TY - JOUR A1 - Falkenberg, Rainer T1 - Simulation of Environmentally-Assisted Material Degradation by a Thermodynamically Consistent Phase-Field Model JF - Key Engineering Materials N2 - Environmentally-assisted material degradation involves mass transport and mechanical processes interacting in the material. A well-known example is hydrogen-induced stress-corrosion cracking. One major challenge within this scope is the quantification of the coupling mechanisms in question. The computational modeling of environmentally-assisted cracks is the key objective of this investigation and realised within the theory of gradient-extended dissipative continua with lengthscales. The modeling of sharp crack discontinuities is replaced by a diffusive crack model based on the introduction of a crack phase-field to maintain the evolution of complex crack topologies. Within a thermodynamical framework allowing for mechanical and mass transport processes the crack phasefield is capable to model crack initiation and propagation by the finite element method. As complex crack situations such as crack initiation, curvilinear crack patterns and crack branching are usually hard to realise with sharp crack models, they can be assessed without the requirement of a predefined crack path within this method. The numerical modeling of a showcase demonstrates a crack initiation as well as a crack propagation situation with respect to the determination of stress-intensity factors; a crack deviation situation with a curvilinear crack path is modeled by the introduction of a geometrical perturbation and a locally enhanced species concentration. KW - Finite-element method KW - Crack growth KW - Crack initiation KW - Mass transport KW - Phase field model PY - 2016 DO - https://doi.org/10.4028/www.scientific.net/KEM.713.38 SN - 1662-9795 VL - 713 SP - 38 EP - 41 PB - Trans Tech Publications CY - Switzerland AN - OPUS4-37152 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Miccoli, Lorenzo A1 - Silva, R. A. A1 - Oliveira, D. V. A1 - Müller, U. T1 - Static behavior of cob: Experimental testing and finite-element modeling JF - Journal of Materials in Civil Engineering N2 - The aim of this paper is to implement a numerical model to reproduce the nonlinear behavior of cob walls under shear loading. Axial compression, pull-off, and diagonal compression tests were carried out to derive the mechanical parameters. In addition, the stressstrain relationships, the nonlinear behavior, and the failure modes were defined. The experimental results were then used to calibrate a finiteelement model. The material behavior was simulated through a macromodeling approach adopting the total strain rotating crack model. A sensitivity analysis was conducted to assess the effects of varying the parameters with higher uncertainty on the structural behavior. The numerical model achieved good correspondence with the experimental results in terms of simulation of the shear stress–shear strain relationship and of damage pattern. KW - Cob KW - Compression behavior KW - Shear behavior KW - Digital image correlation KW - Finite-element method PY - 2019 DO - https://doi.org/10.1061/(ASCE)MT.1943-5533.0002638 SN - 0899-1561 SN - 1943-5533 VL - 31 IS - 4 SP - 04019021-1 EP - 04019021-13 PB - ASCE American Society of Civil Engineers AN - OPUS4-47316 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -