Search results for "Collapse"
showing 10 items of 159 documents
On the Conditions to Prevent Plastic Shakedown of Structures: Part I—Theory
1993
For a structure of elastic perfectly plastic material subjected to a given cyclic (mechanical and/or kinematical) load and to a steady (mechanical) load, the conditions are established in which plastic shakedown cannot occur whatever the steady load, and thus the structure is safe against the alternating plasticity collapse. Static and kinematic theorems, analogous to those of classical shakedown theory, are presented.
On the Conditions to Prevent Plastic Shakedown of Structures: Part II—The Plastic Shakedown Limit Load
1993
Following the results of a companion paper, the concept of plastic shakedown limit load is introduced for an elastic-perfectly plastic material structure subjected to combined cyclic (mechanical and/or kinematical) loads and steady (mechanical) load. Static and kinematic approaches are available for the computation of this load, in perfect analogy with the classic (elastic) shakedown limit load. The plastic shakedown limit state of the structure being in an impending alternating plasticity collapse is studied and a number of interesting features of it are pointed out.
Preparados para el desastre
2019
La actual crisis política y económica que atraviesa nuestra cotidianeidad supone también una crisis individual que afecta y pone en cuestión tanto las manifestaciones hacia el interior (subjetivas) como también hacia el exterior (de sociabilidad, de inter-subjetividad). Lo mencionado se agrava si tenemos en cuenta el complicado escenario de «colapso» al que nos abocamos según el consenso científico en materia medioambiental, entendido este como una especie de «punto cero» que podría desencadenar una catástrofe de consecuencias inimaginables. Ante este panorama, no son pocas las manifestaciones literarias o cinematográficas que en las últimas décadas se han encargado de asumir este colapso c…
The limit state of indefinite plates on elastoplastic continuum
1972
The limit analysis of indefinite plates resting on a continuous elastoplastic medium and subjected to a load distributed over a partial surface with a circular boundary yields the fundamental equation governing the problem. Minimum conditions are set and the solution that supplies the collapse load of the plate-soil system is found by variational calculus.
Ultimate load analysis of plate foundations
1973
The behaviour of circular plates used as isolated foundations is investigated on the basis of earlier studies[6], [7] of the limit state of indefinite plates resting on elastoplastic continua and subjected to distributed loads. The upshot is an easy-to-use procedure of ultimate load analysis that permits the determination of: --the limit load for simultaneous collapse of plate and continuum --and the limit load for collapse of the continuum only according to the different behaviour of the two elements constituting the system.
Effect of progressive collapse of central column on the push-down response of two-span beam-column substructures
2021
Abstract In this paper, a simplified model is proposed for hand calculation of the push-down curve of reinforced two-span beam-column substructures with the mid-span column subjected to a vertical load inducing progressive collapse response. The model takes into account the flexural, arch and catenary strength mechanisms and the axial stiffness of RC compressed columns. The model was validated against experimental data available in the literature. The expressions derived, in a closed form, were useful for hand calculation of push-down responses and robustness evaluation of RC framed structures. The derived explicit expressions can be applied in a step-by-step manner for tracing nonlinear be…
X-ray Computed Tomography for Capillary Collapse of Loose Unsaturated Sand
2016
Abstract The collapse of unsaturated soils consists of the reduction in volume upon wetting at constant total stress. Several studies at the macro scale outline the influence of initial void ratio, confining pressure and matric suction on the onset of collapse of standard laboratory specimens. Conversely, few observations at the micro scale are available in the literature, although the influence of the particles arrangement and intergranular bonding has been formerly supposed. The collapse of fine sand derived by a pyroclastic soil of Southern Italy is investigated in this paper at the microscale using the X-ray Computed Tomography. The experimental procedure, formerly tested on similar pyr…
Self-organization of amphiphilic N-acylated linear polyethyleneimines: investigation of a reversible monolayer collapse
1996
Abstract Poly-N-4-decyloxybenzoylethyleneimine, highly crystalline in bulk, forms a stable monolayer at the air-water interface which undergoes a reversible collapse into a probable bilayer structure at higher surface pressures. We achieved transfer both from the monolayer and “bilayer” region of the polymer film at the water surface onto hydrophilic and hydrophobized quartz supports. Based on X-ray investigations on the deposited Langmuir-Blodgett films, a possible mechanism for the reversible collapse is proposed.
New perspectives for the design of molecular actuators: thermally induced collapse of single macromolecules from cylindrical brushes to spheres.
2004
Interplay between Chain Collapse and Microphase Separation in Bottle-Brush Polymers with Two Types of Side Chains
2010
Conformations of a bottle-brush polymer with two types (A,B) of grafted side chains are studied by molecular dynamics simulations, using a coarse-grained bead−spring model with side chains of up to...