scholarly journals Enhanced impact energy absorption and failure characteristics of novel fully thermoplastic and hybrid composite bicycle helmet shells

2021 ◽  
pp. 110003
Author(s):  
Somen K Bhudolia ◽  
Goram Gohel ◽  
Elisetty Shanmuga Bala Subramanyam ◽  
Kah Fai Leong ◽  
Pierre Gerard
1997 ◽  
Author(s):  
Hongyu Jia ◽  
Frederic Lalande ◽  
Roger Ellis ◽  
Craig Rogers ◽  
Hongyu Jia ◽  
...  

Author(s):  
Mehrdad Hossein Alizadeh ◽  
Mehdi Kamali Dolatabadi ◽  
Saeed Shaikhzadeh Najar ◽  
Reza Eslami-Farsani

2010 ◽  
Vol 26 (1) ◽  
pp. 23-29 ◽  
Author(s):  
Darin R. Lunt ◽  
Deborah A. Mendel ◽  
William A. Brantley ◽  
F. Michael Beck ◽  
Sarandeep Huja ◽  
...  

2015 ◽  
Vol 76 (3) ◽  
Author(s):  
Noor Haznida Bakar ◽  
Koay Mei Hyie ◽  
C.M. Mardziah ◽  
N.R. Nik Roselina ◽  
Nik Rozlin Nik Masdek

This research focuses on the reinforcement of Kevlar in treated kenaf composite, specifically in the study of impact properties as well as the characteristics. The kenaf was treated with 6% Sodium Hydroxide (NaOH) solution at a specific period of time before being made into laminates. Impact test was conducted using an instrumented drop tower device at 36J level according to the standard ASTM D7136. Microstructures of the fractured specimens were also analyzed. The results of the study indicated that treated kenaf/Kevlar hybrid composite has better impact absorption energy than pure kenaf composite. Compared to the pure kenaf composite, the hybrid composite absorbs more impact energy and appears to have lower impact damage at the same impact energy level. This is because the Kevlar fibres play an important role to prevent and delay the destruction of composites.


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).


2009 ◽  
Vol 1 (1) ◽  
pp. 38-45 ◽  
Author(s):  
John D. Currey ◽  
Tomas Landete-Castillejos ◽  
Jose A. Estevez ◽  
Augusto Olguin ◽  
Andres J. Garcia ◽  
...  

2021 ◽  
Vol 1165 ◽  
pp. 47-64
Author(s):  
Saurabh S. Kumar ◽  
Rajesh G. Babu ◽  
U. Magarajan

In this paper, the post ballistic impact behaviour of kevlar-glass fibre hybrid composite laminates was investigated against 9×19 mm projectile. Eight different types of composite laminates with different ratios of kevlar woven fibre to glass fibre were fabricated using hand lay-up with epoxy matrix. Ballistic behaviour like ballistic Limit (V50), energy absorption, specific energy absorption and Back Face Signature (BFS) were studied after bullet impact. The results indicated that as the Percentage of glass fibre is increased there was a linear increment in the ballistic behaviour. Addition of 16% kevlar fabric, composite sample meets the performance requirement of NIJ0101.06 Level III-A. Since the maximum specific energy absorption was observed in Pure Kevlar samples and the adding of glass fibre increases the weight and Areal Density of the sample, further investigations need to be carried out to utilize the potential of glass fibre for ballistic applications.


2019 ◽  
Vol 953 ◽  
pp. 88-94
Author(s):  
Mohamed Zahran ◽  
Mostafa Abdelwahab

Due to the rapid scientific and technological developments in the aerospace industry, the requirement for safety and energy absorption efficiency is increasing, and in order to achieve that target, the analyzing of the sudden crash is required to know how to reduce it. Therefore, the main objective of the present work is to analyze the crashing response of the hybrid composite fuselage structure during different impact landing conditions. Moreover, extract the maximum acceleration at the most important locations in the UAV fuselage where most of the critical system is installed. The explicit non-linear finite element software LS-DYNA/WORKBENCH ANSYS is chosen to simulate the crushing of the referenced and the proposed UAV fuselage and investigate the maximum crushing accelerations responses on the payload under different landing conditions. The numerical results show that strengthen the fuselage structure using hybrid composite material has a notable effect on the energy absorption, and transferred acceleration on the payload. Moreover, the hybrid composite fuselage structure can reduce the transferred acceleration on the payload up to 39.65% in comparison with the metal fuselage. In addition, to study the crash analysis during sudden accidents is very important, in order to find the way to reduce it, but can’t avoid it. Hence, the UAV payload should be arranged to avoid the maximum acceleration.


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