# 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 | $\mathrm{°}$ |