Composite propellers offer high damping characteristics and corrosion resistance when compared with metal propellers. But the design of a hybrid composite propeller with the same strength of metal propeller is the critical task. For this purpose, the present paper focusses on fluid-Structure Interaction analysis of hybrid composite propeller with Carbon/Epoxy, R-Glass/Epoxy and S2-Glass/Epoxy to find its strength at the same operating conditions of the baseline aluminium propeller. The surface and solid models of the hybrid composite propeller are modelled using modelling software (CATIA) and these models are imported into mesh generation software (Hypermesh) to generate the surface mesh and solid mesh respectively. This surface model of the hybrid composite propeller is imported into computational fluid dynamics software (Fluent) to estimate the pressure loads on propeller blades. These pressure loads from Fluent are imported into FEA software (Abaqus) and applied on the propeller to find the deformation and strength of hybrid composite propeller due to fluid-Structure Interaction loads. Optimization study is carried out on hybrid composite propeller with different layup sequences of Carbon/R-Glass/S2-Glass to find the optimum strength. From the optimization study, it is found that the hybrid composite propeller with layup-3 of 550/550/900/00/00/900/450/900/ 00/900/450/900/450/900/00/900/00 generates the least stress compared with other layups for the same pressure load obtained from fluid flow simulations. Damage initiation analysis is also carried out on hybrid composite propeller with optimized layup-3 based on Hashin damage criteria and found that the design is safe.

The modeling and analysis of Structures subjected to earthquake loading are well studied and understood. During an earthquake, however, the behavior of the soil under the Structure plays an important role in determining the superStructure response. In most cases, the soil is not modeled and is ignored. This is due to the reason that the soil, contrary to the Structure, is an infinite domain and can not be treated with the conventional models as used in Structures. Cone models to represent the soil, have been developed for practical engineering applications during the last ten years. Cone models can be utilized for sites with general layering and embedment conditions, capturing all degrees of freedom. Cone models provide sufficient engineering accuracy with physical insight. Cone models can be used both in force-based methods as response spectrum and time history analyses and in displacement-based methods such as push-over calculations. In these models, the soil is represented with a series of bars and beams as one uses in the analysis of superStructures. In this paper, the development of cone models is reviewed. Further, the application of the cone models in two actual seismic retrofitting projects is demonstrated. In both cases, the retrofitting costs were reduced substantially after modeling the soil with cones.

Historical heritage Structures are especially vulnerable to earthquakes because they were designed only for gravity loads without any consideration of lateral loads. For this reason, the preservation and maintenance of these Structures are of great cultural, economic, and social importance. The present study investigates the seismic vulnerability of a historical Structure called Kashan Bazaar, located in Kashan (central Iran), dating back to the 17th century. The detailed 3D geometrical model of this Structure was drawn using SolidWorks software. Finite element numerical method was used to evaluate the response of Bazaar Structure using macro-modeling approach. Static, modal, and nonlinear static (pushover) analyses were carried out using two cases, with soil-Structure Interaction (SSI) and without SSI (fixed-base). According to the results, considering the SSI has a significant influence on the mode shapes, vibration frequencies, and the structural responses. The Structure of Bazaar can withstand gravity loads as well as DBE demands in fixed-base model. However, the results of the SSI analyses show the Structure weakness against lateral loads.

Structures located beside each other interact under dynamic loads through the underlying soil and possibly by impact. In this paper, this dynamic cross-Interaction phenomenon is studied parametrically. While simultaneous modeling of different adjacent buildings would be possible from the beginning, by resorting to simple physical models, the cases susceptible to impact under harmonic loads were identified first with much less e ort. Then, comprehensive models were developed with two nonlinear multistory shear buildings connected at the base with suitable springs and dampers, impacting at the story level. The system was analyzed under selected ground motions. It was observed that impact and cross-Interaction had an increasing effect on lateral displacement for stiff and heavy Structures and a decreasing effect for other cases. Also, the shear forces of stories increased and decreased in the upper and lower stories, respectively, as a result of the mentioned mutual effect. Finally, the study indicated that under a sample ground motion, simultaneous impact and cross-Interaction increased the ductility demand of stories for taller Structures while it decreased the ductility demand of shorter buildings.