Answer to Question #269674 in Mechanical Engineering for Adeel

Question

Design a spring for suspension system of a motorcycle with a weight of two people riding the bike. You should assume the required parameters as per the following table,

Sr. No.

Reg No

Starting d

Difference for selection of diameter

Ends of spring

1

1-10

0.01 x R

0.001 x R

Squared or Closed

2

11-20

0.01 x R

0.001 x R

Squared or Closed

3

21-30

(0.01 x R)/2

0.001 x R

Squared and Ground

4

31-40

(0.01 x R)/2

0.001 x R

Squared and Ground

5

41-50

0.01 x R

0.001 x R

Squared or Closed

6

51-60

0.01 x R

0.001 x R

Squared or Closed

7

61-70

(0.001 x R)/2

0.001 x R

Squared and Ground

8

71-80

(0.001 x R)/2

0.001 x R

Squared and Ground

* where R = Your Registration Number

Start your calculation first by using material 302 stainless steel and if the required result is not output, then change the material till you find one. Select the spring as wound.

HINT: Make an excel sheet for making the table of spring selection.

Answer 1

Assume number of turns = 15

assume deflection = 2 inches = 50mm

Load = 150kg = 1500N

spring stiffness , k = 1500/0.05 = 30000 N/m = 30 kN/m

Material = 302 stainless Steel

E = 210 Gpa

starting (d) , spring wire dia = 0.05mm

D is mean coil diameter

This excel sheet gives us; d and D

use formula,

k = d4G/8D3N

Note- The color coded dimesions of d & D(in mm) are suitable. U can choose any of these dimensions.

You can also see the formula used in formula bar.