Question

Design a leaf spring for the following specifications: Total load=140Kn,Number of springs supported the the load=4,Maximum number of leaves=10, Span of the spring=1000mm,Permisible deflection =80mm,E=200KN/mm and allowable stress in spring material as 600mpa.​

Answer 1

Answer:

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Answer 2

Given:

Total load = 140 KN

Number of springs supporting the load = 4

Maximum number of leaves (n) = 10

Span of spring = 1000mm

2L = 1000

L = 500mm

Permissible deflection = 80mm, E = 200 KN/mm

Allowable stress = 600 mpa = 600 N/$mm^{2}$

To find:

Design a leaf spring.

Solution:

We know that load on each spring

2W = $\frac{140}{4}$ = 35 kN

W = 17.5 kN = 17500 N

let,

the thickness of leaves = t

the width of leaves = b  

we know that bending stress = $\frac{6 W L}{n b t^2}$

600 = $\frac{6. 17500. 500}{n.b.t^2}$

$n.b.t^2$ = 87.5 x $10^3$       ...(1)

we know that deflection = $\frac{6. W. L^3}{n. E . b. t^3}$

80 = $\frac{6. 17500. (500)^3}{n. 200. 10^3. b. t^3}$

$n. b. t^3$ = 0.82 x $10^6$      ....(2)

Dividing (1) and (2) we get

t = 9.37 say 10mm

putting this value of t and n in (1)

b = $\frac{87500}{10(10)^2}$

b = 87.5 mm

putting this value of t and n in (2)

b = $\frac{820000}{10(10)^3}$

b = 82 mm

we will take the larger value of b = 87.5 say 90 mm.

So, the spring will be of leaf thickness 10mm and width of spring 90mm.