• Journal of the Korean Society of Industry Convergence
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• v.23 no.3
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• pp.375-380
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• 2020

In this study, we tried to evaluate the mechanical properties of Polycarbonate(PC) and acrylonitrile-butadiene-styrene(ABS) plastic materials, which are frequently used as parts of home appliances and machinery, when repeated impacts were applied. A repeating impact tester for this research was designed and manufactured to apply repetitive impacts. Two types of plastic were repeatedly impacted under a constant load, and a tensile test was performed on the plastic material that was impacted. The tensile strength of PC plastic materials that received impact more than 2000 times was reduced by about 45 % and elongation was reduced by about 10 % when compared to impact free specimens. On the other hand, in ABS plastic, a reduction of tensile strength of about 20 % was observed at about 2,000 impacted specimen, but at about 20,000 repetitive impacted specimen, a tensile strength decrease of about 65 % was observed. And the elongation was reduced by 10 % due to the cyclic harding behavior of the material.

• Journal of the Korea Concrete Institute
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• v.27 no.4
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• pp.353-362
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• 2015

Cyclic loading tests for the PC moment frame with plastic shear hinges were performed to evaluate the seismic performance. The plastic shear hinges consisted of two steel plates were installed at the mid-length of the beam to connect the PC frames. Three shear links are existed in each steel plate. The three shear links were designed using shear force corresponding to the shear capacity of 50%, 75%, and 100% of the beam shear capacity. The proposed connections showed an efficient energy dissipation capacity and good structural performance. As a result, it is reasonable to design the plastic shear hinges using design shear capacity less than 100% of the beam shear capacity.

• Advances in concrete construction
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• v.10 no.4
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• pp.319-332
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• 2020

The impacts of reinforcing concrete matrix with steel fibers, polypropylene fibers and recycled plastic fibers using different volume fractions of 0.15%, 0.5%, 1.5% and 2.5% on the compressive and tensile characteristics are experimentally investigated in the current research. Also, flexural behavior of plain concrete (PC) beams, shear performance of reinforced concrete (RC) beams and compressive characteristics of both PC and RC columns reinforced with recycled plastic fibers were studied. The experimental results showed that the steel fibers improved the splitting tensile strength of concrete higher than both the polypropylene fibers and recycled plastic fibers. The end-hooked steel fibers had a positive effect on the compressive strength of concrete while, the polypropylene fibers, the recycled plastic fibers and the rounded steel fibers had a negative impact. Compressive strength of end-hooked steel fiber specimen with volume fraction of 2.5% exhibited the highest value among all tested samples of 32.48 MPa, 21.83% higher than the control specimen. The ultimate load, stiffness, ductility and failure patterns of PC and RC beams in addition to PC and RC columns strengthened with recycled plastic fibers enhanced remarkably compared to non-strengthened elements. The maximum ultimate load and stiffness of RC column reinforced with recycled plastic fibers with 1.5% volume fraction improved by 21 and 15%, respectively compared to non-reinforced RC column.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.4_2
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• pp.611-616
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• 2020

Polycarbonate (PC) materials having electrical insulation properties, are thermoplastic material and are easily processed, have excellent strength and heat resistance characteristics, and also have transparent and hard characteristics. In this study, we tried to derive the ε-N curve of strain-life, which shows the relationship between the strain characteristics and the life of the material when repeated impact loads are applied to the PC plastic material. As the impact load increased to 3.0kg, 4.0kg, 5.0kg, and 6.0kg, the strain also increased linearly to 0.033, 0.041, 0.046, and 0.055. At 3.0kg of mass impact, the test piece broke with 12000 impact cycles, 8400 times at 3.5kg, 7400 times at 4.0kg, 6600 times at 4.5kg, 4700 times at 5.0kg, 3000 times at 5.5kg, and 1000 times at 6.0kg. The number of fractures exponentially decreased as the load gradually increased. Using these results, an ε-N curve for PC plastic was derived.

• Journal of Institute of Control, Robotics and Systems
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• v.9 no.10
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• pp.768-773
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• 2003

Injection molding has been widely used for the mass production of a plastic product. With the development of the relative technique, various injection molding techniques have been developed and we could get more precise plastic product. The temperature of a melting resin is an important factor in the injection molding and this temperature has direct influence on the quality of a plastic product. In the present injection molding machine, the deriation of a temperature controlled by PID control method is within 2$^{\circ}C$ in the injection molding machine but PID control method takes too much time to stabilize after preheating and its overshoot is so big. We applied fuzzy control to alleriate the problem. In this research, we experimented the fuzzy temperature control with the usage of PC based PLC.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.4 no.3
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• pp.168-171
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• 2003

Nano pattern structure is produced using the conventional injection molding and the MmSH method. Plastic parts using PC make used of the MmSH method is much better than the other about manufacture showed transcription of nano pattern. The conventional injection molding, transcription of plastic parts with nano pattern using HIPS showed better than PC. In the result, transcription of nano pattern improve when well liquidity and high temperature of mold surface.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.12
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• pp.698-705
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• 2017

Environmental impact of a mobile phone charger containing recycled plastic was quantified using LCA and the environmental benefits from the use of recycled and virgin plastic were compared. The assessment considers potential environmental impacts across the whole life cycle of the charger including; pre-manufacturing; manufacturing; distribution; product use; and end-of-life stages and quantified six environmental impact categories; Abiotic depletion; Acidification; Eutrophication; Global warming; Ozone layer depletion; and Photochemical oxidants creation. The study showed that the environmental impacts of the use stage accounted for 94.4% and 70% in the resource depletion and global warming impact categories, respectively, and the environmental impacts of the pre - manufacturing stage accounted for more than 98% in the other impact categories. The main cause of the environmental impacts in the use stage was electricity consumed by the charger. The main cause in the pre-manufacturing stage was PBA (Printed Board Assembly) and external case manufacturing. In order to quantify the environmental benefits of recycled PC (Polycarbonate) in the exterior case, the environmental impacts of 1 kg production of recycled PC and virgin PC were evaluated. The environmental impact on the abiotic depletion of the recycled PC is estimated to be 30% compared to the virgin PC, and the impacts on the other impact categories of the recycled PC were less than 5% of the virgin plastic. Sensitivity analysis was performed for 12 items including site data and assumptions made. The sensitivity of each item was less than 10%. The results of this study confirm that designing compact and light PBA, improving charging efficiency, and use of recycled plastic are important design factors to reduce the environmental impact of a charger.

• Steel and Composite Structures
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• v.14 no.6
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• pp.571-586
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• 2013

This paper focuses on the buckling capacity of a hybrid grid shell. The eigenvalue buckling, geometrical non-linear elastic buckling and elasto-plastic buckling analyses of the hybrid structure were carried out. Then the influences of the shape and scale of imperfections on the elasto-plastic buckling loads were discussed. Also, the effects of different structural parameters, such as the rise-to-span ratio, beam section, area and pre-stress of cables and boundary conditions, on the failure load were investigated. Based on the comparison between elastic and elasto-plastic buckling loads, the effect of material non-linearity on the stability of the hybrid barrel vault is found significant. Furthermore, the stability of a hybrid barrel vault is sensitive to the anti-symmetrical distribution of loads. It is also shown that the structures are highly imperfection sensitive which can greatly reduce their failure loads. The results also show that the support conditions pose significant effect on the elasto-plastic buckling load of a perfect hybrid structure.

• Journal of the Semiconductor & Display Technology
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• v.20 no.4
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• pp.44-48
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• 2021

Semiconductor inspection equipment makes components using materials with insulating properties for functional inspection including current and voltage of semiconductor parts. A representative insulating material is plastic, and plastic is made of a component through an injection process using plastic pellet. When plastic pellets contain excessive moisture, problems such as performance degradation and product surface defects occur. To prevent this, pre-drying is essential, and the heat convective type is the most applied. However, the heat convective type has a problem of low consumption efficiency and a long drying time. Recently, many studies have been conducted on a drying method using microwaves due to high energy efficiency. In this paper, drying was performed using a microwave for drying PC pellets. Energy consumption and drying efficiency analyzed by set up an experimental apparatus of heat convective, microwave, and hybrid(heat convective + microwave) types. It was confirmed that energy consumption and drying efficiency were high when drying using microwaves, and it was confirmed that the hybrid method improved drying performance compared to the heat convective method. It is expected that the research results of this paper can be used as basic data for drying plastic pellets using microwave.

• Proceedings of the KIEE Conference
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• 2006.04a
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• pp.33-35
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• 2006

We studied the prototypal developments of Plastic Cortex Stimulator (PCS) for stroke patients. The PC sends the stimulation parameters (amplitude, pulse width, cycle, etc.) to the transmitter ZigBee module through serial port. The receiver ZigBee module generates stimulation waveform. The generated output can be controlled by the PC program. Further study can be expanded to portable handset such as PDA using ZigBee. The wireless control of PCS with the handset can help the tele-rehabilitation.