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The jettisoning of a nose cone in space from a spinning rocket has been investigated. The spring-assisted separation system is described with its mathematical model. The resulting nonlinear equations have been integrated numerically. The geometry for safe separation has been analysed and the in¯uences of various imperfections in the system, such as dynamic asymmetry, dynamic imbalance, separation system imperfections, etc., are studied. The analysis presented here enables a clear understanding to be obtained of the separation dynamics of a nose cone in a spinning environment. A closed-form solution has been obtained for the relative motion between the separating dynamically symmetric bodies devoid of any dynamic imbalance under the in¯uence of a perfect separation system. For the same system, simple design formulae have also been derived for collision avoidance, which can be gainfully utilized for initial sizing of separation systems.

The purpose of this paper is to present the corrosion behavior of the Cryorolled (CR) material and its Friction Stir Welded joints. Due to the thermal cycles of Friction Stir Welding (FSW) process, the corrosion behavior of the material gets affected. Here, the cryorolling process was carried out on AA2219 alloy and CR material was joined by FSW process using four different pin tool profiles such as cylindrical, threaded cylindrical, square and hexagonal pin. The FSW joints were analyzed by corrosion resistance with the help of potentiodynamic polarization test with 3.5% NaCl solution. From the analysis, it is found that CR AA2219 material exhibits good corrosion resistance compared to the base AA2219 material, and also a hexagonal pin profile FSW joint exhibits high corrosion resistance. Among the weld joints created by four different tools, the lowest corrosion resistance was found in the cylindrical pin tool FSW welds. Further, the corroded samples were investigated through metallurgical investigations like OM, Transmission Electron Microscopy (TEM), Energy-Dispersive X-ray Spectroscopy (EDX) and X-Ray Diffraction (XRD). It was found that the amount of dissolution of Al2Cu precipitate was present in the weld nugget. The amount of dissolution of Al2Cu precipitate is higher in the weld nugget produced by hexagonal pin tool. This is due to the enhancement of the corrosion resistance.

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