Stiffened structures sandwich core

What kinds of configurations are possible for composite structures The most obvious is that of a fiber-reinforced laminate. With a laminate, we can change laminae orientations, stacking sequence, and laminae materials to arrive at a suitable structure. We can stiffen the laminate, or we can put a sandwich core in the middle of those laminae. We can do all of those possibilities, but recognize that we will also have, in vir-tuaiiy any structure, some kind of hoie or a cutout for some reason. Thus, we must have a procedure to place an appropriate amount of reinforcement around those cutouts so that ioad can be transferred around them. Without that reinforcement, the structure cannot do the job it is required to do. These various possibie configurations are shown in Figure 7-38. 

Out-of-plane joints have been reviewed by Junhou and Shenoi, mainly in the context of marine structures [47]. The most common marine topologies are the monocoque or top-hat stiffened structures, using single skin glass/ polyester or vinyl ester laminates, and the sandwich or double wall structures with a foam core. The authors illustrate six different kinds of out-of-plane joints used in this context with FRP. 

Li, G. and Muthyala, V.D. (2008) Impact characterization of sandwich structures with an integrated orthogrid stiffened syntactic foam core. Composites Science and Technology, 68, 2078-2084. 

Li, G. and Chakka, V.S. (2010) Isogrid stiffened syntactic foam cored sandwich structure under low velocity impact. Composites Part A Applied Science and Manufacturing, 41, 177-184. 

Next, we will present applications of the CTH scheme in several real-world composite stractures. They arc fiber reinforced syntactic foam cored sandwich structures, sandwich stractures with a continuous fiber reinforced grid stiffened syntactic foam core, and 3-D woven fabric reinforced polymer composite structures. Of course, the core or the polymer composite is based on the same thermosetting PSMP as discussed above. 

John, M. and Li, G. (2010) Self-healing of sandwich stmctures with grid stiffened shape memory polymer syntactic foam core. Smart Materials and Structures, 19, paper 075013 (12 pages). 

The main structural component of the SR.N4 (British Hovercraft Corporation) according to Powis (1973) is a large sandwich panel 40 m long, 23 m wide and about 1 m thick. The top and bottom skins of this sandwich panel are made of 2 5 mx 1 25 mx 37 mm sandwich panels which are bolted to an egg-box structure made from aluminium shear web with bonded stiffeners. The skin panels are of 6 4 mm and 3 2 mm cell aluminium honeycomb made from foil 0-05-0-076 mm thick. The higher density core is used in the more highly stressed areas. The superstructure of the craft is composed of two vertical beams running fore and aft, which are fabricated from this aluminium sheet with bonded stiffeners. The roof is one unsupported span between... 

Door panels have a sandwich structure consisting of aluminum or stainless steel surface plates and aluminum or paper honeycomb core bonded with two-part epoxy adhesives. On inspection lids, switchboard covers, and seat side panels, decorated aluminum sheets with melamine resin are bonded with second generation acrylic adhesives (SGAs) to aluminum frames or stiffeners. O Figure 47.9 shows the cross section of a railcar with adhesively bonded parts (Suzuki 2007). 

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