A new drop weight tensile testing system for soft matter at intermediate strain rates

Abstract

This paper presents a novel and versatile tensile testing system based on the drop weight technique, specifically designed for materials that can undergo significant tensile deformation, such as elastomers. The core apparatus comprises of a hanging slender bar, from which a steel sleeve (referred to as the striker) is released under controlled conditions. Accelerated in free fall, the striker impacts a stationary plate, initially held in place by a mechanical detent. The specimen, secured by a gripping system between the hanging bar and the stationary support, undergoes controlled stretching at a nearly constant velocity upon the release of the detent triggered by the striker’s impact. Full-field strain measurement is obtained using a high-speed camera in conjunction with digital image correlation. Additionally, strategically located piezoresistive force sensors enable real-time force measurements. By achieving strain rates ranging from 100 s⁻¹ to 500 s⁻¹, this system addresses a notable gap in the literature concerning intermediate strain rate testing for soft materials.