List of symbols

Symbol	Name of the symbol	Unit
$ $	trapezoidal thread	$\mathrm{ }$
$ $	type of strut mounting	$\mathrm{ }$
$C_c$	coefficient according to load	$\mathrm{ }$
$C_t$	power screw coefficient	$\mathrm{ }$
$D_1$	minor diameter for internal threads	$\mathrm{mm}$
$D_4$	major diameter for internal threads	$\mathrm{mm}$
$E$	Young's modulus	$\mathrm{MPa}$
$F$	force	$\mathrm{N}$
$F_{max}$	maximal (critical) force	$\mathrm{N}$
$H_1$	height of the overlapping	$\mathrm{mm}$
$H_4$	height of internal threads	$\mathrm{mm}$
$I$	second moment of area	$\mathrm{mm^4}$
$L$	strut length	$\mathrm{mm}$
$M_T$	twisting moment	$\mathrm{Nm}$
$M_T$	lifting torque	$\mathrm{Nm}$
$P$	pitch	$\mathrm{mm}$
$P_{B-screw-nut}$	bearing stress in the screw and nut	$\mathrm{MPa}$
$P_{all-B-nut}$	allowable bearing stress the nut	$\mathrm{MPa}$
$P_{all-B-screw}$	allowable bearing stress the screw	$\mathrm{MPa}$
$R_{1max}$	dimension $ R_{1max} $	$\mathrm{mm}$
$R_{2max}$	dimension $ R_{2max} $	$\mathrm{mm}$
$S$	profile area	$\mathrm{mm^2}$
$S_F$	safety factor	$\mathrm{ }$
$S_{FB}$	safety factor buckling	$\mathrm{ }$
$S_{y-nut}$	the minimum yield strength of the nut	$\mathrm{MPa}$
$S_{y-screw}$	the minimum yield strength of the screw	$\mathrm{MPa}$
$a_c$	clearance on the crest	$\mathrm{mm}$
$c$	extreme fiber distance	$\mathrm{mm}$
$d$	major diameter for external thread (nominal diameter)	$\mathrm{mm}$
$d_2$	pitch diameter for external threads	$\mathrm{mm}$
$d_3$	minor diameter for external threads	$\mathrm{mm}$
$e$	eccentricity	$\mathrm{mm}$
$h_3$	height of external threads	$\mathrm{mm}$
$i$	gyration radius	$\mathrm{mm}$
$l$	length nut	$\mathrm{mm}$
$n$	speed	$\mathrm{rpm}$
$v$	screw speed	$\mathrm{m/s}$
$z$	dimension $ z $	$\mathrm{mm}$
$β$	coefficient for buckling	$\mathrm{ }$
$η$	eccentricity parameter	$\mathrm{ }$
$λ$	slenderness ratio	$\mathrm{ }$
$μ$	friction coefficient	$\mathrm{ }$
$σ_{A-screw}$	axial stress in the screw	$\mathrm{MPa}$
$σ_{all-A-screw}$	allowable axial stress the screw	$\mathrm{MPa}$
$σ_{all-C-screw}$	allowable combined stress the screw	$\mathrm{MPa}$
$σ_{tresca-screw}$	combined stress in the screw	$\mathrm{MPa}$
$τ_{S-screw}$	shear stress in the screw	$\mathrm{MPa}$
$τ_{all-S-screw}$	allowable shear stress the screw	$\mathrm{MPa}$