Design, Modelling and Coupled Field Analysis of Missile Nose Cone for Various Distributions using Theoretical Approach and Validation by FEM Analysis

Design, Modelling and Coupled Field Analysis of Missile Nose Cone for Various Distributions using Theoretical Approach and Validation by FEM Analysis

Maheswaran. N1, Stephen. M2, Raja Merline. J3,

Assistant Professor1, Department of Aeronautical Engineering, Hindusthan Institute of Technology, Coimbatore UG Scholar2,3, Department of Aeronautical Engineering, Hindusthan Institute of Technology.

Abstract:-A missile nose cone concept is having an ability to improve the performance over an existing conventional nose cone. A nose cone is mainly used for refer to the forward direction of an aircraft and guiding missile. Nose cones are designed for travel in space, under water and high speed land vehicles. The main objective is to design, modelling and analysis of missile by getting various stress distribution and deformation by coupled field simulation using finite element analysis. There are some factors to be considered such as shape and size, weight drag, sudden application of load, acoustics, fatigue load etc incline to slow down its performance and fatigue life. Nosecone modelled by using 3D cad software and same geometry is imported to ANSYS. To determine the nose cone geometrical shape for optimum performance and evaluates missile nose cone using theoretical approach. We are going to use Al, structural steel and Titanium Ti-6Al-4V of grade II material. This material significantly stronger than commercially pure titanium. The stiffness and thermal properties of a structural loaded due to thermal effects can be calculated by hand calculation and compare with finite element analysis software.

INTRODUCTION

1. Background of Project

   Generally, the history of missiles and guided missiles, find that missiles were used in India around 1000 for fireworks as well as for war purposes. During the 18th century, unguided missile propelled missiles were used by Hyder Ali and his son Tipu Sultan against the British. The current phase in the history of missiles began during the World War II with the use of V1 and V2 missiles by Germany. Since, there is a tremendous and rapid global advancement in this field. An air vehicle like air craft, guided missiles and commercial airplanes and helicopters. An aircraft which gets driven by the reaction forces to the ejection of fast moving thermo – structural from within a missile engine. Missile engines work by action and reaction. Missile engines push missiles forward by expelling their exhaust in the opposite direction at high speed. Missiles are relatively lightweight and powerful, capable of generating large accelerations and of attaining extremely high speeds with reasonable efficiency. Missiles are not reliant on the atmosphere and work very well in space.

2. Problem Statement

   Now days, most of the countries are having missile and aerospace projects. It consists of creation of concept model, design, infrastructure development and manufacturing the air

   vehicles. A research activity is going on for accuracy, technology updating and adoption to the air busses. This project is discussing about the different Mach numbers various shape and size experiences different values of drag by which to select best optimum shape of nose cone. The most of the cases nose profiles used are conical, parabolic ogive and elliptical as per commercial and research purpose. To designing of these nose cone models are done using Creo 2.0 3D CAD software and analysed using ANSYS workbench for different Mach numbers and load conditions under sonic, subsonic and supersonic conditions by comparison of results we can select the optimum shape for particular aircraft.

3. Objective of the project

   The design of the nose cone section of aircraft to travel through a structural analysis, coupled field analysis and compressible thermo – structural medium.Important problem is the determination of nose cone geometrical shape and material used to it for optimum performance. Such tasks require the definition of solid of revolution shape that experiences minimal resistance to rapid motion trough such a thermo – structural medium, which consists of elastic particles. The basic nose cone material majority of manufactures were more comfortable with the known life limitations of structural metal, in particular the aluminium alloys, primarily used by the US manufacturers, these alloys have a tensile strength in excess of mild steel, but the drawback is their susceptibility to corrosion, and to combat this, these materials are clad with a grades are commonly referred as ALCLAD. The 6061 grade is the common weld able grade, and not as bad as the others for corrosion other metals commonly used.

   1. CONCEPT OF NOSE CONE

      Conical:

      A very common nose-cone shape is a simple cone. This shape is often chosen for its ease of manufacture, and is also often mis chosen for its drag characteristics.

      Bi-conic:

      A bi-conic nose cone shape is simply a cone with length L1 stacked on top of a frustum of a cone (commonly known as a conical transition section shape) with length L2, where the base of the upper cone is equal in radius R1 to the top radius of the smaller frustum with base radius R2.

      Elliptical:

      The profile of this shape is one-half of an ellipse, with the major axis being the centreline and the minor axis being the base of the nose cone. A rotation of a full ellipse about its major axis is called a prolate spheroid, so an elliptical nose shape would properly be known as a prolate hemispheroid. This shape is popular in subsonic flight due to the blunt nose and tangent base. This is not a shape normally found in professional missilery, which almost always flies at much higher velocities where other designs are more suitable. If R Equals L, this is a hemisphere A Missile is a vehicle which acquires push by the response of the missile to the discharge of plane of quick moving liquid fumes from missile engine. Solid fuel missiles make their fumes by the ignition of strong charge grain. The subsequent gasses are extended through the spout whose capacity is to change over this inward weight into a supersonic fumes speed.

      Missile engine fumes are shaped altogether from force conveyed inside of the missile before use. Missile motors work by activity and response. Missile motors push missiles forward by ousting their fumes the other way at fast. Missiles depend on energy, air foils, helper response motors, gimballed push, force wheels, diversion of the fumes stream, charge stream, turn, and/or gravity to help control flight. Missiles are moderately lightweight and intense, fit for creating expansive increasing velocities and of achieving amazingly high speeds with sensible productivity. Missiles are not dependent on the climate and work extremely well in space. Missiles for military and recreational uses go back to at any rate 13th century China. Significant logical, interplanetary and modern utilization did not happen until the 20th century, when missilery was the empowering innovation for the Space Age, including setting foot on the moon.

      Missiles are presently utilized for firecrackers, weaponry, launch seats, dispatch vehicles for simulated satellites, human spaceflight, and space investigation. Substance missiles are the most widely recognized sort of high power missile, commonly making a rapid fume by the burning of fuel with an oxidizer. The put away force can be a basic pressurized gas or a solitary thermo – structural fuel that disassociates in the vicinity of an impetus (monopropellants), two thermo – structural that suddenly respond on contact (hypergolic fuels), two thermo – structural that must be touched off to respond, a strong mix of one or more fills with one or more oxidizers (strong fuel), or strong fuel with thermo – structural oxidant (half and half charge framework).

      Concoction missiles store a lot of vitality in an effortlessly discharged frame, and can be exceptionally perilous. Notwithstanding, watchful configuration, testing, development and utilization minimizes dangers. India has made tremendous studies in launch vehicle technology to achieve self-reliance in satellite launch vehicle program with the operationalization of PSLV and GSLV. To minimize the aero acoustic and aerodynamic loads on the vehicle, the slanted strap on nose cone with 250 on the free side and straight on the interference side are selected based on various studies. The change in pressure rise on core will be more for slanted nose cone. But the zone of influence is more in regular nose cones. Appreciable weight savings are possible through the integral section design which also develops high

      resistance to buckling loads. This method improved performance through smoother exterior surfaces by reduction in number of attachments and non – buckling characteristics of skin.

      Design of structural components has to meet specific requirements which influence the complexity of its structure and the materials used in its construction. Aluminum, blended with small quantities of other metals is used on most types of aircraft because it is lightweight and strong. AA2014 aluminum alloy is an aluminum-based alloy often used in the aerospace industry. (1) It is easily machined in certain tempers, and among the strongest available aluminum alloys, as well as having high hardness.

      In many countries aerospace projects involve designing, building, and launching experimental sounding missiles or research missiles and missiles carrying payloads that perform scientific experiments in a sub-orbital trajectory that reach apogees up to 3 to 4 km. but when comes to aircraft in my view they are not more concentrating on nose as much as they concern about missiles. But in sub sonic conditions also nose cone shape plays an important role reducing drag force on entire body and not allowing simulation separation which are adverse effects on efficiency of an aircraft. And I strongly believe that efficiency of an air craft can be increased by producing least drag on air craft. Providing optimum shape to nose is not a difficult when compared to other designs but little care has to be done which I am going to discuss in my paper and this paper is to show at different Mach numbers various shapes experiences different values of drag by which we can select optimum shape of nose cone. The mostly used nose profiles now a day are majorly used are conical, parabolic ogive and elliptical as per commercial purpose.

      Designing of four models is done using solid works and analysed using Ansys structural analysis and computational thermo – structural dynamics for different Mach numbers under sub sonic conditions by comparison of results we can select the optimum shape for particular aircraft. This work totally based on analysis but used in real world which brings a difference in efficiency of air craft and not only this simulation separation also plays an important role in aircrafts which can be controlled by usage of optimum nose cone.

   2. DESIGN & MODELLING NOSE CONE Geometry Modelling CREO 2.0 is chosen for

      modelling the two stage missile body. CREO 2.0 consists of modules each Module specialized in specific design field. There are many types of nosecone shapes followed by cylindrical structured missiles are using for different purposes. The selection of shape is purely depending on the type of application for which it is being developed. Missile having conical nose followed by cylinder and frustum cross section is modelled and analysed in this project due to its wide range of applications. The model chosen for static aeroelastic analysis using ansys. Thermo – structural Analysis Computational structural dynamics, usually abbreviated as STRUCTURAL ANALYSIS, is a branch of structural mechanics that uses numerical analysis and algorithms to solve and analyze problems that involve structuralthermo – structural. Computers are used to perform the calculations

      required to simulate the interaction of liquids and gases with surfaces defined by boundary conditions. With high-speed supercomputers, better solutions can be achieved. ANSYS workbench software package to simulate thermo – structural problems. It uses the finite volume method to solve the governing equations for a structural. It provides the capability to use different physical models such as incompressible or compressible, inviscid or viscous, laminar or turbulent, etc. The mesh models of domain and missile body. The domain including body shown above consists of 7,892 tetrahedral cells, 1,716 triangular wall faces, 1,258 triangular interior faces, 873 triangular pressure far-field faces, 2,743 triangular pressure-outlet faces, 1,384 triangular wall faces. Advanced solver technology provides fast, accurate STRUCTURAL ANALYSIS results, flexible moving and deforming meshes, and superior parallel scalability.

      The integration of ANSYS Sparse into ANSYS Workbench provides superior bi-directional connections to all major CAD systems, powerful geometry modification and creation with ANSYS Design Modeller, and advanced meshing technologies in ANSYS Meshing. The platform also allows data and results to be shared between applications using an easy drag-and-drop transfer, for example, to use a structuralthermo – structural solution in the definition of a boundary load of a subsequent structural mechanics simulation.

      After initializing the solution Calculation was run up to 1,500 iterations to get better and accurate visualization of thermo – structural field patterns at different mach numbers 1.5 to 3.0The residuals plot which shows the resulting iteration and convergence phenomena at 2.5 mach number is presented.

      In the same manner with the thermo – structural conditions described above thermo – structural analysis is carried at other mach numbers 1.5 and 3. After getting the results, pressure loads generated over missile body at various mach numbers is imported into the structural analysis module and then static structural analysis is carried by linking the output file of structural dynamics as input to the structural analysis solver.

   3. Transient Structural Analysis Steps

In performing any finite element analysis we must complete certain tasks which can be thought of as the steps required for completing the analysis. Regardless of what FEA tool is being used, these same tasks must be performed in order to complete the analysis. These tasks are listed below.

1. Generation of the mesh

2. Define/Assign material properties

3. Define the analysis type

4. Set loading and boundary conditions

5. Solve

6. Review the results

   As the steps mentioned above, after linking the output of structural analysis file to static structural analysis again the body is imported and then meshed. The block pictures of these are inserted below indicating figure 3.4 and it consists of 20806 Nodes, 10294 Elements of Tetrahedral shape. Material properties considered for this structure selected are the following since these are the materials with properties widely using in various applications. Young's

   Modulus titanium alloyis 960 GPa, with Poisson's ratio 0.3 having the Density 4620 Kg/m3.

   Modelling of missile nose cone

   Meshing of missile nose cone

   Transient condition

   Total Deformation

   5. CONCLUTION

   In this project work, the nose cone is prepared by the CREO 2.0 and ANSYS software. Applied the structural of air pressure of 18500 (Pa) on the nose cone at the height in the range of 35,000 45,000 (Feet) is investigated for different materials like aluminium alloy, structural steel, and titanium ally. The analysis made to know the behavior of the deformation in the static and dynamic environment. It says that the aluminium alloy is subjected to more deformation, both structural steel and stainless steel subjected to same kind of deformation and titanium alloy becomes less structural deformation. And stress distributions.

   Out of these materials the titanium material is having optimum deformation range of minimum and

   maximum. Along with these materials titanium alloy having better properties which is now a day most popularly used in various fields is chosen for nose cone of an air craft for yielding good results.

   The results are obtained from ANSYS software and design is done using CREO 2.0 software. The help of ANSYS software done structural analysis and model analysis

   .so the results are various models compared with better values obtained by using of Titanium alloys.Titanium Ti-6Al-4V is less deformation value and high withstand value in von misses stress and less weight comparing with other materials, Equivalent elastic strain is max in titanium grade 2.

   Titanium Ti-6Al-4V is better suitable material to missile nose cone compared to aluminum, and some other materials. The results are obtained from ANSYS software and design is done using CREO 2.0software. The help of ANSYS software done structural analysis and model analysis. The purpose of this project is to propose a solution for performance improvement using various Avion nose profiles. By referring to results elliptical nose profile give minimum drag coefficient at which is desirable for the subsonic flows to improve efficiency of vehicle by reducing drag.

   Structural and modalanalysis were carried out to get an understanding of the structural around missile body. Three dimensional simulations of the structural using CREO 2.0and ANSYS were performed. Stress tensor model was adopted to capture the structural. Computations were validated through a simulation of structural around the similar bodies by earlier investigators. After a good agreement with reported results, simulation of the present case was carried out and compared with respect to mach number. Results obtained through the flow analysis linked to transient structural analysis using ANSYS Workbench were performed.

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