scholarly journals Probabilistic and Interval Analyses Contrasted in Impact Buckling of a Clamped Column

2012 ◽  
Vol 80 (1) ◽  
Author(s):  
Isaac Elishakoff ◽  
Wim Verhaeghe ◽  
David Moens
Keyword(s):  
Mode Shape ◽  
Fundamental Mode ◽  
Axial Loading ◽  
Initial Imperfection ◽  
Numerical Data ◽  
The Impact

In this study we contrast two competing methodologies for the impact buckling of a column that is clamped at both ends. The initial imperfection is postulated to be co-configurational with the fundamental mode shape of the column without the axial loading. A solution is also furnished for the case when the initial imperfection is proportional to the Filonenko-Borodich “cosinusoidal polynomial”. Probabilistic and interval analyses are conducted for each case; these are contrasted on some representative numerical data.

Vibration Based Damage Detection in Plate-Like Structure Using Square of Mode Shape Curvature

2019 ◽  
Author(s):  
Ramesh Lanka ◽  
Putti Srinivasa Rao
Keyword(s):  
Mode Shape ◽  
Surface Crack ◽  
Crack Detection ◽  
Numerical Study ◽  
Numerical Data ◽  
Mode Shapes ◽  
Laser Vibrometer ◽  
Study Results ◽  
Before And After ◽  
The Impact

In this current work, a new methodology based on the square of mode shape curvature (SMSC) is presented that relates the mode shapes and its curvature changes before and after the damage for localization and sizing of the surface crack in plate-type structures. The significance of this method is it has the capability to portray accurate shape and exact location of the surface crack in a plate-like structure which are related to low and high elastic modes on dense and coarse measurement grids. The efficiency of the proposed SMSC is examined using experimental and numerical data acquired from modal analysis on the aluminum plate containing single and multi-surface cracks with a fixed-free condition using non-contact measurement a scanning laser vibrometer and on simple finite element plate model. As evidence of experimental and numerical study results, highly accurate crack characterization has been attained through the proposed method. In implementing this method, only a few modes of the structure are required. Further, the impact of the mode order on the effectiveness of crack detection, boundary distortion treatment, and grid density analysis was also performed by the proposed method.

The impact of stirrups on the composite action of concrete-filled steel tubular stub columns under axial loading

Structures ◽  
2021 ◽  
Vol 30 ◽  
pp. 786-802
Author(s):  
De-ren Lu ◽  
Wen-jun Wang ◽  
Fa-xing Ding ◽  
Xue-mei Liu ◽  
Chang-jing Fang
Keyword(s):  
Axial Loading ◽  
Composite Action ◽  
The Impact ◽  
Stub Columns

scholarly journals Advances and Challenging Issues in Subsurface Drainage Module Technology and BIOECODS: A Review

2018 ◽  
Vol 203 ◽  
pp. 07005 ◽  
Author(s):  
Abdurrasheed Sa'id Abdurrasheed ◽  
Khamaruzaman Wan Yusof ◽  
Husna Bt Takaijudin ◽  
Aminuddin Ab. Ghani ◽  
Muhammad Mujahid Muhammad ◽  
...  
Keyword(s):  
Drainage System ◽  
Numerical Data ◽  
Subsurface Drainage ◽  
Infiltration Capacity ◽  
Sustainable Solutions ◽  
Ecologically Sustainable ◽  
The Impact ◽  
Flow Attenuation ◽  
Permeability Rate ◽  
Over Time

Subsurface drainage modules are important components of the Bio-ecological Drainage System (BIOECODS) which is a system designed to manage stormwater quantity and quality using constructed grass swales, subsurface modules, dry and wet ponds. BIOECODS is gradually gaining attention as one of the most ecologically sustainable solutions to the frequent flash floods in Malaysia and the rest of the world with a focus on the impact of the subsurface modules to the effectiveness of the system. Nearly two decades of post-construction research in the BIOECODS technology, there is need to review findings and areas of improvement in the system. Thus, this study highlighted the key advances and challenges in these subsurface drainage modules through an extensive review of related literature. From the study, more work is required on the hydraulic characteristics, flow attenuation and direct validation methods between field, laboratory, and numerical data. Also, there is concern over the loss of efficiency during the design life especially the infiltration capacity of the module, the state of the geotextile and hydronet over time. It is recommended for the sake of higher performance, that there should be an onsite methodology to assess the permeability, rate of clogging and condition of the geotextile as well as the hydronet over time.

scholarly journals Numerical Study of Hydrodynamic Impact on Bubbly Water

2015 ◽  
Author(s):  
Mehdi Elhimer ◽  
Aboulghit El Malki Alaoui ◽  
Kilian Croci ◽  
Céline Gabillet ◽  
Nicolas Jacques
Keyword(s):  
Volume Fraction ◽  
Numerical Study ◽  
Numerical Data ◽  
Void Volume Fraction ◽  
Bubbly Liquid ◽  
Impact Loads ◽  
Hydrodynamic Impact ◽  
Physical Mechanisms ◽  
The Impact ◽  
The Relationship

The phenomenon of slamming on a bubbly liquid has many occurrences in marine and costal engineering. However, experimental or numerical data on the effect of the presence of gas bubbles within the liquid on the impact loads are scarce and the related physical mechanisms are poorly understood. The aim of the present paper is to study numerically the relationship between the void volume fraction and the impact loads. For that purpose, numerical simulations of the impact of a cone on bubbly water have been performed using the finite element code ABAQUS/Explicit. The present results show the diminution of the impact loads with the increase of the void fraction. This effect appears to be related to the high compressibility of the liquid-gas mixture.

scholarly journals Creating Model of Sustainable Performance based Green Management System on The Small and Medium Enterprises

2020 ◽  
Vol 9 (3) ◽  
pp. 340-349
Author(s):  
Vini Wiratno Putri ◽  
Ketut Sudarma
Keyword(s):  
Structural Equation ◽  
Quantitative Research ◽  
Small And Medium Enterprises ◽  
Numerical Data ◽  
Industrial Sector ◽  
Research Approach ◽  
Competitive Advantages ◽  
Green Management ◽  
Sustainability Performance ◽  
The Impact

The aims of this paper is to analyze the effect of the relationship between knowledge and on green management and its implication on competitive advantage and sustainable performannce. This study used a quantitative research approach that explains the phenomenon by collecting numerical data analyzed using structural equation modelling (SEM) with the WarpPLS program application. The population in this study were small or medium business owners (general managers) in the industrial sector in the city of Semarang. Knowledge and green management have a significant effect on competitive advantages and competitive advantages has a significant effect on the sustainability performance. It means that the knowledge and green management simultaneously shows a significant effect on competitive advantages and sustainability performance. The application of green management will also improve sustainability performance. The originality of this study is on the testing of simultaneous relationships between the factors making up the application of green management, namely knowledge as well as the impact of green management implementation on sustainability performance.

scholarly journals Straight to Low-Sinuosity Drainage Systems in a Variscan-Type Orogen—Constraints from Tectonics, Lithology and Climate

Minerals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 933
Author(s):  
Harald G. Dill ◽  
Andrei Buzatu ◽  
Sorin-Ionut Balaban
Keyword(s):  
Chemical Weathering ◽  
Current Model ◽  
Drainage System ◽  
Numerical Data ◽  
Structural Features ◽  
Acute Angle ◽  
Drainage Systems ◽  
Starting Point ◽  
Bedrock Lithology ◽  
The Impact

A holistic-modular approach has been taken to study the evolution of three straight to low-sinuosity drainage systems (=SSS) in an uplifted basement block of the Central European Variscides. The development of the SSS is described by means of a quadripartite model. (1) The geological framework of the SSS: Forming the lithological and structural features in the bedrock as a result of different temperature, pressure and dynamic-metamorphic processes. (2) Prestage of SSS: Forming the paleo-landscape with a stable fluvial regime as a starting point for the SSS. (3) Proto-SSS: Transition into the metastable fluvial regime of the SSS. (4) Modern SSS: Operation of the metastable fluvial regime Tectonics plays a dual role. Late Paleozoic fold tectonic creates the basis for the studied SSS and has a guiding effect on the development of morphotectonic units during the Neogene and Quaternary. Late Cenozoic fault tectonics triggered the SSS to incise into the Paleozoic basement. The change in the bedrock lithology has an impact on the fluvial and colluvial sediments as well as their landforms. The latter reflects a conspicuous modification: straight drainage system ⇒ higher sinuosity and paired terraces ⇒ hillwash plains. Climate change has an indirect effect controlling via the bedrock the intensity of mechanical and chemical weathering. The impact on the development of the SSS can be assessed as follows: Tectonics >> climate ≅ bedrock lithology. The three parameters cause a facies zonation: (1) wide-and-shallow valley (Miocene), (2) wide-angle V-shaped valley (Plio-Pleistocene), (3) acute-angle V-shaped valley (Pleistocene), (4) V-shaped to U-shaped valleys (Pleistocene-Holocene). Numerical data relevant for the hydrographic studies of the SSS are determined in each reference area: (1) Quantification of fluvial and colluvial deposits along the drainage system, (2) slope angles, (3) degree of sinuosity as a function of river facies, (4) grain size distribution, (5) grain morphological categorization, (6) grain orientation (“situmetry”), (7) channel density, (8) channel/floodplain ratios. Thermodynamic computations (Eh, pH, concentration of solubles) are made to constrain the paleoclimatic regime during formation of the SSS. The current model of the SSS is restricted in its application to the basement of the Variscan-Type orogens, to an intermediate crustal maturity state.

scholarly journals IMPACT OF TURBINE-STRUT CLOCKING ON THE PERFORMANCE OF A TURBINE CENTER FRAME

2021 ◽  
pp. 1-17
Author(s):  
Patrick Zeno Sterzinger ◽  
Filippo Merli ◽  
Andreas Peters ◽  
Stephan Behre ◽  
Franz Heitmeir ◽  
...  
Keyword(s):  
Flow Field ◽  
Numerical Data ◽  
Performance Impact ◽  
Test Vehicle ◽  
Low Pressure Turbine ◽  
Second Stage ◽  
University Of Technology ◽  
Turbine Vane ◽  
Carry Over ◽  
The Impact

Abstract Previous studies have indicated a potential for improving the performance of a Turbine Center Frame (TCF) duct by op- timizing the clocking position between the high-pressure-turbine (HPT) vanes and TCF struts. To assess the impact of clocking on the performance, a new test vehicle with a clockable ratio of HPT vanes to TCF struts, consisting of an HPT stage (aero- dynamically representative of the second-stage HPT engine), a TCF duct with non-turning struts, and a first-stage low-pressure turbine vane, was designed and tested in the transonic test tur- bine facility (TTTF) at Graz University of Technology. This paper quantifies the performance impact of clocking and describes the mechanisms causing TCF flow field changes, lever- aging both experimental and numerical data. Other areas in the TCF duct impacted by the choice of the HPT vane circumfer- ential position including the strength of unsteady HPT-TCF in- teraction modes, TCF strut incidence changes, and carry-over effects to the first LPT vane are additionally highlighted. Five-hole-probe (5HP) area traverses and kielhead-rake tra- verses were used to asses the flow field at the TCF-exit and calcu- late the pressure loss. The flow field at the TCF exit shows signif- icant differences depending on the circumferential position of the HPT vane. A relative performance benefit of 5% was achieved.

scholarly journals Cutaneous leishmaniasis a neglected tropical disease: community knowledge, attitude and practices in an endemic area, Northwest Ethiopia

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Helina Fikre Tamiru ◽  
Yohana James Mashalla ◽  
Rezika Mohammed ◽  
Gloria Thupayagale Tshweneagae
Keyword(s):  
Cutaneous Leishmaniasis ◽  
Rural Areas ◽  
Neglected Tropical Diseases ◽  
Numerical Data ◽  
Northwest Ethiopia ◽  
Duration Of Treatment ◽  
Cross Sectional ◽  
Awareness Campaigns ◽  
Modern Treatment ◽  
The Impact

Abstract Background Cutaneous leishmaniasis is one of the neglected tropical diseases in the Ethiopian highlands and studies on assessment of knowledge, attitude and practice of the community in endemic areas are scanty. The study aimed to assess the knowledge, attitude towards cutaneous leishmaniasis and treatment seeking practices in people living in the endemic highlands areas in the Northwest, Ethiopia and to provide evidence-based information to guide development of appropriate interventions to reduce the impact of cutaneous leishmaniasis on communities. Methods Quantitative cross-sectional study was conducted in cutaneous leishmaniasis endemic districts (woredas) using a semi structured questionnaire. Households were randomly selected according to probability proportional to size of households in each enumeration area. Systematic random sampling of eligible households was based on the number of households recorded during listing of households. Descriptive statistics was used to describe numerical data, organise and summarise the data in a manner that gave meaning to the numerical form. Frequency tables were used to show descriptive analysis and regression analysis was used to determine correlation between variables. Results Majority of respondents 321(78.7%) lived in rural areas, age ranged between 18 and 85 years and most were farmers. Illiteracy was high (47.6%) among respondents and majority 358(87.8%) had seen patients with CL. Less than quarter (21.6%) had heard about sand flies and knowledge on the peak transmission period was low (46.3%). About 192 (47.1%) of the respondents indicated disfiguring lesions were the major clinical presentations, less than half 55(27.5%) of urban residents believed CL was treatable compared to 145(72.5%) of rural residents (P < 0.001). Traditional medicines were indicated as best treatment option by 209(51.2%) compared to 114(27.9%) for modern treatment. Major factors influencing treatment options included accessibility to treatment facilities, distance and short duration of treatment. Participants expressed negative experiential attitude and perceived control towards modern treatment because of inaccessibility and distance from where modern treatment is provided. Conclusion Priority should be given to primary prevention and appropriate awareness campaigns on lesion recognition. Information on modern treatment should be intensified.

Geometrical Effects of Channel Configuration on the Performance of Membraneless Fuel Cells

2017 ◽  
Author(s):  
Hector Gomez ◽  
Usama Tohid ◽  
Arturo Pacheco-Vega
Keyword(s):  
Mathematical Model ◽  
Fuel Cell ◽  
Stokes Equations ◽  
Single Channel ◽  
Numerical Data ◽  
Operating Conditions ◽  
Straight Channel ◽  
Wavy Channel ◽  
Channel Configuration ◽  
The Impact

In this study, numerical simulations were performed to find the current-voltage distribution for a laminar flow-based membraneless fuel cell (LFFC). The system uses formic acid and oxygen as the fuel and oxidant, respectively, and has a Y-shaped geometry with two separate inlets that merge into a single channel. The main objective of this work is to analyze the impact of geometry and operating conditions on the performance of these devices. This is done by proposing a novel wavy-channel-based geometry for the side walls, along with planar top and bottom walls, and comparing the behavior of the corresponding system to that of LFFCs based on straight-channel walls. Special attention is placed on the effect of both the amplitude of the sinusoid and its wavelength on the performance of the device. The effect of flow rates — in the range of [200, 350] μL/min — is also studied. The mathematical model is formulated by considering the Navier-Stokes equations along with Butler-Volmer and Fick’s law. For each fuel-cell configuration, the governing equations are discretized and solved using finite elements, and the solutions given in terms of the polarization curves. The model was first verified using published numerical data for a straight-channel-based LFFC. The simulations show that the performance achieved by the device, based on the proposed wavy channel geometry, is slightly better than that of the LFFC with straight channel walls. On the other hand, higher flowrates significantly improve the power density of the device. Although the current mathematical model may be useful in a variety of applications, improvements on it are currently underway to account for the effects of potential distributions on ions within the flow channel, and results from it will be reported in the future.

Manufacture of Ultra-Dense Knitted Superelastic Structures

2018 ◽  
Author(s):  
Henry Koon ◽  
Jack Laven ◽  
Julianna Abel
Keyword(s):  
Mechanical Properties ◽  
Mechanical Performance ◽  
Cell Structure ◽  
Axial Loading ◽  
Consumer Products ◽  
Niti Shape Memory Alloy ◽  
Structural Element ◽  
Loading Tests ◽  
Structural Architecture ◽  
The Impact

Knitted Textiles made from Nickel-Titanium (NiTi) shape memory alloy wires are a new structural element with enhanced properties for a variety of applications. Potential advantages of this structural form include enhanced bending flexibility, tailorable in-plane, and through-thickness mechanical performance, and energy absorption and damping. Inspection of the knit pattern reveals a repeating cell structure of interlocking loops. Because of this repeating structure, knits can be evaluated as cellular structures that leverage their loop-based architecture for mechanical robustness and flexibility. The flexibility and robustness of the structure can be further enhanced by manufacturing with superelastic NiTi. The stiffness of superelastic NiTi, however, makes traditional knit manufacturing techniques inadequate, so knit manufacturing in this research is aided by shape setting the superelastic wire to a predefined pattern mimicking the natural curve of a strand within a knit fabric. This predefined shape-set geometry determines the outcome of the knit’s mechanical performance and tunes the mechanical properties. In this research, the impact of the shape setting process on the material itself is explored through axial loading tests to quantify the effect that heat treatment has on a knit sample. A means of continuously shape setting and feeding the wire into traditional knitting machines is described. These processes lend themselves to mass production and build upon previous textile manufacturing technologies. This research also proposes an empirical exploration of superelastic NiTi knit mechanical performance and several new techniques for manufacturing such knits with adjustable knit parameters. Displacement-controlled axial loading tests in the vertical (wale) direction determined the recoverability of each knit sample in the research and were iteratively increased until failure resulted. Knit samples showed recoverable axial strains of 65–140%, which could be moderately altered based on knit pattern and loop parameters. Furthermore, this research demonstrates that improving the density of the knit increases the stiffness of the knit without any loss in recoverable strains. These results highlight the potential of this unique structural architecture that could be used to design fabrics with adjustable mechanical properties, expanding the design space for aerospace structures, medical devices, and consumer products.

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