Preparation and Ballistic Performance of a Multi-Layer Armor System Composed of Kevlar/Polyurea Composites and Shear Thickening Fluid (STF)-Filled Paper Honeycomb Panels

In this study, the ballistic performance of armors composed of a polyurea elastomer/Kevlar fabric composite and a shear thickening fluid (STF) structure was investigated. The polyurea used was a reaction product of aromatic diphenylmethane isocyanate (A agent) and amine-terminated polyether resin (B agent). The A and B agents were diluted, mixed and brushed onto Kevlar fabric. After the reaction of A and B agents was complete, the polyurea/Kevlar composite was formed. STF structure was prepared through pouring the STF into a honeycomb paper panel. The ballistic tests were conducted with reference to NIJ 0101.06 Ballistic Test Specification Class II and Class IIIA, using 9 mm FMJ and 44 magnum bullets. The ballistic test results reveal that polyurea/Kevlar fabric composites offer better impact resistance than conventional Kevlar fabrics and a 2 mm STF structure could replace approximately 10 layers of Kevlar in a ballistic resistant layer. Our results also showed that a high-strength composite laminate using the best polyurea/Kevlar plates combined with the STF structure was more than 17% lighter and thinner than the conventional Kevlar laminate, indicating that the high-strength protective material developed in this study is superior to the traditional protective materials.

Dynamic cushioning energy absorption of paper composite sandwich structures with corrugation and honeycomb cores under drop impact

The paper composite sandwich structure with corrugation and honeycomb cores has been widely used in civil and national defense industries, and the cushioning energy absorption characteristic is a key indicator to evaluate the performance of this composite structure. Therefore, this paper is focus on the influences of honeycomb thickness on the shock acceleration response and deformation characteristics to analyze cushioning energy absorption performance of the composite structure by various experimental tests. The experimental result shows that, the paper corrugation layer firstly comes into crushed, and then the paper honeycomb layer is crushed. Additionally, the large honeycomb thickness may cause the secondary collapse of paper honeycomb layer. Under the same impact energy or impact mass, the cushioning energy absorption of the single-sided composite sandwich structure is better than that of the double-sided structure with the same honeycomb thickness. However, the impact resistance of the double-sided composite structure is better than that of the single-sided structure. For the paper composite sandwich structures with the honeycomb thicknesses 10, 15, 20 and 25 mm, the increase of honeycomb thickness would decrease the cushioning energy absorption of the whole structure under the drop impact with low energy. However, under the drop impact with high energy, the influence of honeycomb thickness on cushioning energy absorption is contrary. For the paper composite sandwich structure, the specific energy absorption, unit volume energy absorption, and stroke efficiency for the honeycomb thicknesses 10, 15, 20 and 25 mm are higher than those for the honeycomb thickness 70 mm. Therefore, the low honeycomb thickness is more advantageous for the cushioning energy absorption of paper composite sandwich structure.

Mechanical Properties Of Glass Fibers Reinforced Composites: A Concise Review

The utility of composites in today’s modern world is not hidden from anyone. From tiny objects like football to aerospace, everything involves the use of composites. Composites nearly form the backbone of our society. Composites are basically made from matrices and reinforcement. Out of the majority of reinforcement being used, Glass fibers usage cannot be neglected. These are made of fine fibers of glass (made of SiO2). They are used to reinforce various materials like arrows, bows and crossbows, translucent roofing panels, tent poles, boat hulls and paper honeycomb. This review paper is a study of various research papers related to mechanical properties of glass fibers when used with different type of matrices namely, tensile strength, impact strength and flexural strength.

Lightweight Panel for Building Construction Based on Honeycomb Paper Composite/Core-Fiberglass Composite/Face Materials

Lightweight panels for indoor constructions are typically made from composite materials with honeycomb and corrugated structures. The reinforcements are used in this study, one is fiberglass and the other is cellulose fiber, which cellulose from recycled paper. Experimental results indicate that the weight of honeycomb paper panel is light, only 13.6% of fiberglass composite and 32.6% of plywood. The presence of honeycomb structure has a significant effect on mechanical behaviors of composite panels. Both flexural and compressive strengths increase by replacing corrugated structure into honeycomb structure. During compression, the compressive strength and modulus of two-layer honeycomb/core panel are higher than those of monolayer honeycomb/core. Particularly, the honeycomb cell-wall thickness has a little effect on the weight, but has an important effect on mechanical properties. These results can be created low cost and lightweight environment-friendly panels by using recycled paper honeycomb structure.