Michał Gawlicki, M.Sc., Eng.

Department of Intelligent Technologies (ZTI)
Division of Safety Engineering (PIB)
position: doctoral student
telephone: (+48) 22 826 12 81 ext.: 428
room: 432
e-mail: mgawlic

Recent publications
1.Gawlicki M., Stany krytyczne w ciałach z tarciem wewnętrznym, Prace IPPT - IFTR Reports, ISSN: 2299-3657, No.25, pp.1-82, 1986

Conference abstracts
1.Gawlicki M., Jankowski Ł., Identification of moving loads using the l1 norm minimization, CMM-2017, 22nd International Conference on Computer Methods in Mechanics, 2017-09-13/09-16, Lublin (PL), pp.1-2, 2017
Abstract:

This contribution deals with the inverse problem of indirect identification of moving loads. The identification is performed based on the recorded response of the loaded structure and its numerical model. A specific feature of such problems is a very large number of the degrees of freedom (DOFs) that can be excited and a limited number of available sensors. As a result, unless the solution space is significantly limited, the identification problem is underdetermined: it has an infinite number of exact, observationally indistinguishable solutions. We propose an approach based on the assumption of sparsity of the excitation, which can be expressed in the form of a requirement of a bounded l1 norm of the solution. As long as the loads are sparse, the approach allows them to be freely moving, without the usual assumption of a constant velocity. We test the approach in a numerical example with 10% rms measurement noise and describe an experimental setup that is being prepared to perform experimental verification.

Keywords:

inverse problems, structural mechanics, moving load identification, sparsity, l1 norm

Affiliations:
Gawlicki M.-IPPT PAN
Jankowski Ł.-IPPT PAN
2.Gawlicki M., Jankowski Ł., Identification of moving loads via l1-constrained solutions, ECCOMAS - IPM 2017, 4th International Conference on Inverse Problems in Mechanics of Structures and Materials, 2017-05-31/06-02, Rzeszów - Krasiczyn (PL), pp.25-26, 2017
Abstract:

Indirect identification of moving loads based on the measured response is one of the crucial problems in structural health monitoring. It is important in automated assessment of structures and pavements, in traffic monitoring and control, and as a prerequisite for structural control. As such, it has been intensively researched. An important difficulty is that a moving load can excite a very large number of structural Dofs, which all have to be taken into account in the identification procedure based on measurements of a much more limited number of sensors. A straightforward formulation yields thus an underdetermined problem with an infinite number of solutions. Therefore, in most of the approaches so far, the solution space is significantly limited by the assumption that the load corresponds to a single vehicle moving at a constant velocity, which excludes loads of a more general nature (e.g., multiple loads). However, instead of limiting the solution space, it can be noted that in practice moving loads are sparse in time and space, which fits the framework of compressed sensing. Such an a priori knowledge of sparsity is typically expressed by limiting the l1 norm of the solution. To our knowledge, although used in other contexts, the concept has not been applied so far for identification of moving loads. The approach is tested in a numerical example with 10% rms measurement noise. Experimental work is in progress.

Affiliations:
Gawlicki M.-IPPT PAN
Jankowski Ł.-IPPT PAN