Print Email Facebook Twitter Computational modelling of dynamic failure of cementitious materials Title Computational modelling of dynamic failure of cementitious materials Author Pedersen, R.R. Contributor Sluys, L.J. (promotor) Faculty Civil Engineering and Geosciences Department Department of Design & Construction (Section of Structural Mechanics) Date 2010-01-15 Abstract A safe design of civil engineering concrete structures must include dynamic loading conditions. However, the knowledge on crack patterns and tensile failure strength of concrete material as a function of the dynamic loading is not sufficiently understood to accurately predict the risks and consequences of accidents. Concrete is a rate-dependent material in the sense that the tensile strength and fracture energy become higher with increasing loading rates and the failure characteristics change from static to dynamic loading conditions. The rate dependency is associated with different physical processes at different scales of the concrete material. From experimental evidence, variations of the saturation level and applied loading rate are significant for the rate dependency of concrete. In this respect, the thesis explores different computational techniques to examine the dynamic material behavior of concrete, where the physical as pects behind the rate effects and experimental validation are emphasized. A rate dependent visco-elastic visco-plastic damage continuum model is proposed with viscosity terms in both the elastic and inelastic part. The impact and significance of the viscosity terms on the dynamic tensile strength and fracture process is analyzed by means of academic examples, where the physics behind the viscosity terms are justified. The computational model is validated by means of an extensive experimental database, where both the loading rate and saturation level are varied. Macro-scopic analyses show that the dynamic tensile strength is well predicted by the numerical model. However, the corresponding fracture patterns are not comparable to the experimental findings. This is solved with a meso-scopic model, where the experimental tensile strength and fracture patterns for different loading rates and saturation levels are reproduced. The cracks are explicitly modelled with a rate-dependent continuous discontinuous framework, where the crack speed, crack extension and crack orientation are analyzed. Subject rate-dependent failure,cementitious materials,finite-element method,plasticity,damage,visco-elasticity. To reference this document use: http://resolver.tudelft.nl/uuid:4da027f4-0f58-42e7-a777-32405b5e92bc Publisher Ipskamp Drukkers Embargo date 2010-01-15 ISBN 9789490284053 Part of collection Institutional Repository Document type doctoral thesis Rights (c) 2010 Pedersen, R.R. Files PDF thesis_rrpedersen_library.pdf 7.21 MB Close viewer /islandora/object/uuid:4da027f4-0f58-42e7-a777-32405b5e92bc/datastream/OBJ/view