scholarly journals Measurement and Analysis of Horizontal Vibration Response of Pile Foundations

2007 ◽  
Vol 14 (2) ◽  
pp. 89-106 ◽  
Author(s):  
A. Boominathan ◽  
R. Ayothiraman
Keyword(s):  
Dynamic Load ◽  
Power Plants ◽  
Experimental Studies ◽  
Bending Moment ◽  
Vibration Response ◽  
Pile Foundations ◽  
Dynamic Loads ◽  
Horizontal Vibration ◽  
Single Piles ◽  
Pile Length

Pile foundations are frequently used in very loose and weak deposits, in particular soft marine clays deposits to support various industrial structures, power plants, petrochemical complexes, compressor stations and residential multi-storeyed buildings. Under these circumstances, piles are predominantly subjected to horizontal dynamic loads and the pile response to horizontal vibration is very critical due to its low stiffness. Though many analytical methods have been developed to estimate the horizontal vibration response, but they are not well validated with the experimental studies. This paper presents the results of horizontal vibration tests carried out on model aluminium single piles embedded in a simulated Elastic Half Space filled with clay. The influence of various soil and pile parameters such as pile length, modulus of clay, magnitude of dynamic load and frequency of excitation on the horizontal vibration response of single piles was examined. Measurement of various response quantities, such as the load transferred to the pile, pile head displacement and the strain variation along the pile length were done using a Data Acquisition System. It is found that the pile length, modulus of clay and dynamic load, significantly influences the natural frequency and peak amplitude of the soil-pile system. The maximum bending moment occurs at the fundamental frequency of the soil-pile system. The maximum bending moment of long piles is about 2 to 4 times higher than that of short piles and it increases drastically with the increase in the shear modulus of clay for both short and long piles. The active or effective pile length is found to be increasing under dynamic load and empirical equations are proposed to estimate the active pile length under dynamic loads.

Study on Dynamic Response of Hollow Pile Using the Method of Composite Stiffness Principle and Biparameter

2011 ◽  
Vol 243-249 ◽  
pp. 2679-2683
Author(s):  
Yong Mou Zhang ◽  
Min Yang ◽  
Qiang Gang Yan
Keyword(s):  
Dynamic Load ◽  
Bending Moment ◽  
Dynamic Loads ◽  
Concrete Pile ◽  
Side Resistance ◽  
Geological Conditions ◽  
Internal Forces ◽  
The Finite Difference Method ◽  
Composite Stiffness ◽  
Laterally Loaded

The method of composite stiffness principle and biparameter for laterally loaded pile was used in this paper to calculate the amplitude of deflection and rotation of pile on the ground when the vibration frequency of dynamic load is equal to or close to the natural frequency of pile, i.e. when the pile is in the state of resonance. And the amplitude of the maximum bending moment and its location was also calculated. Then the finite difference method which is simple in principle and easy to program was used to calculate the displacement, soil side resistance and internal forces of pile under horizontal dynamic load. By choosing reasonable parameters, rotation, displacement, and the maximum bending moment of hollow concrete pile and solid pile under the same dynamic loads at pile top in the same geological conditions were calculated respectively. On this basis, the performance differences between hollow pile and solid pile were analyzed. Some advantages of hollow pile were obtained. This research provides a theoretical guidance for the using of hollow pile in engineering.

scholarly journals Results of experimental studies of the mutual influence of tenometric sensors on the plane elements of the road machine design

2021 ◽  
pp. 156
Author(s):  
Andrii Koval ◽  
Jurii Rukavyshnikov
Keyword(s):  
Information System ◽  
Dynamic Load ◽  
Mutual Influence ◽  
Experimental Studies ◽  
Dynamic Loads ◽  
Nonlinear Dependence ◽  
Strain Gauges ◽  
Measurement Information ◽  
Mutual Location ◽  
The Road

Analysis of the use of road vehicles in recent years shows an increasing trend continuous mode of their operation. In these circumstances, it is important to know the current technical status condition of the road machine. To a large extent, this is determined by the reliability of the measurement information about dynamic loads on the structural elements of a road machine. In order to increase the accuracy and reliability of dynamic measurements of loads, the authors conducted a number of experimental studies. Experimental studies of the mutual influence of strain gauges on the errors of dynamic load measurements on the structure of the road machine were carried out using a model of the planar element of the structure of the road machine. A computerized four-channel spatially distributed measurement information system was used in the experimental studies. Research results are presented mutual influence of strain gauges under various static and dynamic loads. It is established that due to the action of inertia forces and acceleration, the interaction between the sensors is manifested to a greater extent. Using the methods of comparison, comparison and complex analysis of the results of experimental studies, the dependences of the errors of dynamic load measurements on the angle of action and load removal were established. According to the results of research, the functions of dependence of dynamic loads on the direction and force of action on each of the 4 strain gauges, taking into account their mutual location, are obtained.  It is shown that the experimentally obtained coefficient of the interconnection of strain gauges depends on both the mutual location of the sensors and the spatial direction of the force and has a nonlinear dependence. The experimentally determined error function between the four strain gauges was 3%. The reason for the increase in measurement errors of dynamic planar loads is the displacement of the operating point upwards by the transformation function at positive load, or downwards at negative load. The magnitude of the displacement depends on both the magnitude of the load and its removal.The results obtained will allow optimizing the placement and number of strain gauges on board Measuring Information System on the structure of of the road machine. As a result, the accuracy and reliability of measuring the parameters of the dynamic loads of the road machine will significantly increase.

АКУСТИЧНА ПОМІТНІСТЬ БЕЗПІЛОТНИХ ЛІТАЛЬНИХ АПАРАТІВ З СИЛОВИМИ УСТАНОВКАМИ НА БАЗІ ПОРШНЕВИХ ДВИГУНІВ

2020 ◽  
pp. 62-80
Author(s):  
В. В. Руденко ◽  
И. В. Калужинов ◽  
Н. А. Андрущенко
Keyword(s):  
Control System ◽  
Internal Combustion Engine ◽  
Power Plants ◽  
Combustion Engine ◽  
Spectral Characteristics ◽  
Experimental Studies ◽  
Internal Combustion ◽  
Detection Range ◽  
Acoustic Signature ◽  
Static Conditions

The presence in operation of many prototypes of UAVs with propeller propellers, the use of such devices at relatively low altitudes and flight speeds makes the problem of noise reduction from UAVs urgent both from the point of view of acoustic imperceptibility and ecology.The aim of the work is to determine a set of methods that help to reduce the visibility of UAVs in the acoustic range. It is shown that the main source of noise from the UAV on the ground is the power plant, which includes the engine and the propeller. The parameters of the power plants influencing the processes that determine the acoustic signature of the UAV were investigated. A comprehensive analysis of the factors affecting visibility was carried out. The power plants include two-stroke and four-stroke engines, internal combustion and two-blade propellers. The use of silencers on the exhaust of the internal combustion engine was considered. The spectral characteristics of the acoustic fields of the propeller-driven power plants for the operating sample of the UAV "Eco" were obtained. The measurements were carried out in one-third octave and 1/48 octave frequency bands under static conditions. The venue is the KhAI airfield. Note that the propellers that were part of the power plants operated at Reynolds numbers (Re0,75<2*105), which can significantly affect its aerodynamic and acoustic characteristics. It is shown that when choosing a UAV control system, one should take into account the fact that two-stroke piston engines are the dominant source in the noise of propeller-driven control systems in the absence of a hood and mufflers in the intake and exhaust tracts. The use of a four-stroke internal combustion engine significantly reduces the noise of the control system. In the general case, the position of the boundaries of the zone of acoustic visibility of a UAV at the location of the observer is determined by the ratio between the intensity of acoustic radiation perceived by the observer from the UAV and the intensity of sound corresponding to the natural acoustic background and depends on the degree of manifestation of acoustic effects accompanying the propagation of sound in a turbulent atmosphere - the refraction of sound waves. Absorption and dissipation of acoustic energy. The calculation and comparison of the UAV detection range was carried out taking into account the existing natural maskers.The results of experimental studies are presented that allow assessing the degree of acoustic signature of the UAV. A set of measures aimed at reducing the intensity of the acoustic signature of the UAV in various regions of the radiation spectrum has been determined.

scholarly journals Effect of dynamic loads and vibrations on lithium-ion batteries

2021 ◽  
pp. 146134842110081
Author(s):  
Xia Hua ◽  
Alan Thomas
Keyword(s):  
Lithium Ion Batteries ◽  
Lithium Ion Battery ◽  
Experimental Studies ◽  
Lithium Ion ◽  
Battery Pack ◽  
Dynamic Loads ◽  
Electrical Performance ◽  
Mechanical Degradation ◽  
Energy Storage Devices ◽  
Battery Cell

Lithium-ion batteries are being increasingly used as the main energy storage devices in modern mobile applications, including modern spacecrafts, satellites, and electric vehicles, in which consistent and severe vibrations exist. As the lithium-ion battery market share grows, so must our understanding of the effect of mechanical vibrations and shocks on the electrical performance and mechanical properties of such batteries. Only a few recent studies investigated the effect of vibrations on the degradation and fatigue of battery cell materials as well as the effect of vibrations on the battery pack structure. This review focused on the recent progress in determining the effect of dynamic loads and vibrations on lithium-ion batteries to advance the understanding of lithium-ion battery systems. Theoretical, computational, and experimental studies conducted in both academia and industry in the past few years are reviewed herein. Although the effect of dynamic loads and random vibrations on the mechanical behavior of battery pack structures has been investigated and the correlation between vibration and the battery cell electrical performance has been determined to support the development of more robust electrical systems, it is still necessary to clarify the mechanical degradation mechanisms that affect the electrical performance and safety of battery cells.

Effect of Torsion on Collapse Bending Moment for 24-Inch Diameter Schedule 80 Pipes With Wall Thinning

2012 ◽  
Author(s):  
Kunio Hasegawa ◽  
Yinsheng Li ◽  
Bostjan Bezensek ◽  
Phuong Hoang
Keyword(s):  
Power Plants ◽  
Bending Moment ◽  
Combined Loading ◽  
Bending Moments ◽  
Compressive Stresses ◽  
Wall Thinning ◽  
Nominal Thickness ◽  
Calculation Results ◽  
Loading Modes ◽  
Local Wall Thinning

Piping items in power plants may experience combined bending and torsion moments during operation. Currently, there is a lack of guidance in the ASME B&PV Code Section XI for combined loading modes including pressure, torsion and bending. Finite element analyses were conducted for 24-inch diameter Schedule 80 pipes with local wall thinning subjected to tensile and compressive stresses. Plastic collapse bending moments were calculated under constant torsion moments. From the calculation results, it can be seen that collapse bending moment for pipes with local thinning subjected to tensile stress is smaller than that subjected to compressive stress. In addition, equivalent moment is defined as the root the sum of the squares of the torsion and bending moments. It is found that the equivalent moments can be approximated with the pure bending moments, when the wall thinning length is equal or less than 7.73R·t for the wall thinning depth of 75% of the nominal thickness, where R is the mean radius and t is the wall thickness of the pipe.

Comparing Shock, Random and Sine Vibration Loads of the Electronic Equipment

2005 ◽  
Author(s):  
Frank Fan Wang
Keyword(s):  
Dynamic Load ◽  
Random Vibration ◽  
Sine Wave ◽  
Electronic Equipment ◽  
Dynamic Loads ◽  
Peak Acceleration ◽  
Maximum Acceleration ◽  
Dynamic Excitations ◽  
Dynamic Damage ◽  
Resonant Point

It is a challenge to correlate different dynamic loads. Often, attempts are made to compare the peak acceleration of sine wave to the root mean square (RMS) acceleration of random vibration and shock. However, peak sine acceleration is the maximum acceleration at one frequency. Random RMS is the square root of the area under a spectral density curve. These are not equivalent. This paper is to discuss a mathematical method to compare different kinds of dynamic damage at the resonant point of the related electronic equipment. The electronic equipment will vibrate at its resonance point when there are dynamic excitations. The alternative excitation at the resonant frequency causes the most damage. This paper uses this theory to develop a method to correlate different dynamic load conditions for electronic equipment. The theory is that if one kind of dynamic load causes the same levels of damaging effects as the other, the levels of vibration can then be related.

On the question of the appointment of separate parameters of the roadheaders gathering-stars loading organs

2021 ◽  
pp. 90-93
Author(s):  
N.B. Afonina ◽  
A.V. Otrokov ◽  
G.Sh. Khazanovich
Keyword(s):  
Energy Consumption ◽  
Experimental Studies ◽  
The Other ◽  
Dynamic Loads ◽  
Selective Action ◽  
Side Edge ◽  
Fluidized State ◽  
High Dynamic ◽  
Loading Devices

Most modern roadheaders of selective action are equipped with loading devices with gathering-stars, which have a simpler drive design and increased reliability. As a result of the experimental studies carried out at SRSPU (NPI), it was found that under certain conditions, it is possible to transfer large lump material of a pile into a fluidized state, which reduces the energy consumption of material loading. An increase in the number of beams of the gathering-stars reduces the influence of the other parameters of the loader. Analysis of the process of interaction of the gathering-star’s beam with the receiving conveyor’s side edge to avoid jamming of the picking gathering-star by a lump of material with the implementation of high dynamic loads, it is necessary to set the gathering-beams at an angle of at least 60 degrees against rotation.

Experimental Study on Various Mineral Admixtures in Fibre Reinforced Concrete

2019 ◽  
pp. 309-317
Author(s):  
Kavitha E ◽  
Karthik S ◽  
Eithya B ◽  
Seenirajan M
Keyword(s):  
Fly Ash ◽  
Rice Husk ◽  
Power Plants ◽  
Rice Husk Ash ◽  
Thermal Power ◽  
Experimental Studies ◽  
Mineral Admixtures ◽  
Hardened Concrete ◽  
Polypropylene Fibres ◽  
Concrete Production

The quantity of fly ash produced from thermal power plants in India is approximately 80 million tons each year, and its percentage utilization is less than 10%. An attempt has been made to utilize these cheaper materials in concrete production. This thesis aims at investigating the characteristics of fresh concrete and various strengths of hardened concrete made with various mineral admixtures such as fly ash. GGBFS, silica fume. Rice husk ash along with polypropylene fibres in various proportions.  M20 grade concrete is considered for experimental studies with 53grade Ordinary Portland Cement blended with varying percentages of mineral admixtures. The maximum size of coarse aggregate used is 20mm.  Various mineral admixtures such as fly ash. GGBFS.Silica fume. Rice Husk Ash were added concrete in various percentages by partially replacing cement and the optimum percentage of the mineral admixtures will be found.  Based on the obtained values, the admixture with maximum mechanical strength is determined and to this polypropylene fibre is added by varying 0 to 0.5 % by weight of cement to the mix.  The test results obtained were compared and discussed with conventional concrete.

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.

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