List of symbols

Symbol Name of the symbol Unit
$C$ spring index $\mathrm{ }$
$D$ mean coil diameter $\mathrm{mm}$
$D$ spring outer diameter $\mathrm{mm}$
$D_0$ mean coil diameter (vertex) $\mathrm{mm}$
$D_0$ spring inner diameter $\mathrm{mm}$
$D_1$ mean coil diameter (base) $\mathrm{mm}$
$E$ modulus of elasticity $\mathrm{GPa}$
$E_p$ energy stored $\mathrm{J}$
$F$ force $\mathrm{N}$
$G$ shear modulus $\mathrm{GPa}$
$K_W$ wahl factor $\mathrm{ }$
$L$ effective spring length $\mathrm{mm}$
$M$ applied torque moment $\mathrm{Nm}$
$S_F$ safety factor $\mathrm{ }$
$S_y$ the minimum yield strength $\mathrm{MPa}$
$d$ diameter of the spring wire $\mathrm{mm}$
$f$ spring deflection $\mathrm{mm}$
$k$ spring stiffness $\mathrm{N/m}$
$n$ number of active coils $\mathrm{ }$
$r$ spring length $\mathrm{mm}$
$δ$ spring thickness $\mathrm{mm}$
$σ$ tensile stress $\mathrm{MPa}$
$σ_B$ bending stress $\mathrm{MPa}$
$σ_{adm}$ material admissible stress $\mathrm{MPa}$
$τ_S$ shear stress $\mathrm{MPa}$
$τ_{adm}$ shear admissible stress $\mathrm{MPa}$
$φ$ spring angular deflection $\mathrm{°}$