scholarly journals Impact. Estimation Method for Mixed Mode (I+II) Interlaminar Fracture Toughness of Composite Laminates under Low-Velocity Impact Loading.

2001 ◽  
Vol 50 (3) ◽  
pp. 235-241 ◽  
Author(s):  
Takayuki KUSAKA ◽  
Noriyo HORIKAWA ◽  
Masayoshi MASUDA ◽  
Shinichi ADACHI
Molecules ◽  
2019 ◽  
Vol 24 (18) ◽  
pp. 3367 ◽  
Author(s):  
Ling Chen ◽  
Li-Wei Wu ◽  
Qian Jiang ◽  
Da Tian ◽  
Zhili Zhong ◽  
...  

The effects of thermoplastic polyimide (PI) and polypropylene (PP) fibers and areal density of toughened layer on interlaminar fracture toughness and impact performance of carbon fiber/epoxy (CF/EP) laminated composites were studied. Mode I interlaminar fracture toughness (GIC) was analyzed via double cantilever beam (DCB) tests. When comparing for the toughener type, PI played a positive role in enhancing the mode-I fracture toughness, while PP was not effective due to the less fiber bridge formed during composite curing. The toughening effects of areal density of PI were further investigated by end notched flexure (ENF) testing and low velocity impact testing to better understand the toughening mechanisms. The results revealed that the toughening effect reached its best effectiveness when the areal density of toughened layer was 30 g/m2. Compared with the control group, GIC and GIIC of CF/EP laminated composite were increased by 98.49% and 84.07%, and Fmax and Ee were enhanced by 92.38% and 299.08% under low velocity impact. There is no obvious delamination phenomenon on the surface of laminates after low velocity impact, indicating the improved interlaminar and impact performance of laminated composite.


2018 ◽  
Vol 28 (2) ◽  
pp. 183-199 ◽  
Author(s):  
HN Dhakal ◽  
H Ghasemnejad ◽  
ZY Zhang ◽  
SO Ismail ◽  
V Arumugam

Flax fibre-reinforced unsaturated polyester composite laminates were fabricated by vacuum bagging process and their impact and post-impact responses were investigated through experimental testing and finite element simulations. Samples of 60 mm × 60 mm × 6.2 mm were cut from the composite laminates and were subjected to a low-velocity impact loading to near perforation using hemispherical steel impactor at three different energy levels, 25, 27 and 29 Joules. Post-impact was employed to obtain full penetration. The impacted composite plates were modelled with various lay-ups using finite element software LS-DYNA (LS-DYNA User’s Manual 1997) to provide a validated finite element model for the future investigation in the field. The effects of impact and post-impact on the failure mechanisms were evaluated using scanning electron microscopy. Parameters measured were load bearing capability, energy absorption and damage modes. The results indicate that both peak load and the energy absorption were reduced significantly after the post-impact events. Consequently, it was observed from the visual images of the damages sites that the extent of damage increased with increased incident energy and post-impact events.


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