Model reduction for structures subjected to blast loading by use of dynamic substructuring

• In the present study, strategies are developed to enable time-efficient models for structures subjected to blast loading, appropriate for use in a structural design process. Dynamic sub structuring is employed to obtain reduced models with localized nonlinearities, such as predefined plastic hinges in a beam column structure. The parts of the substructures that remains linear elastic are modeled by Ritz-vectors whereas parts with a nonlinear response are retained as physical degrees-of-freedom. Furthermore, a time-stepping method is presented that is shown to be suitable for reduced models including local and predefined rigid-plastic behavior. The proposed methodology is applied and demonstrated in a numerical example of a concrete frame structure. Both the well-established Craig-Bampton method and reduction bases enriched by so-called correction modes are evaluated. For the load case studied, it is shown that the standard Craig-Bampton technique is suitable for reducing the substructures. Furthermore, it is shown that only a few Ritz-vectors are needed to sufficiently describe the deformation of the structure. However, additional modes are needed to ensure an accurate representation of the interface forces between the substructures.

Subject headings

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik -- Teknisk mekanik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering -- Applied Mechanics (hsv//eng)

Keyword

Beam frame structure

Blast loading

Direct time-integration

Dynamic sub structuring

Publication and Content Type

kon (subject category)

ref (subject category)