Protection of Buildings against Explosions and Earthquakes
Development, Fabrication and Laboratory Testing of New Resonance Mechanical Traps for Protection of Buildings and Engineering Structures against Explosions, Earthquakes
Tech Area / Field
- ENV-EHS/Environmental Health and Safety/Environment
- FIR-PSS/Physical Safety and Security at Facilities/Fission Reactors
- MAN-PDM/Plant Design and Maintenance/Manufacturing Technology
- OTH-BIT/Building Industry Technology/Other
- PHY-SSP/Solid State Physics/Physics
3 Approved without Funding
Russian Academy of Sciences / Semenov Institute of Chemical Physics, Russia, Moscow
- Blagonravov Institute of Machine Science, Russia, Moscow
- Departement Genie Civil et Batiment URA 1652 CNRS / Ecole Nationale des Travaux Publics de l'Etat, France, Vaulx-en-Velin\nUniversity of Illinois At Urbana-Champaign / Department of Mechanical Science and Engineering, USA, IL, Urbana\nUniversity of Illinois At Urbana-Champaign / Department of Aerospace Engineering, USA, IL, Urbana\nLoughborough University, UK, Loughborough
Project summaryA large number of accidents with people sacrifice are related to the damage of buildings and engineering structures such as civil and industrial buildings, bridges, dams, atomic and thermoelectric power stations, sea ships and tankers, storages for oil and others inflammables. The catastrophes damaging such objects mostly result from strong mechanical impulses close to them, caused by explosions (including the ones having terrorist’s origin) and earthquakes. The explosions nearby the buildings, engineering structures and communications can be caused by man-caused damages, terrorists’ attacks, local military conflicts, accidental falls of airplanes or helicopters nearby residential or industrial buildings and by other reasons. Recent examples of such accidents in Russia were ruining many-storied residential buildings by terrorists in Buynaksk and others cities, often explosions of pipelines and oil storages at Caucasus and many others events. Therefore, the development of effective inexpensive and manufacturable systems for protecting big-volume buildings and engineering constructions against damage under action of powerful mechanical impulses is the most important, common to all mankind, and economical task.
The main goal of the project is the development and laboratory experimental testing of the completely new small size inexpensive protective traps which, by their installation on existing and/or new buildings, constructions and engineering structures, could protect the objects from damage or sufficiently lower it. The principal novelty of this traps is that their action is based on resonance transfer of incoming energy (oscillations of ground or water) to a trap having sufficiently non-linear characteristics, with subsequent effective dissipation of the energy. The traps are small as compared with protected construction and therefore inexpensive. non-linear physical laws and due to this traps may effectively accumulate energy of external impulses and dissipate it practically without returning of it to the protected building. Carried out theoretical and experimental investigations demonstrated high efficiency of the proposed traps. End result of the project will be manufacture of the traps of several different types, experimental testing of their protective action on laboratory models of buildings, demonstration of the efficiency of the new traps, and subsequent transfer of data on optimal for different object traps, and also practical recommendations to builders and design engineers about the practical use of the traps.
The problem of the protection against vibration of buildings and technical construction is a long-standing question. The main principle of such protection is to lower the power of action of incoming vibration impulse to safe for the given construction level. The defense implies absorption of the energy of dynamical excitation in special damping elements (absorbers) which are mechanically connected with protected construction; only small portion of the impulse being transmitted to the protected construction.
Traditionally, one uses for such protection the elements working in the framework of linear theory of vibrations or non-linear traps of non-resonant type. Because of several reasons such elements often are ineffective, and the protection level can not be sufficiently raised on this traditional way. Besides, the sizes of the protecting elements are of the order of the sizes of protected construction, which restricts the area of the practical use of the elements.
The successes of physics of non-linear phenomena in last decades open new possibilities of the protection. In this area, new, previously unknown effects were discovered. Mutual compensation of dispersion and non-linear processes in resonant systems leads to creation and propagation of solitons and soliton-like excitations, and these excitation effectively transfer energy. During the last years, in the works of our group, new mechanisms of formation and propagation of solitons and soliton-like excitations in solid polymer media, in particular in polymer and molecular crystals, were discovered. It was shown theoretically that it is possible to localize spatially high frequency vibration excitations (breezers) in such media. In papers prepared together with scientists from US, Israel, Greece, England and France, it was found that in mechanical systems may appear non-linear resonant effects through which the transition from energy transfer to energy localization may be fulfiled. Protective effect is achieved not through going of the system away from the resonance (as it takes place in linear systems or non-linear non-resonant elements), but through “catching” by the trap a resonant regime, which permits effective energy transfer to the trap and the dissipation of the trapped energy in the trap.
The correctly chosen conditions of defense (rigidity of the protecting element, the character of its non-linearity and viscosity) allow to reach high efficiency by energy transfer, as well as by its localization. These results allowed to put a question about new approach to protection of big-volume constructions and buildings against intense mechanical impacts. The estimates showed that the attached to the protected construction resonant trap is able to effectively ‘catch’ energy of incoming impulse, localize the energy in the trap, the back transition to the protected construction being practically absent. In the present project we offer the way of elaboration and laboratory testing of such a method of protection. The theory shows that the sizes of the new traps may be sufficiently less than the protected construction. The restricted sizes of the nonlinear resonant traps make their use economically possible and expedient. Recently, in the joint works of our group with the investigators from France, the predicted ability of the new defensive traps was experimentally checked. On the created in the laboratory model of a building, it was demonstrated that the traps of the new type allow to reach a high level of localization of energy of incoming impulse, the level being much higher than was achieved before.
The research team is collected such that it is able to fulfill all the directions of work optimally. The team consist of theoreticians, who up to now made a lot in the field of non-linear dynamics, people experienced in computer modeling researches (for calculation of protection of specific buildings and constructions), and experimentalists having experience in work with protective elements of different types and able to analyze parameters and efficiency of the processes of energy localization. In addition, the team includes engineers and mechanicians able to assemble, exploit and control laboratory setups for measurements of characteristics of defensive traps.
The institutions – participants have large and well equipped for metal working shops. This gives the confidence in qualified making of the new traps and the laboratory benches for testing the traps. And, finally, there is a design office, the workers of which are able to project the new traps and the benches which than will be made in works. The team is high-qualified and includes 8 Doctors of science, 8 PhDs, 4 engineers and 3 mechanics. The project will be fulfilled in tight collaboration with foreign collaborators from 5 countries, USA, England, France, Greece and Israel. The joint works with collaborators last for several years (2002-2007) already. There are more than 20 joint publications in peer-reviewed scientific journals. We have obtained the consent of all the collaborators for the continuation of the collaboration in the framework of the project. We believe that practical use of the new resonance traps will lead to the new level of defense for modern residential and industrial buildings, constructions and structures, and, finally, people against terrorists’ acts, man-caused catastrophes and natural disasters.
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