본 연구에서는 알루미늄 폼을 TDCB 형태의 시험편으로 설계하여 ModeⅡ 조건에서의 정적 거동 실험 및 전단 피로 실험을 통해 평가 및 검토하였다. TDCB 시험편 모델들의 길이와 두께는 각각 200mm 와 25mm이고, 접착면의 각도는 6°에서 12°까지 2° 간격으로 4가지의 모델을 모델링을 하였다. 세 가지 모델의 실험 과정을 데이터화한 그래프들을 비교해 보면 같은 피로하중 조건에서는 모델의 경사진 각도가 클수록 피로하중을 견딜 수 있는 사이클 수가 많은 것을 알 수 있다. 실제 실험에서와 유사한 결과를 보이기 때문에 본 연구에서 수행한 유한요소법 해석 결과에 대한 검증을 할 수 있었고, 이와 같은 방법을 이용하면 많은 비용과 시간이 들어가는 실험 대신에 시뮬레이션만으로도 그 구조적 안전성을 파악할 수 있을 것으로 사료된다.

The honeycomb aluminum foam of the porous metal has the merit of the impact absorption, the soundproof, the heat conductivity, the light weight. Aluminum 6061-T6 is used at the materials for the automobile, the ship, the machine and various structures. In this study, the sandwich combined with the honeycomb aluminum foam and aluminum 6061-T6 is simulated with the impact. Two kinds of models made by use of CATIA program with 3 kinds of impact energies are analyzed by ANSYS program. As the simulation result, the maximum deformations at the cases of 1 and 2 are shown as 4.8205mm and 11.909mm respectively. And the maximum equivalent stresses at the cases of 1 and 2 are shown as 274.45MPa and 265.6MPa respectively. As the simulation result at case 1 approaches the experimental result, all simulation results can be verified in order to apply into analyzing the impact properties of the honeycomb aluminum foam sandwiches. In cases of three kinds of impact energies, the striker is not shown to penetrate the upper face sheets of case 1. At the impact energy of 100 J, the striker is not shown to penetrate the upper face sheets of case 2. At the impact energies of 200 J and 300 J, the striker is shown to penetrate the upper face sheets of case 2. It is thought to predict and improve the structural safety the composite material combined with the aluminium foam by using this study result.

In this study, in order to improve the efficiency of n-type monocrystalline solar cells with an Alu cell structure, we investigate the effect of the amount of Al paste in thin n-type monocrystalline wafers with thicknesses of 120 μm, 130 μm, 140 μm. Formation of the Al doped p+ layer and wafer bowing occurred from the formation process of the Al back electrode was analyzed. Changing the amount of Al paste increased the thickness of the Al doped p+ layer, and sheet resistivity decreased; however, wafer bowing increased due to the thermal expansion coefficient between the Al paste and the c-Si wafer. With the application of 5.34 mg/cm2 of Al paste, wafer bowing in a thickness of 140 μm reached a maximum of 2.9 mm and wafer bowing in a thickness of 120 μm reached a maximum of 4 mm. The study’s results suggest that when considering uniformity and thickness of an Al doped p+ layer, sheet resistivity, and wafer bowing, the appropriate amount of Al paste for formation of the Al back electrode is 4.72 mg/cm2 in a wafer with a thickness of 120 μm.

본 논문에서는 탄소성 영역 내 패치 로딩 크기에 따른 알루미늄 합금 사각형 판의 초기 처짐 영향을 수치해석방법으로 이용한 탄성 및 탄소성 대변형 시리즈 해석을 수행하였다. 주변 지지조건은 단순지지로 가정하고 초기 처짐 크기(w/t), 종횡비(a/b), 세장비(b/t)를 고려하여 알루미늄 합금 A6082-T6 사각형 판의 임계 탄성 좌굴하중과 좌굴 후 거동을 검토하였다. 탄성 및 탄소성 대변형 시리즈 해석은 상용프로그램을 사용하였다. 초기 처짐 크기가 작을 경우 하중증가와 함께 면내 강성이 처음부터 감소하며 크기가 커질수록 훨씬 두드러지게 발생한다. 종횡비가 커질수록 초기항복강도는 점차 감소하며 판 두께가 두꺼울수록 패치 로딩 크기(l/b) 0.5 이후 초기 항복강도 감소비율은 얇은 두께보다 더 크게 발생한다.

The porous metallic material has the most superior physical property and the best mechanical capability. This study is investigated with the simulation analysis by compressing three kinds of specimens. Three aluminum foams with the thickness of 10 mm are bonded at Case 1. Two aluminum foams with the thicknesses of 10 mm and 20 mm are bonded at Case 2. It is one aluminum foam with the thickness of 30 mm at Case 3. The two dimensional model is done by ANSYS design modeler and the finite element analysis is performed by ANSYS structural analysis. As the forced displacement of 1 mm during the elapsed time of 60 sec is applied, the forced displacement of 10 mm during the total elapsed time of 600 sec is applied. As the analysis result, the most reaction force is shown at case 2 among three cases. Case 2 is estimated as the best structure. The analysis result of this study is thought to be the data necessary for the safe design about mechanical structure and the development of composite material.

Recently, the light weight and the safety of automobile are the important targets of automotive design and the parts for car have been substituted the plastic or the porous material for the steel material. As the aluminium foam has many pores at its surface, it has the fatigue property of bonded face which differs from general material. In this study, two dimensional model is designed and performed with the fatigue analysis as the variable(θ value) becomes the slant angle of bonded face at the specimen with the aluminium foam. As the analysis result on the models with the slant angles of 6°, 8° and 10°, the bonding forces are disappeared when the fatigue loads are repeated during 4000 cycle, 4500cycle and 5000cycle respectively. By comparing with the analysis results of three models, the fatigue cycle to endure fatigue load becomes larger as the slant bonded angle becomes higher. So, the structural safety can be seen by applying only as only a simulation of finite element method instead of the experiment where much cost and time is spent. In this study, the configuration of aluminum foam is designed with the shape of TDCB Mode II. The shear fatigue strength of the bonded structure can be evaluated by the analysis program of ANSYS.

투명 전도성 산화물로서 알루미늄과 붕소가 함께 도핑된 아연산화물(AZOB)이 900℃에서 분무 열분해법에 의해 제조되었다. 얻어진 마이크론 크기의 AZOB 분말은 알루미늄, 붕소 및 아연의 수용액으로부터 얻어진다. 분무 열분해로 얻어진 마이크론 크기의 AZOB 분말은 700℃에서 두 시간동안의 후 소성 과정과 24 시간 동안의 볼 밀링을 통해 나노 크기의 AZOB으로 변환된다. AZOB을 구성하는 일차 입자의 크기를 Debye-Scherrer 식에 의해 계산하였고 압축된 AZOB 펠렛의 표면 저항을 측정하였다.

Aluminum flows into the river from the abandoned mine leachate, industrial wastewater, and sewage and is responsible for acute toxicity in aquatic organisms. Recently, the number of reports have indicated the increased toxicity in a variety of aquatic organisms’ due to the aluminum toxicity. In this study, we reviewed the toxicity of aluminum on aquatic invertebrates, fishes and amphibians and suggested the guideline for management of aluminum residues in aquatic environment and strategies for aluminum toxicity evaluation. In aquatic animals aluminum complexes evoke gill dysfunction primarily, the cytotoxicity, genotoxicity, oxidative stress, disruption of endocrine function, reproductive success, metabolism and homeostasis. Notably, at environmentally relevant concentration, aluminum complex can alter the hormone levels in fish in acidic condition. Further, since the solubility of aluminum is higher in the acidic and basic conditions, thus it is likely that the toxic effects of aluminum may not only occur in acidic water near the abandoned mines but also in lakes and rivers, where pH is raised by algal bloom.

본 연구에서 해양플랜트 구조물에 주로 사용하고 있는 알루미늄 합금 A6082-T6의 재료특성을 반영한 사각형 판에 대한 패치 로딩의 구조 안정성 문제를 검토하였다. 구조 안정성 문제를 검토 시 네 가지 패치 로딩 형태와 종횡비 효과, 주변지지조건을 적용하여 임계 탄성 좌굴하중을 산출하였다. 고유치 좌굴해석 간 사용한 요소는 4절점 쉘요소 shell181을 적용하였다. 패치 로딩을 받는 판은 균일 축 압축하중과 비교 시 상이한 탄성 좌굴거동이 발생되는 것을 관찰할 수 있었으며 하중형태와 위치, 종횡비 효과 등과 같은 변수에 대해 상당히 영향을 받고 있는 것을 확인할 수 있다. 또한, 종횡비(a/b) 1.0, 하중길이(rb) 200 mm 단순지지 사각형 판에서 패치 로딩 형태에 따른 임계 탄성좌굴하중은 67 %(하중 I), 119 %(하중 II), 76 %(하중 III), 160 %(하중 IV)이 각각 산출되었으며 하중 I과 III은 하중 II와 IV보다 훨씬 더 탄성 좌굴거동에 강한 것으로 판단할 수 있다.

Nowadays, the automotive industry has target to improve the fuel consumption due to restricted exhaust gas regulation. For this reason, the applicability of lightweight material, Al alloys, Mg alloys are also being expanded. In this concept, high strength steel, DP780 and light alloy, AL5052 are joined in the right place of the car body. However, it is difficult to join to steel and aluminum by conventional fusion welding. Generally, in respect to dissimilar metal joining by fusion welding, intermetallic compound layer formed at joint interface; hot cracking in generated. To evaluate the welding quality, tensile test and metallographic examination was carried. Especially, correlation between Heat per unit length and formation of intermetallic compound layer was minutely analyzed. Finally, optimal welding condition was selected for improvement of strength at weldment and practical use.

In this study, the specimen of tapered double cantilever beam(TDCB) with aluminum foam is designed and shearing fatigue strength is based on the investigation of static behaviour analysis under the condition of mode Ⅱ. These specimen models have length and width of 200 mm and 25 mm. The inclined angles of adhesive face at the specimens are 6°, 8 °and 10°. As the inclined angle becomes higher, the time for which the model can not be broken during fatigue load becomes longer. The shearing strength of TDCB bonded structure with aluminum foam applied by shearing fatigue load can be evaluated through finite element method.

In this study, the weldability of ADC12 FSW joints obtained by the load control type of the FSW machine is examined. The higher the tool plunge downforce the wider the range of the optimum FSW conditions is obtained. However, there is a limit of optimum range with increasing the tool plunge downforces. The three different types of defects are formed in ADC12 FSW joints, depending on the welding conditions. One is a large mass of flash due to the excess heat input, another is a cavity or groove-like defects caused by insufficient heat input and the other is a cavity caused by the abnormal stirring. As for the abnormal stirring, it is very clearly seen that the shape of the top part on the advancing side in the stir zone is completely different. For this type of defect, the effect of the tool plunge downforce is not significant, though the size of the defect due to insufficient heat input significantly is decreased with the increasing downforce