• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2001년도 춘계학술발표대회 논문집
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• pp.268-271
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• 2001

When compared to other composite materials such as FRP and MMC, hybrid composite material is more attractive one due to the high specific strength and the resistance to fatigue. However, the fracture mechanism of hybrid composite material is extremely complicated because of the bonding structure of metals and FRP. Recently, nondestructive technique has been used to evaluate the fracture mechanism of these composite materials. In this study, AE technique has been used to clarify the fracture mechanism and the degree of damage for Al 7075/CFRP hybrid composite material. It was found that AE event, energy and amplitude among AE parameters were effective to evaluate fracture process of Al 7075/CFRP composite material. In addition, the relationship between the AE signal and the characteristics of failure surface using optical microscope was discussed.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2000년도 추계학술발표대회 논문집
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• pp.67-70
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• 2000

This study was performed to investigate the material behavior of hybrid thermoplastic composites contained glass fiber and calcium carbonate. The composite was prepared with each combination ratio of calcium carbonate, and the content of glass fiber was fixed with 10% by weight. In order to investigate the material behavior for various combination ratio, tension test, flexural test, and impact test were performed. Microscopic observation were conducted to examine the fractured surface of specimen for tension test. And the material behavior of the hybrid thermoplastic composite immersed in salt water with definite time was investigated.

• Structural Engineering and Mechanics
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• 제85권5호
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• pp.573-592
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• 2023

This paper presents a careful theoretical investigation into interfacial stresses in composite aluminum-slab reinforced concrete beam bonded by a prestressed hybrid carbon-glass composite material. The model is based on equilibrium and deformations compatibility requirements in and all parts of the strengthened beam, i.e., the aluminum beam, the slab reinforced concrete, the hybrid carbon-glass composite plate and the adhesive layer. The theoretical predictions are compared with other existing solutions. Numerical results from the present analysis are presented both to demonstrate the advantages of the present solution over existing ones and to illustrate the main characteristics of interfacial stress distributions. It is shown that the stresses at the interface are influenced by the material and geometry parameters of the composite beam. This research is helpful for the understanding on mechanical behaviour of the interface and design of the hybrid structures.

• 한국안전학회지
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• 제24권2호
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• pp.23-29
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• 2009

The hybrid composite materials are recently used in many field as an advanced material due to their high resistance to fracture. However, hybrid composite materials have several problems, especially delamination, compared with homogeneous materials such as an aluminum alloy, etc. In this study, we carried out the tensile test to study the tension failure appearances and tensile ultimate strength of CFRP/Al/CFRP hybrid composite materials. The CFRP material used in the experiment is a commercial material known as CU175NS in unidirectional carbon prepreg. Also Al/CFRP/Al hybrid composites with three kind length of a single edge crack were investigated for the relationship between an aluminium volume fraction and a crack length. The crack length was measured by a traveling microscope under a universal dynamic tester. Futhermore the stress intensity factor behavior was examined according to a volume fraction and an initial crack length ratio to a width.

• Composites Research
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• 제15권5호
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• pp.1-6
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• 2002

하이브리드 복합재료는 FRP나 MMC와 같은 복합재료에 비하여 높은 비강도, 내피로 특성을 가지고 있기 때문에 많은 관심을 받고 있다. 그러나 하이브리드 복합재료는 금속과 FRP의 결합구조로 되어있기 때문에 매우 복잡한 파손기구를 가지고 있다. 최근에는 비파괴 기법을 이용하여 이러한 복합재료의 파손기구를 평가하고자 하는 연구가 수행되어지고 있다. 본 연구에서는 음향방출 기법을 이용하여 Al7075/CFRP 하이브리드 복합재료에 대한 손상정도 및 파손기구를 명확히 하고자 하였다. 특히 AE 사상수, 에너지, 진폭과 같은 AE 파라미터들은 Al7075/CFRP 하이브리드 복합재료의 파손과정을 평가하는데 효과적이었다. 더불어, 광학현미경을 이용하여 AE 신호와 시험편의 표면소상 특성과의 관계를 비교, 검토하였다.

• 한국염색가공학회지
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• 제35권1호
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• pp.29-41
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• 2023

This study is about a hybrid lightweight cowl crossbeam structure with high rigidity and ability to absorb collision energy to support the cockpit module, which is an automobile interior part, and to absorb energy during a collision. It is a manufacturing process in which composite material bracket parts are inserted and injected into existing steel bars. When considering the mounting condition of a vehicle, the optimization of the fastening condition of the two parts and the mechanical properties of the composite material is acting as an important factor. Therefore, this study is about a composite material having a volume content of Polyamide(PA) and Glass Fiber used as a composite material for a composite material-metal hybrid cowl crossbeam. As a result of analyzing the physical properties of the PA/GF composite material, experimental data were obtained that can further enhance tensile strength and flexural strength by using PA66 rather than PA6 used as a base material for the composite material. And based on this, it contributed to securing the advantage of lightening by using high-stiffness composite material by improving the high disadvantage of the weight of the cowl crossbeam material, which was made only of existing metal materials.

• 대한기계학회논문집A
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• 제26권11호
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• pp.2328-2335
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• 2002

A hybrid composite material has many potential usage due to the high specific strength and the resistance to fatigue, when compared to other composite materials such as fiber reinforced plastic(FRP) and metal matrix composite(MMC). However, the fracture mechanism of hybrid composite material is extremely complicated because of the bonding structure of metals and FRP. In this study, Al 7075 sheets and carbon epoxy preprags were used to fabricate the hybrid composite. Recently, nondestructive technique has been used to evaluate the fracture mechanism of these composite materials. AE technique was used to clarify the microscopic damage behavior and failure mechanism of A17075/CFRP hybrid composite. It was found that AE paralneters such as AE event, energy and amplitude were effective to evaluate the failure process of Al 7075/CFRP composite. In addition, the relationship between the AE signal and the characteristics of fracture surface using optical microscope was discussed.

• Composites Research
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• 제32권1호
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• pp.13-20
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• 2019

본 연구에서는 전기 자동차의 주요 부품 중 하나인, Battery Module의 품질 Issue 및 부품특성 개선을 위해 복합재료를 사용하여 구조보강 하였으며, 단일소재의 단점을 극복할 수 있는 Hybrid 개념의 기구 구조 최적화를 수행하고 성능을 비교하였다. 이를 위해 고전 적층 판 이론(Classical Laminated Plate Theory, CLPT)에 따른 복합재료 주요 설계 변수 도출 및 복합재료 물성 예측 알고리즘에 대해 연구하였으며, 설계된 복합재료의 기계적 물성을 바탕으로 유한요소해석(FEM)을 통해 Battery Module의 성능을 검증하였다. 이를 통해 자동차 Battery 부품의 안정성 및 경량화 등의 부품 특성 개선 여부를 확인할 수 있었다. 최종적으로 검증결과에 따르면 Selective Composite Patch로 보강된 Hybrid Battery Module은 기존 Al Battery Module에 비해 30%의 중량 감소 및 제품 두께 32.5%를 줄일 수 있고, 충격 성능 유지 등 Hybrid 구조의 장점을 입증하였다.

• 한국철도학회논문집
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• 제7권2호
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• pp.77-84
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• 2004

In order to determine the most suitable material system for achieving the lightweight design while fulfilling the design requirements of carbody structures of Korean Tilting Train eXpress(TTX), aluminum carbody. composite carbody, and hybrid carbody combined with aluminum and composite structures were considered in the present study. The finite-element analysis was used to verify the design requirements or the TTX carbody structures with the material system considered in the design stages. The stresses in the carbody structures and deflections of underframe against static load cases were used as design criteria. The results show that the hybrid carbody structures are beneficial with regard to weight savings and structural integrity in comparison to aluminum and composite carbody structures.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2002년도 추계학술발표대회 논문집
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• pp.79-82
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• 2002

A finite element method based on the two-dimensional progressive failure analysis considering material nonlinearity is presented for characterizing the strength and failure of the unidirectional-fabric hybrid laminated composite joints under pin loading. The 8-node laminated shell element is incorporated in the updated Lagrangian formulation. Failure criteria including the Maximum Stress and Tsai-Wu are used in conjunction with the complete unloading stiffness degradation method. For the verification, joint tests are conducted for the specimens with two different ply-number ratios of UD composite to fabric composite. Although there are some differences depending on ply-number ratios, the finite element model using the maximum stress criterion considering nonlinear material behavior predicts the failure strength best.