scholarly journals Flat nose low velocity drop-weight impact response of carbon fibre composites using non-destructive damage detection techniques

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Umar Farooq ◽  
Peter Myler

AbstractThis work is mainly concerned with the nondestructive post-impact damage evaluation of carbon fibre reinforced laminated composite panels subject to low velocity drop-weight impact by flat and round nose impactors. Quasi-isotropic laminates consisting of eight-, sixteen-, and twenty-four plies were impacted by flat and round nose impactors at different velocity levels. Load-time history data were recorded and plotted to correlate loaddrop as damage level to the impactor nose profiles. Test produced data, non-destructive damage detection techniques: visual, ultrasonic, and eddy- current, and computer simulations were utilised to identify and quantify status of the impact induced damage. To evaluate damage in relatively thick laminates (consisting of 24-Ply), the damage ratios and deflection quantities were correlated to the corresponding impactor nose profiles. Damage induced by the flat nose impactor to thick laminates was compared against the data produced by the round nose impactor. Results show that relatively thin laminates were largely affected by the impactor nose. Reasonable difference was observed in damage caused by flat and round impactor nose profiles to thick laminates impacted at relatively higher velocity impacts. Resultswere compared and validated against simulation produced data.

2020 ◽  
Vol 55 (33) ◽  
pp. 15741-15768 ◽  
Author(s):  
Haibao Liu ◽  
Jun Liu ◽  
Yuzhe Ding ◽  
Jie Zheng ◽  
Xiangshao Kong ◽  
...  

Abstract The present paper describes the results from experimental and theoretical modelling studies on the behaviour of continuous carbon fibre/polymer matrix composites subjected to a relatively low-velocity or high-velocity impact, using a rigid, metallic impactor. Drop-weight and gas-gun tests are employed to conduct the low-velocity and high-velocity impact experiments, respectively. The carbon fibre composites are based upon a thermoplastic poly(ether–ether ketone) matrix (termed CF/PEEK) or a thermoset toughened epoxy matrix (termed CF/Epoxy), which has the same fibre architecture of a cross-ply [03/903]2s lay-up. The studies clearly reveal that the CF/PEEK composites exhibit the better impact performance. Also, at the same impact energy of 10.5 ± 0.3 J, the relatively high-velocity test at 54.4 ± 1.0 m s−1 leads to more damage in both types of composite than observed from the low-velocity test where the impactor struck the composites at 2.56 m s−1. The computationally efficient, two-dimensional, elastic, finite element model that has been developed is generally successful in capturing the essential details of the impact test and the impact damage in the composites, and has been used to predict the loading response of the composites under impact loading.


2021 ◽  
Author(s):  
Betül Kafkaslıoğlu Yıldız ◽  
Murat Büyük ◽  
Yahya Kemal Tür

Abstract 1 vol% Ni particulate Al2O3 matrix nanocomposites prepared by the heterogeneous precipitation method with ZrO2 (5 vol%) or Cr2O3 (1 vol%) additives were subjected to the low energy drop weight impact tests to compare the behavior of the compositions under low energy impact and to investigate the damage mechanisms. The pure Al2O3, Al2O3/Ni, Al2O3/ZrO2, and Al2O3/Cr2O3 compositions with the same additive ratios were also produced to make the comparison systematically. Also, the Vickers hardness measurements were carried out and a significant increase in hardness was attained for both Al2O3/Ni + ZrO2 and Al2O3/Ni + Cr2O3. The average hardness value around 24.8 ± 1.0 GPa was measured for Al2O3/Ni + ZrO2 and Al2O3/Ni + Cr2O3 which means ∼ 15% improvement compared to the pure Al2O3. Between all the compositions, the maximum force (Fmax) value was obtained for Al2O3/Ni + ZrO2 for 12 J impact energy level (26617 N) according to the low energy drop weight impact test results. Tensile radial crack network formation, cone formation, fracture and crushing of the cone structure were observed as damage mechanisms for all the compositions. The volume of conical frustum structure was evaluated for each composition and the effect of microstructure on possible ballistic performance was also discussed.


2021 ◽  
Vol 118 (5) ◽  
pp. 501
Author(s):  
Yulong Liu ◽  
Dexin Ding ◽  
Wenguang Chen ◽  
Nan Hu ◽  
Lingling Wu ◽  
...  

The relationship between energy input and particle size of ore samples after crushing and effect of microwave pretreatment on impact crushing of lead-zinc ore were studied by drop weight impact test. The results showed that the lead-zinc ore became softer and had higher degree of crushing after microwave pretreatment. Compared with continuous microwave pretreatment, pulsed microwave pretreatment could improve the drop weight impact crushing efficiency of lead-zinc ore. When the specific comminution energy were 5 kW h/t, 10 kW h/t respectively, the crushing characteristic parameters t10 were 60.42% and 67.46% respectively by continuous microwave. But the values of t10 were increased to 68.64% and 75.88% respectively after pulsed microwave radiation under same microwave power and time. In addition, water quenching could more promote the impact crushing efficiency of lead-zinc ore after microwave irradiation.


2017 ◽  
Vol 25 (9) ◽  
pp. 677-682 ◽  
Author(s):  
Faruk Elaldi ◽  
Busra Baykan ◽  
Can Akto

For the last three decades, composites have become very preferable materials to be used in the automotive industry, structural parts of aircraft and military systems and spacecraft, due to their high strength and modulus. Composite materials are sometimes exposed to invisible or visible damage due to impact loading during their service life. In this study, the effect of impactor geometry with four different contact surfaces on woven carbon fibre-reinforced composite plates having three different thicknesses are investigated. In the first stage, composite plates were manufactured with the ply orientations of [45/-45/0/90/45/-45]2s, [45/-45/0/90/45/-45]3s, [45/-45/0/90/45/-45]4s based on conventional usage. In the second stage, carbon fibre-reinforced composite test panels were exposed to low velocity impact tests to obtain force-time, energy-time and force-displacement curves. Finally, semi and full penetration of composite panels and damage magnitude were determined. It was found that the impactor geometries with lower contact surfaces such as conical and ogive types were much more penetrative on composite plates than the other geometries, but they caused larger damage area in the vicinity of the impact point.


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