Mechanical Springs DMM-1 JNTUK video link: https://youtu.be/6NDF2OHZiM0

1. MECHANICAL SPRINGS –
STRESSES & DEFLECTION OF
HELICAL SPRINGS
D. Narendra Varma,
Assistant Professor,
Mechanical Engineering Dept.,
Miracle Educational society Group of Institutions.

2. Applications of Different types of Springs
s.no Type of Spring Application / usage
1 Helical Springs Railway Industry ,
suspension
2 Conical Springs Electrical contacts, such
as push buttons and
battery contacts
3 Volute springs Military tanks
4 Torsional springs Clocks, Automotive,
Medical equipment, Door
hinges
5 Leaf springs Suspension system of
railway carriages and
automobiles
6 Disc or bellevile springs Clutch Spring
7 Air Springs Trucks
8 Rubber Springs Bushes

3. Selection of material for the spring wire
(i) The load acting on the spring
(ii) The range of stress through which the spring operates
(iii) The limitations on mass and volume of spring
(iv) The expected fatigue life
(v) The environmental conditions in which the spring will operate
such as temperature and corrosive atmosphere
(vi) The severity of deformation encountered while making the
spring.

4. Four basic varieties of steel wire materials
(i) patented and cold-drawn steel wires (unalloyed);
(ii) oil-hardened and tempered spring steel wires and valve spring
wires;
(iii) oil-hardened and tempered steel wires (alloyed); and
(iv) stainless steel spring wires.

5. Stresses in Helical Springs of Circular Wire
Consider a helical compression spring made of circular wire and
subjected to an axial load W as shown in Fig.(a).
Let D = Mean diameter of the spring coil,
d = Diameter of the spring wire,
n = Number of active coils,
G = Modulus of rigidity for the spring material,
W = Axial load on the spring,
t = Maximum shear stress induced in the wire,
C = Spring index = D/d,
p = Pitch of the coils, and

8. where K is called the stress factor or Wahl factor

9. Deflection of Helical Springs of Circular Wire

11. Buckling of Compression Springs

12. Surge in springs

13. References
1. Machine Design – V.B.Bhandari .
2. Machine Design – R.S. Khurmi
3. Design Data hand Book - S.Md.Jalaludeen