Analysis of Folded Plate Structures Composed of [$45^{\circ}$/$-45^{\circ}$/$-45^{\circ}$/$90^{\circ}$/$45^{\circ}$/$45^{\circ}$/$-45^{\circ}$]r Type Laminated Composites Plates

$45^{\circ}$/$-45^{\circ}$/$-45^{\circ}$/$90^{\circ}$/$45^{\circ}$/$45^{\circ}$/$-45^{\circ}$r 복합재료 적층판으로 구성된 사각단면 절판구조물의 구조해석

The theory of non-prismatic folded plate structures was reported by the senior author in 1965 and 1966. Fiber reinforced composite materials are strong in tension. The structural element for such tension force is very thin and weak against bending because of small bending stiffnesses. Naturally, the box type section is considered as the optimum structural configuration because of its high bending stiffnesses. Such structures can be effectively analyzed by the folded plate theory with relative ease. The "hollow" bending member with uniform cross-section can be treated as prismatic folded plates which is a special case of the non-prismatic folded plates. Tn this paper, the result of analysis of a folded plates with one box type uniform cross-section is presented. Each plate is made of composite laminates with fiber orientation of [ABBCAAB]$_r$, with A=-B=$45^{\circ}$, and C=$90^{\circ}$. The influence of the span to depth ratio is also studied. When this ratio is 5, the difference between the results of folded plate theory and beam theory is 1.66%. is 1.66%.