• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.6
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• pp.195-200
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• 2001

Composites have wide applications in aerospace vehicles and automobiles because of the inherent flexibility in their design for improved material properties. Composite tribes in particular, are potential candidates for their use as energy absorbing elements in crashworthiness applications due to their high specific energy absorbing capacity and the stroke efficiency. Their failure mechanism however is highly complicated and rather difficult to analyze. This includes fracture in fibres, in the matrix and in the fibre-matrix interface in tension, compression and shear. The purpose of this study is to investigate the energy absorption characteristics of CFRP(Carbon Fiber Reinforced Plastics) tubes on static and impact tests. Static compression tests have been carried out using the static testing machine and impact tests have been carried out using the vertical crushing testing machine. Interlaminar number affect the energy absorption capability of CFRP tubes. Also, theoretical and experimental have the same value.

• Structural Engineering and Mechanics
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• v.42 no.6
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• pp.883-897
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• 2012

Cold-formed channel sections are used in a variety of applications in which they are required to absorb deformation energy. This paper investigates the collapse behaviour and energy absorption capability of cold-formed steel channels with flange edge stiffeners under large deformation major-axis bending. The Yield Line Mechanism technique is applied using the energy method, and based upon measured spatial plastic collapse mechanisms from experiments. Analytical solutions for the collapse curve and in-plane rotation capacity are developed, and used to model the large deformation behaviour and energy absorption. The analytical results are shown to compare well with experimental values. Due to the complexities of the yield line model of the collapse mechanism, a simplified procedure to calculate the energy absorbed by channel sections under large bending deformation is developed and also shown to compare well with the experiments.

• YAKHAK HOEJI
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• v.21 no.2
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• pp.101-109
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• 1977

The effect of humidity on the aging process of hydrous aluminum oxide prepared by the reaction of aluminum chloride and sodium bicarbonate solution at pH 7.8, which was then kept in various atmosphere under relative humidity at 37.deg. was observed by the measurements of acid consuming capacity, X-ray diffraction and IR absorption. The humidity was one of the important factors influencing the aging process of hydrous aluminum oxide during storage. The higer the humidity, the more was accelerated age, crystalize and loss in acid reactivity. Depending on the humidity, the aging product was different, especially, in the case of up to the relative humidity of 72%, it forming bayerite. On the other hand, the hydrous aluminum oxide aged below the relative humidity of 50% was still amorphous even after 120 days storage. When hydrous aluminum oxide was aged under higher humidity, definite IR absorption bands develop as the hydroxys become part of an ordered structure, and it showed their characteristic absorption band around 1630 and 1060 cm$^{-1}$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.11
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• pp.721-726
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• 2015

In this study, the properties of C-V degradation for thermal conductivity silicone rubber sample which is attached by copper-copper, copper-aluminum, aluminum-aluminum on upper-side and under-side has been measured at temperature of $80^{\circ}C{\sim}140^{\circ}C$. The results of this study are as follows. In case the frequency is increased, it found that the electrostatic capacity increased with increasing temperature to $80^{\circ}C$, $110^{\circ}C$, $140^{\circ}C$ regardless of kind of electrode. It found that the electrostatic capacity increased with becoming high temperature range of frequency regardless of kind of electrode. This result is considered to be caused by thermal absorption on the thermal conductivity silicone rubber sample. It found that the electrostatic capacity decreased with increasing temperature and frequency. This result is considered to be caused by molecular motion of C-F radical or OH radical.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.879-884
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• 2002

The objective of this study is to investigate the seismic capacity of the non-seismically detailed RC bridge piers before and after applying a seismic retrofitting method using stainless steel wire mesh. Total nine circular section RC piers were constructed. Different lap splice longitudinal reinforcement details were adapted for four specimens and various types of stainless steel wire mesh were applied for the remaining five specimens. Harmonic cyclic lateral load was applied on each specimen under a constant axial load. The test results indicated that the existing circular piers have low seismic capacity while the stainless steel wire mesh retrofitting method improves the seismic capacity considerably. In addition, test results revealed that the circular section piers could have a considerable amount of ductility if longitudinal bars are not lap-spliced in potential plastic hinge zone. Based on this experimental study it could be concluded that the seismic performance, that is ductility and energy absorption capacity, of the non-seismically detailed RC bridge piers would be increased by applying the stainless steel wire mesh seismic retrofitting method.

• Journal of Energy Engineering
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• v.14 no.3 s.43
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• pp.203-211
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• 2005

To investigate the effects of the number of multiple-cycles and $SO_2$ concentration on $CO_2$ absorption characteristics by means of limestone, $CO_2$ capture capacity has been measured in a bubbling fluidized bed reactor (0.1m 1.D., 1.17m high). Danyang limestone was used as a $CO_2$ sorbent and the number of cycles $(\~10th\;cycle)$ and $SO_2$ concentrations (0, 2000, 4000 ppm) were considered as variables. The measured $CO_2$ capture capacity decreased as the number of cycles increased and it showed $50\%$ or initial value after 10 cycles. Moreover, $CO_2$ rapture capacity decreased with 501 concentrations. For three different $SO_2$ concentrations, the total CaO utilization was almost the same but $SO_2$ capture capacity increased and $CO_2$ capture capacity decreased as $SO_2$ concentration increased. These results suggest that $SO_2$ capture reaction is predominant over $CO_2$ capture reaction in the simultaneous $CO_2/SO_2$ capture conditions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.83-93
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• 2019

The purpose of this study is to suggest implications for maximizing the effectiveness and efficiency of IPP work-learning by studying the effects of the personal characteristics of trainees and firm's field teacher on trainees' employability. The following conclusions were drawn by verifying the causal relationship between factors based on a questionnaire (157 copies) distributed to 200 trainees (learning workers) of 9 universities participating in IPP work-learning training. First, in order to increase the employability of IPP trainees, it is necessary to select trainees with strong core competencies and failure tolerance by verifying individual characteristics of trainees. Secondly, companies should appoint senior staff with strong leadership and teaching capacity as corporate field teachers, and corporate field teacher training institutions should reinforce the training to improve their leadership. Third, work-learning companies should be selected as those with high social integration and absorption capacity, and those companies should try to build an organizational culture of acquiring and learning new technologies. The results of this study are expected to contribute to enhancing the effectiveness of work-learning training by establishing a training system that can systematically select trainees and participating companies and enhance the training capacity of companies and field teachers.

• Korean Journal of Food Science and Technology
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• v.31 no.4
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• pp.924-930
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• 1999

To extract insoluble proteins and improve physical properties of proteins, the sesame meal proteins was irradiated with $5\;kGy{\sim}20\;kGy$ at room temperature. The highest extraction rate of sesame meal protein was showed at irradiation dose of 5 kGy. The foaming capacity, foaming stability, emulsion capacity and emulsion stability of gamma irradiated sesame meal protein (GISP) were all increased as compared to those of the non-irradiated protein. Water absorption capacity of GISP was similar to that of non-irradiated protein and oil absorption capacity of GISP was decreased after treatment by gamma irradiation.

• Journal of the Korea Concrete Institute
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• v.15 no.3
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• pp.462-469
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• 2003

This paper presents an experimental study on the potential durability enhancement of infrastructures repaired by a sprayed high ductile fiber-reinforced cementitious composite (ECC). For this study, a PVA-ECC which exhibits sprayable properties in the fresh state and tensile strain-hardening behavior in hardened state was sprayed and tested. The experimental results show that the sprayed ECC exhibits mechanical properties with strain capacity comparable to the cast ECC with the same mix design. During loading, the crack widths of ECC are tightly controlled with an average of 30${\mu}m$. It is also revealed that when sprayed ECC is used as a repair material, ductility represented by deformation capacity at peak load of repaired beams in flexure are obviously increased in comparison to those of commercial prepackaged mortar (PM) repaired beams. In addition to high delamination resistance, the significant enhancement of energy absorption capacity and crack width control in ECC repair system suggest that sprayed ECC can be effective in extending the service life of rehabilitated infrastructures.

• Earthquakes and Structures
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• v.22 no.6
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• pp.539-548
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• 2022

Steel plate shear walls (SPSWs) are one of the most important and widely used lateral load-bearing systems. The reason for this is easier execution than reinforced concrete (RC) shear walls, faster construction time, and lower final weight of the structure. However, the main drawback of SPSWs is premature buckling in low drift ratios, which affects the energy absorption capacity and global performance of the system. To address this problem, two groups of SPSWs under cyclic loading were investigated using the finite element method (FEM). In the first group, several series of circular rings have been used and in the second group, a new type of SPSW with concentric circular rings (CCRs) has been introduced. Numerous parameters include in yield stress of steel plate wall materials, steel panel thickness, and ring width were considered in nonlinear static analysis. At first, a three-dimensional (3D) numerical model was validated using three sets of laboratory SPSWs and the difference in results between numerical models and experimental specimens was less than 5% in all cases. The results of numerical models revealed that the full SPSW undergoes shear buckling at a drift ratio of 0.2% and its hysteresis behavior has a pinching in the middle part of load-drift ratio curve. Whereas, in the two categories of proposed SPSWs, the hysteresis behavior is complete and stable, and in most cases no capacity degradation of up to 6% drift ratio has been observed. Also, in most numerical models, the tangential stiffness remains almost constant in each cycle. Finally, for the innovative SPSW, a relationship was suggested to determine the shear capacity of the proposed steel wall relative to the wall slenderness coefficient.