Response of Composite Cylinders Subjected to Near Field Underwater Explosions
Experiments were conducted on woven E-glass/epoxy roll wrapped cylinders in three configurations; base composite, and base composite with a thin (100 % composite thickness) and thick (200 % composite thickness) polyurea coating. Each cylinder configuratio
- PDF / 505,634 Bytes
- 5 Pages / 595.276 x 790.866 pts Page_size
- 101 Downloads / 218 Views
Response of Composite Cylinders Subjected to Near Field Underwater Explosions E. Gauch, J. LeBlanc, C. Shillings, and A. Shukla Abstract Experiments were conducted on woven E-glass/epoxy roll wrapped cylinders in three configurations; base composite, and base composite with a thin (100 % composite thickness) and thick (200 % composite thickness) polyurea coating. Each cylinder configuration was subjected to near-field UNDEX loading at charge standoff distances of 2.5 cm and 5.1 cm inside of a large diameter test tank. Results show that the application of a polyurea coating is effective for reducing damage in the cylinders. Keywords Composite • UNDEX • Near Field • Polyurea • Shock
21.1
Introduction
Composite materials have several characteristics which make them particularly appealing in marine environments such as high strength to weight ratios and superior resistance to corrosion. When structures composed of composite materials are fielded in a marine environment they may be subjected to harsh loading conditions such as UNDEX loading, both near and far field in addition to operational loads. Maximizing the benefit of these materials, particularly for minimum weight, requires a full understanding of the response of these materials to such loadings in order to avoid overly conservative designs. Studies on the response of composites subjected to UNDEX have generally focused on far field loading in which the encroaching shock front is nearly planar and there is no interaction between the UNDEX bubble and the structure. LeBlanc and Shukla [1, 2] have studied the response of both flat and curved E-glass/epoxy composite plates to far field loading both experimentally and computationally. In [3] Avachat and Zhou investigated the response of monolithic as well as sandwich structure composite cylinders to underwater impulsive loading. Mouritz, et al., [4], conducted a study of the development of damage in a glass reinforced composite subjected to underwater explosive loading at increasing pressures. Near-field loading is generally characterized by a spherical shock front impinging upon the structure as well as interaction of the UNDEX bubble and the target structure. This can lead to highly localized damage and response in the structure rather than the more global character of the far field loading. In LeBlanc, et al., [5], coated and non-coated flat E-glass/epoxy plates were subjected to near field UNDEX loading. Deflections and damage extents were compared across the plate configurations. Brett, et al., [6, 7], presented a study of steel cylinders subjected to near field UNDEX. They observed that at standoff distances less than the UNDEX bubble radius the bubble was attracted to the cylinder and collapsed upon it resulting in a significant structural response. Recently polyurea has found interest as a potential blast mitigating coating. It is an easy to apply polymer that becomes quite stiff at high rates of loading. Several studies have been conducted to determine polyurea’s ability to reduce structural response to b
Data Loading...
