In this study, tapered double cantilever beam bonded with aluminum foam composite is modelled and analyzed by finite element analysis. The bonding strength on Mode II of this structure is evaluated and investigated. In cases of inclined angles of 6°, 8° and 10°, maximum equivalent stresses occur 1.29, 1.59 and 2.6 MPa respectively at the range of forced displacement of 5 to 6 mm. And maximum reaction forces become 186, 208 and 235 N individually at this range of displacement in these cases. By the analysis result on 3 kinds of models, the maximum reaction load increases as angle of inclination of model increases. And the elapsed time to approach the maximum load and the time to disappear away become shorter. This study result can be applied into the real composite structure with aluminum foam in case that the surface bonded with adhesive is inclined. This fracture behavior can also be investigated and the impact property can be examined

차량, 수송, 조선 등 많은 산업이 발전함에 따라 기계장치를 구성하고 있는 각종 재료의 특성 또한 날로 발전하고 있다. 과거 단순 강만 사용하여 기계를 설계하던 것과 달리 현재는 특수합금강과 복합재료를 사용하여 기계의 성능을 향상시키고 있다. 이처럼 많은 산업 분야에서 재료의 특성을 파악하여 적시 적소에 사용하여 기계를 설계하는 것은 기계설계자들에게 매우 중요한 과제가 되었다. 본 논문에서는 알루미늄 폼 복합재료로 된 TDCB(이중외팔보) 시험편의 파괴 거동을 시뮬레이션 해석과 실험 검증하였다. 실험과 해석에 사용된 모델은 영국 공업규격과 ISO국제규격에 의거한 3D 형태로 하였다. θ=12°일 때의 해석 결과로 한쪽 Beam이 일정한 속도로 이동하면서 접착력에 대한 반력이 발생하는데 Beam이 약 5mm 이동하였을 때 약 270N의 최대 반력이 나타나는 것을 볼 수 있다. 본 연구에서는 실험과 유한요소법을 통한 비교분석으로 물성데이터를 확보하고, 실험결과와 해석결과의 유사성을 검증하여 보다 쉽고 빠른 소재의 특성을 파악하는 방법을 검증해 보았다.

Britsh StandardBS 7991)에 명시된 DCB 시험편을 본 연구에 맞게 수정 후 두께 25mm, 35mm, 45mm, 55mm, 그리고 65mm의 DCB시험편을 제작하였다. 이 후 시험편을 Single-lap 방식으로 접착한 후 정적실험에서 도출된 최대 전단력을 각 시험편에 10Hz로 피로하중을 가하였다. 실험 결과값에 대한 수치해석적 검증을 하고자 상용 해석 프로그램인 ANSYS를 통해 실험과 동일한 시험편과 조건 하에 해석을 수행하였다. 접착력 해석을 하기 위해서 Mesh의 절점(node)들의 관계가 매우 중요하기 때문에 접착된 부분의 모든 절점들은 동일 선상에 있게 Mesh를 형성하였다. 실험 결과와 해석 결과를 비교해 본 결과 피로하중이 약 200cycle 반복되었을 때 최대 등가응력이 발생 하였고, 이때 전단방향으로 변위가 약 11mm 진전 된 것을 볼 수 있었다. 이후 4000cycle가량 피로하중이 반복 될 동안 변위는 일정하게 점점 증가한 후 피로하중이 약 4800cycle 반복 되었을 때 실험과 해석 데이터 모두 접착계면에서 완전한 전단 파괴가 일어난 것을 볼 수 있었다. 이때 변위는 약 20mm 진행 되었다. 해석을 통해 실험 데이터를 검증해 본 결과 두 결과 값은 완전 하게 같지는 않지만 유한요소법 해석 결과에 대한 신뢰를 확보 할 수 있었다. 이는 실제 구조물에 실험 없이 간단한 재료 물성치만으로도 해석을 통하여 구조적 안전성을 알아 볼 수 있는 한 방법이 될 수 있을 것이라고 사료된다.

Adhesive joint method has been used instead of welding, reveted joint, bolt and nut in various industry fields recently. Aluminum foam has hole or crack on adhesive interface which is different from common composite material. To investigate shear characteristic of adhesive interface between aluminum foams, double cantilever beams(DCB) with thicknesses of 25mm, 45mm and 65mm bonded with single-lab joints are designed. The relation between nodes at finite element model is important to investigate adhesive strength in this study. All meshes are generated and some nodes are located on adhesive zone along collinear axis. As reaction force obtained by static experiment is applied, fatigue analysis is carried with 10Hz. In advance, adhesive property is obtained by preliminary experiment for applying adhesive strength to input into simulation analysis. With these conditions, the analysis results show that 2.97MPa, 3.10MPa and 4.2MPa of maximum equivalent stresses are shown respectively in case model thicknesses are 25mm, 45mm and 65mm. By use of the simulation result at this study, it is possible to find adhesive behavior of aluminum foam and be applied to real adhesive joint structure without experiment by sparing experimental cost and time

In this study, simulation analyses on the impact property of aluminum foam are carried and verified by experimental results. When aluminum foams with thicknesses of 25mm and 35mm are applied by impact energy of 14J, impact energy and deformation happened at aluminum foam are investigated by comparing experimental and analysis results. Experimental and analysis results of deformations or absorbed impact energy become similar each other. After verifying these simulation results with experimental results, impact properties of aluminum foams with thicknesses of 45mm and 55mm are also investigated by simulation results. As impact properties of aluminum foam can be studied effectively through only simulation results, it is thought to spare much time and cost by investigating various impact properties of aluminum foams with simulation analysis.

This study aims to evaluate structural safety through FEM on the hollow shaft and the shaft filled with aluminum foam as the impact beam made of high tensile strength steel, Force reactions of impact beams are investigated when the forced displacement of 50mm is applied equally on two beams. When impact velocity of 80km/h is applied onto impact beams equally with the limit velocity of automobile on national road, how much impact energies can be absorbed by beams are also investigated. As study result, impact beams without aluminum foam and with aluminum foam show the maximum reaction forces of 15.53kN and 20.34kN respectively in case of the forced displacement of 50mm. As impact analysis result, impact beams without aluminum foam and with aluminum foam can absorb impact energies of 560J and 820J respectively. As impact beam with aluminum foam has reaction force and impact energy more than 23% and 30% than without aluminum foam, impact beam with aluminum foam has more safety than without aluminum foam.

알루미늄 폼을 볼트나 너트를 이용하여 체결한다면 경량성이 감소되므로 접착제로 접합하는 것이 가 장 효율적이다. 이런 알루미늄 폼 접착 구조물에 대한 충격 피로 특성과 접착 합면에 대한 파괴인성 연 구는 매우 부족하며 또한 중요하다. 이에 따라 본 연구에서는 알루미늄 폼으로 만들어진 DCB모델을 접 착제로 접합한 후 두께를 변수로 하여 25mm 부터 45mm까지 10mm차이를 두어 실험과 컴퓨터 시뮬레 이션을 통하여 수행하였다. 실험은 MTS사의 인장 시험기를 사용하여 강제 변위 100mm를 주어 변위에 따른 전단력을 알아보았고, 실험과 똑같은 조건하에 ANSYS를 이용하여 유한요소해석을 수행하였다. 실험과 유한요소해석 값을 비교하여 접착제로 접합된 알루미늄 폼 구조물의 접착 합면에 대한 파괴인성을 고찰하였다.

본 연구는 알루미늄 폼 복합재료로 접합된 TDCB 모델에 대해 구조적 시뮬레이션 해석을 하였다. 이 해석을 통하여 등가응력, 변형 에너지 및 접착부의 압력에 대한 자료를 얻었다. 또한 실험을 하여 해석 자료에 대한 검증을 하였다. 본 연구의 자료를 통해 알루미늄 폼 재질로 접합된 실제 복합재 구조물에 적용시켜 파괴거동을 분석하고 그 기계적인 특성을 파악할 수 있다.

Aluminum foam has many superb properties such as light weight, impact absorption and thermal resistance by comparing with original metallic materials. Composite materials made of aluminum foam have used at various fields as automotive bumper, shock absorption, vessel and aircraft. But it is inefficient to join aluminum foam with bolt and nut because of the property of light weight. In this study, this approach is investigated by joining aluminum foam with adhesive. Impact fatigue and failure toughness at the commissure of adhesive structure are studied by simulation analysis. This study aims to investigate the shear strength evaluation at shear mode of adhesively bonded joint with double cantilever beam(DCB) made of aluminum foam.

New material which absorbs impact energy effectively and has excellent mechanical property is developed. The used amount is increased at automobile field day by day. Aluminum foam with various air sell lattices within is one of representative porosity metals which are used at many automobile parts because it has the excellent lightness and impact energy absorption function. For this reason, aluminum foam is used widely as a component among composite materials. This study aims to investigate systematically the mechanical property of foam through computer simulation. In order to obtain the property of aluminum foam, aluminum foam is designed as the dimension of 100mm × 100mm × 25mm and the striker that has the diameter of 12.5mm is supposed to impact aluminum foam with impact energies of 6J, 10J, and 14J. Aluminum foam is not penetrated when striker given by energy of 6J or 10J impacts into it, but aluminum foam is penetrated by striker in case of impact energy of 14J. The result can provide the basic data in order to develop the advanced composite material.

four kinds of models designed by the basis of British industrial standard and ISO international standard in this study. Energy release rates at mode 1 are investigated by the fatigue analysis of aluminum foam TDCB model bonded with adhesive. These analysis models are compared each other by classifying four models into m values with 2, 2.5, 3 and 3.5. The value of m as the gradient of model is represented with the function of crack length(a) and height of model(h). Through the correlation relation, the fracture behavior of bonded material is analyzed and these analysis results can be applied to composite structures of various areas. Mechanical property and fracture toughness of composite material are also analyzed in this study.

This study aims to analyze the structural behavior on TDCB models bonded adhesively with aluminum foam composite. These simulation models are designed on the basis of British industrial and ISO standards. The variable of configuration factor(m) is set up to investigate the fracture toughness of bonded joint due to the volume of material. Equivalent stress, deformation energy, pressure at bonded part, reaction force-crack length, energy release rate-crack length are obtained by this analysis. Through the data of this study, the fracture behavior can be analyzed by applying the practical composite structure bonded with aluminum foam and the mechanical property can be understood.

Aluminum foam with porous material has the excellent mechanical property of light weight and impact absorption. It is necessary to obtain the information of fracture toughness at the adhesive work by the joint method. This study is investigated by fatigue analysis with DCB(Double Cantilever Beam) specimen models to evaluate the strengths at adhesive joints on the basis of British industrial and ISO international standards. 4 kinds of specimens are modelled by changing the height of specimen and the analysis results are compared with each other. As the height of specimen becomes lower, the displacement on the y direction, load and energy release rates become higher. Through the correlation obtained by this study result, fracture behaviors are examined and mechanical properties can be understood. Aluminum foam material bonded with adhesive can applied to the real composite structure by use of this study result.

Aluminum foam as porous material in wide use has the excellent mechanical and thermal properties. As adhesive process technique is used by bonding such composites as aluminum foam, fracture toughness at adhesive joint is the main point to investigate. In this study, DCB specimens are manufactured to evaluate the strengths at adhesive joints on the basis of British industrial and ISO international standards. Four kinds of specimens are made by changing the height of the specimen and these experimental results are compared with each other. Energy release rates are also calculated at mode I. As the hight of specimen becomes higher, reaction force and energy release rates become higher. Through the correlation obtained by this study result, aluminum foam material bonded with adhesive can be applied to the real composite structure and mechanical property and fracture toughness are analyzed systematically.

Aluminum foam with the property as the excellent impact absorption has been widely used recently. It is necessary to study fracture energy due to fracture toughness by the use of adhesive joint at aluminum foam. This study aims at strength evaluation about adhesive joint on aluminum foam and the fracture of bonded DCB model with this material property is analyzed by simulation. These models are designed by differing in height on the basis of British industrial and ISO standards. As the value of height at model is higher, bonded part is separated to the end. By comparing some analysis results with experimental data, these data could agree with each other. By the verification with experimental results, these all simulation results in this study can be applied on real composite structure with aluminum foam material effectively. The fracture behavior and mechanical property can also be examined by this study.