Mesh size effect on finite-element modeling of blast-loaded reinforced concrete slab

Alañón, Alejandro; Cerro‐Prada, Elena; Vázquez-Gallo, María J.; Santos, Anastasio P.

doi:10.1007/s00366-017-0564-4

Cited by 32 publications

(29 citation statements)

References 17 publications

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“…Since the mesh size affects every Lagrangian model, a convergence analysis should be performed before beginning the calculations. The element sizes of concrete (solids) and bars (beams) were 18 × 18 × 18 mm and 50 mm thickness, respectively, after this study and considering previous works by the authors [3,17,18].…”

Section: Numerical Modelmentioning

confidence: 97%

Field test and numerical modelling of RC slabs at different scaled distances with two types of external reinforcement

Martínez-Almajano¹,

Castedo²,

López³

et al. 2021

Int. J. CMEM

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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/kg 1/3 , in one test with no extra reinforcement; four tests were made with a scaled distance of 0.42 m/kg 1/3 : one without extra reinforcement, two with carbon fibre reinforcement (CFRP) and one with the E-glass fibre reinforcement (GFRP); finally, 0.21 m/kg 1/3 , 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.

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Section: Numerical Modelmentioning

confidence: 97%

Field test and numerical modelling of RC slabs at different scaled distances with two types of external reinforcement

Martínez-Almajano¹,

Castedo²,

López³

et al. 2021

Int. J. CMEM

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“…All aspects regarding these actions are included in "impact matrices" where they are identified as "hazards". Several hazards can affect the durability of structures, e.g., environmental, social and economic impact; population and consumptions growing; climate change (temperature and humidity) [72]; flooding; hurricanes; explosions of blast waves in the terrorist attacks [73] or in demolitions [74]; seismic hazard [75]; corrosion [76,77].…”

Section: Sustainability Assessment Frameworkmentioning

confidence: 99%

Reviewing Arch-Dams’ Building Risk Reduction Through a Sustainability–Safety Management Approach

Zacchei

Molina

2020

Sustainability

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The importance of dams is rapidly increasing due to the impact of climate change on increasing hydrological process variability and on water planning and management need. This study tackles a review for the concrete arch-dams’ design process, from a dual sustainability/safety management approach. Sustainability is evaluated through a design optimization for dams´ stability and deformation analysis; safety is directly related to the reduction and consequences of failure risk. For that, several scenarios about stability and deformation, identifying desirable and undesirable actions, were estimated. More than 100 specific parameters regarding dam-reservoir-foundation-sediments system and their interactions have been collected. Also, a summary of mathematical modelling was made, and more than 100 references were summarized. The following consecutive steps, required to design engineering (why act?), maintenance (when to act) and operations activities (how to act), were evaluated: individuation of hazards, definition of failure potential and estimation of consequences (harm to people, assets and environment). Results are shown in terms of calculated data and relations: the area to model the dam–foundation interaction is around 3.0 Hd2, the system-damping ratio and vibration period is 8.5% and 0.39 s. Also, maximum elastic and elasto-plastic displacements are ~0.10–0.20 m. The failure probability for stability is 34%, whereas for deformation it is 29%.

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“…If the solution is already good enough, smaller meshes will not result in big different solutions. Assuming that, in general terms, the results obtained with a finer mesh are better although some authors have shown that this is not always the case (Alañón et al, 2018). This technique provides some key advantages when compared with others: an analytical solution is not required, it provides a confidence bound on the estimated error band, and can be used with a minimum of two mesh solutions (though it works better with three).…”

Section: The Grid Convergence Index (Gci)mentioning

confidence: 99%

Application of grid convergence index to shock wave validated with LS-DYNA and ProsAir

et al. 2020

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The discretization error is not always calculated, even though it is essential for the studies of computational solid mechanics. However, it is well known that an error committed by the mesh used can be as large as the measured variable, which greatly invalidates the results obtained. The grid convergence index (GCI) method makes possible to determine on a solid basis, the order of convergence and the asymptotic solution. This method seems to be a suitable estimator despite further research is needed in the context of blast situations and finite element (FE) calculations. For this purpose, field trials were performed consisting in the detonation of a spherical hanging load of homemade explosive. The pressure generated by the shock wave was measured in different positions at two distances. With these data, a TNT equivalent has been obtained and used to calculate the shock propagation with the solvers LS-DYNA and ProsAir. This work aims to verify the GCI method by comparing its results with field data along with the simulations carried out. The comparison also seeks to validate the methodology used to obtain the TNT equivalent.This research shows that the GCI gives good results for both solvers despite the complexity of the physical problem. Besides, LS-DYNA displays better correlation with the experimental data than the ProsAir results, with an error of less than 10% in all values. RESUMENLa estimación del error de discretización no siempre se calcula, aunque es algo fundamental para el estudio de la mecánica computacional de los sólidos. Sin embargo, es bien sabido que el error cometido por la malla utilizada puede ser del mismo orden que la variable medida, lo que llega a invalidar los resultados obtenidos. El método del ındice de convergencia de la malla (GCI) permite determinar sobre una base sólida el orden de convergencia y la solución asintótica, por lo que parece ser un buen estimador, a pesar de que es necesario seguir investigando en el contexto de las situaciones de ondas de choque (explosivos) y de los cálculos de elementos finitos (FE). Para este fin, se realizaron pruebas de campo consistentes en la detonación de una carga esférica colgada de explosivo casero. La presión generada por la onda de choque se midió en diferentes posiciones a dos distancias. Con estos datos, se obtuvo un equivalente de TNT que se utilizó para calcular la propagación del choque con los programas LS-DYNA y ProsAir. Este trabajo pretende verificar el método GCI comparando sus resultados con los datos de campo junto con las simulaciones realizadas. También, la comparación busca validar la metodologıa empleada para la obtención del equivalente TNT.La investigación muestra que el GCI da buenos resultados para ambos programas a pesar de la complejidad del problema fısico. Además, el LS-DYNA produce una mejor correlación con los datos experimentales que los aportados por el ProsAir, con todos los valores por debajo del 10 % de error.Palabras clave: ındice de convergencia de malla (GCI), equivalente de TNT, LS-DYNA, ProsAir.How to ...

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Mesh size effect on finite-element modeling of blast-loaded reinforced concrete slab

Cited by 32 publications

References 17 publications

Field test and numerical modelling of RC slabs at different scaled distances with two types of external reinforcement

Field test and numerical modelling of RC slabs at different scaled distances with two types of external reinforcement

Reviewing Arch-Dams’ Building Risk Reduction Through a Sustainability–Safety Management Approach

Application of grid convergence index to shock wave validated with LS-DYNA and ProsAir

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