• 비파괴검사학회지
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• 제26권2호
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• pp.122-129
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• 2006

본 논문에서는 레이저 응용 비파괴검사 기술인 Shearography를 이용하여 압력 배관 내부 결함의 검출에 있어서 미치는 전단량의 영향을 분석하였다. Shearography는 레이저 응용기법에 비하여 환경 외란에 둔감하며, 대상체 표면의 상대 변위를 검출함으로서 비파괴검사 분야에서 많은 활용이 기대된다. 현재까지 연구는 적용 가능성의 평가와 적용 대상의 확대에 중점을 두어 연구가 진행되어 왔으며, 결함의 정량평가를 위해서는 결함 검출에 있어서 영향을 주는 인자들에 대한 연구가 필요하다. 따라서 본 논문에서는 결함의 검출에 영향을 줄 수 있는 전단량의 변화에 따라 결함의 크기 측정과 길함의 위치 결정에 대한 영향을 예측하고, 압력용기 내부의 길이 방향 인공 결함에 대해 적용하여 검출 결과를 분석하였다.

• 한국수산과학회지
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• 제20권6호
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• pp.484-488
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• 1987

단순만곡형과 슈퍼-V형 모형 전개판의 뒷전 쪽에 각각 flap을 부착하고, 회류수조에서 진행각도와 유속에 따른 항력과 전개력을 측정하여 유체역학적인 전개성능을 분석한 결과는 다음과 같다. 1. flap을 부착한 모형 전개판의 전개력계수 $C_L$은 flap각도 $30^{\circ}$와 $50^{\circ}$일 때 단순만곡형은 최대유효진행각도 $\alpha_{max}=25^{\circ}$ 1.75 정도이었고, 슈퍼-V형은 $\alpha_{max}=20^{\circ}$에서 1.80정도로 flap을 부착하지 않은 경우보다 $20\~30\%$ 정도 $C_L$이 증가하였다. 2. 항력계수 $C_D$는 $\alpha_{max}$ 일 때 flap각도에 관계없이 단순만곡형과 슈퍼-V형 모두가 0.5 정도로 거의 차이가 없었고, flap을 부착하지 않은 경우보다는 약간 $C_D$가 증가하였다. 3. 유체효율 $C_L/C_D$는 flap각도 $30^{\circ}$일 경우가 $50^{\circ}$일 경우보다 약간 높았으나, $\alpha_{max}$일 때는 거의 비슷하였으며, flap를 부착하지 않은 경우보다는 악간 높은 경향을 보였다.

• 한국구조물진단유지관리공학회 논문집
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• 제10권6호
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• pp.175-182
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• 2006

강 콘크리트 합성구조에서 강재와 콘크리트 사이의 경계면에 효과적인 응력전달과 합성거동을 유도하기 위하여 스터드, 채널, 유공강판 등이 사용된다. 가장 광범위하게 사용하는 전단연결재는 스터드 형식이고, 최근에 들어서는 강판에 구멍을 뚫은 유공강판전단연결재인 Perfobond가 주목을 받고 있다. 본 연구는 강 콘크리트 합성교량에 적용하기 위한 Perfobond형 전단연결재의 연성능력과 전단성능을 향상시킬 목적으로 횡방향 전단구속철근을 배치하고, Push-out 실험을 수행하여 전단내력을 비교하였다. 실험결과, 유공강판 전단연결재에 전단구속철근, 횡방향 관통철근, 단부 지압판 등을 설치함에 따른 수평 저항성능이나 다웰효과 등에 의해 전단내력이 상승하였으며, 또한 최대내력 이후 변형능력이 유지되면서 연성거동 특성을 보였다.

• 대한금속재료학회지
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• 제47권9호
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• pp.580-585
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• 2009

The effects of shear speed and tip height on the high speed shear test of Sn-3.0wt.%Ag-0.5wt.%Cu ball joints were investigated. Solder balls of $450{\mu}m$ in diameter were reflowed at $245^{\circ}C$ on a FR4 PCB (Printed Circuit Board) in order to obtain a sample for the high-speed shear test. The UBM was comprised of Cu/Ni/Au, and the shear speed and tip height varied from 0.5 to 3.0 m/s, and from 10 to $135{\mu}m$, respectively. According to the experimental results, faster shear speed enhanced the shear strength of the solder joints, regardless of the tip height. The fraction of ductile (solder) fracture decreased when the shearing speed was raised from 0.5 to 3.0 m/s. With an increasing tip height from 10 to 50 and $135{\mu}m$, the fracture mode changed from pad lift to mixed (ductile and brittle) and ductile fracture, respectively, while the shearing energy also increased in the same order. The shear energy had a proportional relationship with the fraction of the solder fracture.

• 한국재난정보학회 논문집
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• 제3권2호
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• pp.147-169
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• 2007

This study investigates the reinforcing effects of the Multi-bar Spring nails with respect to the conventional Soil-nails in artificial slopes. Based on wide experience related to design and construction, soil nails have been widely applied to reinforce slope in the world. Multi-bar spring nails are one of the improved soil nailing methods. These method maximizes bending, shearing, pull-out resistance for those multi-nails, not unit nail, that are inserted in the borehole using special spacer at regular intervals. In addition, because cutting plane is confined effect resulting from a pressured plate at the end of the nails with compression spring equipment, slope stability is secured using MS-nailing method. Analyzing bending, pull-out, shearing condition of MS-nail, it was examined throughly elastic region, load transfer capacity, reinforcing effect on cutting plate of MS-nails. In addition, Pilot and laboratory tests, numerical analysis were carried out to verify the superiority of MS-nailing method. In case, MS nailing method is applied to reinforce artificial slope, it was analyzed that bending, pull-out, shearing resistance was increased more than existing nailing method was applied. In this study, it was shown that surface failure was more or less prevented using MS-nailing method, confining effect on cutting plane using spring stuck to flexible equipment.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.350-350
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• 2006

We investigated, via atomic force microscopy and transmission electron microscopy, the effect of shear force on the interfacial morphology of a reactive bilayer polymer system composed of PS-mCOOH and PMMAGMA. It has been observed that in the absence of oscillatory shearing the roughness of the interface increased with reaction period, while at large values of ${\gamma}_{0}\;and\;{\omega}$ it became less than that observed in the absence of oscillatory shearing. This observation may be attributable to the possibility that oscillatory shearing might have hindered the diffusion of polymer chains, which are located away from the interface, to the interface of the layers. However, the effect of ${\gamma}_{0}\;and\;{\omega}$ on the roughness of the interface of (PS-mCOOH)/(PMMA-GMA) bilayer is found to be quite different.

• 한국기계가공학회지
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• 제14권4호
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• pp.134-139
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• 2015

PolyJet technology is an additive manufacturing (AM) technology commonly used for modeling, prototyping, and production applications. It is one of the techniques used for 3D printing. The PolyJet technique is a process that joins materials to fabricate a product from 3D CAD data in a layer-by-layer manner. The orientation of a layer can affect the mechanical properties of the product manufactured by the PolyJet technique because of its anisotropy. In this paper, tensile and shearing tests of specimens were developed with the PolyJet technique in order to study the mechanical properties according to the orientation of a layer. The mechanical properties of the specimens were determined on the basis of true stress-strain curves from tensile and shearing tests. In addition, the tensile and shearing tests were simulated under the same conditions as those of experiment, and the experiment and simulated results were compared. Through this study, the fracture criteria could be established.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.679-682
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• 2001

An experiment is carried out to investigate the influences of shearing characteristic factors for the process design of lead frame blanking in copper alloy C194(t=0.205mm). 3 process parameters, e.g., clearance between die and punch, strip holding pressure, and bridge allowance are selected for this study. From the basis condition 6% clearance, 20N/$mm^2$, and 1.5t bridge allowance the seven times of experiment are done by varying the each factor. The square shape specimen is used to study the characteristics of shearing factors. The ratios of roll over, burnish, fracture zone are measured after blanking. The experimental analysis shows that the burnish ratio is decreased as the clearance increases. And the larger strip holding pressure is shown that the roll over and burnish ratio are both decreased. It is found that an optimal strip holding pressure is need for large burnish zone. Finally it is shown that the bridge allowance is less affected than clearance and strip holding pressure.

• Asian-Australasian Journal of Animal Sciences
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• 제14권8호
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• pp.1106-1109
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• 2001

This experiment was conducted with 30 adult wool producing Angora rabbits of either sex, to evaluate the effect of replacing soyflakes (SF), on equal protein basis, with low gossypol containing cottonseed meal (CSM) either alone or in combination with lysine and methionine; on the biological performance, total wool yield, wool yield per shearing, wool characteristics and mortality. Three experimental mash diets were prepared by incorporating SF (6%) as standard / control protein source $(T_1)$ and CSM (9%) as test protein source ($T_2$ and $T_3$). In $T_3$, amino acids-lysine and methionine (0.1 % each) were added. Animals were given the experimental diets about $150g{\cdot}day^{-1}{\cdot}head^{-1}$, for a period of 225 d or three shearing, and ad libitum Kudzu-vines. No significant effect of $T_2$ or $T_3$, on the body weight gain, total wool yield, wool yield per shearing and wool characteristics, was observed compared to $T_1$. However, the digestibility of dry matter, crude fibers, ether extract, acid detergent fibers, neutral detergent fibers, cellulose and hemicellulose was significantly (p<0.05) depressed in CSM based diets. Mortality of about 20% was recorded in $T_2$ and $T_3$, but not related to the addition of CSM or gossypol toxicity. More studies are needed to standardize the safe level of CSM, duration of safe feeding of CSM, and level of amino acids supplementation in CSM based diets.

• Design & Manufacturing
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• 제2권1호
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• pp.15-19
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• 2008

While recent industrial structure is various, it is small quantity batch production structure, and products requiring of various functions are increasing. In order to improve the quality of the sheared surface in cutting of inner structure bonded sheet metal the cut-off operation is mainly investigated, which is the typical shearing process in sheet metal forming technology. The sandwich sheet metals considered have inner structure which is constructed in the form of crimped expanded metal and woven metal. The inner structure is bonded between solid sheet by resistance welding or adhesive bonding. The shearing process is visualized by the computer vision system installed in front of the cut-off die and the sheared surface is measured and quantitatively compared with the help of the optical microscope after cut-off operation. From test results we found that the influence of sheared position can be observed and explained clearly and this result can be utilized to get the better sheared surface.