Nonlinear Dynamic Analysis Of Profiled Steel-concrete Composite Panels Under Blast-induced Excitations
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S T Quek, C M Bian & S D Pang
This paper presents the nonlinear dynamic behavior of profiled steel-RC composite panels subjected to blast-induced excitations using a finite element package, DIANA v7.2. An appropriate finite element model is first formulated and then parametric studies are performed to evaluate the strength and deformation characteristics of selected composite slabs. In the numerical model, perfect bonding between concrete and steel is assumed. The steel elements include the profiled steel deck and the reinforcement. Nonlinear behavior of steel with isotropic hardening using the Von-Mises yield criterion is adopted. The inelastic behavior of concrete is described by the Drucker-Prager model with varying yield surfaces to simulate compression softening, Under tension, a smeared crack model with softening and shear retention is employed. Results confirmed that numerical difficulties encountered using the brittle crack model may lead to inconsistent displacements and strains for the problem considered. The linear and nonlinear softening models give better results but the linear model needs considerably less effort and is attractive for large problems. The use of a variable shear retention model is more realistic as opposed to a constant shear retention model. The behavior of composite panels under blast-induced excitations is studied numerically for various combinations of reinforcement ratio r and panel thickness t. The nonlinear trend exhibited in terms of maximum deflection, concrete strain and crack distribution with respect to r and t indicate that further study must be performed to formulate comprehensive guidelines for the design of such composite elements in protective structures.