Ajit Shenoi

Optimisation Approaches to Design Synthesis of Marine Composite Structures

Abstract This paper develops a method of structural optimisation for stiffened FRP panels allowing optimisation between cost and mass. The approach uses genetic algorithms for optimisation combined with elastic stress modified grillage theory for stiffener structural analysis and third-order shear deformation theory for the plate structural analysis. For top-hat stiffened panels, optimum designs following first principles and classification society rules are compared, showing considerable potential for cost savings by using a first principle approach.

A Gyroscopic Wave Energy Recovery System for Marine Vessels

In this paper, a wave energy capture system for marine vessels is described. The system uses gyroscopic precession to create a relative motion within a vessel to generate power from the wave-induced roll and pitch motions. The governing equations of motion and a numerical model of the system are described in this paper and the behavior and performance of the system is identified. The system has several significant advantages over existing wave energy devices. For marine craft that operate in waves, the system could be very useful, providing a means to recover wave energy, reducing environmental impact, and improving operational effectiveness.

Optimisation of FRP structures for Marine Vessel Design and Production

Structural integrity is an important factor in design and production of any vessel. The design and production of the structure will permeate throughout the other subsystems of a vessel. These interactions require that the structure must be light, hydrodynamic and easy to build allowing an efficient and low cost design to be constructed. During the design process engineers use iterative design methods to improve optimum designs. The ability to have effective reliability data will allow this iteration to be a more quantitative process. The addition of these methods to optimisation techniques will allow a powerful tool that optimises design while producing data for other designers to determine possible changes that could take place. This paper looks at using reliability methods to increase the power of design for production within concurrent engineering and structural optimisation.© 2009 ASME

An analytical model for predicting permanent plastic deflection and strain distributions in aluminium-alloy plates under low velocity impact loading

This paper proposes a new analytical model to predict plastic deformation and strain distributions in aluminium-alloy plates under low velocity impact loading. The low velocity impact load on the fully clamped circular plate was idealized as a quasi-static normal point force acting at the centre of plate. Based on apt geometrical approximation and assumptions, governing equations were established to predict the out-of-plane deflection and the radial tensile, radial and circumferential flexure strains in fully clamped conditions. From the deformation theory of plasticity, a new formula was derived to estimate the impact load by incorporating strain-energy approach, bilinear strain-hardening constitutive model and the one-dimensional Tresca yield criterion. Low velocity impact tests were performed to confirm the proposed model and good correlation was achieved between the predictions and actual experiments, demonstrating the practical and effective use of the proposed model.

Improvements to a Sailing VR Simulator Environment for Assessing and Improving Helm Performance (P149)

The sailing simulator ‘Robo-Race’ is used to examine the effect on sailor performance of enhancing the realism of the simulation. For this purpose, the following two human interface device/display environments were evaluated. Firstly, a Basic Display Environment (BDE) which consists of two screens in conjunction with a joystick. Secondly the Advanced Display Environment (ADE) that consists of three projectors with an additional screen and a steering (or helm) wheel as interface device. A number of sailors who were divided according to their sailing skills and their experience with computer game interface devices had to deal with seven upwind races against two computer controlled America’s Cup Class (ACC) yachts. The experiment shows that the combination of BDE/joystick limits their natural sailing behaviour. However, the combination of ADE/steering wheel significantly improved the sailors’ efficiency. The ADE setup has been shown to enhance the realism of the simulation and allowed the sailors’ to race opponents in a more realistic manner.