3-DIMENSIONAL WAVE-EQUATION FOR A CORD AND N-SPIRAL SOLITARY WAVE SOLUTION

A three-dimensional wave equation which describes large deformations o f a cord (thin rope) is obtained. It is shown that the wave equation h as an N-solitary wave solution propagating with the same velocity and maintaining their initial shapes. In addition, the N-solitary wave sol ution of a factorized form is also derived through an application of o ne-spiral solitary wave solution, which is a time-dependent extension of the one-spiral curve of an elastic wire discussed by H Tsuru J. Phy s. Soc. Japan 56 (1987) 2309.