• Geomechanics and Engineering
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• v.20 no.5
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• pp.371-384
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• 2020

A settlement prediction method based on shear wave velocity measurements and soil nonlinearity was recently developed and verified by means of centrifuge tests. However, the method was only applicable to heavily overconsolidated soil deposits under enlarged yield surfaces. In this study, the settlement evaluation method was refined to consider the stress history of the sublayer, based on an overconsolidation ratio evaluation technique, and thereby incorporate irrecoverable plastic deformation in the settlement calculation. A relationship between the small-strain shear modulus and overconsolidation ratio, which can be determined from laboratory tests, was adopted to describe the stress history of the subsurface. Based on the overconsolidation ratio determined, the value of an empirical coefficient that reflects the effect of plastic deformation over the elastic region is determined by comparing the overconsolidation ratio with the stress increment transmitted by the surface design load. The refined method that incorporate this empirical coefficient was successfully validated by means of centrifuge tests, even under normally consolidated loading conditions.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2019.05a
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• pp.143-144
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• 2019

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2018.11a
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• pp.225-226
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• 2018

• The Journal of Engineering Geology
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• v.31 no.3
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• pp.239-255
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• 2021

Kinematic analyses of magmatic intrusions and faults can provide useful information on stress conditions and chronological relationships between dike emplacement and brittle deformation events. We studied structures in rocks exposed on a coastal platform in Geoje Island off the southern Korean Peninsula because of its well-developed dikes and faults. The geology of the study area includes the Cretaceous Seongpo-ri Formation, which is composed mostly of shale, sandstone, and hornfels intruded by magmatic dikes. Most of the dikes are developed along pre-existing structural features (faults and fractures), indicating that their emplacements were structurally controlled. Because dikes commonly open along the direction of the minimum principal stress, the direction of this stress can be obtained from dike geometry and orientation through the matching of piercing points on either side of a dike. In addition, the deformed dikes can give information regarding later deformation. On the basis of the kinematic analyses, we identified five deformation events in the study area, which are kinematically related to changes of the regional maximum principal stress. Results indicate that the structures in the study area have been controlled predominantly by episodes of reactivation of the NNE-trending Yangsan strike-slip fault, located to the northeast of the study area, under different stress regimes. In a wider tectonic context, the brittle deformation of the rocks of Geoje Island was probably induced by interactions among the Philippine Sea, Pacific, and Eurasian plates, including changes in subduction parameters with respect to the latter two plates over time.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.4
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• pp.88-95
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• 2011

In this study, the deformation, stress, vibration, fatigue life and the probability of damage are analyzed at the pedal applied by the force of 300N. The maximum stress at the lower of pedal is shown as 20.801MPa. And the maximum displacement is 0.85mm at the maximum response frequency as 3800Hz. Among the cases of nonuniform fatigue loads, 'SAE bracket history' with the severest change of load becomes most unstable but 'Sample history' becomes most stable. In case of 'Sample history' with the average stress of 0 to $-10^{5}MPa$ and the amplitude stress of 0 to $10^{5}MPa$, the possibility of maximum damage becomes 0.6%. This stress state can be shown with 5 times more than the damage possibility of 'SAE bracket history' or 'SAE transmission'. The structural result of this study can be effectively improved with the design of pedal by investigating durability against its damage.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.2
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• pp.137-143
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• 2012

This study analyzes flywheel through the analyses of stress, fatigue and vibration. Maximum equivalent stress is 15.271MPa at the mid round shape and maximum deformation is 0.02264mm at the outer teeth. Among the cases of nonuniform fatigue loads, 'SAE bracket history' with the severest change of load becomes most unstable but 'Sample history' becomes most stable. In case of 'Sample history' with the average stress of -$10^4$MPa and the amplitude stress of 1000 to 2900MPa, the possibility of maximum damage becomes 30%. This stress state can be 20 times greater than the damage possibility of 'SAE bracket history' or 'SAE transmission'. The range of natural frequencies becomes 200 to 820Hz and the values of these deformations are not more than 10mm. The structural result of this study can be effectively utilized with the design of flywheel by investigating prevention and durability against its damage.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.1
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• pp.51-57
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• 2012

This study investigates structural and fatigue analyses at bicycle pedal. Maximum deformation at model 1 is 2 times as much as model 2 at static analysis. Models 1 and 2 have the possibility of the weakest strength at the part of contact with chain gear. Among the cases of nonuniform fatigue loads at Models 1 and 2, 'SAE bracket history' with the severest change of load becomes most unstable but 'Sample history' becomes most stable. In case of 'Sample history' with the average stress of 0 to $-10^4$ MPa and the amplitude stress of 0 to $10^4$ MPa, the possibility of maximum damage becomes 4%. This stress state can be shown with 5 to 7 times more than the damage possibility of 'SAE bracket history' or 'SAE transmission'. The analysis result of this study can be effectively utilized with the safe design of pedal.

• The Journal of the Petrological Society of Korea
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• v.15 no.2 s.44
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• pp.49-59
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• 2006

This study clarifies the deformation history of Precambrian metamorphic rocks of Sobaegsan Massif (Wonnam Formation, Pyeonghae granite gneiss, Hada leucogranite gneiss) in Giseong-myeon area, Uljin-gun, Korea. It is based on the geometric and kinematic features and the developing sequence of multi-deformed rock structures. It also reviews the extension of Yecheon Shear Zone and the relative occurrence time of each deformation phase from previous researches. It suggests that the geological structure was formed at least through five phases of deformation after formation of their gneissosity or schistosity. (1) The first phase of deformation took placed under compression of ENE-WSW direction, forming NNW trending regional foliation and very tight isoclinal fold. The general trend of gneissosity or schistosity is inferred to be ENE before the first phase of deformation, being rearranged into NNW by the isoclinal folding. (2) The second phase of deformation formed ENE trending regional foliation and tight, isoclinal, rootless intrafolial folds under compression of NNW-SSE direction [occurrence time: after deposition (Permian age) of Dongsugok Formation, Pyeongan Croup, Janggunbong area]. (3) The third phase of deformation occurred by dextral ductile shearing on the regional foliation, forming stretching lineation of ENE trend and S-C mylonitic structure (after intrusion of Hesozoic homblende granite, Sangunmyeon area-before intrusion of Mesozoic Chunyang granite, Janggunbong area). (4) The fourth phase occurred under (E)NE-(W)SW compression, forming (N)NW trending open fold. (5) The fifth phase took place under N-S compression, forming NNE and NNW trending conjugate strike-slip faults, E-W trending thrust-slip faults, and drag folds related to these fault movements. The deformed structures of fourth and fifth phases result from tectonic movement associated with the developing of the Gyeongsang Basin in Cretaceous age, and it partially rearranged the general ENE trend of the regional foliation in the study area. It also suggests that the Yecheon Shear Zone of E-W trending extends into this area but the ductile shear deformation is weakly developed.

• Proceedings of the KSME Conference
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• 2001.06c
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• pp.586-591
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• 2001

In the cold forging, elastic deformation of the die has been investigated to improve the accuracy of cold forged parts with F.E.M analysis using DEFORM, and with experiments using strain gauges. In the experiments, initial billet was selected to easily find the effect of elastic deformation according to the forging modes, extrusion and upsetting type, and only extrusion type. Elastic deformation of the die can be obtained by the signal from the strain gauges and this signal can be amplified by data acquisition system during the process. In the F.E.M analysis, two types of analysis are used to predict elastic strain of the die. To improve an accuracy of forged product and die dimension, this study compared with strain distribution between experiment and F.E.M analysis. As a result, the history of the deformation of the die and elastic recovery of forged product can be obtained by the elastic strain analysis of forged product and die according to the forging modes.

• International Journal of High-Rise Buildings
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• v.3 no.3
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• pp.231-241
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• 2014

Ductile fracture is one of the most common failure modes of steel beam-to-column connections in moment resisting frames. Most proposed evaluation methods of the plastic deformation capacity of a beam until ductile fracture are based on steel beam tests, where the material's yield strength/ratio, the beam's moment gradient, and loading history are the most important parameters. It is impossible and unpractical to cover all these parameters in real tests. Therefore, a new attempt to evaluate a beam's plastic deformation capacity through analysis is introduced in this paper. Another important issue is about the loading histories. Recent years, the effect on the structural component under long-duration ground motion has drawn great attentions. Steel beams tends to experience a large number of loading cycles with small amplitudes during long-duration earthquakes. However, current research often focuses on the beam's behavior under standard incremental loading protocols recommended by respective countries. In this paper, the plastic deformation capacity of steel beams subjected to long duration ground motions was evaluated through analytical methodology.