Structural Design and Analysis of an Existing Aerodynamically Optimised Mortar Shell

Asfaw, Yohannes (2008) Structural Design and Analysis of an Existing Aerodynamically Optimised Mortar Shell. Masters thesis, Addis Ababa University.

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Abstract

Mortar shell design is one of the most critical components in defence organization of projectile design. Unavilability of data and literature regarding artillery projectiles and rocket warheads, are considered to be one of the main contributors for the failure of manufacturing projectile in a local industry. The need for this study is to design and fabricate this type of mortar shell in Ethiopia itself. Thus, the primary objective of this thesis is to develop a ballistics model of mortar shell and predicting the performance of mortar casing by ANSYS a finite element analysis package. Initially, the model is designed as a simplistic ballistic model capable of predicting the pressure and thrust generated by a propellant from a given set of input parameters. Its structure was determined on the basis of gun design empirical, experimental investigations of ballistic research laboratories (BRL) and weapon design of ammunition and artilleries of high explosive calibers. High explosive warhead performances depend on its geometrical shape and dimensions, mass of explosive charge and explosive type, material of warhead case, initiation way and initiation point position, fuse type, round to round variations, etc. These are important parameters in determining the state of projectile features and stresses during the design of projectile. Thus, in this work a parametric study is conducted by varying the casing thickness and its length to study their effect on the fragmentation and stability of mortar projectile for the selected design parameters. Analysis of stresses and deformation in the casing is an important area of research for projectiles optimal design. This thesis investigates the characteristics of high explosives warhead fragmentation analysis This research not only gives fragmentation analysis of the shell by continuum method and trajectory calculations, but also gives the stress values for three different loading conditions correspond to launching, hitting the target and subsequent pyro blast. To estimate the structural stress, three-dimensional model of a mortar shell was made by finite element method using ANSYS. This thesis also considers the study of variation of primary and secondary propellant charge on range. The results obtained by this research are presented and compared with the available literature. This study not only validates the design of the mortar shell, but also helps the Defense Ministry go ahead with its production for its need.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Mechanical Engineering
Subjects: T Technology > T Technology (General)
T Technology > TJ Mechanical engineering and machinery
T Technology > TL Motor vehicles. Aeronautics. Astronautics
Divisions: Africana
Depositing User: Andriamparany Edilbert RANOARIVONY
Date Deposited: 04 Oct 2018 09:19
Last Modified: 04 Oct 2018 09:19
URI: http://thesisbank.jhia.ac.ke/id/eprint/6686

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