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

Table 4

Non-dimensional fundamental frequencies (𝜔) for laminated composite (+45/−45/+45/−45) 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	137.5363	149.748	156.932	154.6134	147.0345
CSCC	127.6366	139.9845	142.6213	142.2069	133.7437
CCSC	133.1847	157.494	165.9908	157.6214	149.8912
CCCS	123.9139	136.05	139.2721	140.9553	134.9193
CSSC	119.3132	129.2799	129.5345	119.8123	107.4374
CCSS	114.1784	124.2418	126.9562	119.4147	107.3405
CSCS	119.1939	129.2601	133.1178	136.9644	128.4247
SCSC	117.6296	129.2476	135.318	141.1146	143.7385
CSSS	102.7485	106.9623	109.5824	110.3696	103.1902
SSSC	105.2055	111.0251	113.482	110.7912	101.8345
SSCS	103.0713	107.6771	111.8604	118.8297	123.5415
SSSS	89.8159	91.6626	94.3912	89.284	83.3021
Point supported	26.4022	26.8267	27.3666	28.542	30.1836

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.