Design of

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Design of Helical spring
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What is helical spring
Helical spring is a spiral wound wire with a
constant coil diameter and uniform pitch.
Function of Helical spring

• Used to store energy and subsequently release
  it
• To absorb shock
• To maintain a force between contacting surfaces

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Design consideration of helical spring
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Nomenclature of Helical spring
C Spring Index D/d d wire diameter (m)D
Spring diameter (m)Di Spring inside diameter
(m)Dil Spring inside diameter (loaded ) (m)E
Young's Modulus (N/m2)F Axial Force (N)G
Modulus of Rigidity (N/m2)K W Wahl Factor
(4C-1)/(4C5) (0,615/C)L 0 Free Length
(m)L s Solid Length (m)n t Total number of
coilsn Number of active coilsp pitch (m)y
distance from neutral axis to outer fibre of
wire (m)t shear stress (N/m2)t max Max
shear stress (N/m2)? Deflection (radians)
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Spring material

• 4. Copper based alloy
• Phosphor Bronze (Grade A) - ASTM B159
• Beryllium Copper - ASTM B197
• Monel 400 (AMS 7233)
• Monel K500 (QQ-N-286
• Nickel based alloy
• A286 Alloy
• Inconel 600 (QQ-W-390)
• Inconel 718
• Inconel X-750 (AMS 5698, 5699)

• High carbon steel
• Music Wire (ASTM A228)
• Hard Drawn (ASTM A227)
• High Tensile Hard Drawn (ASTM A679)
• Oil Tempered (ASTM A229)
• Carbon Valve (ASTM A230)
• Alloy spring steel
• Chrome Vanadium (ASTM A231)
• Chrome Silicon (ASTM A401)
• Stainless steel
• AISI 302/304 - ASTM A313
• AISI 316 - ASTM A313
• 17-7 PH - ASTM A313(631)

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Effect of End treatment.
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The module calculates the following design
parameters
1. Outer Diameter (Do)
5. Maximum load
2. Spring Index (C)
6. Corrected maximum stress
index range is 4 to 12
3. Slenderness ratio
7. Uncorrect maximum stress
8. Wahl correction factor
4. Spring rate (k)
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12. Shear stress
9. Maximum deflection
10. Spring mass
13. uncorrected Shear stress
11. Wire length
14. Natural frequency
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CHECKING

1. Stability of spring (buckling)

2. Fatigue loading
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Spring testing machine
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Thanks