HELICAL SPRINGS
FOLLOWING DIN EN 13906-1,2,3
Order : Dware
Project : HeliSpring
Subproject : Dimensioning compression spring
Project item : Metallfedern
Spring ID : S.198
Calculated by : André Dewispelaere
Organization : Dware
Date : 03.12.2025 




   Spring wire grade




 Nr, Cl, Spring Wire Grade       ,      E,     G,  rho,  Rm1, Rco




125, DM, EN 10270-1 DM           , 206000, 81500, 7.85, 1980, 740
1 Calculated wire properties Symbol Unit Value
2 Wire diameter d mm 5.000
3 Minimal ultimate tensile strength Rm N/mm˛ 1460
4 Module of rigidity G N/mm˛ 81500
5 Module of Elasticity E N/mm˛ 206000

1 Design Specifications Symbol Unit Value
2 Minor axial spring force F1 N 280.0
3 Axial stroke sh mm 21.0
4 Major axial spring force F2 N 620.0
5 Design stroke stress τh N/mm˛ --
6 Design major stress τ2 N/mm˛ --
7 Influence factor spring seat ν -- 0.5
8 Number of loading cycles Ncy Mcy 10.000
9 Type of spring end A ETA -- D squar+grnd
10 Extra inactive conjoint coils nnaA -- 0.00
11 Type spring end B ETB -- D squar+grnd
12 Extra inactive conjoint coils nnaB -- 0.00
13 Outside diameter not greater than De mm 40.0
14 Target coil ratio w -- 0.00
15 Coiling -- -- cold
16 Shot peening -- -- No
17 Hand of coiling -- -- right
18 Geometry calculation Symbol Unit Value
19 Calculated wire diameter dc mm 4.80
20 Selected wire diameter d mm 5.000
21 Diameter deviation Ad mm 0.025
22 Mean diameter of coil D mm 35.00
23 Spring index w -- 7.00
24 Outside diameter of spring De mm 40.0
25 Inside diameter of spring Di mm 30.0
26 Required spring rate Rr N/mm 16.190
27 Number of active coils n -- 9.50
28 Spring rate R N/mm 15.632
29 Sum of smallest coil spaces Sa Nm 12.3
30 Total number of coils nt -- 11.5
31 Compressed length to solid state Lc mm 57.8
32 Permissible minimal spring length Ln mm 70.1
33 Nominal free length of spring L0 mm 118.6
34 Coil pitch at free length m0 mm 10.900
35 Coil space at free length a0 mm 5.900
36 Calculation spring diagram Symbol Unit Value
37 Minor axial deflection s1 mm 17.9
38 Length at minor axial deflection L1 mm 100.7
39 Minor axial spring force F1 N 280.0
40 Major axial deflection s2 mm 38.9
41 Length at major axial deflection L2 mm 79.7
42 Calculated major axial load force F2 N 608
43 Permissible maximal deflection sn mm 48.6
44 Permissible minimal spring length Ln mm 70.1
45 Permissible maximal spring force Fn N 760.1
46 Axial deflection to solid state sc mm 60.8
47 Compressed length to solid state Lc mm 57.8
48 Spring force at solid state Fcth N 950.0
49 Strength calculation Symbol Unit Value
50 Stress correction factor k -- 1.200
51 Corrected minor torsional stress τk1 N/mm˛ 240
52 Corrected major torsional stress τk2 N/mm˛ 520
53 Permissible static torsion stress τP N/mm˛ 730
54 Safety factor major torsion stress SF -- 1.40
55 Torsion stress permiss max deflect τn N/mm˛ 542
56 Permissible static torsion stress τP N/mm˛ 730
57 Safety fact permiss max deflection SFn -- 1.35
58 Stress at solid state τc N/mm˛ 677
59 Permissible stress at solid state τcP N/mm˛ 820
60 Safety factor stress at solid stat SFc -- 1.21
61 Strength domain -- -- endurance
62 Permissible endurance stress τeN N/mm˛ 328
63 Permissible upper torsion stress τkO N/mm˛ 537
64 Safety factor upper torsion stress SFO -- 1.03
65 Lower torsional stress τkU N/mm˛ 240
66 Corrected stroke torsional stress τkh N/mm˛ 281
67 Permissible stroke stress τkH N/mm˛ 298
68 Safety factor on stroke stress SFH -- 1.06
69 Weight calculation Symbol Unit Value
70 Length of wire for spring lw mm 1270
71 Mass of spring mw g 196
72 Calculation buckling diagram Symbol Unit Value
73 Influence factor spring seat ν -- 0.5
74 Slenderness grade νL0/D -- 1.694
75 Major deflection/length ratio s2/L0 -- 0.328
76 Buckling at deflection of sK mm 0.0
77 Safety factor on buckling SK -- 0.00
78 Is spring buckling safe -- -- Yes