scholarly journals Numerical Study on Scale Effect of Repetitive Plate-Loading Test

2019 ◽  
Vol 9 (20) ◽  
pp. 4442 ◽  
Author(s):  
Min Son ◽  
Hyuk Jung ◽  
Hwan Yoon ◽  
Deokyong Sung ◽  
Jin Kim
Keyword(s):  
Numerical Analysis ◽  
Scale Effect ◽  
Numerical Study ◽  
Field Tests ◽  
Loading Test ◽  
Plate Loading Test ◽  
Strain Modulus ◽  
Plate Size ◽  
Loading Methods ◽  
Plate Loading

Repetitive plate-loading test is intended to identify the elastic modulus of a target structure subjected to dynamic loading; such tests are mainly applied to railway roadbeds. The repetitive plate-loading test uses the same equipment as the plate-loading test but different loading methods. The plate-loading test derives the subgrade reaction modulus (k30), while the repetitive plate-loading test derives the strain modulus (Ev2). The former considers the scale effect of the loading-plate size, whereas the latter does not, thereby reducing the reliability of the results. Therefore, numerical analysis was conducted to propose a scale effect that can applied to field tests. First, to verify the 50-mm loading plate, a previous study comparing the results of the 300-mm loading plate in a field test was simulated by a numerical analysis, and the results were compared and analyzed. Next, the strain modulus was investigated according to the loading-plate size under subgrade conditions. An equation to estimate the scale effect applicable to loading plates with diameters of less than 762 mm was derived. The relationship between the calculated strain and elastic moduli was additionally analyzed.

scholarly journals Experimental and Numerical Study of Pre-Swirl Stators PSS

2020 ◽  
Vol 8 (1) ◽  
pp. 47 ◽  
Author(s):  
Kourosh Koushan ◽  
Vladimir Krasilnikov ◽  
Marco Nataletti ◽  
Lucia Sileo ◽  
Silas Spence
Keyword(s):  
Numerical Analysis ◽  
Energy Saving ◽  
Scale Effect ◽  
Financial Incentives ◽  
Numerical Study ◽  
Considerable Improvement ◽  
Scale Model ◽  
Propulsion Efficiency ◽  
Wake Field ◽  
Additional Resistance

Energy saving within shipping is gaining more attention due to environmental awareness, financial incentives, and, most importantly, new regional and international rules, which limit the acceptable emission from the ships considerably. One of the measures is installation of energy saving devices (ESD). One type of such a device, known as pre-swirl stator (PSS), consists of a number (usually 3 to 5) of fins, which are mounted right in front of the propeller. By modifying the inflow and swirl into the propeller, the fins of a PSS have the possibility to increase the total propulsion efficiency. However, at the same time, they may introduce additional resistance either due to changes in pressure distribution over the aft ship or due to its own resistance of fins. In this paper, the authors present experimental and numerical investigation of a PSS for a chemical tanker. Numerical analysis of the vessel with and without PSS is performed in the model and full scale. Model testing is performed with and without PSS to verify the power savings predicted numerically. Among other quantities, 3D wake field behind the hull is densely measured at different planes, starting from the PSS plane to the rudder stock plane. 3D wake measurements are also conducted with a running propeller. The measurements show considerable improvement in the performance of the vessel fitted with PSS. On the numerical side, analyses show that scale effect plays an important role in the ESD performance. Investigation of the scale effect on the vessel equipped with an ESD provides new insight for the community, which is investing more into the development of energy saving devices, and it offers valuable information for the elaboration of scaling procedures for such vessels.

scholarly journals Relationship between deformation moduli obtained using light falling weight deflectometer and static plate test on various types of soil

2014 ◽  
Vol 9 (4) ◽  
pp. 251-259 ◽  
Author(s):  
Karel Pospisil ◽  
Petr Zednik ◽  
Josef Stryk
Keyword(s):  
Test Methods ◽  
Falling Weight Deflectometer ◽  
Loading Test ◽  
Plate Test ◽  
Plate Loading Test ◽  
Static Modulus ◽  
Different Types ◽  
Falling Weight ◽  
The Relationship ◽  
Plate Loading

There is increasing effort to optimize test methods for evaluation of subgrade. It takes effect in aspiration in replacement of static plate loading test by other faster test methods. One of them is the use of Light Falling Weight Deflectometer. In many countries in Europe both static and dynamic plate tests are standardized. The presented paper introduces results of the research project dealing with the sensitivity of the relationship between static modulus and modulus obtained from the Light Falling Weight Deflectometer on specific types of soil. It is shown that there are significant differences in relationship between moduli values obtained using both methods on different types of soil.

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