Nonlinear Dynamic Stress Analysis of an Orthotropic Steel Plate under Uniform Loading

This paper presents a geometrically nonlinear dynamic stress analysis of a stiffened orthotropic steel plate subjected to a uniformly distributed sinusoidal transverse load. The plate is reinforced by longitudinal and transverse T-section stiffeners and modeled using a nonlinear dynamic finite element formulation. The material behavior is assumed to be linearly elastic, while geometric nonlinearity is incorporated via the von Kármán theory. Four edge-support configurations are examined-SSSS, SCSC, SCCS and CCCC―in order to clarify the influence of boundary conditions on the time-dependent normal and shear stresses at the junction of the longitudinal stiffener and the plate. The results show that the boundary conditions have a pronounced effect on the dynamic stress components S۱۱, S۲۲ and S۱۲. For S۱۱, the maximum difference between configurations reaches about ۱۱% (between SCCS and CCCC), while the minimum discrepancy is approximately ۰.۰۱۷% (between SCSC and SSSS). For S۲۲, the deviation relative to the SSSS case varies from about ۰.۱۹۷% (SCSC) up to ۳۱.۷۲% (CCCC). The shear stress S۱۲ exhibits differences ranging from ۰.۱۵۸% (SCSC vs. SSSS) to ۴۹.۳% (CCCC vs. SSSS). These findings highlight the critical role of edge restraints in governing dynamic stress demands in stiffened orthotropic plates and provide practical guidance for their accurate modeling and safe design under dynamic loading.

کلیدواژه ها:

Nonlinear dynamic stress analysis ، stiffened orthotropic steel plate ، boundary conditions ، finite element method ، von Kármán geometric nonlinearity