000013318 001__ 13318
000013318 005__ 20161114160336.0
000013318 04107 $$aeng
000013318 046__ $$k2009-06-22
000013318 100__ $$aLavan, O.
000013318 24500 $$aContact analysis in the mixed lagrangian framework

000013318 24630 $$n2.$$pComputational Methods in Structural Dynamics and Earhquake Engineering
000013318 260__ $$bNational Technical University of Athens, 2009
000013318 506__ $$arestricted
000013318 520__ $$2eng$$aPrevious research has shown many advantages of the Mixed Lagrangian Formulation (MLF) for the solution of dynamic problems. Unlike standard approaches, MLF leads to a convex well-behaved optimization problem with forces as primary variables. The solution of dynamic problems by using the MLF has shown to be robust in the case of yielding structures, hence allowing larger time steps than those usually considered. In this paper a new contact element is introduced. The new contact element allows compression forces only, when the relative displacement between its edges is zero. By adding a linear spring and a slider in series with the new contact element, the contact force could be modeled to have an elastic-plastic behavior, thus, plasticity in the contact can be accounted for in a natural manner. Additional elements could be added in series or in parallel to this system to result in different behavior of the contact force. After presenting details of the formulation and computational algorithms, the new element is used for the solution of two examples. In the first example, pounding between adjacent buildings is considered, while the second example analyses a base isolated structure with gap elements. These examples illustrate that relatively large time steps can be considered even for contact problems. Furthermore, the reasons for this capability of the algorithm are discussed in the paper.

000013318 540__ $$aText je chráněný podle autorského zákona č. 121/2000 Sb.
000013318 653__ $$aProgressive Collapse, Mixed Lagrangian Formulation, Contact analysis, Pounding. Abstract. Previous research has shown many advantages of the Mixed Lagrangian Formulation (MLF) for the solution of dynamic problems. Unlike standard approaches, MLF leads to a convex well-behaved optimization problem with forces as primary variables. The solution of dynamic problems by using the MLF has shown to be robust in the case of yielding structures, hence allowing larger time steps than those usually considered. In this paper a new contact element is introduced. The new contact element allows compression forces only, when the relative displacement between its edges is zero. By adding a linear spring and a slider in series with the new contact element, the contact force could be modeled to have an elastic-plastic behavior, thus, plasticity in the contact can be accounted for in a natural manner. Additional elements could be added in series or in parallel to this system to result in different behavior of the contact force. After presenting details of the formulation and computational algorithms, the new element is used for the solution of two examples. In the first example, pounding between adjacent buildings is considered, while the second example analyses a base isolated structure with gap elements. These examples illustrate that relatively large time steps can be considered even for contact problems. Furthermore, the reasons for this capability of the algorithm are discussed in the paper.

000013318 7112_ $$aCOMPDYN 2009 - 2nd International Thematic Conference$$cIsland of Rhodes (GR)$$d2009-06-22 / 2009-06-24$$gCOMPDYN2009
000013318 720__ $$aLavan, O.
000013318 8560_ $$ffischerc@itam.cas.cz
000013318 8564_ $$s92298$$uhttps://invenio.itam.cas.cz/record/13318/files/CD466.pdf$$yOriginal version of the author's contribution as presented on CD, section: Algorithms and computational tools in structural dynamics (MS).
000013318 962__ $$r13074
000013318 980__ $$aPAPER