scholarly journals Dynamic Tests of a Leg in a Powered Roof Support Equipped with an Innovative Hydraulic System

2018 ◽  
Vol 41 ◽  
pp. 03019 ◽  
Author(s):  
Dawid Szurgacz ◽  
Jarosław Brodny
Keyword(s):  
Control System ◽  
Dynamic Load ◽  
Hydraulic System ◽  
Free Fall ◽  
Dynamic Loads ◽  
Hydraulic Control ◽  
Powered Support ◽  
Static And Dynamic Loads ◽  
The Impact ◽  
Roof Support

Static and dynamic loads impact on a powered roof support during its operation. The dynamic loads lead to a number of consequences for the construction and the entire hydraulic system. With the increase of depth and intensity of exploitation, the number of events during which the dynamic load is greater increases. Therefore, it is necessary to research the whole unit of the support and its components under the impact of dynamic load. The article presents the results of tests of a hydraulic leg designed to work in the powered support and dynamically loaded with free fall drop. An innovative hydraulic system type DOH was mounted in the subject leg. As a result of the conducted tests, the dynamic parameters of the tested system were determined. The aim of the research was also to determine the impact of drop’s energy on the operating parameters of the tested system. The tested hydraulic system is a part of an innovative electro hydraulic control system of the powered roof support. The Authors believe that the obtained results will allow to create opportunities for the practical application of the tested system and the entire wireless control system of the mining roof support.

scholarly journals IMPACT OF INTERLAMINAR ELLIPTICAL DEFECTS UPON BEHAVIOR OF RECTANGULAR CARBON PLASTIC PLATE AT STATIC AND DYNAMIC LOADS

2020 ◽  
Vol 2020 (12) ◽  
pp. 19-30
Author(s):  
Aleksandr Medvedskiy ◽  
Mihail Martirosov ◽  
Anton Homchenko ◽  
Darina Dedova
Keyword(s):  
Rectangular Plate ◽  
Dynamic Load ◽  
Static Load ◽  
Dynamic Loads ◽  
Carbon Plastic ◽  
Plastic Plate ◽  
Investigation Methods ◽  
Static And Dynamic Loads ◽  
The Impact ◽  
Distribution Of Stresses

The purpose of this work is to investigate the impact of the inner defects of elliptical stratification type upon behavior of the rectangular carbon plastic plate at the impact of static and dynamic loads. The investigation methods: the problem is solved in a numerical way with the aid of a finite ele-ment method (FEM) in the LS-DYNA software com-plex (Livermore Software Technology Corp.). The investigation results: the distribution of stresses in plate layers under the impact of static and dynamic loads is obtained. The distribution of destruc-tion indices with the use of different destruction criteria for unidirectional composites (on the basis of carbon band) is defined. Conclusions: the impact of defects of the type of specified shape stratification, dimensions, amount and places of location with regard to the plate under consideration under the action of compressive static load does not practically tell. Under the action of the compressive dynamic load there is observed a noticeable impact of inner defects upon rectangular plate behavior.

The Specific Characteristics of Shock and Blast Impacts on Construction Sites

2021 ◽  
pp. 81-88
Author(s):  
A.A. Komarov ◽  
Keyword(s):  
Dynamic Load ◽  
Static Load ◽  
Dynamic Loads ◽  
Potential Hazard ◽  
Construction Sites ◽  
Static Loads ◽  
Equivalent Static Loads ◽  
Plane Crash ◽  
Nuclear Plants ◽  
The Impact

The practices of hazardous and unique facilities’ construction imply that specific attention is paid to the issues of safety. Threats associated with crash impacts caused by moving cars or planes are considered. To ensure safety of these construction sites it is required to know the potential dynamic loads and their destructive capacity. This article considers the methodology of reducing dynamic loads associated with impacts caused by moving collapsing solids and blast loads to equivalent static loads. It is demonstrated that practically used methods of reduction of dynamic loads to static loads are based in schematization only of the positive phase of a dynamic load in a triangle forms are not always correct and true. The historical roots of this approach which is not correct nowadays are shown; such approach considered a detonation explosion as a source of dynamic load, including TNT and even a nuclear weapon. Application of the existing practices of reduction of dynamic load to static load for accidental explosions in the atmosphere that occur in deflagration mode with a significant vacuumization phase may cause crucial distortion of predicted loads for the construction sites. This circumstance may become a matter of specific importance at calculations of potential hazard of impacts and explosions in unique units — for instance, in the nuclear plants. The article considers a situation with a plane crash, the building structure load parameters generated at the impact caused by a plane impact and the following deflagration explosion of fuel vapors are determined.

Research of Properties of Austenitic Steels

2021 ◽  
Vol 887 ◽  
pp. 242-246
Author(s):  
A.A. Peregudov ◽  
S.A. Vologzhanina ◽  
A.F. Igolkin
Keyword(s):  
Low Temperatures ◽  
Far East ◽  
Austenitic Steels ◽  
Dynamic Loads ◽  
Complex State ◽  
Corrosion Resistant ◽  
The Far East ◽  
Static And Dynamic Loads ◽  
The Impact ◽  
Strength And Ductility

Active development of the territories of Siberia and the Far East requires the use of materials that are able to work under the combined influence of low temperatures and a complex state. When operating equipment parts at low temperatures, it is necessary to take into account the impact of static and dynamic loads, as well as the influence of an external aggressive environment. The paper studies corrosion-resistant cold-resistant metastable austenitic steels, which are widely used for manufacturing parts of low-temperature equipment. Tests were performed to assess the strength and ductility characteristics of smooth samples and samples with annular notches for static stretching in the temperature range from 293 to 77 K.

scholarly journals Analysis of load of a powered roof support’s hydraulic leg

2018 ◽  
Vol 71 ◽  
pp. 00002 ◽  
Author(s):  
Dawid Szurgacz ◽  
Jarosław Brodny
Keyword(s):  
Rock Mass ◽  
Hydraulic System ◽  
Impact Load ◽  
Load Condition ◽  
Dynamic Impact ◽  
Registration System ◽  
Free Falling ◽  
The Impact ◽  
Impact Mass ◽  
Roof Support

The main purpose of the powered roof support is to protect headings from the impact of the rock mass. The result of such impact is static and dynamic load impacting the support section, which is carried by its construction. The basic elements of the construction of the support are hydraulic legs, whose task is to ensure adequate strength of its setting. Particularly in the case of dynamic impact of the rock mass, these legs are exposed to a very unfavourable load condition. Therefore, it is necessary to conduct tests to determine the parameters of operation for this type of loads. The paper presents the results of tests on the hydraulic leg subjected to impact load with free falling impact mass. The purpose of the research was to determine the parameters of the leg's operation, i.e. the time periods of pressure in the space under the piston and other elements of the hydraulic system. The tests were conducted in compliance with designed methodology and included innovative registration system. The obtained results clearly indicate the correctness of the adopted assumptions. According to the authors, the results should be applied during selection and operation of a powered roof support.

Study Control System Based on Creep Test in High Density Baler

2010 ◽  
Vol 139-141 ◽  
pp. 1624-1627
Author(s):  
Wei Lee ◽  
Chun Guang Wang
Keyword(s):  
Control System ◽  
Data Acquisition ◽  
Creep Test ◽  
Hydraulic System ◽  
Electrical Contact ◽  
Hydraulic Cylinder ◽  
High Density ◽  
Hydraulic Control ◽  
Creep Tests ◽  
Relief Valve

Hydraulic transmission system controls hydraulic cylinder forward and backward movement freely, in order to achieve high density hydraulic baler work circulation. Creep test required hydraulic system to output constant stress, and study creep tests can not be completed when used succeeding the electrical contact style in the past time. The system used programmable logic controller (PLC) to instead of succeeding the electrical contact style and realized freely forward and backward movement of hydraulic cylinder, electro-hydraulic proportional relief valve can adjust hydraulic system and make it stepless pressure regulation and then degree of automation and reliability in hydraulic control system to be improved. This paper introduces aspects: including the selection, hardware configuration and program of PLC, meanwhile, giving specific realization method. Through the control system to study creep test in hydraulic baler, adopting the National Instrument (NI) company's multi-channel data acquisition card, which type is USB-6251,applying Labview8.2 to write data acquisition program on my own, the versatility and flexibility of system was verified, which was able to complete creep test successfully.

The Kinematic and Dynamic Analysis of Hydraulic Control System Based on the Lagrangian Force Method

2018 ◽  
Vol 15 (05) ◽  
pp. 1850041
Author(s):  
Thi-Na Ta ◽  
Cao-Sang Tran ◽  
Yunn-Lin Hwang
Keyword(s):  
Control System ◽  
Dynamic Analysis ◽  
Hydraulic System ◽  
Lagrange Equation ◽  
Control Parameters ◽  
Hydraulic Control ◽  
Hydraulic Systems ◽  
Dynamical Parameters ◽  
Characteristic Effect ◽  
Hydraulic Control System

In this paper, the hydraulic control system design and dynamic analysis are considered in superior calculation efficiency based on Lagrangian method and fundamental laws for getting control algorithms to investigate about hydraulic system how to control hydraulic system and take hydraulic controller to the optimization. The systems built in dynamical parameters are associated hydraulic control system achieved with control parameters. And then, an interface is achieved. The relations between control parameters are obtained. The numerical tools are going to determine all kinematic parameters of bodies such as displacement, velocities, accelerations as well as reaction forces are responded. The AMESim and RecurDyn are used such Computer Aided Engineering (CAE) techniques to solve the numerical examples in this paper. Those examples will imply that the equation of motion based on Euler–Lagrange equation and characteristic effect of force is executable. Through results, we could achieve control improvement at different hydraulic systems.

scholarly journals STATIC AND DYNAMIC LOADS ON THE BOTTOM ROW OF ARMOUR UNITS: A THEORETICAL AND PHYSICAL MODEL STUDY

2012 ◽  
Vol 1 (33) ◽  
pp. 44
Author(s):  
Michael Alexander Van de Koppel ◽  
Michiel Muilwijk ◽  
Henk Jan Verhagen
Keyword(s):  
Physical Model ◽  
Dynamic Load ◽  
Packing Density ◽  
Single Layer ◽  
Dynamic Loads ◽  
Model Study ◽  
Static And Dynamic Loads

A physical model study on the row averaged static and dynamic load on the bottom row of single layer armour units in order to investigate the influence of various parameters such as the number of rows on the slope of a breakwater and the initial relative packing density.

scholarly journals Dynamic Mechanical Characteristics of Impact Rock under the Combined Action of Different Constant Temperatures and Static and Dynamic Loads

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Enlai Zhao ◽  
Enyuan Wang ◽  
Zesheng Zang ◽  
Xiaojun Feng ◽  
Rongxi Shen
Keyword(s):  
Mechanical Properties ◽  
Dynamic Load ◽  
Incident Energy ◽  
Dynamic Mechanical Properties ◽  
Image Correlation ◽  
Dynamic Loads ◽  
Dissipated Energy ◽  
Dynamic Mechanical ◽  
Combined Action ◽  
Static And Dynamic Loads

The complex mechanical environment of deep coal and rock masses leads to obvious changes on their dynamic mechanical properties. However, there are few reports on the dynamic mechanical properties of rocks under the combined action of medium temperature (normal temperature ∼100°C) and static and dynamic loads. In this paper, a dynamic load and temperature combined action Hopkinson pressure bar experimental system is used to experimentally study the impact type of a fine sandstone under temperature conditions of 18°C, 40°C, 60°C, 80°C, and 100°C, an axial static load of 3 MPa, a gas chamber pressure of 0.06 MPa, and a constant temperature time of 4 h. The dynamic characteristics of the change law of the fine sandstone and the energy dissipation characteristics of the load process are analyzed, and the characteristic law of the fine sandstone surface response is analyzed using digital image correlation technology. Our results indicate the following. (1) Under conditions in which the other experimental conditions remain unchanged, the dynamic stress-strain of the fine sandstone presents a bimodal shape with a “rebound” phenomenon. Increasing temperature causes the peak strength of the fine sandstone to increase; however, the relative strength can increase or decrease. The relative increase in the strength is 1.14 MPa (°C) when the temperature increases from 40°C to 60°C, 0.15 MPa (°C) when the temperature increases from 60°C to 80°C, and 0.62 MPa (°C) when the temperature increases from 80°C to 100°C. (2) The digital image correlation results show that, under the action of a dynamic load stress wave, the fine sandstone experiences a displacement vector change on the sample surface; furthermore, under the combined action of the temperature and dynamic and static loads, the fine sandstone experiences macroscopic shear failure. The surface strain in the propagation direction of the stress wave is obviously higher and can even reach values of more than 10 times that of the strain in other directions. (3) From the perspective of energy dissipation, the incident energy, reflected energy, and dissipated energy of the fine sandstone under an impact load have the same change law. After being affected by a dynamic load, the energy rapidly increases to a certain value and then remains relatively stable. The transmitted energy is relatively small and can be approximated as a horizontal line. As the temperature increases, the incident energy, reflected energy, and dissipated energy tend to first decrease and then increase, and most of the incident energy in the fine sandstone is dissipated in the form of reflected waves.

scholarly journals Numerical study on the fracture characteristics and failure mode of hard coal under coupled static and dynamic loads

2020 ◽  
Vol 192 ◽  
pp. 04002
Author(s):  
Lihai Tan ◽  
Ting Ren ◽  
Xiaohan Yang ◽  
Xueqiu He
Keyword(s):  
Fracture Mode ◽  
Stress Level ◽  
Coupling Effect ◽  
Numerical Study ◽  
Dynamic Loads ◽  
Hard Coal ◽  
Fracture Characteristics ◽  
Shpb Test ◽  
Static And Dynamic Loads ◽  
The Impact

It has been well accepted by mining researchers that coal tends to undergo abrupt fracture under the coupling effect of dynamic and static loads. Hence, the study of influence of coupled static and dynamic loads on coal failure behaviour is meaningful for the understanding of coal burst. In this paper, PFC modelling of SHPB test is adopted to investigate the fracture mode and energy evolution of Australian hard coal under different combinations of pre-stress levels and impact velocities. Results have shown that high dynamic load will make the fracture mode and energy release of coal samples more violent even the static load is low. Although the strain energy increases with pre-stress level, the kinetic energy remains on a low level with the increase of pre-stress level when the impact velocity is 4 m/s.

scholarly journals Behavior of normal strength concrete slabs under static and dynamic loads

2021 ◽  
Author(s):  
Turky Sami Jeddawi
Keyword(s):  
Impact Loading ◽  
Static Load ◽  
Dynamic Loads ◽  
Concrete Slabs ◽  
Normal Strength Concrete ◽  
Deformation And Failure ◽  
Absorption Energy ◽  
Static And Dynamic Loads ◽  
Normal Strength ◽  
The Impact

An experimental investigation has been conducted to determine the deformation and failure characteristic of slab under static and dynamic loads. Two identical reinforced concrete (RC) of dimensions 1950 x 1950 x 100 mm are tested under same boundary conditions. All top and bottom reinforcement are 10 M doubly plates reinforcement with total 1.0 % steel ratio. The static load is applied at the midpoint of the slab by using load cell 400 x 400 mm with a capacity of 250 kN. The static load increment used in this investigation is 5 kN. The dynamic load is applied at the midpoint of the slab by using a drop-weight of 475 kg from a height of 4.15 m generating an impact energy of 19.24 kJ with impact velocity of 9 m/s. The experimental results revealed that the absorption energy of the impact loading is about 1.4 times the static loading. The maximum deflection is found to be slightly higher for impact loading.

Sign in / Sign up

Export Citation Format

Share Document