reinforcement for masonry subjected to out-of-plane loads. In particular, both a micro-modeling technique and a homogenization approach are compared. The first approach is a tridimensional heterogeneous procedure where constituent materials (bricks, joints, reinforcing mortar and reinforcing grid) are modeled separately. The second technique is a consolidated two-step homogenization where the meso-scale homogenization problem is solved discretizing the elementary cell with few elastic constant stress triangles (bricks) and non-linear interfaces (joints). The non-linear structural analyses are performed replacing masonry at the macro-scale with an assemblage of rigid elements interconnected by non-linear homogenized springs (HRBSM modelling). Both models are directly implemented in the commercial software Abaqus. Advantages and limitations of the two approaches are discussed in detail -especially as far as the rather different computational effort required by the two strategies is concerned-with reference to their ability in reproducing global force-displacement curves and crack patterns of some reinforced wallettes in simple bending
Application of homogenization approaches for modeling of FRCM-strengthened masonry
No full textThe creation of an effective, accurate finite element mesh is crucial for running whatsoever numerical analysis on structural models. This is especially true when micro-scale, mesoscale, and homogenization-based approaches are used, since they involve a precise and distinct representation of the constitutive materials. One fitting example is embodied by masonry with irregular bond, where blocks are randomly assembled and often present different shapes and dimensions. This work presents a Matlab script for the generation of a full 3D finite element mesh, which is created directly from a simple rasterized picture of the masonry element under investigation. A voxel approach is here used, where one pixel of the image is turned into one solid finite element. The resulting 3D mesh is employed into a broader Matlab script which derives homogenized failure surfaces for masonry test-windows. In particular, the effectiveness of the 3D mesh is validated by comparing the homogenized failure surfaces obtained for an in-plane loaded masonry panel to those retrieved from the 2D version of the script with a 2D mesh, whose reliability has already been established
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