• Journal of the Korean Society for Precision Engineering
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• v.16 no.4 s.97
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• pp.13-18
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• 1999

섬유강화금속적층재(Fiber Reinforced Metal Laminates. FRMLs)는 고강도금속과 섬유강화복합재료(Fiber Reinforced Composite Materials)를 적층한 새로운 종류의 하이브리드 재료이다. 국산 아라미드 섬유인 헤라크론(Heracron, 코오롱)과 국내 복합재료 제작기술(한국화이바)을 사용하여 섬유강화금속적층재를 제작하고, 이를 HERALL(Heracron Reinforced Aluminum Laminate)이라 명명하였다. HERALL(Heracron Reinforced Aluminum Laminate)의 피로균열성장특성 및 피로균열진전 방해기구를 ARALL(Aramid-fiber Reinforced Aluminum alloy Laminates) 및 Al 2024-T3과 비교해석하였다. HERALL과 ARALL은 균열진전을 저지하는 아라미드 섬유로 인해 뛰어난 피로균열성장특성 및 피로저항성을 보여주었다. 아라미드 섬유의 균열브리드징으로 인한 $K_{max}$의 감소량과 Al 2024-T3의 균열닫힘으로 인한 $K_{max}$의 증가량을 구할 수 있는 응력-COD법을 사용하여 실제로 균열성장에 영향을 준 유효응력확대계수범위를 측정하였다. 균열선단으로부터 균열을 가공하면서 COD 변화량을 측정하여 균열브리징 영역을 구하였다.

• Composites Research
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• v.12 no.4
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• pp.42-54
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• 1999

FMLC(Fiber-Metal Laminate Composites) is a new structural material combining thin metal laminate with adhesive fiber prepreg, it nearly include all the advantage of metallic materials, for example: good plasticity, impact resistance, processibility, light weight and excellent fatigue properties. This research studied the optimum design of the FMLC subject to various loading conditions using genetic algorithm. The finite element method based on the shear deformation theory was used for the analysis of FMLC. Tasi-Hill failure criterion and Miser yield criterion were taken as fitness functions of the fiber prepreg and the metal laminate, respectively. The design variables were fiber orientation angles. In genetic algorithm, the tournament selection and the uniform crossover method were used. The elitist model was also used to be effective evolution strategy and the creeping random search method was adopted in order to approach a solution with high accuracy. Optimization results were given for various loading conditions and compared with CFRP(Carbon Fiber Reinforced Plastic). The results show that the FMLC is more excellent than the CFRP in point and uniform loading conditions and it is more stable to unexpected loading because the deviation of failure index is smaller than that of CFRP.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2001.11a
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• pp.349.2-363
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• 2001

안전성의 측면에서 기계설비 및 구조물의 파손을 유발할 수 있는 재료손상에 대한 평가는 매우 중요하기 때문에, 사용 목적에 부합되는 우수한 첨단재료의 개발과 그 특성을 파악할 필요성이 있다 그 중에서 섬유강화 복합재료는 금속재료보다 높은 비강도와 비강성을 가지며 적층각도, 적층순서 및 경화방법에 따라서 원하는 강도와 강성을 가질 수 있다 특히, 탄소섬유강화복합재료(CFRP)는 스포츠용품에서 최신 항공기의 구조재료에 이르기까지 경량화 관점에서 기존의 재료를 대체해 나가고 있다.(중략)

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.10
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• pp.963-970
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• 2015

Laminate structures are used in the automobile, aerospace, and display industries. The advantages of fiber metal laminates are well known. Fiber metal laminates are useful for reducing the weight and improving impact resistance . However, currently, the mechanical properties of fiber metal laminates are not derived. In this paper, we use thickness as a factor for comparing the properties of laminates of various thickness combinations. The properties fiber metal laminates are analyzed using design of experiments. In addition, the finite element method is used to analyze elastic and plastic strains of fiber metal laminates and aluminum plates. The final goal of this paper is to find a suitable finite element model of fiber metal laminates under bending.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1378-1381
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• 2003

Recently, high-performance composite materials have been used for various industrial fields because of their superior high strength, high stiffness and lower weight. In this study, manufactured fiber reinforced metal laminate materials are composed of two parts. One is hard-anodized A15083-O alloy as a face material and the other is high strength aramid fiber (Twaron CT709) and polyethylene fiber(Dyneema HB25) laminates as a back-up material. Resistance to penetration is determined by protection ballistic limit(V$\sub$50/, a static velocity with 50% probability for complete penetration) test method. V$\sub$50/ tests with 0$^{\circ}$ obliquity at room temperature were conducted with 5.56mm ball projectiles that were able to achieve near or complete penetration during high velocity impact tests.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.8
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• pp.881-887
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• 2012

CFRP composite materials have been widely used in various fields of engineering because of their excellent properties. They show high specific stiffness and specific strength compared with metallic materiasl. Woven CFRP composite materials are fabricated from carbon fibers with two orientation angles ($0^{\circ}/90^{\circ}$), which influences the mechanical properties. Therefore, woven CFRP composite materials show different types of fracture behavior according to the load direction. Therefore, the fracture behavior of these materials needs to be evaluated according to the load direction when designing structures using these materials. In this study, we evaluate the fracture strength of plain-woven CFRP composite materials according to the load direction. We performed tests for six different angles (load direction: $0^{\circ}/90^{\circ}$, $30^{\circ}/-60^{\circ}$, $+45^{\circ}/-45^{\circ}$) and estimated the fracture strength for an arbitrary fiber angle by using the modified Tan's theory and harmonic function.

• Composites Research
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• v.31 no.6
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• pp.332-339
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• 2018

Fiber metal hybrid laminate (FML) can be used as an economic material with superior mechanical properties and light weight than conventional metal by bonding of metal and FRP. However, there are disadvantages that it is difficult to predict fracture behavior because of the large difference in properties depending on the type of fiber and lamination conditions. In this paper, we study the failure behavior of hybrid materials with laminated glass fiber reinforced plastics (GFRP, GEP118, woven type) in Al6061-T6 alloy. The Al alloys were coated with GFRP 1, 3, and 5 layers, and fracture behavior was analyzed by using a static test and a low cycle fatigue test. In the low cycle fatigue test, strain - life analysis and the total strain energy density method were used to analyze and predict the fatigue life. The Al alloy did not have tensile properties strengthening effect due to the GFRP coating. The fatigue hysteresis geometry followed the behavior of the Al alloy, the base material, regardless of the GFRP coating and number of coatings. As a result of the low cycle fatigue test, the fatigue strength was increased by the coating of GFRP, but it did not increase proportionally with the number of GFRP layers.

• Composites Research
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• v.30 no.2
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• pp.158-164
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• 2017

The fiber metal laminate is a type of hybrid materials laminated thin metallic sheets with fiber reinforced plastic sheets. The laminate has been researched or applied in automotive and aerospace industries due to their outstanding impact absorbing performance in view of light weight aspect. Specially, the replacement of side-impact beam as the fiber reinforced plastic has been researched actively. The objective of this paper is the primitive investigation in the development of side-door impact beam using the fiber metal laminate. First, the three-point bending simulations were conducted to decide the shape of impact beam using the numerical analysis. Next, two cases impact beam (pure DP 980 and fiber metal laminate) were installed in the side-door, and then the bending tests (according to FMVSS 214S) were simulated using the numerical analysis. It is noted that the side-door impact beam can be replaced with the fiber metal laminate sufficiently based on the numerical analysis results.

• Composites Research
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• v.14 no.1
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• pp.47-56
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• 2001

In order to enhance high speed stability the composite air spindle system composed of a high modulus carbon fiber composite shaft, powder contained epoxy composite squirrel cage rotor and aluminum tool holder was designed and manufactured. For the optimal design of the composite air spindle system, the stacking sequence and thickness of the composite shaft were selected by considering the fundamental natural frequency and deformation of the system. The analysis gave results that the composite air spindle system had 36% higher natural frequency relative to a conventional air spindle system. The dynamic characteristics of the composite spindle system were compared with those of a conventional steel air spindle system. From the calculated and test results, it was concluded that the composite shaft and the power contained composite rotor were able to enhance the dynamic characteristics of the spindle system effectively due to the low inertia and high speific stiffness of the composite materials.

• Composites Research
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• v.20 no.4
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• pp.25-30
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• 2007

The advanced fiber-reinforced laminated composites are widely used in a variety of engineering applications such as aerospace, marine, mechanical and civil engineering for weight savings because of their high specific strength and stiffness. The material properties of ply is known to have larger variations than that of conventional materials and very sensitive to the loading direction. Therefore, it is important to consider the variations on designing the laminated composite. This paper demonstrates the importance of considering uncertainties through examining the effect of material properties variations on various design requirements such as tip deflection, natural frequency and buckling stress using COMSOL-MATLAB interface.