Informatics Publishing Limited

B. Santhosh ¹, C. G. Nandakumar ², S. Sundararajan ¹

Affiliations
1 Composites Entity, Vikram Sarabhai Space Centre, Indian Space Research Organisation, Trivandrum, IN
2 Cochin University of Science and Technology, Cochin, IN

Abstract

Reusable launch vehicles are designed for multiple missions and it undergoes severe aerodynamic loading conditions during its operation. Nosecap is one such hot structure in a reusable vehicle, which is a doubly curved conical structure whose cross-section varies with respect to height. Carbon-Carbon composite is mainly used in these hot environments. Generally the 3D composite structures for the hot structures are made from 3D textile preforms. The Nosecap experiences high temperature variations during the re-entry phase of the flight. Heat transfer analysis and thermo-structural analysis of the Nosecap are essential for estimating the design margins. The output of heat transfer analysis, which is the temperature distribution with respect to time, will be added to the corresponding pressure loads for carrying out thermo-structural analysis. Analytical methodology has been arrived at based on Representative Unit Cells for evaluating the 3D composites properties from the basic unidirectional material properties. In the present study thermo-mechanical properties of 3D Carbon-Carbon composite has been determined and selection of the best suitable textile preform has been addressed based on heat transfer and thermo-structural analysis of Nosecap using the finite element software NASTRAN. A total thermo-structural design procedure has been presented with the support of suitable numerical investigations.

Keywords

Reusable Launch Vehicle, 3D Textile Composite, Thermal Analysis, Thermo-Structural Design, Representative Unit Cell.

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P. S. Prashob , C. G. Nandakumar

Abstract

Offshore jacket structures are extensively used for exploration and exploitation of offshore hydrocarbons since seventies. These bottom fixed lattice structures are subjected to wave loading throughout its lifetime. Tubular joints are prone to high stress level and their fatigue life is decided by this. Offshore structural design codes such as API, DNV etc., have given the procedure for the fatigue life estimation based on the stress level predicted at local level. This procedure has been adopted to predict influence of soil structure interaction on fatigue life of jackets and the results are reported. The scope of numerical investigations extends to the influence of depth of fixity as well.

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K. Sivaprasad , S. Jayaram , C. G. Nandakumar

Abstract

Main characteristic of ship recycling is the interdisciplinary nature of the engineering processes associated with it. These processes are multidimensional and have certain shortcomings, which make ship recycling a complex industry. The product design and life cycle stage management of naval fleet differ from that of merchant ships, still they also reach the same destination for dismantling. This demands implementation of new methodologies being implemented in merchant ship recycling, in naval ship recycling field as well. This paper presents two important ship recycling design and development tools, viz., Design for Ship Recycling and Recyclability Analysis which would add to the effectiveness of clean and safe recycling of naval fleet. Application of Design for Ship Recycling concept in naval ship design has been discussed. The concept of Recyclability Analysis of products and equipment with respect to ship recycling is presented as a guideline.

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