Grid-stiffened structures

Huybrechts SM, Hahn SE, Meink TE. Grid-stiffened structures a survey of fabrication, analysis and design methods. In Proceedings of 12th international conference on composite materials (ICCM), Paris France 1999. 

Huybrechts, S.M., Meink, T.E., Wegner, P.M., and Ganley, G.M. (2002) Manufacturing theory for advanced grid stiffened structures. Composites Part A Applied Science and Manufacturing, 33, 155-161. 

Fiber reinforced thermosetting polymer composites have been used in the form of laminate, sandwich, grid stiffened, stitched, Z-pinned, three-dimensional (3-D) woven fabric, and hybrid structures. In addition to carrying the designed static/dynamic loads, most composite stmcmres experience some kind of low or high velocity impact incidents during their life cycle. A low velocity impact is not uncommon. For example, dropping a tool on to a composite stmcmre... 

Jadhav, P. and Mantena, P.R. (2007) Parametric optimization of grid-stiffened composite panels for maximizing their performance under transverse loading. Composite Structures, 77, 353-363. 

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). 

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. 

In the following, we will present the test results of this new grid stiffened smart sandwich structure for closing (healing) low velocity impact induced damages. 

Figure 6.47 Grid weaving, fabrication, and finished grid stiffened sandwich structure. Source [47] Reproduced with permission from lOP Publishing...

Li, G. and Cheng, J.Q. (2007) A generalized analytical modeling of grid stiffened composite structures. Journal of Composite Materials, 41, 2939-2969. 

Core support structure The grid plate is supported on the core support structure (CSS) which also supports the shielding subassemblies via the auxiliary grid plate and the irmer vessel. It is a radially stiffened structure supported on the main vessel bottom by a cylindrical shell. 

Core support structure design with square grids at the central portion and radial stiffeners around the periphery has been recommended. Structural integrity assessment has demonstrated that even with the absence of the most critical radial stiffener, the reduction of rigidity of the structure is within the acceptable limits from reactivity insertion considerations. 

---