Device and method for investigation of mechanical properties of the materials under high-strain rate tensile load

TL;DR

This paper introduces the Split Flying Bar, a novel apparatus and method for investigating material behavior under high-strain-rate tensile loads, allowing scalable testing of various materials with high strain to failure.

Contribution

The paper presents a new scalable apparatus and method for high-strain-rate tensile testing, enabling analysis of materials with high strain to failure, unlike traditional methods.

Findings

The method allows tuning of stress and strain rate by adjusting mass and velocity.

It can test specimens from single filaments to macroscopic sizes.

The apparatus enables investigation of materials with very high strain to failure.

Abstract

A new apparatus and method is proposed for the investigation of material behavior under high-strain-rate tensile loads. We refer this apparatus as a Split Flying Bar. The method is based on using the inertia of a working mass attached to a specimen. The specimen is placed between the working mass (front part of the bar) and backing part of the bar, which is captured in flight by special brake. When the back part of the flying split bar is stopped, the working mass continues the flight by inertia, creating specimen tension with strain rate depending on the length of specimen and velocity of flying bar. Properly choosing the working mass and the speed of the flying bar, one can tune maximal stress and strain rate over a wide range. The method is highly scalable and can be used for investigation of specimens from single filament up to reasonable macroscopic size. Contrary to tensile SHPB, the method provides a way to investigate materials with practically arbitrary strain to failure. For example, polyuria, whose strain to failure reaches hundreds of percent. Also, the method can be used for high-strain rate pull-out tests or to measure the quality of adhesion layers under high-stress rates, e.t.c. In this paper I introduce the basics of the method and interpretation of the data.