• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.9 no.6
• /
• pp.1518-1522
• /
• 2008

The design technology to be developed in this study is technology related to the metal panel corner processing method of very high value-added, interior and exterior cladding material, in the architecture. This study is aimed at designing a Bending Die System that enables metal panel corner processing for the first time in Korea, by improving corrosion resistance (durability), weather resistance and elegances (design) for the connecting part of right angle cornering, where most serious problems occur in using metal steel plates of 2.5mm or thicker. This is used as a kind of metal ball and as architectural interior and exterior cladding material.

• Structural Engineering and Mechanics
• /
• v.84 no.2
• /
• pp.225-238
• /
• 2022

In order to improve the cracking resistance of reinforced concrete and give full play to the advantages of prefabricated assembly structure in construction, prestressed reinforced concrete composite beam (PRCC) is proposed. Through the bending static test of seven I-shaped beam specimens, the bending failure modes and bearing capacity of PRCC and reinforced concrete composite beam are compared and analyzed, and the effects of prestress size, prestressed reinforcement layout and prestress application sequence on the flexural behavior of PRCC beams are studied. The results show that the cracking load and ultimate load of PRCC beams significantly increased after prestressing, and prestressed tendons can effectively control the crack development. With the increase of prestressing degree, the deformation resistance and bending stiffness of PRCC beams are increased. The application sequence of prestress has little influence on the mechanical properties of PRCC beams. The crack width, stiffness and normal section bearing capacity of PRCC beam are analyzed, and the calculated results are in good agreement with the experimental results.

• The Korean Journal of Ceramics
• /
• v.2 no.4
• /
• pp.212-215
• /
• 1996

This paper focuses the strength and wear resistance of CVD diamond films. The strength of free-standing CVD diamond films synthesized by microwave plasm CVD, DC plasma CVD, RF plasma CVD and arc discharge plasma jet CVD has been measured by three-point bending test. The wear resistance of CVD diamod films has been evaluated by the pin-on-disk type testing. diamond films coated on the base of sintered tungsten carbide pin by hot filament CVD have been rubbed with a sintered diamond disk in muddy water. Volume removed wear of CVD diamond has been compared with stellite, WC alloy and bearing steel.

• Restorative Dentistry and Endodontics
• /
• v.44 no.2
• /
• pp.19.1-19.9
• /
• 2019

Objectives: The purpose of this study was to evaluate the cyclic fatigue, bending resistance, and surface roughness of EdgeEvolve (EdgeEndo) and ProTaper Gold (Dentsply Tulsa Dental Specialties) nickel-titanium (NiTi) rotary files. Materials and Methods: The instruments (n = 15/each) were tested for cyclic fatigue in single- ($60^{\circ}$ curvature, 5-mm radius) and double-curved (coronal curvature $60^{\circ}$, 5-mm radius, and apical curvature of $30^{\circ}$ and 2-mm radius) artificial canals. The number of cycles to fracture was calculated. The bending resistance of both files were tested using a universal testing machine where the files were bent until reach $45^{\circ}$. Scanning electron microscopy and x-ray energy-dispersive spectrometric analysis were used for imaging the fractured segments, while the atomic force microscope was used to quantify the surface roughness average (Ra). Results: EdgeEvolve files exhibited higher cyclic fatigue resistance than ProTaper Gold files in single- and double-curved canals (p < 0.05) and both files were more resistant to cyclic fatigue in single-curved canals than double-curved canals (p < 0.05). EdgeEvolve files exhibited significantly more flexibility than did ProTaper Gold files (p < 0.05). Both files had approximately similar Ni and Ti contents (p > 0.05). EdgeEvolve files showed significantly lower Ra values than ProTaper Gold files (p < 0.05). Conclusions: Within the limitation of this study, EdgeEvolve files exhibited significantly higher cyclic fatigue resistance than ProTaper Gold files in both single- and double-curved canals.

• Journal of the Korea Institute of Building Construction
• /
• v.23 no.5
• /
• pp.537-546
• /
• 2023

For the purpose of fire delineation within buildings, steel walls in Korea are mandated to undergo rigorous certification as fire-resistant entities, substantiated via a series of qualitative assessments. Predominantly, these evaluations comprise the fire resistance test paired with supplementary examinations; specifically for steel walls, these encompass the gas hazard and panel bending strength tests. Given the prevalence of semi-noncombustible core materials, gas hazard tests are largely rendered superfluous, pivoting the focus solely onto the panel bending strength test during the certification trajectory. This particular test is designed to gauge the flexural robustness of individual wall panels. An enhanced bending strength is postulated to fortify both the structural integrity and thermal insulation of the wall by mitigating potential deformations. In this scholarly exploration, an analytical deep dive was undertaken into extant, valid certification test datasets. The endeavor aimed to ascertain the depth of correlation between the designated fire resistance metric and the bending strength, the latter being the sole supplementary assessment for steel walls. In distilling the findings, it was discerned that temperature elevations beyond baseline values exhibited no statistically salient linkage with the panel's bending strength.

• Proceedings of the KSME Conference
• /
• 2001.06a
• /
• pp.345-350
• /
• 2001

In order to perform elastic-plastic fracture mechanical analyses, fracture resistance curves for concerned materials are required. 1T-CT specimen was used to obtain fracture resistance curves. But the fracture resistance curve by the 1T-CT specimen was very conservative to evaluate the integrity of the structure. And fracture resistance curve was affected by the specimen geometry and crack plane orientation. The objective of this paper is to be certain the conservativeness of the fracture resistance curve by the 1T-CT specimen and to provide the additional safety margin. For these, the fracture tests using the real pipe specimen and standard 1T-CT specimen test were performed. 4-point bending jig was manufactured for pipe test and direct current potential drop method was used to measure the crack extension and length for pipe test. From the pipe and the 1T-CT specimen test results, it was observed that the J-integral of the 1T-CT specimen test at the crack initiation point was very small compare to that of the pipe specimen test.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.29 no.1 s.232
• /
• pp.107-114
• /
• 2005

In order to analyze the elastic-plastic fracture behavior of a structure, the fracture resistance curve of the material should be known first. The standard CT specimen was used to obtain the fracture resistance curves of a piping system. However, it is known that the fracture resistance curve by the standard CT specimen is very conservative to evaluate the integrity of a structure. Also the fracture resistance curve is effected by the specimen geometry and the dimensions because of the constraint effect. The objective of this paper is to be certain the conservativeness of the fracture resistance curve by the standard CT specimen and to provide an additional safety margin. For these, the fracture tests using a real pipe specimen and the standard CT specimen test were performed. A 4-point bending jig was manufactured for the pipe test and the direct current potential drop method was used to measure the crack extension and the length for the pipe test. Also finite element analyses were performed with a CT specimen and a pipe in order to prove the additional safety margin. From the result of tests and analyses of the pipe and the standard CT specimen, it was observed that the fracture analysis with the standard CT specimen is conservative and the additional safety margin was proved.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.11
• /
• pp.105-117
• /
• 1972

This experiment has been made to study the relationship between several characters affecting the field lodging and to establish some useful standards for selection of lodging resistant varieties and to classify the degree of lodging resistance in wheat and barley varieties of different sources. The experiment was carried at the Crop Experiment Station, Suwon in 1968. The results obtained are summarized as followings. a. The lodging index modified with bending moment of culm at breaking seemed to be the most useful character in checking the lodging resistance. Highly significant positive correlation (Barley; r=0.40-0.67, Wheat; r=0.46-0.68) was obtained between the lodging index and actual field lodging. b. Between two essential components expressing bending stiffness of the culm, the bending moment at breaking and secondary moment of inertia, a highly significant positive correlation (Barley; r=0.59, wheat; r=0.46-0.53) was observed. c. The bending stiffness of culm got stronger as the dry weight per unit culm, which express the quantity of accumulated dry matters in culm, increased. The correlation coefficient between those two factors was 0.35 to 0.40 in barley and 0.33 to 0.76 in wheat respectively. d. In both wheat and barley, highly significant negative correlation between lodging index and the other factors such as dry weight per unit culm (Barley; r=-0. 51 to -0.70, Wheat; r=-0.65 to -0.83) and bending moment of culm at breaking (Barley; r=-0.29 to -0.69, Wheat: r=-0.54 to -0.89) were observed. Particulary, weight of culm at breaking, secondary moment of inertia and section modulus showed significant negative correlation with lodging index in wheat. e. Outside diameter of culm expressed more intimate relationship with physical characteristics of culm than inside diameter and also showed highly significant correlation with weight of culm at breaking (Barley; r=0.42-0.56, Wheat; r=0.39-0.44) and with bending moment of culm at breaking (Barley; r=0.40-0.41, Wheat; r=0.38-0.49) and with secondary moment of inertia (Barley; r=0.56-0.57, Wheat; r=0.28-0.98) and with section modulus (Wheat; r=0.22-0.96). Between the thickness of culm and physical characteristics of culm also showed the positive correlation. f. There was positive correlation between the culm length and actual field lodging in several groups of variety among the varieties tested. But the culm length seemed to undesirable as a selection measure for the selection of the lodging resistant variety considering the stiffness of culm. g. In classification of lodging resistance for the varieties tested, many Korean barley varieties expressed excellent lodging resistant than wheat, but most of the wheat and barley varieties from Japan considered quite resistant to lodging. h. In selection of lodging resistant varieties, lodging index lower than 1.67 in barley and 1. 76 in wheat considered highly resistant to actual field lodging.

• Proceedings of the KSME Conference
• /
• 2008.11a
• /
• pp.1283-1288
• /
• 2008

The FPCB is used as the important component of the sliding mechanism of mobile phones. FPCB have been used as jumper cables(fixed wiring) in various types of circuits because of their flexibility and bending property. The dominant failure mode of the FPCB is open that was caused by fatigue. The fatigue is repeated whenever the sliding is open, so it is a mainly cause of FPCB fatigue. We examined the bending-fatigue lifetime of FPCB. we focused on observing the contact resistance degradation of FPCB of mobile phones according to different test condition of bending strain. As a result, it has proved that lifetime decreased by increasing bending strain.

• Transactions of Materials Processing
• /
• v.10 no.1
• /
• pp.53-58
• /
• 2001

Set-up reference values, used in determining the optimum downcoiling tension, we experimentally verified in this study. During the actual downcoiling, the strip suffers both tension and bending force through the rotation of mandrel. Therefore, simulative test which can measure both tension and bending resistance of strip was performed to estimate set-up reference value for strip tension during downcoiling operations. The values obtained from the simulative test were correlated with the yield stress which has conventionally been used as reference values for downcoiling tension. The correlative analysis showed that the yield stress of strip can be a good reference value for downcoiling tension. Furthermore, the bending load also shows strong correlation with simulated values due to the close relationship between yield stress and bending load.