Impact Behavior Of Fiber Metal Laminates Research Articles

Influence of impactor shape on low-velocity impact behavior of fiber metal laminates combined numerical and experimental approaches

Abstract Fiber metal laminates (FMLs) are fabricated with composite laminates and metallic alloys. This paper systematically investigates the influence of impactor shape on the low-velocity impact response of FMLs by combining the experimental and numerical methods. A series of impact experiments are conducted to study the low-velocity impact behavior of different FMLs under various impactor shapes and impact energies. The commercially available digital image correlation measuring system is applied to scan the exterior deformations of FMLs after impact. Subsequently, a progressive damage model based on the Hashin and Yeh delamination failure criteria is employed to characterize the damage evolution and failure mechanisms of composite materials through a user defined subroutine (VUMAT) in ABAQUS/Explicit. The study's results demonstrate that the impact behavior of FMLs is strongly dependent on impactor shape, impact energy and metal layer distribution. For the complete penetration case, the smooth perforation resulted from shear effect occurs in FMLs impacted by blunter impactor, while the petaloid cracks caused by tensile tearing damage appears for sharper impactor case in the process of penetration. The predicted results for different impact cases show a good comparison with experimental results in terms of impact loads, total absorbed energies and damage morphologies, which indicate that the numerical simulation could be a helpful tool to evaluate the impact response of FMLs.

Investigation on impact behavior of FMLs under multiple impacts with the same total energy: Experimental characterization and numerical simulation

This paper aims to investigate the low-velocity impact behavior of fiber metal laminates (FMLs) consisting of carbon fiber-reinforced layers and aluminum sheets under multiple impacts with the same total energy. Experimental and numerical methods are implemented to explore the influence of impact energy division, load sequence and metal layer distribution on multiple impact behavior and damage morphologies of FMLs. A series of repeated drop impact tests with different impact energy combinations are implemented on FMLs. Subsequently, an integrated numerical model based on multiple consecutive steps is established to characterize the damage accumulation and failure mechanisms of FMLs, in which a user defined subroutine VUMAT, is developed to consider the stiffness degradation and damage evolution of composite material. The numerical predictions show a good correlation with the corresponding experimental results. The results reveal that multiple impacts with lower energy division and smaller initial impact energy can cause minor damage in FMLs. Generally, the impact load, energy absorption, damage morphologies and the interfacial delamination are closely related to the magnitude, sequence and division of impact energy. In addition, the strain hardening of aluminum sheets after first impact can improve the stiffness of FMLs, and further strengthen the impact resistance significantly.

Fabrication of high-stiffness fiber-metal laminates and study of their behavior under low-velocity impact loadings

This study investigates the impact behavior of fiber-metal laminates (FMLs) (Carbon FMLs and Glass FMLs), which were fabricated by using high-stiffness steel, carbon prepreg, and glass prepreg through autoclave molding. The mechanical behavior of the FMLs was evaluated by performing tensile, compressive, in-plane shear, and low-velocity impact tests. Drop-weight impact tests were conducted to induce cracking of the FMLs, and the crack initiation along with crack propagation behavior of the different laminate sequences ([0/0], [0/90], [0/90/0], [90/0/90] and [0/90/90/0]) were also studied. The results show that the fabricated FMLs have higher strength and stiffness than conventional FMLs. Their impact strengths increased, and weights decreased simultaneously. The absorption energy was proportional to the crack length that was induced by the low-velocity impact. Moreover, it was found that the fiber orientation mainly affected the direction of crack propagation in the FMLs. This investigation facilitates the design of high-stiffness and lightweight FMLs for automotive parts.

Simulation on impact response of FMLs: effect of fiber stacking sequence, thickness, and incident angle

Abstract We built a three-dimensional finite element (FE) model to investigate the impact response of fiber-metal laminates (FMLs). This FE model comprises two metal layers as facesheets and a carbon woven fabric-reinforced plastic laminate as inner core. Simulation was performed on ABAQUS/Explicit platform, and stiffness progressive degeneration criteria were implemented to evaluate damages in composites. The Johnson-Cook model was selected to calculate failures in metal, while surface-based cohesive behavior was adopted to simulate the delamination phenomenon. We studied the fiber stacking sequence, panel thickness, and incident angle effect on the impact behavior of FMLs. The critical penetration energy of the FMLs was determined, and the impact parameter history was discussed.

섬유/금속 적층판의 저속 충격 거동

섬유금속 적층판(FMLs)은 손상허용도를 향상시키고 무게를 줄이는데 적합하여 항공우주 응용의 신소재로 각광을 받고 있다. 본 연구에서는 우선 섬유와 알루미늄을 이용하여 적층판을 제조하여 인장시험을 수행 후 FMLs의 기계적 물성을 평가하였다. 또한 알루미늄과 섬유적층의 변화를 주어 낙추충격시험기(Drop Weight Impact Tester)를 이용하여 저속충격하에서 낙추 높이를 조절하여 각 종류의 시험편 마다 충격시간에 따른 하중과 충격흡수에너지를 각각 비교하였다. 추가로 유한요소해석을 이용하여 시험조건과 동일 조건하 인장과 충격거동해석을 수행한 결과를 실험치와 비교하여 실험과 이론해석이 잘 일치함을 보였다. The Fiber/Metal Laminates (FMLs) have been developed as a new composite material for aerospace application to reduce weight and improve damage tolerance. In this study, firstly FMLs were manufactured and the tensile test was performed to investigate the mechanical properties of FMLs. Furthermore, impact behavior of the low velocity on FMLs which consisted of different types of aluminum or fiber/epoxy layers was tested by the drop weight impact tester based on the different impact energy conditions. The load-time and energy-time curves were employed to evaluate the impact performance of different specimens. Moreover, finite element analysis (FEA) was also performed to simulate the tensile test and impact behavior of FMLs under the same conditions with the tests and good agreements have been obtained between the FEA predictions and experimental results.