Multi-Corrugated Indented Foldcore Sandwich Panel for Energy Absorption

Sandwich panels, which consist of light core structure in middle and two outside skins, have been widely used for load bearing and energy absorption. Recently, origami foldcores, which can be used as light core structures in sandwich panels, are of interest of many for their open-channel design, continuous manufacturing process, and abundant number of design parameters in comparison with honeycomb and foams. However, one main drawback of origami foldcores is their relatively low energy absorbing capacity. In this paper, we propose a new origami foldcore design, which is based on a zigzag origami pattern known as Miura pattern. The new design has a multi-corrugated shape as its cross-section, and asymmetric dents in it. It achieves a more efficient failure mechanism with both shell buckling and inversing modes, and doubles the energy absorption of Miura pattern foldcore.

Optimal lined channel design

The optimum values of the section variables (side slope, bottom width, flow depth, and radius) for triangular, rectangular, trapezoidal, and circular channels are computed by minimizing the cost of the channel section. Manning's uniform flow formula is treated as the constraint of the optimization model. The cost function is arranged to include the cost of lining, the cost of earthwork, and the increment in the cost of earthwork with depth below the ground surface. The optimum values of section variables are expressed as explicit functions of unit cost terms. Unique values of optimum section variables are obtained for the case of minimum area or minimum wetted perimeter problems. Key words: open channel design, optimization, minimum cost, best hydraulic section.

Tractive force channel design aid

The Manning formula and the tractive force equation are combined and written in terms of dimensionless parameters. Predetermined solutions to this equation have been obtained and presented in chart form. Also, a mathematical expression is obtained that approximates the chart to determine the channel width explicitly.Key words: open channel, design, tractive force, erodible, shear stress.