• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2010년도 춘계학술대회 논문집
• /
• pp.621-626
• /
• 2010

According to development of method and device of Finite Element Analysis, the strength of welded joint is demonstrated by Finite Element Analysis not classical calculations. On the FEA, all of the joints for carbody are assumed to be ideal connections and the yield stress of welded joint is assumed to be the same to base metal. On these assumption, FEA is appropriate to evaluate the overall stability and strength of whole carbody. The classical calculation is appropriate to evaluate strength of specific welded joint and to determine the weld method and properties. Some project request strength calculation of the specific welded joints in addition to FEA, because of the demonstration of stability. The objective of this paper is the check of the consistency of the FEA result for the welded joints by the stress comparison between Detailed FE Model and classical calculation and the evaluation of the reliability of FEA result.

• 대한조선학회지
• /
• 제23권3호
• /
• pp.27-38
• /
• 1986

In the recent years, the finite element method has been a leading method in calculating the strength of ship hull structural members. But such a calculation has many difficulties in constructing data, reducing CPU-time and connecting it with optimal design. This paper describes more efficient method for three dimensional strength calculation of the hull structure of oil tanker by using the slope-deflection method, and the computer program based on this method is developed. The results of the calculation by using this method are compared with those by using the SAP4 program based on the finite element method. Some advantages are obtained from the application of the slop-deflection method described in this paper in the calculation of the hull structure oil tanker.

• Geomechanics and Engineering
• /
• 제21권3호
• /
• pp.247-258
• /
• 2020

The shear strength of unsaturated soils, a research hotspot in geotechnical engineering, has great guiding significance for geotechnical engineering design. Although kinds of calculation models for the shear strength of unsaturated soil have been put forward by predecessors, there is still need for new models to extensively consider the nonlinear variation of shear strength, particularly for the nonlinear effect of the net normal stress on the shear strength of unsaturated soil. Here, the shear strength of unsaturated soils is explored to study the nonlinear effects of net normal stress with the introduction of a general nonlinear Mohr-Coulomb (M-C) strength criterion, and the relationship between the matric suction (or suction stress) and degree of saturation (DOS) constructed by the soil-water characteristics curve (SWCC) of van Genuchten is also applied for unsaturated soil. Then, two calculation models (i.e., an envelope shell model and an effective stress model) are established for the shear strength of unsaturated soils under the nonlinear strength theory. In these two models, the curve of the shear strength of unsaturated soils versus the net normal stress exhibits a tendency to gently. Moreover, the proposed formulas have flexibility and convenience with five parameters (for the effective stress model) or six parameters (for the envelope shell model), which are from the M-C strength parameters of the saturated soil and fitting parameters of SWCC of van Genuchten. Thereafter, by comparison with the classical theory of the shear strength of unsaturated soils from some actual cases, the rationality and accuracy of the present models were verified.

• 대한조선학회지
• /
• 제22권4호
• /
• pp.17-27
• /
• 1985

In this paper, an approximate calculation method on the transverse strength of oil tankers by use of slop-deflection method os described which considers the effect of shear deflection and varing section in elements and the result of calculation in models and actual ships, is presented. The object of this paper is focused on the development of program which can be used widely regardless strut numbers in transverse frame rings. To examine the reliability of the above method, the results in this paper are compared with the results which are obtained by use of SAP4(Structure Analysis Program) based on finite element method. The application of the Slope-Deflection Method on the transverse strength of oil tankers has the advantage that this method takes less than the other methods in calculation.

• Membrane and Water Treatment
• /
• 제12권1호
• /
• pp.37-41
• /
• 2021

This paper presents the multiscale calculation results of the very fast volume transport in micro/nano cylindrical tubes with the wall slippage. There simultaneously occurs the adsorbed layer flow and the intermediate continuum fluid flow which are respectively on different scales. The modeled fluid is water and the tube wall is somewhat hydrophobic. The calculation shows that the power loss on the tube no more than 1.0 Watt/m can generate the wall slippage even if the fluid-tube wall interfacial shear strength is 1 MPa; The power loss on the scale 104 Watt/m produces the volume flow rate through the tube more than one hundred times higher than the classical hydrodynamic theory calculation even if the fluid-tube wall interfacial shear strength is 1 MPa. When the wall slippage occurs, the volume flow rate through the tube is in direct proportion to the power loss on the tube but in inverse proportion to the fluid-tube wall interfacial shear strength. For low interfacial shear strengths such as no more than 1 kPa, the transport in the tube appears very fast with the magnitude more than 4 orders higher than the classical calculation if the power loss on the tube is on the scale 104 Watt/m.

• 인터넷정보학회논문지
• /
• 제23권2호
• /
• pp.53-59
• /
• 2022

3단계 자율주행 차량 이후, 4, 5단계의 자율주행 기술은 차량의 완벽한 주행뿐만 아니라 탑승객의 상태를 최적으로 유지하기 위해 노력하고 있다. 그러나 현재 자율주행 기술은 LiDAR, 전방 카메라 등 시각적 정보에 과하게 의존하기 때문에 지정된 도로 이외의 도로에서 완벽하게 자율주행을 실행하기 힘들다. 따라서 본 논문은 차량이 시각 정보 외의 데이터를 사용하여 도로의 상태를 분류하고, 도로 상태와 주행 상태에 따라 최적의 제동 강도를 계산하는 BSCS (Braking Strength Calculation System)를 제안한다. 본 논문에서 제안하는 BSCS는 KNN 알고리즘을 기반으로 도로의 상태를 분류하는 RCDM (Road Condition Definition Module)과 RCDM의 결과와 현재 주행 상태를 통해 주행 중 최적의 제동 강도를 계산하는 BSCM (Braking Strength Calculation Module)로 구성된다. 본 논문의 실험 결과, KNN 알고리즘에 가장 적합한 K의 수를 찾을 수 있었고, 비지도 학습인 K-means 알고리즘보다 본 논문에서 제안한 RCDM이 더 정확한 것이 증명되었다. 해당 논문의 BSCS는 시각 정보뿐만 아니라 서스펜션에 가해지는 진동 데이터를 사용함으로써, 시각 정보가 제한되는 여러 환경에서 자율주행 차량의 제동을 더 원활하게 만들 수 있다.

• 한국항해학회지
• /
• 제8권2호
• /
• pp.43-50
• /
• 1984

When the static load is applied to the ship's hull the deflection due to the bending moment from longitudinal direction has not been considered in the usual calculation of maximum bending moment. In fact, however, the deflection of ship's hull must be affected by the above-stated bending moment, and in this case the value of the maximum bending moment would be lessened in comparision with the result of usual calculation. In this paper, the author at first calculated the difference between the two values in case of rectangular barge, and suggested a practical criterion of longitudinal strength.

• 대한화학회지
• /
• 제41권8호
• /
• pp.427-436
• /
• 1997

A simple relation exists between electronegativities of cations and their oxidation states and ionic radii. An empirical law is proposed: X = 0.274 z-0.15 z r - 0.01 r+1+${\alpha}$, z being oxidation number, r ionic radius in $\AA$ and ${\alpha}$ a term related to the atomic number. this relation permits to calculate an electronegativity scale covering a large set of electronic and crystallographic situations. An application to the calculation of acid strengths of cations is presented.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2002년도 봄 학술발표회 논문집
• /
• pp.227-232
• /
• 2002

This paper describes a calculation of an average crack spacing and the maximum crack width for the high-strength concrete tensile and flexural members. Based on the uniform bond stress distribution of the average steel and concrete strains over the transfer length, the crack spacing and the crack width are proposed to utilize influence of the concrete strength and the cover thickness. This analytical results presented in this paper indicate that the proposed equations can be more effectively estimated the maximum crack width and the average crack spacing of the reinforced concrete flexural and tensile members.

• 대한조선학회논문집
• /
• 제52권5호
• /
• pp.380-386
• /
• 2015

Panel methods are useful tools for analyzing fluid-flow around a wing section. It has the advantage of fast and accurate calculation, compared to other CFD Methods such as RANS solvers. This paper suggests a piecewise linear panel method in order to improve accuracy of existing panel methods by changing the piecewise constant singularity strength to linear singularity strength(for dipole strength). The piecewise linear panel method adopts the linear distribution of singularity strength, while control point is located at the node of each panel. Formulation of the piecewise linear panel method is given, and some calculation results are shown for typical wing sections.