Naval Surface Warfare Center

About: Naval Surface Warfare Center is a facility organization based out in Washington D.C., District of Columbia, United States. It is known for research contribution in the topics: Sonar & Radar. The organization has 2855 authors who have published 3697 publications receiving 83518 citations. The organization is also known as: NSWC.

Generalized Vector Explicit Guidance

Abstract: This paper proposes and evaluates a new guidance law termed generalized vector explicit guidance (GENEX). This guidance law can simultaneously achieve design specifications on miss distance and final missile-target relative orientation. The latter may be used to enhance the performance of warheads the effectiveness of which is influenced by the terminal encounter geometry. The GENEX guidance law is parameterized in terms of a design coefficient that determines the degree of curvature in the trajectory. Feasibility of GENEX guidance was demonstrated by its application to two weapon scenarios. The first was an air-to-air missile terminal homing scenario. Assuming ideal sensor information and a single-lag missile response model, the guidance was shown to perform well against an air target performing evasive maneuvers. A specified zero-aspect terminal encounter angle was achieved while simultaneously minimizing miss distance. The second application involved an air-to-surface munition released from an unmanned air vehicle. The GENEX guidance law was able to produce trajectories satisfying a terminal impact angle constraint. In addition, an engagement region of sufficient size was shown to be achievable using guidance gains scheduled with target location and weapon release altitude.

A Study on the Effect of the Stress State on Ductile Fracture

Abstract: The main purpose of this paper is to demonstrate that besides the stress triaxiality parameter, the Lode angle, which can be related to the third invariant of the deviatoric stress tensor, also has an important effect on ductile fracture. This is achieved by conducting a series of micromechanics analyses of void-containing unit cells and experimental-numerical studies of carefully designed specimens experiencing a wide range of stress states. As a result, a fracture criterion is expressed in terms of the equivalent failure strain as a function of the stress triaxiality and the Lode angle (or the third invariant of the stress deviator) and this function is calibrated for a DH36 steel plate.