Failure of composites to projectile impact
Major failure modes of thick laminated composites were identified upon examination of ballistically impacted composite panels. Materials covered in the study include glass and Kevlar reinforced composites. Impact velocities range from 2,000 to 4,000 feet per second. A simplified spring-mass analytical model based on an equivalent energy dissipating system was developed to solve an idealized ballistic impact/penetration process for generic thick fiber-reinforced composites. The projectile is assumed to have mass and can deform elastoplastically. A punching shear damage process, which represents the major mode of energy absorption during high velocity impact and, in turn, is responsible for the deceleration of the projectile, has been idealized by a inner spring. The equivalent variable mass of the composite target is included by considering the 2-D shear wave propagations and its effective stiffness represented by a second nonlinear spring stiffness. At some point during the penetration process, delamination and subsequent bending failures may dominate. An approach determining when primary delamination initiates and extension of primary delamination is taken within the scope of this effort. The problem is formulated spatially and solve numerically under the framework of a finite element approach, and temporarily under finite difference. Projectile penetration and target deflection are calculated as a function of time. Based on this proposed model, a preliminary composite armor design concept can be established.
- OSTI ID:
- 175199
- Report Number(s):
- CONF-950686-; TRN: 95:006111-0120
- Resource Relation:
- Conference: Joint applied mechanics and materials summer meeting, Los Angeles, CA (United States), 28-30 Jun 1995; Other Information: PBD: 1995; Related Information: Is Part Of AMD - MD `95: Summer conference; PB: 520 p.
- Country of Publication:
- United States
- Language:
- English
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