Operational Modal Response Characterization of a Buried Pipe Structure

2020 ◽  
Author(s):  
Haobin Chen ◽  
Ron Hugo ◽  
Ron Chik-Kwong Wong ◽  
Simon Park
Keyword(s):  
Reynolds Number ◽  
Transient Flow ◽  
Water Flow Rate ◽  
Research Work ◽  
Axial Direction ◽  
Dry Density ◽  
Buried Pipe ◽  
Maximum Dry Density ◽  
Vibration Transmission ◽  
Modal Response

Abstract As a novel non-invasive structural health monitoring (SHM) technique for application to buried pipelines, in-situ vibration-based detection offers an approach to achieve continuous monitoring. Modal characteristics are often quantified using vibration signals, with traditional modal analysis performed using either impact-response testing or mechanical-shaker excitation. Both methods, however, are not suitable for a buried pipeline. In this research work, the operational modal response of a buried-pipe structure is investigated, and the application of transient flow event detection is presented. Experiments are conducted on a buried 160-inch horizontal stainless-steel pipe section with an inner diameter of 2-inch. Soil compaction is performed to 95% of the maximum dry density (proctor compaction). During experiments, water flow rate through the pipe (Reynolds number) is increased and turbulent pressure fluctuations provide the varying structural excitation source. Vibration measurements are made using one tri-axial and four single-axis accelerometers. Accelerometers directly mounted to the pipe are to perform on-pipe measurement to investigate the operational modal response of the buried pipe structure. Accelerometers positioned in soil are to investigate the vibration transmission through the soil in both the horizontal and vertical directions, examining the feasibility of the modal response characterization through non-contact measurement. The operational modal response collected through on-pipe measurement showing that vibration energy is decreased due to the soil and the vibration of the axial direction (along the pipe) has highest sensitivity than the other two directions with increasing Reynolds number. The abnormal signal induced by a transient flow event is visualized using short-time spectral analysis, and its propagation and source are determined using acoustic methods. The vibration transmission of the buried pipe propagating through the soil is heavily attenuated both horizontally and vertically.

scholarly journals Effect on CBR Values with Addition of Coir Geotextile and Marble Dust in Silty Sands

2021 ◽  
Vol 889 (1) ◽  
pp. 012005
Author(s):  
Maninder Singh ◽  
Sachin Kamboj ◽  
Kunal Jain ◽  
S.K. Singh
Keyword(s):  
Ground Improvement ◽  
Research Work ◽  
Dry Density ◽  
Virgin Soil ◽  
Test Results ◽  
Maximum Dry Density ◽  
Maximum Value ◽  
Cbr Test ◽  
Marble Dust ◽  
The Cost

Abstract The subgrade is the foundation of pavement. The conventional method of replacing weak soil with good soil can cause an increase in the cost of a project. Due to this reason ground improvement techniques are much popular nowadays. The major goal of this research work is to compare California Bearing Ratio (CBR) values of the virgin soil and soil reinforced with coir geotextile in one layer and a combination of two layers at different heights from the top surface of the soil. To see the change in CBR values one layer of coir geotextile was reinforced at three different heights (i.e., H/3; H/2 and 2H/3). After that, the effect on CBR values by reinforcement of combination of two layers of coir geotextile at different heights (i.e., H/3 and H/2; H/2 and 2H/3; and H/3 and 2H/3) from the top surface of the soil was studied. Thereafter, the soil is replaced by various percentages of marble dust ranging from 10% to 25% with an increment of 5% and again CBR values of soil samples reinforced with one layer of coir geotextile and a combination of two layers of geotextile at three different heights were compared with virgin soil. The test results reviewed that the maximum dry density (MDD) decreased and optimum moisture content (OMC) increased with the replacement of marble dust in the soil. The CBR test results specify an enhancement of the value of CBR with the addition of coir geotextile and marble dust. The maximum value of CBR is obtained when one layer of coir geotextile was introduced at the height of H/3 and in the case of a combination of two layers of coir geotextile maximum CBR values is obtained when the coir geotextile was introduced at a height of H/3 and 2H/3 from the top surface of the soil.

Influence and correlation of maximum dry density on soaked & unsoaked CBR of soil

2021 ◽  
Author(s):  
A. Bharath ◽  
M. Manjunatha ◽  
Tangadagi Ranjitha B. ◽  
T.V. Reshma ◽  
S. Preethi
Keyword(s):  
Dry Density ◽  
Maximum Dry Density

scholarly journals An investigation into the cause of road failure along Sagamu-Papalanto highway southwestern Nigeria

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Ubido Oyem Emmanuel ◽  
Igwe Ogbonnaya ◽  
Ukah Bernadette Uche
Keyword(s):  
Construction Materials ◽  
Road Construction ◽  
Linear Shrinkage ◽  
Liquid Limit ◽  
Dry Density ◽  
Maximum Dry Density ◽  
Southwestern Nigeria ◽  
Low Resistivity ◽  
The Road ◽  
Cause Of Failure

AbstractInvestigation into the cause of road failure has been carried out along a 60 km long Sagamu –Papalanto highway southwestern Nigeria. Geochemical, mineralogical, geotechnical and geophysical analyses were conducted to evaluate the cause of failure along the study area. The results of the laboratory tests showed that the percentage amount of fines ranges from 12 to 61.3%, natural moisture content from 6.8 to 19.7%, liquid limit in the range of 25.1–52.2%, linear shrinkage between 3.96 to 12.71%, plastic limit ranges from 18.2–35%, plasticity index ranges from 5.2 to 24.6%, free swell in the range from 5.17–43.9%, maximum dry density ranges from 1.51–1.74 g /cm3, specific gravity ranges from 2.52–2.64 and CBR between 3 and 12%. The Cone Penetrometer Test (CPT) shows a resistance value of 20–138 kgf/cm2. The major clay mineral that is predominant in the studied soil is kaolinite. The major oxides present are SiO2, Al2O3, Fe2O3, K2O, Na2O, MgO and CaO. The result of the 2D Electrical Resistivity Imaging revealed a low resistivity values for profile 2 and 3 ranging from 100 Ωm – 300 Ωm, between a distance of 20 m – 240 m along the profile to a depth of 7.60 m and a low resistivity value ranging from 50 Ωm – 111Ωm, between a distance of 80 m − 120 m along the profile to a depth of 15 m. It was concluded that the low CBR, low MDD and the class of subsoils namely A-26, A-7, A-2-7 (clayey soils) which were identified are responsible for the cause of failure experienced in the study area. These makes the soils unsuitable as road construction materials and hence, there is need for stabilization during the reconstruction and rehabilitation of the road.

scholarly journals Characterization and Comparison Research on Composite of Alluvial Clayey Soil Modified with Fine Aggregates of Construction Waste and Fly Ash

2021 ◽  
Vol 28 (1) ◽  
pp. 83-95
Author(s):  
Qu Jili ◽  
Wang Junfeng ◽  
Batugin Andrian ◽  
Zhu Hao
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Unconfined Compressive Strength ◽  
Clayey Soil ◽  
Dry Density ◽  
Maximum Dry Density ◽  
Construction Waste ◽  
Comparison Research ◽  
Fine Aggregates ◽  
Optimum Water Content

Abstract Fine aggregates of construction waste and fly ash were selected as additives to modify the characteristics of Shanghai clayey soil as a composite. The laboratory tests on consistency index, maximum dry density, and unconfined compressive strength were carried out mainly for the purpose of comparing the modifying effect on the composite from fine aggregates of construction waste with that from fly ash. It is mainly concluded from test results that the liquid and plastic limit of the composites increase with the content of two additives. But their maximum dry density all decreases with the additive content. However, fine aggregates of construction waste can increase the optimum water content of the composites, while fly ash on the contrary. Finally, although the two additive all can increase the unconfined compressive strength of composites, fly ash has better effect. The current conclusions are also compared with previous studies, which indicates that the current research results are not completely the same as those from other researchers.

Radial lift on a suspended finite-sized sphere due to fluid inertia for low-Reynolds-number flow through a cylinder

2013 ◽  
Vol 722 ◽  
pp. 159-186 ◽  
Author(s):  
Sukalyan Bhattacharya ◽  
Dil K. Gurung ◽  
Shahin Navardi
Keyword(s):  
Reynolds Number ◽  
Particle Diameter ◽  
Axial Direction ◽  
Perturbation Scheme ◽  
Fluid Inertia ◽  
Regular Perturbation ◽  
Cross Sectional ◽  
First Order ◽  
Reynolds Number Flow ◽  
Freely Suspended

AbstractThis article describes the radial drift of a suspended sphere in a cylinder-bound Poiseuille flow where the Reynolds number is small but finite. Unlike past studies, it considers a circular narrow conduit whose cross-sectional diameter is only $1. 5$–$6$ times the particle diameter. Thus, the analysis quantifies the effect of fluid inertia on the radial motion of the particle in the channel when the flow field is significantly influenced by the presence of the suspended body. To this end, the hydrodynamic fields are expanded as a series in Reynolds number, and a set of hierarchical equations for different orders of the expansion is derived. Accordingly, the zeroth-order fields in Reynolds number satisfy the Stokes equation, which is accurately solved in the presence of the spherical particle and the cylindrical conduit. Then, recognizing that in narrow vessels Stokesian scattered fields from the sphere decrease exponentially in the axial direction, a simpler regular perturbation scheme is used to quantify the first-order inertial correction to hydrodynamic quantities. Consequently, it is possible to obtain two results. First, the sphere is assumed to follow the axial motion of a freely suspended sphere in a Stokesian condition, and the radial lift force on it due to the presence of fluid inertia is evaluated. Then, the approximate motion is determined for a freely suspended body on which net hydrodynamic force including first-order inertial lift is zero. The results agree well with the available experimental results. Thus, this study along with the measured data would precisely describe particle dynamics inside narrow tubes.

scholarly journals Experimental Investigation of Tandem Blade Cascades With Double-Circular ARC Profiles

1985 ◽  
Author(s):  
Wu Guochuan ◽  
Zhuang Biaonan ◽  
Guo Bingheng
Keyword(s):  
Experimental Investigation ◽  
Reynolds Number ◽  
Mach Number ◽  
Total Pressure ◽  
Incidence Angle ◽  
Axial Direction ◽  
Geometrical Parameters ◽  
Optimal Conditions ◽  
Turning Angle ◽  
Circular Arc

24 double circular are tandem blade cascades of three different chord-ratios were investigated under different displacements in peripheral and axial direction. The inlet Mach number was 0.3. The Reynolds number based on blade chord was 2.7×105. The characteristics of the tandem blade cascades, such as the dependence of turning angle and coefficient of total pressure loss on incidence angle were obtained. The ranges of main geometrical parameters under optimal conditions were recommended.

Effect of Lime on Compaction, Strength and Consolidation Characteristics of Pontian Marine Clay

2015 ◽  
Vol 72 (3) ◽  
Author(s):  
Siaw Yah Chong ◽  
Khairul Anuar Kassim
Keyword(s):  
Construction Material ◽  
Soft Clay ◽  
Engineering Properties ◽  
Dry Density ◽  
Marine Clay ◽  
Maximum Dry Density ◽  
Stabilization Phase ◽  
Compaction Curve ◽  
Stabilized Soil

Marine clay is a problematic construction material, which is often encountered in Malaysian coastal area. Previous researchers showed that lime stabilization effectively enhanced the engineering properties of clay. For soft clay, both strength and consolidation characteristics are equally important to be fully understood for design purpose. This paper presented the effect of lime on compaction, strength and consolidation characteristics of Pontian marine clay. Compaction, unconfined compression, direct shear, Oedometer and falling head permeability tests were conducted on unstabilized and lime stabilized samples at various ages. Specimens were prepared by compaction method based on 95 percent maximum dry density at the wetter side of compaction curve. It was found that lime successfully increased the strength, stiffness and workability of Pontian marine clay; however, the permeability was reduced. Unconfined compressive strength of stabilized soil was increased by 49 percent at age of 56 days whereas compressibility and permeability was reduced by 48 and 67 percent, respectively. From laboratory tests, phenomenon of inconsistency in engineering characteristics was observed for lime stabilized samples below age of 28 days. This strongly proved that lime stabilized soil underwent modification phase before stabilization phase which provided the long term improvement.

Effective Fuel Consumption by Improving Cooling Water Flow Rate in IC Engine

2015 ◽  
Vol 812 ◽  
pp. 112-117
Author(s):  
K.M. Kumar ◽  
P. Venkateswaran ◽  
P. Suresh
Keyword(s):  
Flow Rate ◽  
Cooling System ◽  
Water Flow Rate ◽  
Research Work ◽  
Cooling Water ◽  
Major Change ◽  
Clear Understanding ◽  
Water Pump ◽  
Ic Engine ◽  
Cooling Water Flow Rate

The coolant (water) pump assumes an important role of cooling system in IC engines. With upgrading of the engine power by turbocharging and turbo inter cooling, the water pump capacity needs to be increased corresponding to the power. This capacity enhancement has to be achieved without calling for a major change in the existing water pump, envelop and related fitment details. This requires a clear understanding of centrifugal pump for its performance parameter. One such engine is upgraded by turbocharging from 195PS to 240PS @2200 rpm. Improving water pump flow by changing the impeller dimensions, impeller casing, increase the suction, delivery pipe diameter had been done. Validation of the water pump in its actual engine installation was taken up as a part of the research work. Flow rate comparison of the new pump with the existing pump was made and the results were analyzed. The new water pump gives better flow rates for the engine speeds up to1800 rpm, beyond which the flow rate is slightly lesser than the existing pump.

scholarly journals Geotechnical properties of reinforced clayey soil using nylons carry’s bags by products

2018 ◽  
Vol 162 ◽  
pp. 01020 ◽  
Author(s):  
Nahla Salim ◽  
Kawther Al-Soudany ◽  
Nora Jajjawi
Keyword(s):  
Soil Stabilization ◽  
Clayey Soil ◽  
Ground Improvement ◽  
Soft Soil ◽  
Liquid Limit ◽  
Waste Material ◽  
Industrial Wastes ◽  
Dry Density ◽  
Maximum Dry Density ◽  
Replacement Technique

All structures built on soft soil may experience uncontrollable settlement and critical bearing capacity. This may not meet the design requirements for the geotechnical engineer. Soil stabilization is the change of these undesirable properties in order to meet the requirements. Traditional methods of stabilizing or through in-situ ground improvement such as compaction or replacement technique is usually costly. Now a safe and economic disposal of industrial wastes and development of economically feasible ground improvement techniques are the important challenges being faced by the engineering community. This work focuses on improving the soft soil brought from Baghdad by utilizing the local waste material for stabilization of soil, such as by using “Nylon carry bag’s by product” with the different percentage and corresponding to 1 %, 3% and 5% (the portion of stabilizer matters to soil net weight) of dried soil. The results indicated that as Nylon’s fiber content increases, the liquid limit decreases while the plastic limit increases, so the plasticity index decreases. Furthermore, the maximum dry density decreases while, the optimum moisture content increases as the Nylon’s fiber percentage increases. The compression index (decreases as the Nylon’s fiber increases and provides a maximum of 43% reduction by adding 5% nylon waste material. In addition, the results indicated that, the undrained shear strength increases as the nylon fiber increases.

scholarly journals Low Reynolds number flow in a heated tube of varying section

1983 ◽  
Vol 25 (2) ◽  
pp. 244-260 ◽  
Author(s):  
A. R. Bestman
Keyword(s):  
Reynolds Number ◽  
Free Convection ◽  
Asymptotic Series ◽  
Convection Heat Transfer ◽  
Axial Direction ◽  
Reynolds Number Flow ◽  
Free Convection Heat ◽  
Number Flow ◽  
Convection Parameter ◽  
Constricted Tube

AbstractIn this paper we study the effect of forced and free convection heat transfer on flow in an axisymmctric tube whose radius varies slowly in the axial direction. Asymptotic series expansions in terms of a small parameter ∈, which is a measure of the radius variation, are obtained for the velocity components, pressure and temperature on the assumption that the Reynolds number (R) is of order one. The effect of the free convection parameter or Grashof number (G) on the axial velocity, temperature distribution, shear stress and heat flux at the wall are discussed quantitatively for a locally constricted tube.

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