# Calculating a leaf spring

1. Dec 29, 2008

### assafwei

Hi,

I cant figure out how to calculate forces exerted by a leaf spring.
The spring is made out of an 0.3mm sheet of s.s 302 and is bent to the shape of the letter Z with another half circle bend in one of the Z's ends, the other flat end is fixed and i want to calculate what force the springs exerts at a given deflection of the spring. The external force on the spring is at the end of the spring with the half circle. A drawing is attached.

Thanks,

Assaf.

#### Attached Files:

• ###### spring.JPG
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2. Dec 29, 2008

### nvn

assafwei: We would need all dimensions, including where the fixed support stops, the cross-sectional width, the point of application of the applied load, and the angle of the applied load.

3. Dec 30, 2008

### assafwei

I attached a sketch
Thnaks.

#### Attached Files:

• ###### lspring.jpg
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4. Dec 30, 2008

### assafwei

forgot 2 things...

The force is exerted at the TIP of R3 (bottom left side of drawing), normal to the tangent at that point, and is fixed at the whole surface with DIM 9.3 (top of rdrawing).

5. Dec 30, 2008

### nvn

assafwei: Assuming E = 193 GPa, the leaf spring at the point of application of the applied load deflects to the left 0.130 mm and upward 0.187 mm per newton of applied resultant load P. If the resultant deflection exceeds 1.01 mm, the above answer might begin to become slightly inaccurate, because the deflection would then begin to exceed small deflection theory.

Last edited: Dec 31, 2008
6. Dec 31, 2008

### assafwei

Thank you for the quick reply.

Is it possible to describe the general method of solving the problem?

Thanks,

Assaf.

7. Dec 31, 2008

### nvn

8. Dec 31, 2008

### assafwei

Isnt there an analytic way of solving this problem?

9. Dec 31, 2008

### nvn

Yes, you could break the leaf spring into six cantilever beams, and use superposition to compute the deflection. But it would be a large amount of work.