scholarly journals Cogwheel loading as a moving test load for bridges – analysis and laboratory experiments

2020 ◽  
Vol 310 ◽  
pp. 00030
Author(s):  
Jan Bayer ◽  
Shota Urushadze ◽  
Jong-Dar Yau ◽  
Yeong-Bin Yang
Keyword(s):  
Numerical Simulation ◽  
Dynamic Load ◽  
Laboratory Experiments ◽  
Test Load ◽  
Laboratory Conditions ◽  
Impulse Load

A moving impulse load generated by a heavy cogwheel can be used as a testing excitation for bridges. This novel type of dynamic load acts along the entire driving path, its intensity is adjustable, and it can be very efficient in the case of resonance. Verification tests were performed on a model under laboratory conditions and compared to numerical simulation. The results are extensively discussed.

scholarly journals Study on Occurrence Mechanism of Coal Pillar in L-Shaped Zone during Fully Mechanized Mining Period and Prevention Technology

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Zeng-qiang Yang ◽  
Hong-mei Wang ◽  
De-quan Sun ◽  
Xian-jian Ma ◽  
Ming-bao Xu ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Rock Burst ◽  
Dynamic Load ◽  
Static Load ◽  
Coal Pillar ◽  
Simulation Software ◽  
In Situ Investigation ◽  
Simulation Results ◽  
Occurrence Mechanism

In order to study the occurrence mechanism of rock burst in L-shaped zone during a fully mechanized mining period, the No. 705 working face which is located in Baojishan Colliery is taken as a typical engineering background. By means of in situ investigation, theoretical analysis, numerical simulation, in situ tests, and relevant monitoring methods, the occurrence mechanism of rock burst and corresponding prevention technology are studied. The results show that a coal pillar with some confining pressure in the L-shaped zone is established by FLAC3D numerical simulation software, and the numerical simulation results indicate that the change in static load has a greater effect than dynamic load on coal pillar unstable failure; the static load plays a role in storing energy, and dynamic load plays a role in inducing rock burst; the bolt-mesh-cable support and high-pressure water jet unloading combined technology is put forward to prevent rock burst in roadways, and the numerical simulation results show that stress distribution of surrounding rock meets the model of strong-soft-strong (3S) structure, and the moment distribution is reasonable. In the follow-up mining, a limit value of coal fines is used to determine that this measure is a reasonable method to prevent rock burst. The study conclusions provide theoretical foundation and new guidance for preventing rock burst by synergistic effect technology in roadways.

Protein-feeding by the males of the Australian bushfly Musca vetustissima Wlk. in relation to mating performance

1971 ◽  
Vol 60 (4) ◽  
pp. 607-614 ◽  
Author(s):  
Marina Tyndale-Biscoe
Keyword(s):  
Life Span ◽  
Sexual Activity ◽  
Mating Success ◽  
Laboratory Experiments ◽  
Lucilia Cuprina ◽  
Behaviour Pattern ◽  
Laboratory Conditions ◽  
Protein Feeding ◽  
Mating Performance

Male bushflies (Musca vetustissima Wlk.) are attracted to and feed on proteincontaining substances, although under laboratory conditions they ingested smaller quantities of blood and dung than did the females. Laboratory experiments showed that they are able to obtain water from fresh dung and blood, but no physiological requirement for the protein was found. Feeding on protein did not increase the life span or the total numbers of matings; it did not improve the mating success of males that had previously been multiple-mated; and it did not enhance sexual activity, contrary to the situation found in Lucilia cuprina (Wied.). It is concluded that protein feeding in male bushflies is casual, possibly a behaviour pattern that ensures their presence near females.

A combined computational algorithm for solving the problem of long surface waves runup on the shore

2016 ◽  
Vol 31 (4) ◽  
Author(s):  
Yurii I. Shokin ◽  
Alexander D. Rychkov ◽  
Gayaz S. Khakimzyanov ◽  
Leonid B. Chubarov
Keyword(s):  
Numerical Simulation ◽  
Shallow Water ◽  
Nonlinear Waves ◽  
Laboratory Experiments ◽  
Computational Algorithm ◽  
Analytic Solutions ◽  
Shallow Water Theory ◽  
Sph Method ◽  
Weakly Nonlinear ◽  
Strongly Nonlinear

AbstractIn the present paper we study features and abilities of the combined TVD+SPH method relative to problems of numerical simulation of long waves runup on a shore within the shallow water theory. The results obtained by this method are compared to analytic solutions and to the data of laboratory experiments. Examples of successful application of the TVD+SPH method are presented for the case of study of runup processes for weakly nonlinear and strongly nonlinear waves, and also for

Effect of Wolastonite Mineral (CaO SiO2) Content in Continuous Casting Powder to SEN Erosion

2007 ◽  
Vol 352 ◽  
pp. 107-110
Author(s):  
Snezana Dević ◽  
R. Carli
Keyword(s):  
Continuous Casting ◽  
Refractory Material ◽  
Erosion Rate ◽  
Laboratory Experiments ◽  
Mineral Content ◽  
Treatment Time ◽  
Material Behavior ◽  
Laboratory Conditions ◽  
Slag Zone ◽  
Research Experiment

The basic idea of the work was to analyze the effect of the wollastonite mineral CaO SiO2 content in the continuous casting powder related to the SEN erosion. In order to realize the research, experiments were conducted in the laboratory conditions. The research, experiment, was realized in the Magnohrom Kraljevo laboratory, and cryptonym furnace EV16 was used for refractory material behavior. Cut SEN pieces from the slag zone in the reduction atmosphere were treated in the furnace with three types of casting powder of different mixtures ratio of SRD1 (without wollastonite) and SRD2 (with wollastonite): Casting powder 1 - SRD1/SRD2 = 50/50 %, Casting powder 2 - SRD1/SRD2 = 25/75 % and Casting powder 3 - SRD1/SRD2 = 75/25 %. Temperature of the experiment was in the range of 15200C – 15400C, and treatment time was changed simulating the average casting time of the heat; one heat (45 min), two heats (90 min), and three heats (135 min). The experiment pointed out that the erosion of the SEN was reduced with the increased ratio of wollastonite in the casting powder. The erosion rate of the SEN exposed to the casting powder 2 in the laboratory conditions was 0.0055 mm/min, whilst the erosion rate of the SEN exposed to the casting powder 3 (with the least wollastonite content) was 0.0075 mm/min. Erosion rate of SEN exposed to the casting powder 2 was lower for the 26.27 % related to the casting powder 3, and 17.90% lower than the erosion rate of the casting powder 1 (the erosion rate of the casting powder 1 was 0.0067 mm/min). These laboratory experiments are very consistent with results obtained in the plant conditions [1,2,3]. At that time, results indicated that SRD1 casting powder without wollastonite has the erosion rate 46 % higher than SRD2 casting powder with wollastonite. On the basis of the laboratory researches and earlier plant conditions researches it could be concluded that wollastonite mineral content in the casting powders has significant effect on the SEN erosion, in the way that the SEN erosion rate was decreased with the increased wollastonite content in the casting powders.

Research of the Permafrost Dynamic Load Direct Shear Apparatus

2013 ◽  
Vol 405-408 ◽  
pp. 454-459
Author(s):  
Ying Hui Cui ◽  
Jian Kun Liu ◽  
Peng Lv
Keyword(s):  
Numerical Simulation ◽  
Power Systems ◽  
Engineering Design ◽  
Control Systems ◽  
Dynamic Load ◽  
Dynamic Parameters ◽  
Direct Shear ◽  
Direct Shear Apparatus ◽  
And Control ◽  
Measurement And Control

The dynamic parameters of the permafrost are very important for engineering design, also using in the numerical calculation. The dynamic parameters directly affect the correctness of engineering design and numerical simulation. Beijing Jiaotong University developed a novel dynamic load direct shear apparatus to measure these parameters. In the paper, it is analyzed Power systems, measurement and control systems of the dynamic load direct shear apparatus, and gave a verification experiment, the results show that dynamic load direct shear apparatus can complete its purpose.

scholarly journals MODEL TESTING OF PILED CLUSTERS AND LARGE MONO-PILES OF IMPROVED DESIGN

2017 ◽  
Vol 2 (49) ◽  
pp. 38-44
Author(s):  
M. P. Doubrovsky ◽  
I. Yu. Dobrov ◽  
A. V. Gerashchenko ◽  
O. M. Dubrovska
Keyword(s):  
Laboratory Experiments ◽  
Model Testing ◽  
Scale Model ◽  
Small Scale ◽  
Pile Head ◽  
Laboratory Conditions ◽  
Improved Design ◽  
Energy Absorbing ◽  
Small Scale Model ◽  
Flexible Pile

When constructing piled clusters and structures supported by large mono-piles, piles designed are used to take up significant lateral and pressing-in loads. New effective and less resource-demanding design of piled cluster was considered before. At this paper some results of its model testing in laboratory conditions are analyzed and discussed. To increase energy-absorbing capacity of mooring/fender dolphins it was worked out and researched a new design of combined tubular mono-pile structure, incorporating internal flexible pile and damping element placed at the zone of pile head. This design has been tested by laboratory experiments using small scale model. Obtained results confirm its effectiveness and practicability.

scholarly journals Computational Behavioral Models in Public Goods Games with Migration Between Groups

2021 ◽  
Author(s):  
Marco Tomassini ◽  
Alberto Antonioni
Keyword(s):  
Numerical Simulation ◽  
Public Goods ◽  
Laboratory Experiments ◽  
Replicator Dynamics ◽  
Behavioral Models ◽  
Public Goods Games ◽  
Heterogeneous Behavior ◽  
Simulation Results ◽  
Human Participants ◽  
Simple Sets

Abstract In this study we have simulated numerically two models of linear Public Goods Games where players are equally distributed among a given number of groups. Agents play in their group by using two simple sets of rules that are inspired by the observed behavior of human participants in laboratory experiments. In addition, unsatisfied agents have the option of leaving their group and migrating to a new random one through probabilistic choices. Stochasticity, and the introduction of two types of players in the population, help simulate the heterogeneous behavior that is often observed in experimental work. The numerical simulation results of the corresponding dynamical systems show that being able to leave a group when unsatisfied favors contribution and avoids free-riding to a good extent in a range of the enhancement factor where defection would prevail without migration. Our numerical simulation results are qualitatively in line with known experimental data when human agents are given the same kind of information about themselves and the other players in the group. This is usually not the case with customary mathematical models based on replicator dynamics or stochastic approaches. As a consequence, models like the ones described here may be useful for understanding experimental results and also for designing new experiments by first running cheap simulations instead of doing costly preliminary laboratory work. The downside is that models and their simulation tend to be less general than standard mathematical approaches.

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