surface development, Study notes of Civil Engineering

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CE 100: CIVIL ENGINEERING DRAWING

Shaika Sharkia

Lecturer, Department of Civil Engineering University of Asia Pacific (UAP), Dhaka

SURFACE

DEVELOPMENT

• CHAPTER –

IMPORTANCE OF SURFACE

DEVELOPMENT

Knowledge of development is very useful in sheet metal work , construction of storage vessels , chemical vessels , boilers , and chimneys. Such vessels are manufactured from plates that are cut according to these developments and then properly bend into desired shaped. The joints are then

Boilers^ welded or riveted.

Chemical Vessel

Metal Sheet Works

Storage Vessels

Chimney

METHODS OF DEVELOPMENT

 Parallel-line development

 Radial-line development

 Triangulation development

 Approximate development

PARALLEL-LINE DEVELOPMENT

It is used for developing Prisms and single

curved surfaces like Cylinders , in which all the

edges/generation of lateral surfaces are parallel

in each other.

TRIANGULATION DEVELOPMENT

It is used for developing transition pieces.  Transition pieces are usually made to connect two different forms, such as round pipes to square pipes.  These transition pieces will usually fit the definition of a non developable surface that must be developed by an approximation.  This is done by assuming the surface to be made from a series of triangular surfaces laid side-by-side to form the development.  This form of development is known as Triangulation

APPROXIMATE DEVELOPMENT

It is employed for double curved surfaces like Spheres , as they are theoretically not possible to develop. The surface of the sphere is developed by approximate method. When the surface is cut by a series of cutting planes, the cut surfaces is called a zone.

Develop the surface of the cube of 1 "

LEFT BOTTOM^ RIGHT TOP

1"

1"

1

2

3

Develop the surface of a triangular prism

1"

3"

1

2

EXAMPLES OF RADIAL-LINE

DEVELOPMENT

Develop the surface of a pyramid

B

A B

C

E

E

C

1

2

TRUE LENGTH

Draw the development of a square pyramid from its plan and front elevation which stands vertically on its base on H.P with one edge of the base parallel to V.P.

E

E A B

D^ C

AB BC

O

1"

O

2"

O

B′^ C′

D′

A′

O′

SIDE SIDE^ SIDE

SIDE

Take, OO′ = OE (True Length)

A cone of base 50 mm diameter and height 65 mm rests with its base on H.P. It front elevation is cut by a plane at an angle to 30o^ with horizontal plane at 30 mm above base. Draw the development of the lateral surface of the truncated cone.

O

30 o

2 3 1

65 mm^4

30 mm

C

D

E

F

G H A

B

O

L O

(^12) 3 4 5

1 8 6 7 A B C D E^ F

G

H

A

= 360o×r/L L