Directions for future research are also suggested. Target containing a 9 internal elliptical defects; and b 10 internal elliptical defects. Higher efficiency allows the armor system to be thinner and lighter weight, which in many cases, could be enabling factors for current and future ground and air platforms. It should be noted, however, that during the impact event, failure modes appear consistent. The sample plate is surrounded by a glass collar whose purpose is to eliminate converging unloading waves, and maintain uniaxial strain in the sample for the duration of the load pulse.
Hot pressing inherently has higher product yields due to reduced cracking and warping of the plates. Currently performed 3D simulation on targets containing conical surface defects tend to confirm this hypothesis. Projectile velocity measurements were obtained with infrared screens and counter chronographs. The ballistic resistance of the seams were tested under multi-hit conditions. Sample A was a hot pressed high density Sic specimen while sample B was a sintered Sic specimen containing 15 volume percent of a TiB2 additive. This meeting continued the tradition of an unclassified forum on an unprecedented international scale.
Ellingson, Rachel Lipanovich, Jeffrey Wheeler, and Chris Deemer. Table 11: Com ariso Sapphire thickness armor thickness mm mm it armor to ilass armor Thickness savings with sapphire armor 58 20. Observations are then made on the predicted penetration depth and damaged glass strength for borosilicate and soda lime glass with different constitutive models. As noted previously, the plate undergoes at least 20% shrinkage in every dimension during sintering. This may be a possible indication of changing of the polytype of S i c in the presence of a glassy phase. Figure 7 shows the size distribution of fragments having radii up to 30 microns. The next step was to number and label them individually to determine their properties Figures 3 and 10.
High and low amplitude regions in the C-scan image were examined using diced pieces from those areas. It is a collection of papers from The American Ceramic Society s 32nd International Conference on Advanced Ceramics and Composites, January 27-February 1, 2008. As mentioned before, the compressive forces associated with yielding occur below the surface, and are only minimally affected by surface condition. For the conditions of these experiments. Both processes require that the spinel powder be beneficiated, but in different ways. This is a valuable, up-to-date resource for researchers in industry, government, or academia who are working with ceramic armor. The 2-D Euler solver produced results for all defect shapes.
Hot pressing allows the materials to be formed to 100% of their theoretical density which is desirable for many contact-related applications because porosity can decrease the initiation force for apparent yielding. The band at 1023 cm-' can be attributed to the Si-0 asymmetric stretching vibration since it is similar in shapc to the band obscrved in amorphous silica', indicating the presence of a silicon oxide layer on the S i c powder. Constitutive Model for Damaged Borosilicate Glass Sidney Chocron, James D. Internal defects The simulation showed clearly that the internal defects have a reduced effect on the target resistance to penetration when compared to surface defects. Additionally, indenter-related considerations can arise with Hertzian indentation of hard ceramics. The cover plates had a central hole to allow the impacting rod to hit only glass. The measured average apparent yield loads and the calculated yield strengths determined from Eq.
Section through target showing damage around impact site. Determination of limiting distance interevent distance R The plateau that was mentioned above can be observed between the values of 20 pm to 30 pm. Nearest neighbor distance distributions enables us to determine the uniformity of a microstructure by comparing the distributions to that of a complete random case. Our results indicate that the larger decrease of the resistance to penetration caused by the presence of the surface defects may be attributed to the damage wave traveling through intact spinel before its exit from the spinel to the polyurethane. Substitution of calculated penetration velocity values into Eqn.
As the first step in the analysis. The initial observable indent in Hexoloy occurred at 300 N 6. Another remark is the largest sized features found in samples from the both regions. Typical dome green preforms are shown in Figure 6. Grain Boundary Engineering of Silicon Carbide by Means of Coprecipitation Steven Mercurio, Mihaela Jitianu, and Richard A. Figure I shows that we idealize the fragment crosssections as squares. However, Figure 4 shows that the delay simply reduces the first wave to low amplitude, resulting in a poor correlation.
Pure and Applied Mathematics, Vol. LaSalvia, Brian Leavy, Herbert T. Dandekar, and Daniel Casem Automated Nondestructive Evaluation System for Hard Armor Protective Inserts of Body Armor 21 1 Nicholas Haynes, Karl Masters, Chris Perritt, David Simmons, James Zheng, and James E. Penetration-time pf data with associated impact velocities for 38. These values were collected and plotted in histogram form based on the number of occurrences of each size y-axis and the size range x-axis.