Static and dynamic behavior of concrete and granite in tension with damage J.T. Gomez a , A. Shukla b, * , A. Sharma b a Code 8232, Naval Undersea Warfare Center, Newport, RI 02841, USA b Dynamic Photomechanics Laboratory, Department of Mechanical Engineering and Applied Mechanics, University of Rhode Island, 92 Upper College Rd., Wales Hall, Kingston, RI 02881-0805, USA Abstract A series of dynamic and static tensile-splitting experiments were performed on concrete and granite specimens to investigate the eect of induced damage on their tensile strength. These experiments were performed as part of a larger eort investigating the penetration process into the two materials. The strain rate each specimen was subjected to remained constant for these experiments, while the level of induced damage was increased. Damage was induced into the specimens through repeated drop-weight impacts and quanti®ed using a statistical technique. The dynamic splitting experiments were performed using a split Hopkinson pressure bar SHPB), while the static splitting experiments were conducted per the ASTM standard procedures D3967 and C496. As part of the investigation, photoelastic dynamic tensile-splitting experiments were also performed to establish the validity of using static relations for the determination of dynamic tensile strength. The experiments showed that the static splitting strength was highly dependent on the orientation of the induced damage with regard to the applied loading; however the dynamic tensile strength decreased with increasing damage with no apparent dependency on the random damage orientation. Photoelastic experiments have shown that the mechanism of failure changes for the dynamically tested damaged specimens, reducing their de- pendence on damage orientation. Ó 2001 Elsevier Science Ltd. All rights reserved. 1. Introduction This experimental study of the dynamic be- havior of concrete and granite with induced damage is a portion of a larger study into the multiple impact penetration of these materials. During the penetration process caused by multiple impacts, damage is accumulated in the region around the impact zone. The strength of cemented materials is a function of the inherent ¯aws present throughout the materials [1]. By inducing damage into a material, the inherent ¯aws will grow in size and number, and the strength should decrease. Therefore, it becomes important to understand the eect of damage on dynamic material strength in the study of multiple impact penetration. To study the eect of induced damage on the strength of the G-mix Air Force concrete and Barre granite materials, whose properties are shown in Table 1, damage was induced into the specimens by repeatedly dropping a weight onto the face of each specimen. The amount of specimen damage was quanti®ed by a measure of the crack surface area created by the damage. Theoretical and Applied Fracture Mechanics 36 2001) 37±49 www.elsevier.com/locate/tafmec * Corresponding author. Tel.: +1-401-874-2283; fax: +1-401- 874-2950. E-mail addresses: gomezjt@npt.nuwc.navy.mil J.T. Go- mez), shuklaa@egr.uri.edu A. Shukla), sharmaa@egr.uri.edu A. Sharma). 0167-8442/01/$ - see front matter Ó 2001 Elsevier Science Ltd. All rights reserved. PII:S0167-844201)00054-4