Journal of the Mechanics and Physics of Solids 50 (2002) 1547–1564 www.elsevier.com/locate/jmps Intersonic crack propagation in homogeneous media under shear-dominated loading: theoretical analysis Dhirendra V. Kubair a; b , Philippe H. Geubelle a; b; * , Yonggang Y. Huang c a Department of Aeronautical and Astronautical Engineering, MC 236, University of Illinois at Urbana-Champaign, 306 Talbot Lab.; 104 South Wright Street, Urbana, IL 61801, USA b Center for the Simulation of Advanced Rockets, University of Illinois at Urbana-Champaign, 306 Talbot Lab.; 104 South Wright Street, Urbana, IL 61801, USA c Department of Mechanical and Industrial Engineering, University of Illinois at Urbana-Champaign, 306 Talbot Lab.; 104 South Wright Street, Urbana, IL 61801, USA Received 6 June 2001; accepted 29 January 2002 Abstract The mechanics of cohesive failure under mixed-mode loading is investigated for the case of a steadily propagating subsonic and intersonic dynamic crack subjected to a follower tensile and shear distributed load. The cohesive failure model chosen in this study is rate independent but accounts for the coupling between normal and tangential damage. Special emphasis is placed here on mixed-mode cases with predominantly shear loading. The analysis shows that the size of the mixed-mode cohesive zone is smaller than that obtained in the pure shear case. The relative extent of the shear and tensile cohesive damage zones depends on the crack speed and the mode mixity. In the intersonic regime, the failure process takes place exclusively in shear, even under remote mixed-mode loading conditions. ? 2002 Published by Elsevier Science Ltd. Keywords: A. Dynamic fracture; B. Elastic material; C. Boundary integral equations 1. Introduction In a recent article, Geubelle and Kubair (2001) have presented the results of a numerical analysis of the intersonic motion of a planar crack (i.e., for which the crack * Corresponding author. Tel.: +1-217-244-7648; fax: +1-217-244-0720. E-mail address: geubelle@uiuc.edu (P.H. Geubelle). 0022-5096/02/$ - see front matter ? 2002 Published by Elsevier Science Ltd. PII:S0022-5096(02)00005-4