PipeDev — Expansion Joint (Bellows)

Expansion Joint

Thin-walled bellows — sinusoidal profile revolved; each convolution develops to a flat annular sector.

Principle & formula

Meridional profile r(x)=R₀+A·sin(2π·n·x/L). One convolution develops to an annular sector of mean radius R₀ and radial width = meridional arc length ∫√(1+(dr/dx)²)dx.

Mean diameter (D)

Wave amplitude (A)

Convolutions (n)

Pitch length (L)

Advanced — material & allowance

Material thickness (t)

Hem / seam allowance (a)

Second plate (companion)

Development Pattern

Print at 100% scale. Dimensions are in millimetres.