Behaviour and Optimization Aids of Composite Stiffened Hypar Shell Roofs with Cutout under Free Vibration

Table 1

Natural frequencies (Hz) of centrally stiffened clamped square plate.

Mode no.	Mukherjee and Mukhopadhyay [14]	Nayak and Bandyopadhyay [15]		Present method
		N8 (FEM)	N9 (FEM)
1	711.8	725.2	725.1	733

𝑎=𝑏=0.2032 m, shell thickness =0.0013716 m, stiffener depth 0.0127 m, stiffener width =0.00635 m, stiffener eccentric at bottom.
Material property: 𝐸=6.87×10¹⁰ N/m², 𝜈=0.29, 𝜌=2823 kg/m³.