Ballistic impact analysis of balsa core sandwich composites

2014 ◽  
Vol 67 ◽  
pp. 160-169 ◽  
Author(s):  
N. Jover ◽  
B. Shafiq ◽  
U. Vaidya
Author(s):  
YAOKE WEN ◽  
GUANGYU CUI ◽  
JUNBIN ZHANG ◽  
CHENG XU ◽  
XUEYING HUANG

Author(s):  
Laura Ferrero ◽  
Ugo Icardi

A finite element simulation of impacts on sandwich composites with laminated faces is presented; it is based on a refined multilayered plate model with a high-order zig-zag representation of displacements, which is incorporated through a strain energy updating process. This allows the implementation into existing commercial finite elements codes, preserving their program structure. As customary, the Hertzian law and the Newmark implicit time integration scheme are used for solving the contact problem. The contact radius and the force are computed within each time step by an iterative algorithm which forces the impacted top surface to conform, in the least-squares sense, to the shape of the impactor. Nonlinear strains of von Karman type are used. As appearing by the comparison with experimental results, the present model is able to accurately predict the impact force, the core damage and the damage of face sheets in sandwich composites with foam and or honeycomb core. Moreover, this paper also assesses the accuracy and the range of application of stress based criteria in predicting the onset and evolution of delamination in service. These criteria are widespread by virtue of their low run time and storage costs, although no exhaustive proofs are known weather they are accurate enough for a reasonably wide range of applications. Since where highly iterative solutions are involved (e.g., impact and geometric, or material nonlinear problems) they are the only currently affordable failure models, it appears of primary importance to fill this gap. Aimed to contribute to the knowledge advancement in this field, a comparison is presented with more sophisticate fracture mechanics and progressive delamination models.


2012 ◽  
Vol 22 (2) ◽  
pp. 145-187 ◽  
Author(s):  
NK Naik ◽  
Santosh Kumar ◽  
D Ratnaveer ◽  
Makarand Joshi ◽  
Kiran Akella

An analytical model is presented for the ballistic impact behavior of ceramic-composite armors. The model is based on wave theory and energy balance between the kinetic energy of the projectile and the energy absorbed by different mechanisms. The armor analyzed consists of front composite cover layer, ceramic plate, rubber layer and the composite backing plate. The projectile is cylindrical. The major damage and energy-absorbing mechanisms are compression of the target directly below the projectile, compression in the surrounding region around the point of impact, formation of ring cracks and radial cracks in the ceramic leading to tensile failure, shear plugging, pulverization of the ceramic, tension in the yarns, delamination and matrix cracking in the composite, bulge formation on the back face of the composite backing plate and friction between the target and the projectile. Projectile erosion and deformation are also considered. Kinetic energy, velocity and deceleration of the projectile, distance traveled by the projectile and the contact force are presented as a function of time. Ballistic limit velocity, contact duration and damage progression are also given. Further, solution procedure is presented for the study of ballistic impact behavior of ceramic-composite armors. Analytical predictions are validated with the experimental results. Finally, performance of a typical ceramic-composite armor is presented.


Author(s):  
Rizal Zahari ◽  
John Regan Pillai ◽  
Andrew Ordys ◽  
Mohamed Thariq Hameed Sultan ◽  
Noorfaizal Yidris

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