• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2006년도 춘계학술논문 발표대회 제6권1호
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• pp.53-56
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• 2006

Recently, trouble of sand supplying is occurred according to exhaustion of natural sand resources. Therefore various measures are proposed for solution of trouble of sand supply and crushed sand among measures is used as one of most universal measures. But because crushed sand have poor particle shape and plenty of makes micro particle, the quality of concrete using crushed sand deteriorated. Therefore, this study evaluated engineering property of concrete with replacement ratio of crushed sand and EEZ sand and applied evaluation result to fundamental data for quality control of concrete using crushed sand and EEZ sand. The result of this study have shown that quality of concrete using crushed sand and EEZ sand and The compressive strength of concrete up to 50, 70% EEZ sand replacement by crush sand, nearly equal to that of general sand.

• 한국포장학회지
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• 제28권1호
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• pp.55-66
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• 2022

In this study, forty corrugated fiberboard (CF) boxes for fresh produce were collected from farms located in Gyeongsan city and evaluated its characterizations and physical properties according to Korean Standard (KS). The basis weight, flute, and paperboard combination were determined for the characterizations of CF boxes. The measured basis weights of all samples were within the tolerance limit referred to KS and the flutes were B/F, EB/F, and AB/F flute, respectively. The bursting strength (BS), edgewise crush resistance (ECR), and compression strength (CS) were tested to evaluate the physical properties. There are four single-walled (SW) CF boxes showed BS and ECR higher than 638 kPa and 3.30 kN/m, respectively. One SW CF boxes showed BS and ECR higher than 785 kPa and 3.43 kN/m, respectively. In case of double-walled (DW) CF boxes, sixteen CF boxes showed BS and ECR higher than 785 kPa, 4.96 kN/m (AB flute), or 4.90 (EB flute), respectively. The other nineteen CF boxes showed BS and ECR higher than 981 kPa, 5.29 kN/m (AB flute), or 5.20 (EB flute), respectively. All the CF boxes except two samples showed the acceptable compression strength in reference to the guideline of KS.

• 대한기계학회논문집A
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• 제26권12호
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• pp.2703-2714
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• 2002

본 연구에서는 유한요소해석을 통해 점용접된 정사각 모자형 박판튜브의 적정 용접간격을 제시해보았다. 적정 용접간격은 에너지흡수 측면에 기준을 두었다. 이를 위해 먼저, 실제 압괴특성을 반영하는 유한요소 모델이 확립하였다. 실제 압괴 특성을 반영하는 유한요소 모델은 본 연구에서 수행된 실험결과에 기초하여 설정하였다. 이 과정에서 다음과 같은 결과들을 도출하였다. (1) 모자형 박판튜브의 압괴해석시 원활한 접힘을 유도하고 과도변형과 접촉에 의한 수치오류 및 비정상 압괴거동을 방지하기 위해 적정 요소크기와 해석시간에 대한 예비연구가 필요하다. (2) 다양한 용접간격의 유한요소모델들에 대한 압괴해석을 거쳐 주어진 폭에 대해 최대 에너지 흡수 용접간격 [식 (1)]을 제시하였다. 또한 최적용접 간격의 모자형 박판튜브는 후폭비 (t/w)가 커질수록 에너지흡수능력 이 증가한다. (3) 다양한 두께와 폭을 갖는 사각튜브에 대한 유한요소해석을 통해, 사각튜브 흡수에너지 예측에 있어 평균압괴하중 방법의 유효성을 검증하였다. 이를 토대로 후폭비항으로 표현되는 수정된 평균 압괴하중으로 최적용접간격을 갖는 모자형 박판튜브의 흡수에너지식 (5)를 제시하였다. 식 (5)의 적용시, 주어진 폭에 대해 (최적)용접간격을 유지함과 동시에 식 (6)의 한계후폭비를 만족해야 한다.

• 펄프종이기술
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• 제39권3호
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• pp.12-23
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• 2007

Frequently spraying of natural starch slurry onto the formed wet web has been adopted to improve properties of paperboards. This conventional starch spraying technique, however, becomes less effective in strength improvement. In this study the effects of various factors including wet web dryness, quantity of starch slurry sprayed, and drying temperature on paperboard properties were investigated. Migration of starch granules into the webs appeared to cause a reduction in plybond strength when the web dryness was lower than this level. Wet webs should contain enough water to swell the starch granules, and at the same time they should be heated to a temperature high enough for complete cooking of the sprayed starches to occur. This suggested that preheating of the wet web can be employed to improve the plybond strength.

• 한국식품저장유통학회지
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• 제3권2호
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• pp.195-202
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• 1996

The compression strength of the corrugated fiberboard boxes is very important information to the manufacturers and the end users. The computer program being used to design the compression strength of the boxes was developed by using Korean Standards for the corrugated fiberboard box and some other data. The developed computer program could be applied to only the boxes produced according to the Korean Standards. Also this program needs to be revised continuously by the newly added and developed data.

• 펄프종이기술
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• 제48권1호
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• pp.61-66
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• 2016

In order to improve the bonding efficiency of starch adhesives and water resistance of corrugated board, mixing ratio of additives dosage was changed and its effects were analyzed. When the additives dosage was increased, bonding strength, vertical compression strength, bursting strength and water resistance were increased, because of hydroxyl groups or acetyl groups in starch adhesives and cellulose fibers of corrugated board were cross-linked by additives. When 1.0% glyoxal dosage was added, flat crush strength and vertical compression strength were increased. With 1.5% glyoxal, bonding strength and bursting strength were increased. However, 2.0% glyoxal dosage was added, most of strength except bursting strength were decreased. Thus, when the appropriate amount of additives are added during corrugated board production process, increased bonding efficiency of starch adhesives and higher water resistance of corrugated board can be achieved.

• 한국식품저장유통학회지
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• 제6권3호
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• pp.303-307
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• 1999

온도 및 습도 변화에 따른 라이너원지의 압축강도 열화를 측정한 결과 압축강도는 온도변화에 영향이 없는 것으로 나타났다. 습도변화의 경우 66% RH에서는 IK원지의 강도저하가 가장 낮은 것으로 나타났다. 93% RH에서는 KA원지의 강도저하가 40%로 가장 낮았으며 SK원지가 56%로 가장 높게 나타났다. 비압축강도의 경우 66% RH에서는 SC 마니라와 IK 원지가, 93% RH에서는 IK원지와 KA원지가 가장 우수하였다. 원 단위 압축강도에서는 습도를 무시할 경우 SK원지가 우수하였으나 66% RH와 93% RH에서는 모두 KA원지가 다른 원지보다 우수한 것으로 나타났다. 따라서 농산물 포장용 라이너로 KA원지를 사용할 경우 경제적이면서도 압축강도가 높은 골판지상자를 제조할 수 있을 것으로 판단된다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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• pp.623-628
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• 2001

The objective of this study is to find out the effect of Horizontal vibration on the compressive strength for 7 days and 28 days cured concrete specimens according to the kind of fine aggregates and the variation of vibration velocities, and times began to vibrate. Three kinds of fine aggregate(river sand, sea sand, crush sand), three types of vibration velocities(0.25, 0.5 0.1kine(cm/sec)), and four steps of times(0, 3, 6, 9 hours after concrete casting) were chosen as the experimental parameters in this study, the vibrations are applied for 30 minutes in each case. From this study, the variation with type of fine aggregate doesn't show tendency and the compressive strength decreases with increasing vibration velocity. When the vibration force time is more than 6 hour, It shows that compressive strength decreases under the condition of vibration velocity which the value is 0.5 kine and 1 kine, respectively.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1995년도 춘계학술발표회논문집(2)
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• pp.703-708
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• 1995

지진 및 냉각재상실사고와 같은 외력에 대한 집합체 구조적 건전성 분석을 위한 해석시 필요한 지지격자의 동적 특성치들을 얻기 위해 17$\times$17 JDFA 중간지지격자에 대한 충격시험을 수행하였으며, 지지격자에 대한 허용충격하중값(Crush Strength)을 구하고 Impact Duration Method를 이용하여 집합체 구조해석에 필요한 지지격자의 동적 강성도 (Dynamic Stiffness)를 구하였다.

• 자동차안전학회지
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• 제13권4호
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• pp.26-32
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• 2021

This study is intended to augment the Roof strength test being evaluated by IIHS (Insurance Institute for Highway Safety). In order to find solutions for increasing Roof Crashworthiness Evaluation SWR (Strengthto-weight ratio). This study introduces that Integrated Connection Structure Between Center Pillar and Roof Center Rail is proposed as a critical solution.