Longitudinal shock waves in a class of semi-infinite stretch-limited elastic strings

TL;DR

This paper introduces a new mathematical model for wave propagation in stretch-limited elastic strings, analyzing shock waves, stability, and finite-time tension blow-up in semi-infinite strings without external forces.

Contribution

It develops a novel shock front problem for stretch-limited strings, proving existence, uniqueness, and stability of solutions, and explores finite-time tension blow-up scenarios.

Findings

Existence and uniqueness of local solutions for the shock problem.

Orbital asymptotic stability of specific stretch motions.

Finite-time tension blow-up under increasing tension at infinity.

Abstract

In this paper, we initiate the study of wave propagation in a recently proposed mathematical model for stretch-limited elastic strings. We consider the longitudinal motion of a simple class of uniform, semi-infinite, stretch-limited strings under no external force with finite end held fixed and prescribed tension at the infinite end. We study a class of motions such that the string has one inextensible segment, where the local stretch is maximized, and one extensible segment. The equations of motion reduce to a simple and novel shock front problem in one spatial variable for which we prove existence and uniqueness of local-in-time solutions for appropriate initial data. We then prove the orbital asymptotic stability of an explicit two-parameter family of piece-wise constant stretched motions. If the prescribed tension at the infinite end is increasing in time, our results provide an open set of initial data launching motions resulting in the string becoming fully inextensible and tension blowing up in finite time.