טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentBitton Yitzahk
SubjectElasto-Plastic Dynamic Behavior of Plane Frames by
Finite Number of Degrees
DepartmentDepartment of Civil and Environmental Engineering
Supervisor Professor Emeritus Izhak Sheinman


Abstract

This work is concerned with the analysis of frame structures subjected to blast loads. The difficulties that arise from the complexity of the problem, which involves time - dependent and nonlinear inelastic material behavior, have motivated various assumption and approximation to simplify the models.

It is frequently possible to represent beam, slab and frame structures by an equivalent single degree of freedom (SDOF) system.  This SDOF system is consisting of a mass, a damper, and a spring. In this work the SDOF parameters was obtain by equate separately the energy component, based on the static mode shape. This procedure is, in effect, an idealization of the actual dynamic system and is under examination here.

The overall response of a structure, when subjected to a blast load, is generally dominated by elastic and elasto plastic deformation. While the treatment of the plastic behavior is carried out using the moment curvature relationship, the overall response of the structure was treated by the resistant function. In order to simplify the calculation, the moment curvature relationship is approximated by the rigid, perfectly plastic idealization and only ideal plastic hinges are allowed to form. These assumptions are also under investigation.

In this work, the structural beam and frame is simplified as an equivalent SDOF system. For the SDOF representation, a computer program, DALS [2], is used to calculate the dynamic response. To prove the adequacy of the SDOF representation, a finite element model was generated using ADINA [1]. The objective of this study is to verify the validity of the SDOF representation of the frame structures subjected to blast load. This work present results from a parametric investigation of the SDOF representation of the structural beams and frame, as well as investigate the effects of the others assumptions and approximations.