SIMULASI NUMERIK DAN ANALISIS RESPONS PELAT CFRP DAN GFRP LAMINATE DENGAN VARIASI PARAMETER LAPISAN TERHADAP IMPAK BALISTIK

• Main Author: Ezekiel Halor Jatmiko, Fito
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/66847
• Institution: Institut Teknologi Bandung

Composite’s main characteristics as a strong yet lightweight material has been the main reason for its ever-expanding implementation and steady development. One of those implementations is as a structural protection against ballistic impact. The understanding of energy absorbing mechanisms, damage modes, and ballistic resistance of composites upon receiving a high-velocity ballistic impact must be developed and explored so that in the end, a more reliable and cost-effective ballistic protection design made out of composites can be made. When exposed to a ballistic impact, composites sustain several kinds of damage modes such as fiber breakage, matrix cracking, delamination and interfacial debonding which happens as the composite plates undergoes shear plugging, cone deformation, and petalling due to the impact. The finite element method numerical simulation research will be done to evaluate how the different characteristics of CFRP and GFRP laminate plates affects the ballistic response or performance from a 9x19 mm MU1-TJ bullet moving with an initial velocity of 380 m/s. The composite plates are modelled in meso-scale with tiebreak contact for the interlaminar bond, whereas the projectile is modelled as a rigid body with an eroding contact definition. The ballistic response that would be evaluated comprises of the projectile’s residual velocity, absorbed energy, and damage modes. Analysis is done to eight variation of plate thickness, with two kinds of each CFRP and GFRP material. A parametric study is also carried out. Observed aspects involves the change in material strength and material elongation at break. It is also perceived how the difference of tension, compression, and shear strength would affect the ballistic performance. Other parameters are also studied: SOFT, FBRT, and BETA. The simulation is conducted using nonlinear explicit software LS-DYNA. Results shows that the increase of thickness creates an almost linear increase in ballistic performance. CFRP plates which have the biggest strength to weight ratio has the relative best ballistic performance with a high specific energy absorption (SEA) value. Damage modes on CFRP are shown to be more localized and brittle, whlist GFRP plates shows a bigger damage and clearer deformation. Ballistic performance of a composite plate are observed to have a strong relation with material toughness. The parametric study has shown that tension strength plays a bigger role in increasing ballistic performance when compared to compressive and shear strength. More than that, it’s been observed that the increase of strength affects the ballistic performance more than the increase of the material’s capability to strain (elongation at break). Lastly, the rest of the parametric studies result in SOFT having an influence to the energy absorption values whilst FBRT and BETA don’t result in any significant change.