Search

Your search keyword '"Sluys, L. J."' showing total 184 results
Start Over Author "Sluys, L. J."
184 results on '"Sluys, L. J."'

2. Modeling of progressive high-cycle fatigue in composite laminates accounting for local stress ratios

Author

Hofman, P., van der Meer, F. P., and Sluys, L. J.

Subjects
Computer Science - Computational Engineering, Finance, and Science
Abstract

A numerical framework for simulating progressive failure under high-cycle fatigue loading is validated against experiments of composite quasi-isotropic open-hole laminates. Transverse matrix cracking and delamination are modeled with a mixed-mode fatigue cohesive zone model, covering crack initiation and propagation. Furthermore, XFEM is used for simulating transverse matrix cracks and splits at arbitrary locations. An adaptive cycle jump approach is employed for efficiently simulating high-cycle fatigue while accounting for local stress ratio variations in the presence of thermal residual stresses. The cycle jump scheme is integrated in the XFEM framework, where the local stress ratio is used to determine the insertion of cracks and to propagate fatigue damage. The fatigue cohesive zone model is based on S-N curves and requires static material properties and only a few fatigue parameters, calibrated on simple fracture testing specimens. The simulations demonstrate a good correspondence with experiments in terms of fatigue life and damage evolution., Comment: 31 pages, 15 figures, 1 table

Published
2024
Full Text
View/download PDF

7. Reply to the note by Li Piani et al.

Author

Piani, T. Li, Weerheijm, J., and Sluys, L. J.

Subjects
PROJECTILES, PENETRATION mechanics, COMPUTER simulation, EQUATIONS of motion, HYPOTHESIS
Abstract

This article is a response to a critique of a ballistic model used to simulate the penetration of small caliber projectiles into adobe walls. The authors of the model defend their approach, explaining that it is consistent with the physics of the problem. They acknowledge that the model is not scale-independent, but argue that claims of scale independence are not supported by physical principles or theories. The article discusses various models and equations used to analyze projectile penetration into adobe, but emphasizes that these models are simplistic interpretations and further experimental research is needed to fully understand the physics involved. [Extracted from the article]

Published
2024
Full Text
View/download PDF

37. Size Dependence and Dynamic Properties of Adobe Masonry Bricks tested at high strain rates.

Author

Gálvez Díaz-Rubio, F., Cendón Franco, D. A., Li Piani, T., Weerheijm, J., Peroni, M., and Sluys, L. J.

Subjects
STRAIN rate, MASONRY, ARMED Forces, DUCTILITY
Abstract

Masonry is a construction technique which typically reacts in compression. Characterization of its material properties in compression is thus of paramount importance. This especially counts for adobe bricks because their material properties are still unknown to a large extent. This traditional masonry, made of locally available soil and fibres, is spread in areas currently involved in military conflicts, where also European forces operate. Therefore, not only its static properties in compression, but even more the dynamic strength is a relevant parameter. Laboratory characterization of material properties still pose several challenges, among which so-called size dependence is one of the most controversial topics. This entails the possible variation of material properties values from tests on specimens of different size and shape. Several factors may concur to its determination and a well-founded theory does not exist yet. This counts for statics and even more in dynamics. Addressing the properties in compression of bricks at high strain rates is rare, namely no studies of size dependence on masonry bricks in dynamic regimes are published. Lately, a series of experimental campaigns were conducted by the authors at the Joint Research Centre of the European Commission. In these campaigns, a series of compression tests were performed on several types of adobe bricks. Different soil mixtures were used to produce cylindrical samples of different sizes. Compressive tests from 2e-5 s-1 to 10 s-1 and 100 s-2 were executed using hydraulic machines as well as split Hopkinson bars. Next, the static as well as the dynamic material properties as calculated from tests on specimens of different sizes and material compositions have been qualitatively and quantitatively compared and interpreted. In this paper, the experimental program is presented, next the material properties in strength and ductility as well as the dynamic increase factors are investigated. [ABSTRACT FROM AUTHOR]

Published
2021
Full Text
View/download PDF

46. A multi-scale computational scheme for anisotropic hydro-mechanical couplings in saturated heterogeneous porous media

Author

Benoît Mercatoris, Massart, T. J., and Sluys, L. J.

Subjects
hydraulic material non-linearities, hydro-mechanical couplings, saturated porous media, anisotropy, computational homogenisation, multi-scale modelling, Physics::Geophysics
Abstract

This contribution discusses a coupled two-scale framework for hydro-mechanical problems in saturated heterogeneous porous geomaterials. The heterogeneous nature of such materials can lead to an anisotropy of the hydro-mechanical couplings and non-linear effects. Based on an assumed model of the mesostructure, the average macroscopic hydro-mechanical behaviour is extracted by means of a computational homogenisation procedure in a monolithic way. The ingredients needed to upscale the hydro-mechanical couplings are outlined. The two-scale simulation results are compared with direct numerical simulation for the consolidation of a particle-matrix porous material.

Published
2013

47. Ballistic model for the prediction of penetration depth and residual velocity in adobe: A new interpretation of the ballistic resistance of earthen masonry.

Author

Li Piani, T., Weerheijm, J., and Sluys, L. J.

Subjects
RESIDUAL stresses, URBAN warfare, VELOCITY, BALLISTICS, MORTAR
Abstract

In this paper, a new one-dimensional phenomenological model is developed for the assessment of the ballistic performance of Adobe. Adobe is a masonry largely spread in areas of the world involved in military operations. Addressing fundamental ballistic parameters such as residual velocity or penetration depth for this building technology is necessary. The model follows the hypotheses for the ballistic response of concrete targets to high velocity impacts, provided with a dominant contribution of shear friction typical of soils. The hypotheses at the basis of the model are consistent with all experimental evidence collected by authors on Adobe. Adobe brick and mortar belong to the material class of concrete, whereas the overall mechanical parameters are determined by the internal soil mixture, including the percentage of fibre reinforcement. Despite its relative simplicity, the model is capable of well predicting ballistic test results currently available in literature for Adobe, including the data of an experimental campaign recently performed by the authors on real Adobe walls in the field. [ABSTRACT FROM AUTHOR]

Published
2018
Full Text
View/download PDF

48. Objective multiscale analysis of random heterogeneous materials

Author

Oriol Lloberas-Valls, Everdij, F. P. X., Rixen, D. J., Simone, A., Sluys, L. J., Universitat Politècnica de Catalunya. Departament d'Enginyeria Civil i Ambiental, and Universitat Politècnica de Catalunya. RMEE - Grup de Resistència de Materials i Estructures en l'Enginyeria

Subjects
voncurrent multiscale analysis, domain decomposition, Finite element method, strain localization and softening, Concurrent multiscale analysis, domain decomposition, strain localization and softening, Plasticity, Plasticity -- Mathematical models, Plasticitat, Elements finits, Mètode dels, Matemàtiques i estadística::Anàlisi numèrica::Mètodes en elements finits [Àrees temàtiques de la UPC], Plasticitat -- Models matemàtics
Abstract

The multiscale framework presented in [1, 2] is assessed in this contribution for a study of random heterogeneous materials. Results are compared to direct numerical simulations (DNS) and the sensitivity to user-defined parameters such as the domain decomposition type and initial coarse scale resolution is reported. The parallel performance of the implementation is studied for different domain decompositions.

Published
2013

50. Modelling of rate effects at multiple scales

Author

Pedersen, R.R., Simone, A., Sluys, L. J., Schrefler, B. A., and Perego, U.

Abstract

At the macro- and meso-scales a rate dependent constitutive model is used in which visco-elasticity is coupled to visco-plasticity and damage.A viscous length scale effect is introduced to controlthe size of the fracture process zone.By comparison of the widths of the fracture process zone,the length scale in the meso-model and the macro-modelcan be coupled. In this fashion, a bridging of length scales can beestablished. A computational analysis of a Split Hopkinson bar test at medium and highimpact load is carried out at macro-scale and meso-scale including information from the micro-scale.

Published
2008

Catalog

Books, media, physical & digital resources
See catalog results