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Ibragimov Bakhrom Toshmuratovich, Raupov Dilmurod Rasulovich, Mirzaev Shakhzod Vakhidovich, Ilashov Ziyovuddin Raupov Anvar Razzakovich, The Institute of Fire Safety of the Ministry of Internal Affairs of the Republic of Uzbekistan E-mail: jasrash@mail.ru
DAMPING PROPERTIES OF SEISMIC PROTECTIVE SYSTEMS
Abstract. The article describes the results of testing new fire retardant compositions on the damping properties of seismic protection systems. Tests have shown that the strength of the proposed material remains higher than the "initial position" of the composition with neoprene (25.6% vs. 23.6%). Thermal impact on the samples leads to the fact that the building structure with a neoprene composition in comparison with a composition based on ebonite reinforced by wollastite and basalt fiber loses its strength almost 4 times, whereas the strength of the ebonite base is lost by 21.2%.
Keywords: Seismic risk, dynamic effects, explosion, fire, arson, neoprien, seismic protection, ebonite, wollas-tonite.
Seismic risk, i.e. the probability and scale of seismic disaster is determined not only by danger, but also by another equally important factor, namely: the seismic vulnerability of various objects of urban development, engineering and transport infrastructure of cities and other settlements. The probability of providing contains the security of complex systems, contains a multifactor analysis. Research and design developments in recent years are characterized by the adoption of various seismic protection systems, including damping systems and devices that ensure the reliability of objects during intensive earthquakes, dynamic effects, explosions, fires, and arson. This circumstance is especially relevant for shockproof, anti-dumping damping devices [1; 2].
When they are introduced into the practice of design and construction, there is a decrease in seismic and impulsive loads on bearing and enclosing structures, technological equipment and, as a result, a reduction in the estimated cost of construction, material and labor intensity of construction and installation works, and an increase in the industrialization of the entire construction process.
The achievement of increasing the sustainability of the operation of technological equipment and structural elements of industrial facilities in industries requiring seismic protection occurs through the use of damping systems and anti-dump, anti-shock devices, which significantly reduce the effect of external influence at a relatively low cost compared to other systems and devices used in earthquake-resistant construction. Construction of foundations with supporting elements in the form of swinging pillars (kinematic
supports), suspended type supports, seismic insulating belts and on neoprene supports, according to the works, without metal layers, besides reducing the cost of seismic isolation, also reduced the frequency of vertical oscillations of the building to 2.03 Hz, and horizontal - up to 0.64 Hz. When deciding on the use of seismic protection, it must be borne in mind that the effectiveness of the use of certain seismic isolating devices depends on many factors, and requires serious theoretical and experimental research. In this regard, the properties of materials used for damping and shockproof devices are investigated.
For testing the damping qualities of materials of seismic isolation systems, cubes with a rib size of 10 cm were prepared. To increase fire protection, ebonite with wollastonite additives. The cube was struck with a steel ball weighing 5 grams. from a distance of 1 meter (by the experience of Sol-datova).
For testing the damping qualities of materials of seismic isolation systems, cubes with a rib size of 10 cm were prepared. To increase fire protection, ebonite with wollaston-ite additives. The cube was struck with a steel ball weighing 5 grams. from a distance of 1 meter (by the experience of Soldatova). The distance of the ball rebound, the resistance of the samples to compression after they received the Nth number of impacts, and the resistance of the samples to compression were measured. After a single heat treatment in an oven at 500 °C for 15 minutes. Samples were installed in the installation. From the diagram in fig. 4.9 that ebony + wollastonite initially had a "springing effect" is understated.
DAMPING PROPERTIES OF SEISMIC PROTECTIVE SYSTEMS
However, after 60 strokes of ebonite with the addition of continues to maintain damping qualities, but already greater wollastonite, especially with the addition of wollastonite, it than that of neoprene.
Figure 1. Curves of the range of the ball rebound after heat treatment
A sharp jump down on the graph for neoprene after 70 strokes is apparently related to the onset of material fatigue. Something similar happens with the material of ebonite-based building construction, but later (and not, quite explicitly), i.e. after drawing 80 hits. This fact suggests that the proposed material has a certain margin of safety, which will be necessary when operating in real conditions, as this can increase the life of the damping device. The results show that the composi-
tion based on neoprene quickly loses the damping advantages, compared with ebonite + wollastonite, after 100 beats, the indicator for all three materials is equalized [3]. From the graph in (fig. 2) it can be seen that when using neoprene for a building structure, the strength begins to decrease already after the application of 30 blows, and when performing a building structure based on ebonite with wollastonite additives, the strength decreases only after 40 blows.
Q_
E
ju E
35 30 25 20 15 10
R2 = 0,8841
10
30
50
70
90
110
130
150
180
5
0
0
— Neoprene Ebonite + wollastanite
•• Line (Neoprene) ......... Line (Ebonite +wollastanite)
The number of strokes on the ball
Figure 2. Curves of resistance of samples to thermal effects
This graph also shows that after applying 50 strokes for neoprene, the strength begins to decrease faster, whereas with the proposed composition of the material with liquid glass with wollastonite additives this occurs only after 80 strokes are applied.
Analysis of the results shown in the graphs of (fig. 1_ and 2 shows that a neoprene-based building structure loses
its strength more quickly. After 180 blows, it decreases by a factor of 2-2.3 times, whereas a building structure based on ebonite with the addition of liquid glass loses its strength by 11.3%.
Thus, at the same time, the strength of the proposed material remains higher than the "initial position" of the composition with neoprene (25.6% vs. 23.6%). Thermal
impact on the samples leads to the fact that the building structure with the neoprene composition loses its strength almost 4 times, whereas the strength of the ebonite base is lost by 21.2%.
To check the degree of impact of shocks on the mass of samples ofbuilding structures, the same cube was checked (after applying the designated number of blows, the sample was weighed). It should be noted that this graph also confirms that neoprene begins to lose its strength characteristics faster. Tests have shown that if neoprene loses more than 10% of its mass after 180 strokes, then the proposed material based on ebonite + wollastonite loses a little more than 7%. This circumstance also speaks of the greater strength of the proposed material [4-5]. It is well known that the use of seismic protection de-
vices reduces the risk of vulnerability in the whole building and structure. The test results showed that the most optimal in terms of reducing the risk for building structures, and therefore for structures (in which seismic protective devices are installed), developed ebonite-based damping devices.
Thus, in the theoretical aspect, the practical use of elastic plastic properties of the tested building structures and materials to identify the degree of destruction of buildings and structures can be considered as another mechanism to ensure the safety of industrial and civil construction, for the process of development of protectology. Fatigue tests also revealed that the endurance limit of prototypes of building structures of the proposed option, a damping device, is higher than the initial position when using a neoprene material.
References:
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2. Suleymanov A. A., Tolibov O. S., Musaev M. N., Abdurakhmanov M. R. Probability theory to ensure the safety of complex systems. In the collection: Innovations, quality and service in engineering and technology. Collection of scientific papers of the VIII International Scientific and Practical Conference. Executive editor A. A. Gorokhov. 2018.- P. 365-369.
3. Ibragimov B. T., Suleimanov A. A. The importance of composite on the basis of paronite for damping devices in production in seismic protection // Farghona Polytechnic Institute "FerPI Akhborotnomasi". Ilmi Magazine, 2017.- No. 1.- P. 58-59.
4. Ibragimov B. T., Zhumabayev F. U. Fire hazard damping devices (based on plastics) for seismic isolation foundations // The journal of international scientific and practical conference. (P P X B B X O))) - T. 2013.- P. 188-191.
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