Modeling of the fatigue cracks in welded beam-to-column connection of steel moment frame buildings submitted to earthquake

in Aliabadi, M. H.; Planas, J.; Buchholz, F.-G. (Eds.) et al Proceedings of the 4th International Conference on Fracture and Damage Mechanics (2005)

Fatigue cracks in welded connections of steel moment frame buildings submitted to earthquakes are studied. The connections of beams with thick flanges designed to resist to seismic phenomena by plastic ... [more ▼]

Fatigue cracks in welded connections of steel moment frame buildings submitted to earthquakes are studied. The connections of beams with thick flanges designed to resist to seismic phenomena by plastic dissipation are presented. The structural components, the materials and the crack mechanics are described. To predict the crack initiation, the knowledge of residual internal stresses, generated by the welding process, is required. So these stresses are assessed by a FEM thermo-mechanical analysis. The potential sites of crack locations are detected by using an FEM model of the connection with the continuum damage model of Lemaître and Chaboche. After these FEM analyses, new meshes with specific elements located at the potential crack locations are defined. A cohesive zone law is used to model the crack propagation. This model describes the crack growth by analyzing the energy released by the generation of the new surfaces and damage micro-phenomena behind the crack tip. A constitutive tension-separation law computes this energy. In these cases of low cycle fatigue, the damage and the cyclic loading conditions are taken into account. [less ▲]

Modeling of the liquid phase distribution in a packed column based on the analysis of X-ray tomography images

Poster (1997)

Modeling of Thin Insulating Layers in Dual Magnetodynamic Formulations

in Proceedings of the 10th IEEE Conference on Electromagnetic Field Computation (CEFC'2002) (2002)

Modeling Operational Risk Based on Multiple Experts’ Opinion

in Gregoriou, Greg (Ed.) Operational Risk Towards Basel III (2009)

While the Basel II accord has now gone live in most parts of the world, many discrepancies still remain on advanced modeling techniques for operational risk among large international banks. The two major ... [more ▼]

While the Basel II accord has now gone live in most parts of the world, many discrepancies still remain on advanced modeling techniques for operational risk among large international banks. The two major families of models include the loss distribution approaches (LDAs) that focus on observed past internal and external loss events and the scenario-based techniques that use subjective opinions from experts as the starting point to determine the regulatory capital charge to cover operational risk. A major methodological challenge is the combination of both techniques so as to fulfill Basel II requirements. In this chapter we discuss and investigate the use of various alternatives to model expert opinion in a sound statistical way so as to allow for subsequent integration with loss distributions fitted on internal and/or external data. A numerical example supports the analysis and shows that solutions exist to merge information arising from both sources. [less ▲]

Modeling post-combustion CO2 capture with amine solvents

Conference (2010)

Oral communication at the Cape-forum, Aachen, 2010. Modeling CO2 capture process and optimization of some process parameters with an equilibrium-based model.

Modeling post-combustion CO2 capture with amine solvents

in Pistikopoulos, E. N.; Georgiadis, M. C.; Kokossis, A. C. (Eds.) 21st European Symposium on Computer Aided Process Engineering – ESCAPE 21 - Proceedings (2011)

Carbon capture and storage is a technology that can contribute to face the challenge of rising energy demand combined with a growing environmental awareness. In the present work, the CO2 capture process ... [more ▼]

Carbon capture and storage is a technology that can contribute to face the challenge of rising energy demand combined with a growing environmental awareness. In the present work, the CO2 capture process with monoethanolamine (MEA) is modeled using the simulation tool Aspen Plus. Two different modeling approaches are studied and compared: the equilibrium and the rate-based approaches. An optimization of key process parameters is performed and process modifications are studied with the objective of improving the global process energy efficiency. [less ▲]

Modeling recent bark stripping by red deer (Cervus elaphus) in South Belgium coniferous stands

in Annals of Forest Science : a Multidisciplinary and International Journal (2012)

Modeling Route Choice of Car Travelers using an Activity-Based Segmentation

in Proceedings of the 90th Annual Meeting of the Transportation Research Board (DVD-ROM) (2011)

The aim of this research is to identify the relationships between activity patterns and route choice decisions. The focus is turned to the relationship between the purpose of a trip and the road ... [more ▼]

The aim of this research is to identify the relationships between activity patterns and route choice decisions. The focus is turned to the relationship between the purpose of a trip and the road categories used for the relocation. The data for this study were collected in 2006 and 2007 in Flanders, the Dutch speaking and northern part of Belgium. To estimate the relationship between he primary road category traveled on and the corresponding activity-travel behavior a multinomial logit model is developed. The results point out that route choice is a function of multiple factors, not just travel time or distance. Crucial for modeling route choices or in general for traffic assignment procedures is the conclusion that activity patterns have a clear influence on the road category primarily driven on. Particularly, it was shown that the likelihood of taking primarily through roads is highest for work trips and lowest for leisure trips. This certainly suggests that traffic assignment procedures should be developed that explicitly take into account an activity-based segmentation. In addition, it was shown that route choices were similar during peak and off-peak periods. This is an indication that car drivers are not necessarily utility maximizers. A potential pathway for further investigating route choice decisions might lie in the roots of more psychological underpinnings. [less ▲]

Modeling Stationary and Evolving Discontinuities with Finite Elements

in Owen, D. R. J.; Onate, E. (Eds.) VII International Conference on Computational Plasticity COMPLAS 2003 (2003)

A methodology for treating non-planar three-dimensional cracks with geometries that are independent of the mesh is summarized. The method is based on the extended finite element method, in which the crack ... [more ▼]

A methodology for treating non-planar three-dimensional cracks with geometries that are independent of the mesh is summarized. The method is based on the extended finite element method, in which the crack discontinuity is introduced as a Heaviside step function via a partition of unity. In addition, branch functions are introduced for all elements containing the crack front. The crack geometry is described by two signed distance functions (level sets), which in turn can be defined by nodal values. Consequently, no explicit representation of the crack is needed. A Hamilton-Jacobi equation is used to update the level sets as the crack grows. Numerical experiments show the robustness of the method in treating cracks with significant changes in topology. The method is readily extendable to inelastic fracture problems. [less ▲]

A modeling system handling the wide range of time scales involved in sediment transport processes

Conference (2009, October 08)