The Effect of Crystallinity on the Impact Properties of Advanced Thermoplastic Composites

Author(s):  
D. Leicy ◽  
P. J. Hogg
2018 ◽  
Vol 38 (1) ◽  
pp. 31-45 ◽  
Author(s):  
Gaye Kaya

This study aims to compare the low-velocity impact and post-impact properties of intra-ply hybrid carbon/E-glass/polypropylene non-crimp thermoplastic composites with non-hybrid carbon/PP and E-glass/PP non-crimp thermoplastic composites. Impact test was performed at four energy levels as 15 J, 30 J, 45 J and 60 J. Post-impact properties of hybrid thermoplastic composites were tested by compression after impact method for each energy level to understand the impact damage tolerance of intra-ply hybrid carbon/E-glass/PP non-crimp thermoplastic composites. The effect of hybridization on energy absorption of composites was not significant, while C-scan results showed that the intra-ply hybrid non-crimp thermoplastic composites had smaller impact damage areas in comparison to the non-hybrid samples. Compression and compression after impact tests results confirmed that the intra-ply hybridization increased the toughness of the composite laminates. Also, the residual compression strength/modulus increased with hybridization which indicated to damage tolerance.


2021 ◽  
pp. 089270572110214
Author(s):  
Muhammad Imran Khan ◽  
Muhammad Umair ◽  
Rizwan Hussain ◽  
Mehmet Karahan ◽  
Yasir Nawab

During impact, thermoset composites show brittle behaviour, whereas thermoplastic composites show a relatively ductile behaviour with higher absorption of impact energy. The research on the investigation of the impact performance of composites with thermoplastic resin and/or with a blend of thermoplastic and thermoset resins found rare. In the present study, both thermoset (phenolic, vinyl ester) and thermoplastic (Polyvinyl butyral – PVB) matrices were used with Para-aramid reinforcement for the development of five-layered composite samples. Drop weight impact, Charpy impact, flexural (three-point), and hardness tests were conducted to assess the performance of the composite samples. The developed thermoplastic composites showed superior impact properties as compared to thermoset composites except for out-of-plane deformation (trauma). This deformation was reduced using a blend of PVB and Phenolic. The composite made with blend absorbs 8–9% more energy as compared to Phenolic composites with almost the same value of trauma. Overall, damage area is also lesser in the case of composite made using a blend. The experimental results are validated by one-way ANOVA (Tukey) statistical analysis.


Author(s):  
Fatemeh Alizadeh ◽  
Navid Kharghani ◽  
Carlos Guedes Soares

Glass/Vinylester composite laminates are comprehensively characterised to assess its impact response behaviour under moisture exposure in marine structures. An instrumented drop weight impact machine is utilised to determine the impact responses of dry and immersed specimens in normal, salted and sea water. The specimens, which had three different thicknesses, were subjected to water exposure for a very long period of over 20 months before tested in a low-velocity impact experiment. Water uptake was measured primarily to study the degradation profiles of GRP laminates after being permeated by water. Matrix dissolution and interfacial damage observed on the laminates after prolonged moisture exposure while the absorption behaviour was found typically non-Fickian. The weight of the composite plates firstly increased because of water diffusion up to month 15 and then decreased due to matrix degradation. The specimens with 3, 6 and 9 mm thickness exhibited maximum water absorption corresponding to 2.6%, 0.7% and 0.5% weight gain, respectively. In general, the results indicated that water uptake and impact properties were affected by thickness and less by water type. Impact properties of prolonged immersed specimens reduced remarkably, and intense failure modes detected almost in all cases. The least sensitive to impact damage were wet specimens with 9 mm thickness as they indicated similar maximum load and absorbed energy for different impact energies.


Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3613
Author(s):  
Baohui Yang ◽  
Yangjie Zuo ◽  
Zhengping Chang

Foams are widely used in protective applications requiring high energy absorption under impact, and evaluating impact properties of foams is vital. Therefore, a novel test method based on a shock tube was developed to investigate the impact properties of closed-cell polyethylene (PE) foams at strain rates over 6000 s−1, and the test theory is presented. Based on the test method, the failure progress and final failure modes of PE foams are discussed. Moreover, energy absorption capabilities of PE foams were assessed under both quasi-static and high strain rate loading conditions. The results showed that the foam exhibited a nonuniform deformation along the specimen length under high strain rates. The energy absorption rate of PE foam increased with the increasing of strain rates. The specimen energy absorption varied linearly in the early stage and then increased rapidly, corresponding to a uniform compression process. However, in the shock wave deformation process, the energy absorption capacity of the foam maintained a good stability and exhibited the best energy absorption state when the speed was higher than 26 m/s. This stable energy absorption state disappeared until the speed was lower than 1.3 m/s. The loading speed exhibited an obvious influence on energy density.


2015 ◽  
Vol 158 ◽  
pp. 325-328 ◽  
Author(s):  
A.R. Dabiri ◽  
R. Yousefi Mojallal ◽  
E. Ahmadi ◽  
M. Fattahi ◽  
S. Amirkhanlou ◽  
...  

2018 ◽  
Vol 51 (1) ◽  
pp. 64-74 ◽  
Author(s):  
Akar Dogan ◽  
Yusuf Arman

In this study, the effects of temperature and impactor nose diameter on the impact behavior of woven glass-reinforced polyamide 6 (PA6) and polypropylene (PP) thermoplastic composites were investigated experimentally. Impact energies are chosen as 10, 30, 50, 70, 90, 110, 130, and 170 J. The thickness of composite materials is 4 mm. Impact tests were performed using a drop weight impact testing machine, CEAST-Fractovis Plus, and the load capacity of test machine is 22 kN. Hemispherical impactor nose diameter of 12, 7, and 20 mm were used as an impactor. The tests are conducted at room temperature (20°C and 75°C). As a result, the PP composites of the same thickness absorbed more energy than PA6 composites. The amount of absorbed energy of PP and PA6 composites decreased with temperature.


2021 ◽  
Vol 802 ◽  
pp. 140671
Author(s):  
Maverick Giovagnoli ◽  
Marialaura Tocci ◽  
Annalisa Fortini ◽  
Mattia Merlin ◽  
Matteo Ferroni ◽  
...  

2019 ◽  
Vol 38 (2019) ◽  
pp. 362-369 ◽  
Author(s):  
Ming-ming Song ◽  
Yu-min Xie ◽  
Bo Song ◽  
Zheng-liang Xue ◽  
Nan Nie ◽  
...  

AbstractThe microstructures and impact properties of the heat affected zone (HAZ) in steel treated by rare earth (RE) under different welding processes were discussed. The effect of Al on the impact properties of the HAZ in RE treated steel was analyzed. It finds that when the welding t8/5 is smaller than 111 s, the main microstructure in steels is bainite/widmanstatten. The impact toughness of the HAZ is lower than that of the steel matrix. When t8/5 is more than 250 s, the microstructure is mainly acicular ferrite (AF) in the steel treated by RE, and the impact toughness of HAZ is obviously improved. Even under the welding processing with t8/5 about 600 s in RE treated steel can still obtain a lot of AF. While in the steel killed by Al and treated by RE, the main microstructure is parallel cluster of bainite/widmanstatten, and the impact toughness of HAZ is significantly lower than that of low-Al RE treated steel. Al can deteriorate the optimizing of RE treatment on HAZ.


2016 ◽  
Vol 838 ◽  
pp. 29-35
Author(s):  
Michał Landowski ◽  
Krystyna Imielińska

Flexural strength and low velocity impact properties were investigated in terms of possibile improvements due to epoxy matrix modification by SiO2 nanoparticles (1%, 2%, 3%, 5%, 7%wt.) in glass/epoxy laminates formed using hand lay-up method. The matrix resin was Hexion L285 (DGEBA) with Nanopox A410 - SiO2 (20 nm) nanoparticle suspension in the base epoxy resin (DGEBA) supplied by Evonic. Modification of epoxy matrix by variable concentrations of nanoSiO2 does not offer significant improvements in the flexural strength σg, Young’s modulus E and interlaminar shear strength for 1% 3% and 5% nanoSiO2 and for 7% a slight drop (up to ca. 15-20%) was found. Low energy (1J) impact resistance of nanocomposites represented by peak load in dynamic impact characteristics was not changed for nanocompoosites compared to the unmodified material. However at higher impact energy (3J) nanoparticles appear to slightly improve the impact energy absorption for 3% and 5%. The absence or minor improvements in the mechanical behaviour of nanocomposites is due to the failure mechanisms associated with hand layup fabrication technique: (i.e. rapid crack propagation across the extensive resin pockets and numerous pores and voids) which dominate the nanoparticle-dependent crack energy absorption mechanisms (microvoids formation and deformation).


Sign in / Sign up

Export Citation Format

Share Document