Dynamic Characters of Stiffened Composite Conoidal Shell Roofs with Cutouts: Design Aids and Selection Guidelines

Table 3

Non-dimensional fundamental frequencies (𝜔) for laminated composite (0/90/0/90) stiffened conoidal shell for different sizes of the central square cutout and different boundary conditions.

Boundary conditions	Cutout size (𝑎^′/𝑎)
	0	0.1	0.2	0.3	0.4
CCCC	105.7679	118.9136	124.386	127.4786	124.4929
CSCC	79.3544	87.8992	91.4718	96.4778	97.0499
CCSC	104.0259	117.3182	120.8486	122.5918	119.586
CCCS	79.0009	86.457	91.1477	95.8592	97.0069
CSSC	76.7919	84.417	87.445	91.1546	90.359
CCSS	76.4645	83.126	87.1684	90.6361	90.3194
CSCS	70.8733	76.0322	80.215	86.5974	91.9972
SCSC	96.4607	106.1886	112.2644	116.5409	114.8718
CSSS	65.7562	69.5302	72.8659	77.5964	81.1403
SSSC	65.7398	70.72	75.0802	79.9808	82.2204
SSCS	62.3308	65.2487	69.3811	74.7187	80.4246
SSSS	54.7734	56.6793	59.276	62.3683	65.2097
Point supported	21.1813	21.686	22.6166	24.2309	25.5361

𝑎/𝑏=1, 𝑎/ℎ=100, 𝑎^′/𝑏^′=1, 𝑎/ℎ_ℎ=5, ℎ_𝑙/ℎ_ℎ=0.25, 𝐸₁₁/𝐸₂₂=25, 𝐺₂₃=0.2𝐸₂₂, 𝐺₁₃=𝐺₁₂=0.5𝐸₂₂, and 𝜈₁₂=𝜈₂₁=0.25.