Extension Spring EN 13906-2

Extension Spring EN 13906-2 calculates basic quantities of an extension spring according to EN 13906-2 and perfoms static and dynamic check

USE:

1. Insert data related to material and geometry
2. Insert load data
3. Spring static check, aimed to avoid plastic deformation > 2%
4. Spring dynamic check, aimed to avoid fatigue failure

REMARKS:
Remarkable results are highlighted in yellow

MATERIALE
E [MPa]	Modulus of elasticity
G [MPa]	Shear modulus of elasticity
ρ [kg/dm3]	Density
Rm [MPa]	Tensile Strength, ultimate
τk0(τk1) [MPa]	Torsional fatigue load limit (alternate)
	Kind of material	Ferrous material without "presetting" Non ferrous material without "presetting" Ferrous material with "presetting" Non ferrous material with "presetting"
GEOMETRY
D [mm]	Mean diameter
n	Number of active coils
d [mm]	Wire diameter
L0 [mm]	Free length
g [mm]	Initial distance beetween coils
Lc ~ [mm]	Solid height
λ	"Slimness" ratio (L0/D)
w	Spring index (D/d)
De [mm]	Outer diameter
R [N/mm]	Stiffness
Fe [Hz]	Resonant frequency
LOAD DEFINITION
	Define using:	Load     Deflection
Fo [N]	Preload
so [mm]	Preload
Fmax [N]	Maximum load
Fmin [N]	Minimum load
smax [mm]	Maximum deflection
smin [mm]	Minimum deflection
Δs [mm]	Stroke
ξ(s)	Relative deflection (smax/L0)
STATIC CHECK
Ks	Curvature ratio
τc zul [Mpa]	Acceptable stress
Fstatmax [N]	Acceptable maximum load
f_statmax [mm]	Acceptable maximum deflection
	Safety ratio	OK, c.s.=

Spring behaviour

Deflection (mm)

Legenda:

———

Load curve

– – –

Overload (if exists)

▲

Minimum load

◆

Maximum load

●

Solid length

FATIGUE CHECK
τmax [Mpa]	Maximum torsional stress
τmin [Mpa]	Minimum torsional stress
Kw	Wahl correction factor
τk2 [Mpa]	Maximum torsional stress (corrected)
τk1 = τkU [Mpa]	Minimum torsional stress (corrected)
τkh [Mpa]	Stress amplitude
	Unlimited fatigue check