## NUMERICAL: (APPROACH TO SOLVE PROBLEMS)-

Numerical related to Helical Compression Springs should be done with proper designing procedure. This procedure involves various factors such as to find values corresponding to the given questions and applying **Load Stress and Load Deflection Equations.**

So as to know more about** LOAD-STRESS & LOAD-DEFLECTION EQUATIONS;** Plz refer to the link of blog given below and study it thoroughly.

### Numerical** 1**:

*To design a Helical compression spring(H.C.S), subjected to a Max. force of 1250 N. The deflection of spring corresponding to Max. force should be approximate 30 mm. The Spring Index(C)=6. Spring made of Patented and Cold drawn steel wire of Grade1. The constants ( A=1753, m=0.182, G=81370 N/mm ^{2}) given as shown. Permissible Shear stress for spring wire taken as 50% of the Ultimate tensile strength (S_{ut}). Find The following ;*

*1) Wire diameter(d)*

*2) Mean Coil diameter (D)*

*3) No. of active coils (N)*

*4) Total no. of coils (N _{t})*

*5) Free length of the coils*

*6) Pitch of coil (p)*

**Also Design the spring and draw it.**

### Num. **2**:

* A Helical compression spring(H.C.S), subjected to a force ranging from 1000 N to 2000 N. The deflection of spring corresponding to this range should be approximate 5 mm. The Spring Index(C)=5. Spring has square and grounded ends. Spring made of Patented and cold drawn steel wire of Grade1. .The constants ( A=1753, m=0.182, G=81370 N/mm ^{2}) given as shown. Permissible shear stress for spring wire= 50 % of Ultimate tensile strength (S_{ut}).*

**Calculate the following and design the spring:**

*1) Wire diameter(d)*

*2) Mean Coil diameter (D)*

*3) No. of active coils (N)*

*4) Total no. of coils (N _{t})*

*5) Free length of the coils* (F.L)

6) Solid length (S.L)

7) Required spring rate

8) Actual spring rate

### Num.**3**:

**Design a H.C.S with P _{max}=7.5kN. The mean coil diameter (D) Should be 150 mm from space considerations. k=75 N/mm .Spring made of coil hardened and Tempered steel wire ( S_{ut} = 1250 N/mm^{2} ). Permissible shear stress= 30 %of Ultimate tensile strength (S_{ut}). G=81370 N/mm^{2} **

**Calculate :**

*1) Wire diameter (d)*

*2) No. of active coils(N)*