Ballistic Damage Assessment of a Thin Compound Curved B4C Ceramic Plate Using XCT

Abstract

Not all ceramic armor plates are flat. The current study looks at characterizing ballistic impact damage in a thin boron carbide, B4C, body armor torso plate with a compound curvature impacted by lead core rifle ball ammunition. The non-invasive characterization and visualization of this impact damage was conducted post-mortem using previously established x-ray computed tomography, XCT, diagnostic techniques [1-11]. Despite being impacted from three separate hits, the ceramic plate remained essentially intact. Our initial and in-situ damage observations include: large cratering on the impacted B4C front surface, three complete penetrations of B4C plate but apparently not through the composite backing plate, substantial bulging on the rear of the composite backing plate at each hit location, extensive mesoscale cracking and ceramic fragmentation in the B4C plate, and multiple small high density projectile fragments embedded in the composite backing plate. These qualitative and quantitative ballistic impact damage initial results are reported and discussed along with 2D and 3D virtual images. The results are considered significant in permitting the cognitive visualization of such in-situ impact damage and thus aid in improving our understanding of both the physical damage and penetration manifestations in such a target. INTRODUCTION The non-invasive x-ray computed tomography, XCT, diagnostics of impact damage in terminal ballistic laboratory target materials of relatively simplistic shapes has been explored and reported by the authors and their collaborators for the past decade [1-11]. In the present work, the authors have applied the non-invasive XCT diagnostic modality to the inspection of ballistic impact damage in a commercially produced compound curved body armor torso plate assembly consisting of a B4C ceramic plate adhered to an organic composite backing plate. This target had been impacted by three successive shots of lead core rifle ball ammunition prior to our examination. The purpose of this work was not to qualify the body armor target materials or configuration, but rather, to demonstrate the feasibility of the XCT inspection modality to provide a more comprehensive, yet still non-invasive, characterization of resulting internal impact damage in a realistic body armor component. BACKGROUND Currently, the quality assurance inspection techniques generally applied during the manufacturing stage of body armor ceramic components are visual, metrological, and projection x-ray (i.e. film or digital) modalities. In-service or post-battle damage inspection results are not well documented in the open literature. In any case, internal inspections, before or after impact, are normally conducted either with destructive and/or non-destructive 2-dimensional approaches. Similarly, 2-D examination modalities are most frequently utilized in the laboratory research and development stages of various armor materials and their architectural designs. Page 1 of 8