• KCI Concrete Journal
• /
• v.13 no.2
• /
• pp.33-41
• /
• 2001

This paper presents the crack effect on CIP anchors and prediction of tensile capacity, as governed by concrete cone failure. Single anchors where located at center of concrete specimen. Three different types of cracks such as crack width of 0.2 mm and 0.5 mm, crack depth of 10 cm and 20cm , and crack location of center and off-center point were simulated. Static tensile load was applied to 7/8-in. CIP anchors of 10 cm and 20 cm embedment length in concrete with compressive strength of 280 kgf/$\textrm{cm}^2$. Tested pullout capacities were compared to the values determined using current design methods (such as ACI 349-97, ACI 349 revision and CEB-FIP which is based on CCD Method). The comparison of CCD Method and ACI revision showed almost the same values in uncracked concrete specimen. In cracked concrete, CCD Method predicted conservative values. Three-dimensional non-linear FEM modeling also has been performed to determine the stresses distribution and crack inclination.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
• /
• 2003.10a
• /
• pp.146-151
• /
• 2003

Reduced Activation Ferritic/Martenstic (RAFs) are leading candidates for structural materials of D-T fusion reactor. One of The RAFs, JLF-1 (9Cr-2W-V, Ta) has been developed and proved to have good resistance against high-fluency neutrino irradiation and good phase stability. Recently, in order to clarify the strengthening mechanical at high temperature, a new scheme to improve high temperature mechanical properties is desired. Therefore, the creep properties and creep life prediction by Larson-Miller Parameter method for JLF-1 to be used for fusion reactor materials or other high temperature components were presented at the elevated temperatures of $500^{\circ}C$, $550^{\circ}C$, $600^{\circ}C$, $650^{\circ}C$ and $704^{\circ}C$. It was confirmed experimentally and quantitatively that a creep life predictive e벼ation at such various high temperatures was well derived by LMP.

• Journal of the Korean Home Economics Association
• /
• v.48 no.9
• /
• pp.125-136
• /
• 2010

The purpose of this study is the systematization of the contents analysis to develop school dietary education based on the government-published textbooks for elementary school students. The components of the content are divided into several categories that include a general perspective of the pages, illustrations, table of contents, introductory remarks, summary evaluation, and etc. This study carried out as basic fundamental research to propose a theoretical framework for the elementary school dietary education. We examined and analyzed the nature and characteristics, the educational goals, and the structural framework of the contents of the textbooks. We have developed a systematic structure with 4 large content elements for dietary education as foods & cooking, nutrition & health, dietary environment & consumption, and food culture & industry. This analysis will definitely play an important role in establishing a standard framework and the curriculum contents for school dietary education in elementary school.

• Journal of Korean Association for Spatial Structures
• /
• v.19 no.4
• /
• pp.77-84
• /
• 2019

This study introduces a newly developed PC non-bearing wall system to prevent the damage of RC wall-type apartments that have been heavily damaged by the 2017 Pohang Earthquake. In order to evaluate the performance of the developed PC non-bearing wall system, a static cyclic test is conducted. The prototype of test specimen is from the RC wall-type apartment which has been severely damaged by the 2017 Pohang Earthquake. The specimen with the conventional non-bearing wall system showed the similar damage of RC wall type apartment suffered from the Pohang Earthquake. In case of the specimen with the developed PC non-bearing wall system, cracks and damages were not transmitted between the walls due to the seismic slit and there were almost no cracks in the non-bearing walls. Therefore, the proposed non-bearing wall system, separated from the structural walls, could prevent spreading cracks to bearing walls and make it possible to effectively control damage due to earthquake loads.

• Journal of the Korea Institute of Building Construction
• /
• v.1 no.1
• /
• pp.143-150
• /
• 2001

Permanent-Form is one of system forms for reducing human labor, work costs, oscillation, noise, construction wastes and so on. Permanent-Form is made from precast method in facilities, and carried in construction site to assemble with no demolding. The biggest expense to produce permanent-Form is about manufacturing mold. This papers about structural efficiency evaluation, construction efficiency test. The result of this study is below. (1) In the compressive strength test of column. Fly ash specimen and polymer specimen's strength developed as each 8%, 14% to comparison with standard specimen. The reason of this result from form section area increase and form's reinforcing bar (2) The Degree of column crack in permanent form is lower than another one's The glass fiber's fiber reinforcement effect brings like this. (3) In the flexural load test of beam, the early crack load and maximum load of permanent form use specimen showed 20% higher than standard specimen's. (4) In field application experiment, an constructional error is satisfied with the allowable margin of error, $\pm$5mm (5) When the concrete is placed into the form inside, The transformation degree of permanent form is lower than plywood form's. (6) The concrete packing ability of permanent form is satisfactory. (7) The bonding strength of permanent form shows enough strength - 6kgf/$\textrm{cm}^2$.

• Composites Research
• /
• v.17 no.1
• /
• pp.18-28
• /
• 2004

In order to evaluate the strength of carbody structures of railway rolling stock made of laminated fiber-reinforced composite materials, total laminate approach was introduced. Structural analyses were conducted to check the basic design of hybrid composite carbody structures of the Korean Tilting Train eXpress(TTX) with the service speed of 180km/h. The mechanical tests were also conducted to obtain strengths of composite laminates. The results show that all stress components of composite carbody structures are inside of failure envelopes and total laminate approach is recommended to predict the failure of hybrid composite carbody structures at the stage of the basic design.

• Health Policy and Management
• /
• v.25 no.4
• /
• pp.295-306
• /
• 2015

This study aims to examine the performance of public municipal hospitals through the analysis of data envelopment analysis, efficiency, profitability, and publicness by using panel data during period from 2006 to 2010. The main findings of the study are as follows. First, as a result of efficiency analysis during the period from 2006 to 2010, it was revealed that the number of staff by each job category, labor cost ratio, the number of operating beds need to be decreased. Second, the performance data represented by the indicators of efficiency, profitability and publicness were complementary and showed a tendency of being increased or decreased in same direction. Third, from the result of panel analysis, the efficiency was mainly influenced by the structural factors, while the profitability was influenced by managerial factors, and the publicness by medical environment. In conclusion, in order to enhance the performance of public municipal hospitals in Korea, it is important to harmonize the effort for efficiency, financial and policy support by central and local government, and the continuous participation of community residents.

• Laser Solutions
• /
• v.13 no.4
• /
• pp.1-6
• /
• 2010

Recently the use of ultra high strength steels (UHSS) in structural and safety component is rapidly increasing in the automotive industry. For example, 1.5GPa grade hot stamping with die-quenching of boron steel 22MnB5 could apply crash-resistant parts such as bumpers and pillars. The development of laser welding process of hot stamping steels, fundamental bead-on-plate welding and lap joint welding test were carried out using 3kW Nd:YAG laser. Local hardening & HAZ softening occurred in hot stamping steel as a result of metallurgical change caused by the welding heat input in the Nd:YAG laser welding process. The size of soft zones in the hot stamping steel was related to the welding heat input, being smaller at high speeds which generated a smaller heat input. Also in the case of lap joint design structure, same welded characteristics were shown. The HAZ softening degree was controlled to ensure the joint strength.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.34 no.12
• /
• pp.75-81
• /
• 2006

In this paper, the 6-dof electric motion platform system designed for the helicopter simulator satisfying the class of the CASA(Civil Aviation Safety Authority) level 2 is presented. From the kinematic, dynamic and structural analyses for motion base and electrical actuator systems, we show the feasibility of the developed motion platform system by producing the acceptable results of the test and evaluation according to the requirements specified in the CASA level 2. Furthermore through this development we suggest newly the adaptability of the electrical actuator system up to 10 ton class motion platform system, whose usage will be broaden rapidly, substituting with the advantage over the conventional hydraulic system.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.24 no.3
• /
• pp.271-279
• /
• 2006

Acoustic Emission (AE) technology is an effective nondestructive testing for continuous monitoring of defect formation and failures in structural materials. This paper presents a source location model using Acoustic Emission (AE) sensors in a Pre-Stressed Concrete (PSC) beam and the evaluation of the model was performed through lab experiments. 54 AE events were made on the surface of the 5m-PSC beam using a Schmidt Hammer and arrival times were measured with 7AE sensors. The source location f3r each event was estimated using least squares. The results were compared with actual positions and the RMSE (Root Mean Square Errors) was about 2cm.