Numerical simulation of crack propagation in solid propellant with extrinsic cohesive zone model

To further investigate the fracture properties of solid propellant, crack propagation simulation technique is proposed for mode I fracture problems in conjunction with extrinsic cohesive zone model (CZM). Viscoelastic constitutive model for solid propellant and extrinsic Park-Paulino-Roesler (PPR) model constructed to characterize the fracture process are introduced in detail for the computational fracture mechanics approach using finite element method. Topological operations are employed to update the finite element information when extrinsic cohesive elements which represent the new crack facets are inserted. Single edge-notched tension (SENT) and three-point bending test are analyzed to demonstrate the accuracy and effectiveness of the proposed computational framework. Computational results demonstrate that crack propagation simulation technique with extrinsic CZM can provide more accurate fracture response than intrinsic CZM with predefined crack path.