GKM COLLEGE OF ENGINEERING AND TECHNOLOGY (AN ISO 9001 : 2008 &NBA ACCREDITED INSTITUTION)
DEPARTMENT OF AERONAUTICAL ENGINEERING
AE6413 CAD AND AIRCRAFT COMPONENT DRAWING Manual PREPARED BY
Dr. K.MOHAMED BAK
AE6413 CAD AND AIRCRAFT COMPONENT DRAWING OBJECTIVES To introduce the concept of design of basic structural components and to draft both manually and using modelling package. LIST OF EXERCISES 1. Design and drafting of riveted joints 2. Design and drafting of welded joints. 3. Design and drafting control components cam 4. Design and drafting control components bell crank 5. Design and drafting control components gear 6. Design and drafting control components push-pull rod 7. Three view diagram of a typical aircraft 8. Layout of typical wing structure. 9. Layout of typical fuselage structure. 10. Layout of control system
UNIVERSITY PRACTICAL EXAMINATION
ALLOTMENT OF MARKS
INTERNAL ASSESSMENT
= 20 MARKS
PRACTICAL EXAMINATION
= 80 MARKS
INTERNAL ASSESSMENT [20 Marks]
STAFF SHOULD MAINTAIN THE ASSESSMENT REGISTER AND THE HEAD OF THE DEPARTMENT SHOULD MONITOR IT.
SPLIT UP OF INTERNAL MARKS
Record Note
10 marks
Model Exam
5 marks
Attendance
5 marks
Total
20 marks
Page|4
UNIVERSITY EXAMINATION
THE EXAMINATION WILL BE CONDUCTED FOR 100 MARKS. THEN THE MARKS WILL BE CALCULATED TO 80 MARKS.
ALLOCATION OF MARKS
Aim and Procedure
30 marks
Modeling
30 marks
Simulation
20 marks
Result
10 marks
Viva Voce
10 marks
Total
100 marks
AE225 INTRODUCTION TO DESIGN AND DRAFTING TOOLS EXPT.NO: 1
DATE:
Design and Drafting comprises Linkages Dynamic, velocity, acceleration Design of elements - using drafting mechanics - using design tools Machines drawing – purely drafting Component drawing Assembly drawing Isometric drawing When we can use computer Wire – frame models 3-d shaded models Formation of flow charts (or process charts) Hydraulic system of an aircraft Pneumatic pressure lines Fire extinguisher systems Manufacturing information systems (MIS) Graphs Bar charts Graphics Monochromatic Colour graphics (i) Animatories (ii) Model analysis Related acronyms are CADD which stands for “computer aided design and drafting”. It is a computer based tool that assign engineer, architects and other design professionals in their design activities. It is the main geometry authoring tool and involves both software and sometimes special-purpose hardware. CADD is extensively used for the detailed engineering of 30 models and 1 or 20 drawings of physical components but it is also used throughout the engineering process from conceptual design and layout of products through strength and dynamic analysis of assemblies to definition of manufacturing methods of components. CADD has become an especially important technology with benefits such as lower product development costs and greatly shortened design cycle, because CADD helps designers to layout and develop their work on screen, print it out and save it for future editing saving a lot of time on their drawings.
RIVITED JOINTS EXPT.NO: 1
DATE:
INTRODUCTION Riveted joints are usually used in various engineering structures such as bridges, ships, aircrafts, boilers and cranes etc. In case of riveting, the holes are made in plates which are to be connected and rivets are inserted into the holes of the plates. The rivets are generally hammered, for permanent fastening. Recently welding has replaced riveting because riveting consumes more material and labour output. ADVANTAGES OF RIVETED JOINTS Riveted joint is the only method of making permanent connection of alloys like duraluminium for which so far there is no reliable method of power welding. Riveted joints damp the vibration of structures. DISADVANTAGES OF RIVETED JOINTS More material is required due to large weight of rivets, 3.5 to 4% of the Wright of structures while the weight of welded joints is 1% and 1.5% of the structures weight. Higher labour input (layout punches or drilling holes). Riveting process is more complicated and less productive than welding. TERMINOLOGIES Pitch (P) Distance between the centres of adjacent rivets is measured on a row. Back pitch / Traverse pitch (Pt) Distance between two adjacent rivets in the same plane. It varies from 2.5 to 3.5 times the rivet diameter. Diagonal pitch (Pd) Distance between the centres of adjacent rivets on adjacent rows of rivets and the nearest edge of the plate. m = 1.5 d where d – diameter of rivets hole Gauge line The line of rivets parallel to the direction of stress is called gauge line. Gauge distance
The distance between two consecutive rivets is called gauge distance.
Repeating section A graph of rivets, whose pattern repeats itself along the length of the joint referred to as repeating section. Nominal diameter Diameter of the cold rivet measured before driving is referred to as nominal diameter. Edge distance The distance of the edge of the meter of the cover plates from extreme rivets hole. Efficiency Minimum of Ft, Fg, Fb η = ----------------------------------------Maximum F1 = σt Pt TYPES Lab Joint When the ends of the plate overlap each other, the joint is known as lap joint. 1. Single riveted lap joint 2. Double riveted lap joint 3. Triple riveted lap joint In case of lap joints, if the joint is made by only one row of rivets used for connecting two plates, it is known as the single riveted lap joint. A joint with two rows of rivets used for connecting two plates is known as double riveted lap joint, whereas three rows of rivets are used for connecting the two plates, it is known as triple riveted lap joint. Butt Joint In case of butt joints, the edges of the two plates to be joint together butt (i.e., touch) against each other and a cover plate is placed either on one side or on both sides of two main plates as known as shown in figure. In case of butt joints, at least two rows of rivets on each side of the joints are required 1. Single riveted butt joint 2. Double riveted butt joint 3. Triple riveted butt joint
In case of a single riveted butt joint, one row of rivet is used on each side of the joint. Hence in total, there are two rows of rivets. In case of double riveted butt joint, two rows of rivets are used on each side of the joint and hence in total three or four rows of rivets in double riveted butt joint. In case of triple butt joint, three rows of rivets are used on each side of joint. 1. Chain riveted joint 2. Zig zag riveted joint 3. Diamond riveted joint Chain riveted joint Every rivet of a row is opposite to the other rivet of the other row. Zig zag riveted joints Spacing of rivets is staggered in such a way that every rivet is in middle of two rivets of opposite row as shown in figure. Diamond riveted joints Every rivet is joint in such a way that they form a diamond structure. VARIOUS FAILURE ON RIVETED JOINTS A riveted joint may fail in following ways 1. Failure due to tearing of plate along the centre line of a row of rivets Let p – pitch of the rivet d – diameters of the rivet t – thickness of the plate σt – permissible tensile stress Resistance to tearing per pitch length, Rt = Ft = (p-d) t x σt 2. The failure of the joint occurs when the rivets undergo shear. Shear strength = Area of resisting shear x Allowable shear π Fg = -------- d 2 x τ 4 For double shear / boiler joints, π
Fg = 1.875 -------- d 2 x τ 4 3. Failure due to crushing (bearing) of rivet or plate If one of the plates in a joint is weaker than the other plate, crushing will take place. Let the top plate of a lap joint shown in figure is weaker than the bottom plate. Now if the top plate is pulled by a load p, the crushing stress or bearing stress will be induced between the top plate and rivet. Fb = σ b x d x t
where d = (dr + 1.5 )mm
NUMERICALS Find the efficiency of the riveted joints. (i) single riveted lap joint for 8mm thick plates with 16mm diameter rivets and a pitch of 50mm rivets. d = dr + 1.5mm = 16 + 1.5 = 17.5 mm Ft = σt (p-d) t
dr = 16mm p = 50mm t = 8 mm πd2 Fs = σs (--------- ) 4
= 150 (50 – 17.5) 8 = 39KN
Fb = σ t d t = 300 x 17.5 x 8
π = 100 x -------- x 17.52 4
= 42 KN
= 240.05 KN η=
24.05 x 103 x 100 ------------------------ = 40% 150 x 50 x 8
(ii) Double riveted lap joint for 8mm thick plates with 16mm diameter rivets at a pitch of 75mm centres, if the allowable tensile, shearing and bearing stresses are 150 N / mm 2, 100 N / mm2 and 300 N / mm2. d = dr + 1.5mm = 16 + 1.5 = 17.5mm Ft = 150 (75 – 17.5) 8 = 69 KN
dr = 16mm p = 75mm t = 8mm 3.14 Fs = 2 x 100 (--------- x 17.52) 4
= 48.08 KN
Fb = 2 σb dt = 2 x 300 x 17.5 x8 = 84 KN η=
48.081 x 103 x 100 ------------------------- = 63% 150 x 75 x 8
WELDING JOINTS EXPT.NO: 1
DATE:
INTRODUCTION Welding is the process of joining similar metals by the application of heat. It can be done with or without the application of pressure and with or without filler metal called electrode. If the pressure is fixed for joining the two parts, the process is known as forge welding whereas if the metals are joint without any pressure but if a separate weld metal is used, is called fusion welding. ADVANTAGES OF WELDED JOINTS 1. The welded structures are usually lighter than corresponding riveted structure. 2. The welded joints have greater strength as compared to the riveted joint. Hence the efficiency of welded joint is more than that of riveted joint. 3. Addition and alteration can be easily made in the existing welding structure than in riveted structures. 4. Method of joining is quick and economical. 5. Welded joint is as strong as original plate. 6. It is possible to weld any part of the structure at any point but riveting requires enough clearance. 7. In welded connections, the tension members are not weaker as in the case of riveted joints. DISADVANTAGES OF WELDED JOINTS 1. Welded joints are not permanent and cannot be disassembled like riveted joints. 2. As there is an uneven heating and cooling during the fabrication, the members may get distorted or additional stresses may develop. 3. Since no provision is kept for expansion and contraction in the frame, there is possibility of cracks developing in it. 4. It requires skilled labour and supervision. TYPES Welded joints are classified according to the method of joining butt, lap, strapped and corner joints. 1. Butt weld joint 2. Plug or slot weld joint 3. Fillet weld joint
1. Butt weld joint It is a joint in which the edges of 2 members butt (touch) against each other, and they are joint together by welding. Inside force is given by F = Inside stress x area = Ft x l x t This equation is also used to calculate the strength of the butt weld joint. The following types of butt weld joints are used:1. 2. 3. 4. 5. 6.
Square butt weld joint Single v-butt weld joint Single u- butt weld joint Double v- butt weld joint Double u- butt weld joint T butt weld joint
2. Fillet weld joint It is a joint in which the two members meet each other at about 90 o and the two members are joint together by welding. It is of approximately triangular cross-section and is used for overlapping joints and corner joints. The fillet used may be subjected to a load p as shown in fig (i) and fig (ii). In fig (ii), it is clear incase of shear stress, while in fig (i), it is assumed to be a combination of normal and shear stress. However it is a general practice to design for both the cases, assuming the failure occurs at the throat by shearing. The following types of fillet weld joint are mostly used:1. Single fillet lap joint 2. Double fillet lap joint 3. Parallel fillet lap joint Single fillet lap joint Area aof fillet weld
= length of the weld x throat thickness = ℓ x 0.707h
Double fillet lap joint Area of fillet weld Parallel fillet weld
= ℓ x throat thickness + ℓ x throat thickness = 2 x ℓ x throat thickness = 1.414 x ℓ x h
Area of the parallel fillet weld = 1.414 x ℓ x h
NOTE:1. For strength calculation of welded joints, throat area is taken but a weld is specified by its size or length. 2. The throat thickness of depth of weld in case of that weld joint – thickness of plate (t) whereas throat thickness for lap joint for fillet weld joint = 0.707h 3. Single and double fillet lap joints are designed for tensile strength whereas parallel fillet weld is designed for shear strength. SPECIFICATIONS OF WELDED JOINTS The location of weld is specified by on arrow mark and a reference line in welding symbol. The arrow points to the joints where the weld is to be made. Arrow side The side of joint near to the arrow in the welding symbol is called arrow side. Other side The side of the joint remote to the arrow in the welding symbol is called the other side. DIMENSIONING OF WELDED JOINTS The following dimensions shall be indicated for welded joints, whenever required in mm. 1. Size of weld 2. Length of spacing of weld 3. Plug or slot weld Sometimes sufficient space is not available for providing necessary length of fillet weld in such cases, a circular hole is made of a fillet weld provided along the circumference of hole. WELD SUBJECTED TO BENDING If a load or force acting on a welded joint does not pass through the centroid of the weld lines, it will pass some lending moments to the welded joints in addition to the direct load. The governing equation of bending moment is given by M σ M
--------- = --------- => σ = I y
--------Z
Where, Z – Section modulus (I / Ymax) I – Moment of inertia of area about the axis of lending Y – Distance of weld from the natural axis While calculating moment of inertia of welded joints, following points are to be noted. Parallel axis theorem is to be noted. Ixx = ICG + Ay2 bh3 Ixx = --------- + (bh) d2 12 In this case, moment (due to load) is acting perpendicular to that of weld. A little consideration will show that the weld has to offer resistance to the following two types of displacement. 1. Linear displacement 2. Horizontal displacement WELDS SUBJECTED TO TORSION In this case, the moment due to load p is acting in a plane containing the welds. A little consideration will show that the weld has to offer resistance of the following two types. a. Linear displacement b. Rotary displacement For the weld shown in figure, the force p causes the direct shear stress as well as the shear stress to rotating of plate about which is maximum radius. Resistance against linear displacement This resistance (stress) is assumed to be uniform in all the weld P P σ = ------ = ------A tℓ Where t is effective throat thickness Resistance against rotary displacement Following two assumptions are made for finding out the resistance against the rotary displacement. The force of resistance at any point in a weld is proportional to its distance from the centroid of the weld lines.
The direction of the force of resistance is perpendicular to the line joining point and centroid of the weld line.
Let p – load acting on the connection r – distance between centroid of the weld lines and the point Where the resistance is required to be found out. P Z1 – direct shear stress = -------A Z2 – shear stress due to twisting T Z2 ---------- = -------J r pxℓ ℓ J – polar moment of inertia ----------- = -----J rmax NUMERICALS 1. Find the size of weld if the permissible shear stress is 80 mpa and the load acting is 60KN. Load, p = 60KN Weld length = 60 x 2 = 120mm P σ = ------A P 60 x 103 6 80 x 10 = ----------------- = --------------------0.707h x ℓ 0.707h x 0.120 h = 8.8mm Standard dimension = 10mm 2. A tie bar is welded to a plate as shown in figure. Find the strength of the weld (take size of the fillet as 6mm and working strength of fillet weld as 1025 Kg / m2) size of the weld (h) = 0.6cm effective throat thickness (t) = 0.707h = 0.707 x 0.6 = 0.42cm stress (σ) = 1025 Kg / m2 length, ℓ = 10 + 10 + 10 = 30cm p σ = ---------------0.707 x ℓ x h strength of weld, p = 6 x 0.707 x h x ℓ = 1025 x 0.42 x 30 = 12.915 tonne.
3. Find the weld size if p = 120KN and σ = 80Mpa Length of weld (ℓ) = 80 + 2 x 75 = 230mm p σ = ------------------------0.707 x ℓ x h 120 x 103 h = ----------------------------- = 9.22mm 80 x 106 x 0.707 x 230 h = 10 mm (standard) 4. A 120mm x 120mm plate connected to another plate by fillet weld around the end of the bar and also inside a machine as shown in figure. Determine the size of the weld if the joint subjected to a full of 100KN. The working stress for the transverses weld and longitudinal weld are 102.5 MN / m 2 respectively. Length of the longitudinal weld, ℓ = (2 x 120) + (2 x 60) =360 mm Length of the transverse weld, ℓ =120 + 2 x 20 = 160 Let p – force of resistance of weld = 160 mm h – size of the weld effective thickness, t = 0.707h p p σ = -------- = ---------A ℓxt P1 = ℓ1 x t1 x σ1 = 360 x 0.707h x 10-6 x 84 x 106 = 21379 h N P2 = ℓ2 x t2 x σ2 = 160 x 0.707h x 10-6 x 102.5 x 106 = 11595 h N Total force of resistance, P = P1 + P2 = (21379 + 11595) = 32974 h N Equating the total force of resistance to the pull on the joint, we get 32974 h = 100 x 103 h = 3.03 mm h = 3 mm (standard)
5. A circular plate of diameter 150 mm is welded on to another plate by means of 10mm fillet. Determine the maximum twisting which can be applied to circular plate if the permissible shear stress is 100MN / m2. Size of the weld = 10mm Thickness of throat = 0.707h Length of fillet = circumference of circular plate ℓ = πd = π x 150 = 471.2 mm Total shear force = throat area x shear stress = ℓ x t x τ1 = (471.2 x 0.707 x 100 x 10 x 10-3) = 333.1N Maximum twisting moment = τ x r = 333.1 x 75 x 10-3 = 24.98 Nm
WINGS AND MAIN PLANES EXPT.NO: 1
DATE:
INTRODUCTION Wings are designed to support the total weight of the aeroplane while in flight and also hold control surfaces such as ailerons, flaps, spoilers, speed breakers, wing fences and slats. Nowadays they even hold undercarriage, engines and fuel tanks. In addition to these, defence aircraft wings can hold drop tanks, rocket pods, missiles and bombs. Wings can be made in single piece, two pieces and three pieces as per span length. Single pieces is usually preferred for making micro-light aircraft while two piece types for making low speed light weight low altitude category aircrafts. But a three piece is preferred for large size transport category aero planes. The three pieces are named as port wing, central section and starboard wing. The centre section is usually coupled to the fuselage bulk-head bottom and the outer wing sections are coupled to the centre section through floating ribs and wing tips are usually held by number of machined screws. CLASSIFICATION OF WINGS Wings can be classified by its function, position, numbers, attachments, shapes and construction. Under construction, it is classified as monologue, monasper, spar and multi-spar types. MONOCOQUE WING This type consists of only a thickness tapered single skin with false spar (to hold control surface) and all the loads are met only by the skin. It is directly coupled to the fuselage at its flanged inboard root end. MONO-SPAR WINGS This type comprises of a single spar for attachment with fuselage and a dummy spar which is held by the fuselage to provide partially in to the wing to prevent twisting of wing due to shifting in centre of pressure. It also has a false, spar, number of ribs, stringers and stiffeners with skin covering. It is preferred for short span aircrafts as it is low speed. TWO SPAR WINGS This type of wings comprises of a minimum of two spars with or without false spar and ribs, stringers, stiffereners which are into frame work and they covered by fabric or by thin alloy light sheets. It is preferred for making medium speed and size aircrafts with short cords. MULTI – SPAR WINGS
This type comprises of more than two may have false number of ribs with or without false ribs, stringers and stiffeners which are built into a frame work and then covered by thin light alloy sheets. It is preferred for making large hauling type transport category aircrafts. WING GEOMETRY The plan form of a wing is the shape of the wing seen on a plan view of the aircraft. WING SPAN The wing span is the dimension is the distance between the extreme wing tips. The distance is from each tip of the centre line is the wing semi-span. CHORDS The two length CT and CO are the tip and root chords respectively with the alternative convention, the root chord is the distance between the intersections with the fuselage centre line of the leading and trailing edges produced. The ratio CT / CO is the taper ratio. Sometimes the reciprocal of this namely CO / CT is taken as the taper ratio. It must wings, CT / CO < 1. WING AREA The plan area of the wing including the continuation within the fuselage is the gross wing area, SG. The unqualified term wing area S is usually intended to mean this gross wing area. The plan area of the exposed wing i.e., excluding the continuation within the fuselage is the net wing area, SN. MEAN CHORDS A useful parameter, the standard mean chord or the geometric mean chord, is denoted by C, defined by C = S G / b or SN / b. It should be stored whether S G or SN is used. This definition may also be written as where y is the distance measured from the centre line towards the stand board tip. This standard mean chord is often abbreviated as SMC. Another mean chord is the aerodynamic mean chord (AMC) denoted by CA or C, and is defined. ASPECT RATIO The aspect ratio is a measure of the narrowness of the wing plane form. It is denoted by A.R. and is given by Span b ------------- = -----SMC C b2 (Span)2 Or A = --------- = ------------------bc Area
A.R. =
SWEEP BACK The sweep back angle of a wing is the angle between a line drawn along the span at a constant fraction of the chord from the leading edge and a line perpendicular to the centre line. It is usually denoted by either Ω or ф. Sweepback is commonly measured on the leading edge (ΩLE or Ω TE), on the quarter chord line i.e., the line ¼ of the chord behind the leading edge (Ω ¼ or Ω ¼) or on the trailing edge (Ω TE or ф TE). DIHEDRAL ANGLE If an aeroplane is looked at from directly ahead, it is seen that the wings are not in general in a single plane but are instead inclined to each other at a small angle. Then the angle 2Γ is the dihedral angle of the wings. If the wings are inclined upwards, they are said to be dihedral, if inclined downwards, they are anhedral.
FUSELAGE EXPT.NO: 1
DATE:
INTRODUCTION Fuselage is the main body of an aeroplane primarily designed to hold together all other major components and also to accommodate the crew passengers and or materials depending upon the role of the aeroplane. CLASSIFICATION OF FUSELAGE Basically fuselage are classified as - truss type - monocoque The truss type can be further classified as “strut traced” or “wire traced” in which the frame types. All the loads (internal and external) are borne out by the truss only and skin is not subjected to any load. Merits and Demerits The strut trace type frame work cannot be adjusted incase of a deformation due to damage, however, it is strong enough than a wire trace type. But a wire trace type can be adjusted incase of deformation due to damage but it is weaker than the strut trace type. Monocoque (single shell) Pure monocoque comprises of thick tapered skin with integral projections as attachment provision for holding other major components. It may have internal cross members to hold or support other small units and these members will not have share the external loading through the skin. In other words, the shell / skin only carries all the external and internal loadings. Demerits Heavier than truss type Increased production cost Increased maintenance cost
Load are met only by skin
Semi monocoque type fuselages comprise of a minimum of four longerons, a fire wall, few bulk heads and number of frames with few formers, stringers and stiffeners which are built into a frame work of circular / oval Skelton. The frame work is usually covered by then light alloy sheets by riveting. All the bulk heads may have either integral projections and detachable fittings to provide attachment of other major components.
Merits
Increased strength by weight ratio due to hollow sectioned light alloy structures.
Increased fail safe features by duplicating the structure at junctions by providing alternate path of load in the event of main attachment failures.
A low maintenance cost due to use of built-up structures.
A low production cost due to mass production.
LANDING GEAR EXPT.NO: 1
DATE:
INTRODUCTION It is primarily designed to support the static weight of the aircraft indefinitely while on ground and also to provide smooth take-off run and landing run, with a smooth take-off and landing without overstressing the aircraft structures under normal and emergent conditions. It is basically of two types namely fixed type and retractable type. FIXED TYPE Rarely designs were all of fixed type and the evaluation in speed resulted in invention of retractable under carriage. The fixed type is further classified as straight axle type, split axle, cantilever type suspended lever type and tri-pod type. However fixed type comprises of a shock strut of specific type (rubber in tension, rubber in compression, spring in tension, spring in compression, liquid springing and oleo pneumatic types), wheels and types with brake units. Presently this type is preferred for all the low speed, light weight, low altitude and shout endurance aircrafts. RETRACTABLE TYPE In order to improve speed by reduction in drag and also to reduce load on aircraft structures, the retractable type under-carriages are used for high speed and long endurance aircrafts i.e., on completion of take-off, the under-carriage assemblies are folded and taken inside the engine throttling in increased. The retraction path can be in any one of the desired direction such as into the wing, along the wind, straight forward with outboard inclination and sometimes vertically up and down into the fuselage bottom, depending upon the type of the aircraft. A retractable landing gear can be retracted and or extended either by mechanical system or by electrical system or by hydraulic system or by pneumatic system depending upon the role of the aircraft. RETRACTION SYSTEM The retraction system consists of the following sub-systems: - Main extension and retraction system of landing gear under normal conditions. - Emergency extension system for lowering only in went of main system failure. - Up lock mechanism to prevent lowering of landing gear during flight due to vibration or due to system failure. - Down lock mechanism to prevent collapsing / retraction of extending legs either on touch down or while landing. - Position indicating system to permit pilot to continue flight or not. - Interlocking systems with another control such as lowering of wing flaps or increasing the throttle / power rating.
-
Wheel auto brake systems to prevent wheel rotation during and after the retraction (in wheel bay), and it should not be automatically get released while extending the landing gear to prevent type burst. INTRODUCTION TO AUTOCAD
Being very user-friendly and comprehensive, AUTOCAD is the most popular Computer Aided Design and Drafting Software from Autodesk, a leading us based company. COMMUNICATING WITH AUTOCAD AUTOCAD is a perfect servant; it does everything you tell it to and no more. You can communicate with AUTOCAD using the pull-down menus, screen menus, command line and the button on the toolbars. A command is a single-word instruction from the user to perform the required task. When you invoke a command, AUTOCAD responds by presenting messages in the command prompt area, or by displaying a dialog box. The message in the command prompt area often tell you, what to do next, or they offer a lot of options. A dialog box is like a form, you fill out on the computer screen and it lets you adjust the settings or make selections from a set of options pertaining to a command. FUNCTION KEYS AUTOCAD provides a set of function keys for quick access to certain commands. Listed below are the function keys defined for AUTOCAD 2004. BRIEF SUMMARY OF AUTOCAD COMMANDS ABOUT
: Displays information about AUTOCAD
ARC
: Creates an arc
ARRAY
: Creates multiple copies of objects in pattern
ATT EDIT
: Changes attribute informations
BATCH
: Tills an enclosed area or selected objects with a batched pattern.
BLOCK
: Creates a block definition from objects of your selection.
CHAMFER
: Bevels the edges of objects
CHANGE
: Changes the properties of existing objects
CH Prop
: Changes the colour, layer, line type, scale factor, line weight, thickness and plot style of an object.
CIRCLE
: Creates a circle.
COLOUR
: Defines colour for new object.
COPY
: Duplicates object
DD EDIT
: Edit text and attribute definitions.
DD TYPE
: Specifies the display mode and size of point objects.
DIM ALIGNED
: Creates an aligned linear dimension.
DIM ANGULAR
: Creates an angular dimension.
DIM DIAMETER
: Creates diameter dimensions for cycle.
DIM ORDINATE
: Create ordinate point dimensions
DIM RADIUS
: Creates radial dimensions for circle.
DIM STYLE
: Creates and modifies dimensions style.
DIST
: Measures distance and angle between two points
DONUT
: Creates solid circles as rings
ELLIPSE
: Creates an ellipse or an elliptical arc.
ERASE
: Removes objects from drawing
EXPLODE
: Changes a compound object into its components
EXTRUDE
: Creates a unique solid primitive by extruding existing 2-dimensional objective
EXTEND
: Extends an object to meet another objects
FILLET
: Round and fillets the edges of objects.
GRID
: Displays a dot grid in the current view point
ISO PLANE
: Specifies the current isometric plane
LEADER
: Creates a line connecting notations and features
MIRROR
: Creates a mirror image of objects
M LINE
: Creates a multi parallel lines
M TEXT
: Creates a multi line text
NEW
: Creates a new drawing file
OFFSET
: Creates concentric circles, parallel lines and parallel curves
COPS
: Restores erased objects
ORTHO
: Constrains cursor movement
OPEN
: Opens an existing drawing file
OSNAP
: Sets objects snap mode
PAN
: Moves the drawing in current view
PLINE
: Creates two dimensional polylines
POINT
: Creates a point object
POLYGON
: Creates on equivalent closed polyline
Q SAVES
: Quickly saves the current drawing
Q TEXT
: Controls the display and plotting of text and attribute objects
QUIT
: Exits AUTOCAD
RECTANGLE
: Draws a rectangular polyline.
TEXT
: Displays text on screen as it enters
UNDO
: Reserves the effects of commands.
2 – D MODEL OF SINGLE LAP JOINT USING AUTOCAD EXPT.NO: 1
DATE:
\AIM To draw the top view and section of a single lap riveted joint using AUTOCAD. COMMANDS USED 1. 2. 3. 4. 5. 6.
Line Arc Circle Dimension M text Hatch
RESULT Thus the CAD layout of a single lap riveted joint has been drawn.
2 – D MODEL OF DOUBLE COVER BUTT JOINT OF AUTOCAD EXPT.NO: 1
AIM To draw the 2- D layout of a double cover butt joint on AUTOCAD. COMMAND USED 1. 2. 3. 4. 5. 6.
Line Arc Circle Dimension Batch M text
RESULT Thus the CAD layout of a double cover butt joint has been drawn.
DATE:
2 – D MODEL OF AN AIRCRAFT LANDING GEAR USING AUTOCAD EXPT.NO: 1
AIM To draw the CAD layout of Aircraft landing gear. COMMAND USED 1. 2. 3. 4. 5.
Line Arc Circle Dimension M text
RESULT Thus the CAD layout of an aircraft landing gear has been drawn.
DATE:
2 – D MODEL OF TYPICAL WING ASSEMBLY USING AUTOCAD EXPT.NO: 1
AIM To draw the 2 – D model of a wing section and its spam on AUTOCAD. COMMANDS USED 1. 2. 3. 4. 5. 6.
Line Arc Dimension Leader copy spline
RESULT Thus the CAD layout of an aircraft wing assembly has been drawn.
DATE:
2 – D CAD LAYOUT OF AIRCRAFT FUSELAGE EXPT.NO: 1
DATE:
AIM To draw the CAD layout of the connection of a semi-monocoque fuselage. COMMANDS USED 1. 2. 3. 4. 5. 6.
Circle Offset Lines Array Leader Hatch
RESULT Thus the CAD layout of the connection of an aircraft fuselage (semi-monocoque) has been drawn.
2 – D CAD LAYOUT OF AIRCRAFT CONTROL SYTEMS EXPT.NO: 1
DATE:
AIM To draw the CAD layout of the connection of a control sytems COMMANDS USED 1.Circle 2.Offset 3.Lines 4.Array 5.Leader 6.Hatch
RESULT Thus the CAD layout of the connection of an aircraft control systems has been drawn.
2 – D CAD LAYOUT OF TYPICAL AIRCRAFT FUSELAGE EXPT.NO: 1
DATE:
AIM To draw the CAD layout of the connection of a fuselage COMMANDS USED 1.Circle 2.Offset 3.Lines 4.Array 5.Leader 6.Hatch
RESULT Thus the CAD layout of the connection of an aircraft fuselage has been drawn.
Commercial Airplane (Boeing - 727 / 200) Specifications Wingspan Length Tail Height Gross Maximum Taxi Weight Power
Cruising Speed Cruising Altitude Range Passenger Capacity Fuel
Advanced 727 - 200 108 feet (32.91 m) 153 feet 2 Inches (46.69 m) 34 feet (10.36 m) Standard : 191,000 pounds (86,000 kg) Optional : 210,000 pounds (95,300 kg) Three Pratt & Whitney JT8D turbofans: - 15 rated at 15,500 pounds thrust - 17 rated at 16,000 pounds thrust - 17R rated at 17,400 pounds thrust 570 to 605 mph (890 to 965 km / h) 30,000 to 40,000 feet (9,144 to 12,192 m) 1,500 to 2,500 miles (2,750 to 4,020 km) 148 to 189 8,186 U.S. gallons (31,000 L) standard at lower gross weights 9,806 U.S. gallons (37,020 L) standard for 208,000 pounds
S.No. 1.
Desired weld Fillet weld of size 5mm weld on arrow side
Symbolic Representation
Section Representation
5
2.
Fillet weld of 10x6mm size weld on other side
10x 6 66666
10
6
3.
Plug or slot weld
b
Ch
d
h
Ch
Pitch
Gauge Pitch
length
Gauge lines Back pitch
Edge distance
Repeating selection
CHAIN RIVETED JOINT
ZIG ZAG RIVETED JOINT
DIAMOND RIVETED JOINT
