Isogeometric level set topology optimization for elastoplastic plane stress problems

International Journal of Mechanics and Materials in Design - This article aims to utilize IsoGeometric analysis (IGA) and Level set method for topology optimization of elastoplastic plane stress...     

Cost-benefit analysis of seismic-isolated structures with viscous damper based on loss estimation

This paper presents a methodology to utilise performance-based seismic design procedure for evaluating isolated structures with or without viscous dampers (VD) considering cost-benefit analysis. A non-linear four-story archetype of conventional steel structure, a lead-rubber-bearing isolated structure and a natural rubber-bearing isolated structure with the linear VD are compared with each other under far-field (FF) and near-field (NF) ground motions. Also, loss parameters, such as expected annualised loss, expected annualised repair time, expected annualised fatalities and expected annualised injuries based on loss estimation process, are utilised for evaluating the structures. Sensitivity analysis is used to study the effect of modelling uncertainty variations in the loss estimation process. It has been found that the effectivity of supplemental damping for low damping isolated structures increases in the NF comparing with the FF ground motions. Finally, the cost-benefit analysis is done to calculate payback period of investment for additional cost of the isolation system with or without the supplemental damping. The advantage of loss estimation is an improved method to evaluate the effectiveness of the isolation system in terms of loss parameters that are useful in the cost-benefit studies and for determining rational insurance premiums.     

Theoretical and numerical analysis and design of stiffened steel plate shear walls having unequal subpanels

Following the adequate seismic behavior, the steel plate shear walls have gained popularity among the designers worldwide, and many buildings have been designed employing such walls as their lateral load‐carrying system. Despite the fact that the steel shear walls using unstiffened thin plates outnumber the ones benefitting from stiffeners, it should be kept in mind that application of stiffeners prevents the buckling induced by lateral loads such earthquake or wind. On the other hand, the stiffeners enhance the stiffness and shear strength of the plate. Accordingly, this paper deals with an analytical and numerical investigation into the steel plates stiffened by unequaled vertical and horizontal stiffeners. The results obtained for the analyses led to the development of the analytical relations to compute the shear strength, stiffness, and displacement. To validate the proposed relations, analytical outputs were compared with those obtained from the numerical investigation indicating great accuracy of the proposed analytical relations. Moreover, in this paper, the design process of the stiffened steel plate shear walls has been presented based on the interaction between the plate and frame. The results indicate the addition of stiffeners to the steel plate, improves its shear strength by 6 to 15%.