Impact Response Of Fiber Metal Laminates And Aluminum Composite Sandwich Structures

Fiber metal laminates (FMLs) were prepared by laminating aluminum sheets with glass fiber-reinforced thermoplastic prepreg. The tensile properties of the FMLs were characterized using a Universal Test Machine (UTM). The sandwich structure consists of FMLs skin and polypropylene (PP) honeycomb...

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Bibliographic Details
Main Author: Tan, Chin Yeong
Format: Thesis
Language:English
Published: 2013
Subjects:
Online Access:http://eprints.usm.my/43971/1/Tan%20Chin%20Yeong24.pdf
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Summary:Fiber metal laminates (FMLs) were prepared by laminating aluminum sheets with glass fiber-reinforced thermoplastic prepreg. The tensile properties of the FMLs were characterized using a Universal Test Machine (UTM). The sandwich structure consists of FMLs skin and polypropylene (PP) honeycomb core is then subjected to flexural test to determine its flexural properties prior to drop-weight impact tests. Force-time history were recorded and analyzed from the impact test. Comparisons between aluminum (AL) skin and FMLs on impact response were investigated using various impact-sensitive parameters such as impact force-time history, maximum impact load, contact duration and total absorbed energy. It was found that both skin types showed plateauing of maximum impact force occurred at impact energy higher than 12.36J. This suggested that the impact damage threshold energy for both skin types with PP honeycomb core sandwich structure are 12.36J. However, FMLs samples showed a better energy absorbing capabilities compared to AL samples. It was found that the contact duration was significantly higher for samples which show global bending on the structure. Post-impact damage evaluations were also carried out by comparing the damage area between optical and C-scan method. As a result, C-scan was able to produce a more accurate measurement of damage area compared to optical method. Plate-like structure of FMLs samples showed higher maximum impact loads when compared to beam-like structure. However, absorbed energy remained higher in the beam-like structure. The post-impact damage area for platelike structure showed linear increase while beam-like structure shows a plateauing at approximately 1200mm2 due to the bending of the structure. Comparison also showed that 20mm core thickness sample has the highest amount of absorbed energy compared to 30 and 40mm. By increasing the temperature, maximum impact force recorded has dropped under the same impact energy, being lowest at the 50°C and highest at the -10°C. However, the energy absorbed for the sandwich structure increased when the temperature was raised. The damage area at 25°C and 50°C shows almost the same measurement of damage area, however, it is more likely that the damage is more severe at 50°C due to the bending on the structure.