HELICAL SPRINGS
FOLLOWING DIN EN 13906-1,2,3
Order : Dware
Project : HeliSpring
Subproject : Compression Spring Verification
Project item : Metallfedern
Spring ID : S.198
Calculated by : André Dewispelaere
Organization : Dware
Date : 03.11.2025 




   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 Spring Specifications Symbol Unit Value
2 Outside diameter of spring De mm 39.60
3 Nominal diameter of wire d mm 5.000
4 Deviation of diameter of wire Ad mm 0.025
5 Number of active coils n -- 9.50
6 Total number of coils nt -- 11.50
7 Free spring length L0 mm 105.8
8 Influence factor spring seat ν -- 0.5
9 End type A ETA -- D squar+grnd
10 Number of inactive coils nnaA -- 0.00
11 Type spring end B ETB -- D squar+grnd
12 Number of inactive coils nnaB -- 0.00
13 Hand of coiling -- -- right
14 Coiling -- -- cold
15 Shot peened -- -- No
16 Spring load Symbol Unit Value
17 Calculation on base of -- -- forces
18 Minor axial spring force F1 N 280.0
19 Major axial spring force F2 N 620.0
20 Expected service life Lh h 2000
21 Load frequency fF Hz 50.000
22 Operating temperature of spring θ °C 20
23 Extern mass in mass-spring-system m kg 0.500
24 Calculation of geometry Symbol Unit Value
25 Mean diameter of coil D mm 34.60
26 Spring index w -- 6.92
27 Inside diameter of spring Di mm 29.60
28 Modulus of rigidity in f(th) G(th) N/mm˛ 81500
29 Spring rate R N/mm 16.181
30 Sum of minimal coil spaces Sa mm 12.3
31 Length of active coils free spring Lw mm 90.7
32 Coil pitch of free spring m0 mm 9.547
33 Coil space of free spring a0 mm 4.547
34 Calculation spring diagram Symbol Unit Value
35 Minor axial deflection s1 mm 17.3
36 Spring length at deflection s1 L1 mm 88.5
37 Minor axial spring force F1 N 280.0
38 Major axial deflection s2 mm 38.3
39 Spring length at deflection s2 L2 mm 67.5
40 Major axial spring force F2 N 620.0
41 Stroke sh mm 21.0
42 Stroke force Fh N 340.0
43 Permissble maximal deflection sn mm 35.7
44 Permissible minimal spring length Ln mm 70.1
45 Permissible maximal force Fn N 577.7
46 Deflection to solid sc mm 48.0
47 Length compressed spring to solid Lc mm 57.8
48 Theoretical spring force to solid Fc N 776.7
49 Strength calculation Symbol Unit Value
50 Stress correction factor k -- 1.203
51 Corrected minor torsional stress τk1 N/mm˛ 238
52 Corrected major torsional stress τk2 N/mm˛ 526
53 Permissible static torsion stress τP N/mm˛ 730
54 Safety factor static tors stress SF -- 1.39
55 Tors stress at permiss max deflect τn N/mm˛ 407
56 Permissible static torsion stress τP N/mm˛ 730
57 Safety factor permiss max deflect SFn -- 1.79
58 Torsional stress at solid state τc N/mm˛ 548
59 Permissible tors stress solid stat τcP N/mm˛ 820
60 Safety factor tors stress solid st SFc -- 1.50
61 Number of load cycles Ncy Mcy 360.000
62 Strength domain -- -- endurance
63 Permissible endurance stress τeN N/mm˛ 328
64 Permissible upper torsional stress τkO N/mm˛ 536
65 Safety factor on upper tors stress SFO -- 1.02
66 Lower torsion stress τkU N/mm˛ 238
67 Corrected stroke stress τkh N/mm˛ 288
68 Permissible stroke torsion stress τkH N/mm˛ 299
69 Safety fact stroke torsion stress SFH -- 1.04
70 Calculation of spring mass Symbol Unit Value
71 Length of developed spring wire lw mm 1254
72 Mass of spring mw g 193
73 Calculation of buckling diagram Symbol Unit Value
74 Influence factor spring seat ν -- 0.5
75 Slenderness ratio νL0/D -- 1.529
76 Major deflection/length ratio s2/L0 -- 0.362
77 Solid deflection/length ratio sc/L0 -- 0.454
78 Deflection causing buckling sK mm 0.0
79 Safety factor on buckling SK -- 0.00
80 Is spring buckling safe -- -- Yes
81 Spring work Symbol Unit Value
82 Minor spring work W1 J 2.422
83 Major spring work W2 J 11.873
84 Work exchange DW J 9.451
85 Power exchange DP W 472.550
86 Calculation natural frequency Symbol Unit Value
87 Natural frequency spring coils fe Hz 159
88 Condition fe > 12 * fF satisfied -- -- No
89 Mass in mass-spring system mred kg 0.693
90 Resonance freq mass-spring system fr Hz 26.9