THE RULE OF COMBINING A PRIORI AND EXPERIMENTAL INFORMATION IN THE TASKS OF MANAGING TESTS OF COMPLEX TECHNICAL PRODUCTS ACCORDING TO THE BERNOULLI SCHEME

Author(s):  
Yu. I. Buryak ◽  
A. A. Skrynnikov

The article is devoted to the substantiation of the procedure for testing complex technical systems to assess the probability of performing the task, taking into account a priori data obtained from the results of modeling, field tests of components and prototypes, operation of analogues, etc. The conditions for the formation of a combined sample consisting of field experiments and experiments counted on the results of modeling are justified. Data uniformity is checked using the Student's criterion. The minimum volume of full-scale tests is determined by the requirement of equality of the amount of Fischer information about the estimated parameter obtained during full-scale tests and at the expense of a priori data A strategy for conducting field experiments is proposed, in which the required quality of evaluating the probability of completing the task is achieved with the minimum possible number of field experiments. At the first stage, a series of experiments with a volume equal to half of the required sample size is performed. At the second stage, the experiments are conducted sequentially with an assessment after each experiment of the requirements for the amount of information about the evaluated parameter and for the uniformity of data. Experiments are terminated when the specified requirements are met, and then a combined sample is formed, which is used to evaluate the probability of the system performing the task. A model example is considered. The estimation of the gain in the number of experiments performed at different probability values was carried out.

2013 ◽  
Vol 103 (6) ◽  
pp. 665-674 ◽  
Author(s):  
Á. Egri ◽  
M. Blahó ◽  
D. Száz ◽  
G. Kriska ◽  
J. Majer ◽  
...  

AbstractHost-seeking female tabanid flies, that need mammalian blood for the development of their eggs, can be captured by the classic canopy trap with an elevated shiny black sphere as a luring visual target. The design of more efficient tabanid traps is important for stock-breeders to control tabanids, since these blood-sucking insects can cause severe problems for livestock, especially for horse- and cattle-keepers: reduced meat/milk production in cattle farms, horses cannot be ridden, decreased quality of hides due to biting scars. We show here that male and female tabanids can be caught by a novel, weather-proof liquid-filled black tray laid on the ground, because the strongly and horizontally polarized light reflected from the black liquid surface attracts water-seeking polarotactic tabanids. We performed field experiments to reveal the ideal elevation of the liquid trap and to compare the tabanid-capturing efficiency of three different traps: (1) the classic canopy trap, (2) the new polarization liquid trap, and (3) the combination of the two traps. In field tests, we showed that the combined trap captures 2.4–8.2 times more tabanids than the canopy trap alone. The reason for the larger efficiency of the combined trap is that it captures simultaneously the host-seeking female and the water-seeking male and female tabanids. We suggest supplementing the traditional canopy trap with the new liquid trap in order to enhance the tabanid-capturing efficiency.


2021 ◽  
Vol 2021 (10) ◽  
pp. 45-52
Author(s):  
Denis D'yakov ◽  
Iskander Valiulin ◽  
Dmitriy Lihovidov ◽  
Aleksey Velikanov

The purpose of the research in this paper is to develop a promising airfield driverless tow truck to increase the economic efficiency of aircraft towing facilities, including unmanned aircrafts as well as to ensure reliable operation in various climatic conditions. The research methods include the analysis of the experience of using such driverless airfield tow trucks abroad, the theory of calculating traction and speed indicators and experimental studies conducted during the creation and study of field tests of devices used to load the driving wheels of a tractor. To achieve the goal, the configuration of the structure being designed and its intended composition are determined analytically. The operation of the designed device in the traction mode is considered, and the characteristic of calculating its indicators when moving along the support surface is presented. The presented material briefly illustrates the process from creating a model of a driverless airfield tow truck to the created design of an existing sample, which will later be used to conduct its full-scale tests and a comprehensive assessment of its strength traction and speed characteristics.


2000 ◽  
Vol 37 (2) ◽  
pp. 414-437 ◽  
Author(s):  
Asim Haldar ◽  
VSN Prasad Yenumula ◽  
T R Chari

The results of eight full-scale tests on directly embedded steel pole foundations are presented. Fully instrumented poles were tested to measure the various design parameters. Different types of backfills such as sand, in situ gravelly sand, crushed stone, and flowable material were used. Various parameters were measured, including applied moment, ground line deflection-rotation, rotation of the pole below the ground level, soil pressures, and bending moments in the poles. The behaviour of these foundations was explained through ultimate capacity and moment-rotation characteristics. Based on these test results, it was found that the capacity of the directly embedded pole foundation depends primarily on the compaction levels of backfill and the embedment length of the pole. Flowable backfill material, which does not require any compaction, was found to be most effective and promising. Even when the backfill was loose, the lateral capacity significantly increased by the addition of a baseplate or by installing the pole with an additional embedment depth. Various theories developed for laterally loaded rigid piles were used to predict the moment-rotation behaviour and the ultimate capacity of the directly embedded pole foundation with different types of backfill material. Results from the analytical investigations were compared with those obtained from the full-scale load tests. Comparisons show that the ultimate capacities predicted by the models ranged from 0.30 to 2.20 times the measured capacities.Key words: backfill, compaction, full-scale tests, laterally loaded rigid piles, transmission steel poles, ultimate moment.


2020 ◽  
Vol 212 ◽  
pp. 02015
Author(s):  
Mikalai Shalabyta ◽  
Andrei Shuryn ◽  
Tatsiana Shalabyta ◽  
Viacheslav Dragan

There are quite often statically complex structures, the reliability of theoretical calculations of which needs experimental verification in the world practice of design and construction. Studies of building structures functioning can be full-scale or carried out on their models in laboratory conditions depending on the goals set. Full-scale tests of building structures are more expensive, therefore, their implementation requires a special approach and justification. However, to check the operation of complex, critical structures which primarily include metal spatial large-span structures of coatings of buildings and structures especially those used for the first time to assess their bearing capacity, to establish the degree of participation in the construction of each of the elements, to study the operation of individual new nodal elements etc., only full-scale tests are required.


Vestnik MGSU ◽  
2019 ◽  
pp. 188-198
Author(s):  
Evgeniya N. Sychkina ◽  
Vadim V. Antipov ◽  
Yan V. Ofrikhter

Introduction. Reviewed the features of the work of the pile on Permian claystones with the help of numerical and field experiments, analytical calculations. Materials and methods. Numerical modeling was performed in the Plaxis 3D and Midas GTS NX software packages. Full-scale tests of driven piles are made in accordance with the requirements of GOST 20276-2012. The obtained results are compared with the results of analytical calculations according to SP 24.13330.2011. Results. The scientific novelty of the investigation consists in a comparative analysis of the results of numerical modeling of the interaction of a driving pile with claystones with the results of field tests and analytical calculations. Finite element analysis in software package Plaxis 3D using Hardening Soil model shows higher values of settlement (up to 6 times) in relation to stabilized settlement of full-scale pile tests. Calculations in the software package Midas GTS NX showed overestimated values of pile settlements in relation to full-scale pile tests (13-24 times). Analytical calculations in accordance with SP 24.13330.2011 also showed overestimated (up to 3 times) values of the maximum pile settlement in relation to the stabilized settlement during full-scale pile tests. Conclusions. The calculations by the finite element method in the package Plaxis 3D and Midas GTS NX, by the analytical method according to SP 24.13330.2011, show overestimated values of settlement in relation to the stabilized settlement of piles on claystones. Using the Linear-Elastic model for claystones in numerical calculations in Plaxis 3D provides a value close to the settlement of full-scale pile. However, the use of this model is not fully justified for claystones due to the presence of residual deformations and the nonlinear character of pile settlement during loading. Necessary to correct the existing numerical and analytical methods for calculating pile foundations on claystones. It is necessary to continue the work on the further generalization of the experience of arranging piles on weathered claystones in order to evaluate the long-term work of not only a single pile, but also a pile foundation.


2021 ◽  
Vol 26 (1) ◽  

Full-scale tests are widely used to reliably evaluation the service life of paint and varnish coatings by assessing changes of their protective and decorative properties. Four-year exposure program was carried out in the tropical marine climate in South Vietnam (Dam Bay climate station of the Tre island, Nha Trang) of alkyd, chlorinated rubber coatings on low carbon steel, as well as epoxy coatings of various thicknesses with zinc-rich primer, urethane and acrylic outer layers. The tests were conducted on the base of the existing standards in the field of paints and varnishes intended for coastal and ship structures and were accompanied by the data collection and analysis of the meteorological factors for the classification of the area according to the degree of corrosiveness of the atmosphere. The change in the decorative properties of paint coating was assessed by visual and instrumental methods. The protective efficiency of the coatings was assessed by the time of occurrence of the first local defects or complete destruction of coating layers. According to the results of the conducted field tests, it was found that paint coating combinations correspond to expected lifetime in tropical climate from 2 to 5 years. A typical group suitable for a given climate is a two-component epoxy paint with an acrylic topcoat. A zinc-containing primer is recommended as an anticorrosive undercoat.


1996 ◽  
Vol 23 (2) ◽  
pp. 536-548 ◽  
Author(s):  
C. E. Ventura ◽  
A. J. Felber ◽  
S. F. Stiemer

This paper presents the results of full-scale tests performed at the Colquitz River Bridge near Victoria, British Columbia (B.C.), Canada, during September 1992 to determine the dynamic characteristics of the structure. The five-span bridge was completed in 1954 and is part of the Trans-Canada Highway. It is 82.68 m long and 11.89 m wide, and has six continuous steel girders supporting a 175 mm thick concrete deck. This particular bridge was chosen for testing because of its typical nature of many B.C. bridges, its location in an area of high seismic risk, and its excellent site accessibility. The tests included extensive measurements of ambient vibrations induced by traffic and other sources to determine the dynamic characteristics of the bridge. The most significant vertical and lateral mode shapes and associated periods of vibration were determined from vibration measurements at more than 50 different locations of the deck, piers, and abutments. Although a large amount of data were collected, they were quickly processed and analyzed with an innovative system developed at The University of British Columbia. One of the important features of this system is that it permits the identification of the principal modes of vibration immediately after the data have been collected. In addition to the ambient vibration tests, quick release pullback tests were conducted to verify modal frequencies determined from the ambient vibration tests and to determine the damping of the fundamental modes. These tests consisted of loading the bridge at a selected location with a force of about 90 kN and then releasing this load very quickly to induce free vibrations. The information obtained from the field tests was used to refine a computer finite element model of the bridge, which, in turn, was used to gain insight into the dynamic behaviour of specific components of the bridge. Further, this information was used later by the bridge owner to evaluate the bridge's expected response during an earthquake. Key words: steel bridges, dynamic response, full-scale tests.


1987 ◽  
Vol 109 (4) ◽  
pp. 191-199 ◽  
Author(s):  
M. C. Osterman ◽  
A. K. Wojtanowicz ◽  
S. D. Field

A full-scale study was performed of a centrifuge-based process for dewatering oilfield production waste sludges in order to investigate an application of the process to an oilfield production pit closure. Full-scale experiments were performed to analyze the centrifugal sedimentation of both raw and chemically destablized production pit sludge. The two-stage process was tested: primary solids removal by centrifugal classification followed by chemical conditioning and dewatering. Also, full-scale tests were run to understand the effects of the fundamental centrifuging parameters (the bowl-scroll differential speed and the centrifugal force) on the composition and quality of the dewatering products. The concentration of metals in the production pit sludge, before and after dewatering, was analyzed in terms of the present environmental regulations. The removal of heavy metals from the centrifuge overflow was also evaluated. This study provided qualitative information on how to design an on-site, centrifuge-based system for oilfield production pits closure. The system yielded up to 60 percent volume reduction, the solids-free effluent, and the low-moisture (42 percent vol.) cake discharge. The side-product of the process was an oily, low-solids emulsion (skim layer). The study revealed a technique for minimizing the skim layer through a compromise between the centrifugal force and the differential speed.


2019 ◽  
Vol 6 (2) ◽  
pp. 11-15
Author(s):  
Nyan Min Htet Min Htet ◽  
Igor Valentinovich Volkov

This article presents a qualitatively new developed technology of out-of-band registration of speckle holograms in the study of deformations in the concentration zone on samples with holes. Summary. One of the most important aspects of speckle-holographic interferometry is the quality of the resulting speckle-hologram, which largely determines its diffraction efficiency. In this case, the improvement of diffraction efficiency in solving practical problems is carried out through the selection of the developer of photographic plates, the installation of a certain exposure time and the choice of methods for processing photographic plates. However, in practice, there are often problems of obtaining the maximum diffraction efficiency of holograms. We made a choice of developer, exposure time, as well as methods of photo processing of speckle holograms in colliding beams in the process of practical experiment. Practical significance. The technology of out-of-band registration of speckle holograms described in the article can be used in the process of research of SSS of full-scale aircraft structures in areas of stress concentration, as well as their detection during industrial full-scale tests.


2012 ◽  
Vol 524-527 ◽  
pp. 1651-1655
Author(s):  
Zhi Yong Pan ◽  
Chun Feng ◽  
Hua Jia Zhang ◽  
Dong Feng Li ◽  
Peng Yang

Research on a round thread casing connection pullout case and a buttress thread casing connection pullout accident was carried out combining relative theorys with tests. Macroscopic analysis and dimension measurement and material’s physical and chemical properties were checked for casings and couplings. Thread inspection and full-scale tests were done for casing simples that are same lot with pullout casing. Comprehensive analysis was carried out on these results. Two cases history showed that casing connection dropout may take place if make-up location cann’t reach standard location or make-up torque is too little even if the quality of casing and coupling are in accordance with corresponding standards.


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