000004504 001__ 4504
000004504 005__ 20141118192701.0
000004504 0177_ $$2doi$$a10.3850/978-981-07-2219-7_P179

000004504 0247_ $$210.3850/978-981-07-2219-7_P179
$$adoi
000004504 04107 $$aeng
000004504 046__ $$k2012-05-23
000004504 100__ $$aKanno, Yoshihiro
000004504 24500 $$aWorst-Scenario of Deficiency of Structural Elements in Plastic Limit Analysis

000004504 24630 $$n5.$$pProceedings of the 5th Asian-Pacific Symposium on Structural Reliability and its Applications
000004504 260__ $$bResearch Publishing, No:83 Genting Lane, #08-01, Genting Building, 349568 SINGAPORE
000004504 506__ $$arestricted
000004504 520__ $$2eng$$aThe redundancy of a structure usually refers to the extent of degradation which the structure can suffer without losing some specified functionality. For example, Frangopol and Curley (1987) defined the <em>strength redundant factor</em> by l<sub>i</sub>/(l<sub>i</sub> ..l<sub>d</sub>), where l<sub>i</sub> is the ultimate strength of the intact (i.e., undamaged) structure, and ld is that of the damaged structure. In such a redundancy analysis, it is often that the plastic limit analysis is performed with the given set of deficient structural elements (Ohi <em>et al.,</em> 2004). However, for a real-world structure, we cannot predict in advance which structural elements will be actually damaged.
  This contribution discusses the worst scenario of deficiency of structural elements. Specifically, we consider the deterioration of the plastic limit load factor of a finitedimensional structure. When the maximum number of damaged structural elements is specified, the worst scenario is defined as the set of damaged elements with which the limit load factor attains the minimum (i.e., worst) value. Thus redundancy is related to robustness against uncertainty in structural deficiency (Kanno and Ben- Haim, 2011).
  A major difficulty of this worst-scenario detection problem stems from the fact that the worst scenario corresponds to the <em>global</em> optimal solution of a <em>nonconvex</em> optimization problem. Therefore, conventional nonlinear programming approaches are not guaranteed to find the worst scenario. To overcome this difficulty, the present study proposes to reformulate the worst-scenario detection problem as a mixed integer linear programming (MILP) problem. An MILP problem is minimization (or maximization) of a linear function under linear inequality constraints, in which some of the unknown design variables are required to be integers. We can obtain the global optimal solution of an MILP problem with, e.g., a branch-and-cut method. This means that the reformulated worst-scenario detection problem can be solved globally. Numerical examples show that the worst scenario of the deficiency of structural elements depends on the number of damaged numbers.

000004504 540__ $$aText je chráněný podle autorského zákona č. 121/2000 Sb.
000004504 653__ $$aRobustness, Uncertainty, Structural degradation, Structural integrity, Plastic limit analysis, Integer optimization.

000004504 7112_ $$a5th Asian-Pacific Symposium on Structural Reliability and its Applications$$cSingapore (SG)$$d2012-05-23 / 2012-05-25$$gAPSSRA2012
000004504 720__ $$aKanno, Yoshihiro
000004504 8560_ $$ffischerc@itam.cas.cz
000004504 8564_ $$s177059$$uhttps://invenio.itam.cas.cz/record/4504/files/P179.pdf$$yOriginal version of the author's contribution as presented on CD, .
000004504 962__ $$r4180
000004504 980__ $$aPAPER