Search results for " minimum volume."

Targeted steel frames by means of innovative moment resisting connections

2021

Abstract The present paper proposes the use of stepped cross section devices on steel frames aiming at reproducing a pre-established target push-over curve. To this aim a Limited Resistance Plastic Device (LRPD) to be inserted along selected structural members is proposed. The following two main specific features for LRPD are required: any elastic flexural stiffness variation of the original selected member must be avoided; an ultimate plastic bending moment value equal to an assigned percentage of the original limit resistance value must be ensured. Steel frames equipped with LRPD are modeled by means of an extension of a recently proposed Fibre Smart Displacement Based (FSDB) beam element…

A new design problem in the formulation of a special moment resisting connection device for preventing local buckling

2021

In the present paper an improved formulation devoted to the optimal design problem of a special moment resisting connection device for steel frames is proposed. This innovative device is called a Limited Resistance Plastic Device (LRPD) and it has been recently proposed and patented by some of the authors. It is thought to be preferably located at the extremes of the beam, connecting the beam end cross section with the relevant column. The typical device is a steel element characterized by symmetry with respect to three orthogonal barycentric planes and constituted by a sequence of three portions with abrupt cross section changes. The main novelty of the present proposal is related to the d…

Analysis and design of elastic plastic structures subjected to dynamic loads

In the last decades, the concept of “optimization” has reached considerable value in many different fields of scientific research and, in particular, it has assumed great importance in the field of structural mechanics. The present study describes and shows the scientific path followed in the three years of doctoral studies. The state of the art concerning the optimization of elastic plastic structures subjected to quasi-static loads was already well established at the beginning of the Ph.D. course. Actually, it was already faced the study of structures subjected to quasi-static cyclic loads able to ensure different structural behaviors in relation to different intensity levels of the appli…

Dynamic shakedown design of structures under repeated seismic loads

2013

The paper is devoted to the formulation of an optimal design (minimum volume) problem of elastic perfectly plastic structures subjected to suitable combinations of static (fixed) and dynamic (seismic) loads. The structure is constrained to simultaneously respect two different safety criteria; actually, it must exhibit an elastic shakedown behaviour for the combination of loads characterizing the serviceability conditions and it must prevent the instantaneous collapse for the highest expected load condition (combination of loads characterized by the presence of fixed loads and maximum expected intensity of seismic action). The shakedown limit behaviour for the optimal structure will be impos…