• Proceedings of the KSME Conference
• /
• 2001.06a
• /
• pp.217-222
• /
• 2001

For the life evaluating of notched members, it is the best way that performing the real fatigue test of structure containing notch. But this method required generally much times and costs to evaluate fatigue life. So, generally we use the modified S-N curve or several methods to predict fatigue life. In this study, crack initiation life was evaluated by fatigue testing the SAE keyhole specimen and smooth specimen made of Al 7075-T6 alloys using the constant load then obtained S-N curve of smooth specimen and P-N curve of SAE keyhole specimen. And, fatigue lives of keyhole specimen are predicted using some life prediction methods (Nominal range I method, Nominal range II method, FEM analysis) for investigating experimented results, and that were compared with experimental data. Predicted fatigue lives by FEM analysis were corresponded with experimental data between 1/3times and 3times on the whole, and predicted fatigue lives using modified S-N curve (Nominal range I method, Nominal range II method) were nonconservative compared with that of FEM analysis.

• Transactions of Materials Processing
• /
• v.29 no.6
• /
• pp.316-322
• /
• 2020

The flow stress curve is usually determined via uniaxial tensile or simple compression test. However, the flow stress curve up to high strain cannot be obtained using these two tests. This study presents a simple method for obtaining the flow stress curve up to high strain via FE analysis, a simple compression test, and an indentation test. In order to draw the flow stress curve up to high strain, the indentation test was carried out with the pre-stained specimen using the simple compression test. The flow stress curve of Al6110 was evaluated up to high strain using the proposed method, and the result was compared with the flow stress curve of the uniaxial tensile test of the initial material.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2006.05a
• /
• pp.429-430
• /
• 2006

To estimate the fatigue life of flange-shaft assembly, fatigue test for flange material and bending fatigue test for flange-shaft assembly were conducted. Also, finite element analysis for flange-shaft assembly was conducted. Then, we have changed the obtained P-N curve to S-N curve using the finite element analysis results which were stress values at the location of fracture. The S-N curve of flange material itself was almost consistent with that of flange-shaft assembly, so it seems that the fatigue life of flange-shaft assembly could be estimated by using S-N curve for flange material and the stress at the location of fracture calculated by finite element methods.

• PNF and Movement
• /
• v.7 no.2
• /
• pp.1-10
• /
• 2009

This research measures the conditions of spinal scoliosis of college students and analyses the factors that affect spinal scoliosis. From September 15, 2008 to October 30, 2008, the study was conducted with 142 C College students and measured the degrees of spinal scoliosis. The analysis was evaluated according to the Pneumex Analysis program. The collected data was compiled into statistics using the SPSS PC+ 12.0 program. The results were as follows: 1. It appeared that in the cases of C curve, reverse C curve, S curve, and the normal, there was a statistical significance(p=.010) between the conditions of spinal scoliosis of the two genders. 2. It appeared that the comparison among the three groups according to the characteristics of the subjects showed a statistical significance in spinal length(p=.000) in the C curve group, age(p=.019) and spinal length(p=.004) in the reverse C curve group, and spinal length (p=.035), difference in apparent leg length(p=.019), and difference in true leg length(p=.012) in the S curve group. 3. It appeared that in the normal group without spinal scoliosis, the results of comparing the differences in apparent true leg length and spinal length according to the characteristics of the subjects showed a statistical significance in spinal length and gender(p=.000), age (p=.008), height(p=.000), and whether or not there was a regular exercise over once per week(p=.001). 4. On the correlations between C curve, reverse C curve, and S curve and differences in apparent true leg length and spinal length, it appeared that: (a) As the difference in apparent leg length gets bigger the difference in true leg length gets big in C curve(r=.551, p=.000). (b) As the difference in apparent leg length gets bigger the difference in true leg length gets big in reverse C curve(r=.511, p=.006). (c) There is no correlation in S curve.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.29 no.6D
• /
• pp.663-673
• /
• 2009

Driver's perceived curve radius is different from actual curve radius at curve sections. This is called visual distortion. It has effect on operation speed according to driver's perception and finally bad effect on safety at curve sections. At present, however, there is no research on quantitatively analysis of visual distortion and no criteria for curve section design considering the visual distortion. Therefore, this study focus on finding degree of visual distortion and suggesting design criteria by visual distortion analysis. The process of this study is as below; First, a calculaiton model of perceived curve radius was developed by survey using computer simulation. In this model, a dependent variable is perceived curve radius and an independent variable is geometric factors. Second, degree of visual distortion was calculated from ratio of perceived curve radius to actual curve radius. Finally, design criteria were suggested through influencing factor analysis of visual distortion at curve sections.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.5 no.6
• /
• pp.69-78
• /
• 1982

Traditional CVP (Cost-Volume-Profit) analysis employs linear cost and revenue functions within some specified time period and range of operations. Therefore CVP analysis is assumption of constant labor productivity. The use of linear cost functions implicity assumes, among other things, that firm's labor force is either a homogenous group or a collection homogenous subgroups in a constant mix, and that total production changes in a linear fashion through appropriate increase or decrease of seemingly interchangeable labor unit. But productivity rates in many firms are known to change with additional manufacturing experience in employee skill. Learning curve is intended to subsume the effects of all these resources of productivity. This learning phenomenon is quantifiable in the form of a learning curve, or manufacturing progress function. The purpose d this study is to show how alternative assumptions regarding a firm's labor force may be utilize by integrating conventional CVP analysis with learning curve theory, Explicit consideration of the effect of learning should substantially enrich CVP analysis and improve its use as a tool for planning and control of industry.

• Proceedings of the KSME Conference
• /
• 2001.06e
• /
• pp.789-794
• /
• 2001

In this study, a program for the off-design performance prediction of multi-stage axial-compressors is developed based on stage-stacking method. To account for the increased losses at off-design conditions, generalized performance curve is applied. The purpose of this study is to investigate the influence of the choice of generalized performance curve and stator exit angle. For this purpose, we tested various generalized performance curves and stator exit angles. In conclusion, Muir's pressure coefficient curve gives a good prediction results regardless of the efficiency curve for a low-stage compressors. On the other hand, for high-stage compressors, The combination of Muir's pressure coefficient curve and Stone's efficiency curve gives a optimistic results. Stator exit angle has a small effect on overall performance curve.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.26 no.12
• /
• pp.1984-1994
• /
• 1989

Techniques for approximating digitalcurves by polygonal lines are a valuable tool for image analysis and data compression. S. Shilien proposed a method for segmenting a digital curve into digital straight line segments digital straight line segments which are not satisfied with the structural properties, and have more than one break point by Shilien's method. Here, the structural representation of digital straight lines and digital staight line segments is described. And a method for segmenting a digital curve into digital straight line segments which are not satisfied with the structural properties, and have more than one break point by Shilien's method. Here, the structural representation of digital straight lines and digital staight line segments is described. And a method for segmenting a digital curve into digital straight line segments which may be not satisfied with the structural properties is proposed. The number of break points extracted by this method is less than that by S. Shilien's method from the digital curve which includes the digital straight line segments not satisfied with the structural properties.

• Journal of the Korean Society of Safety
• /
• v.27 no.5
• /
• pp.211-218
• /
• 2012

Two experiment are planed to identify driver's safe driving behaviour by curve radius, road surface condition in curve section. At four-lane and two-lane road, conducted experiments are check on driver's feeling of safety that 30 subjects do not feel discomfort. And using the data from these experiments, this study compare physical speed (not slipping, fall our of the road) with safety driving speed(drivers felt a comfortable and safe speed) each curve radius and fiver road surface condition(drying, wet, rain, snow and ice). As a result, safe driving behaviour factors that are derived to curve radius of 100m units, five road surface conditions enable to represent quantitative analysis of driver's discomfort. This study will develop road design method and evaluation reflected ergonomic aspects.

• Journal of the Korean Society of Costume
• /
• v.50
• /
• pp.5-22
• /
• 2000

The study on the past costume should be done first for the creation of new style of fashion. That is one of the reasons why we have to annalize characteristic style in each period. Before the latter of nineteenth century one must have made the costume by draping design. Because the complicated clothes can be expressed by draping deign think that the subject draping design is even more important than other subject. But there haven't been the studies that analyzed the pattern of Art Nouveau style by draping design in Korea. Art Nouveau style is a certain one that was relatively more changeable than the ones of other periods. The purpose of this study is the analysis about the patterns of hourglass and S-curve style which represented the Art Nouveau style. The results of the study summarized as follows. 1. Bodice pattern : In the front Hourglass silhouette has the princess line for fitting bodice while S-curve silhouette has the wide midriff due to the blousing. There is the yoke in S-curve one. In the pattern of back bodice we can't see the much differences but Hourglass silhouette is used the princess line like the front one while S-curve is made use of the waist darts for fitting back. 2. Sleeve pattern : Hourglass silhouette is made of two pieces the upper part and lower part besides S-curve is consisted of one pieces. The former has the big upper part in order to the emphasis of the shoulder and the tight lower part. The latter is the tight sleeve that similar to the basic sleeve pattern at present. 3. Skirt pattern: There is partially a gored line in the front skirt in Hourglass silhouette however S-curve silhouette is consisted of the six pieces gored skirt. At this part we can also see the fact that s-curve is more complicated than Hourglass silhouette. 4. Others: Wecan find out the differences between Hourglass and S-curve pattern easily at the parts of the collar flounce wing and so on. Summing up, the patterns of S-curve style are more expanded than those of Hourgalss style for the most part.