Cohesive Zone Modeling of Propellant and Insulation Interface Debonding

Extraction of rate-dependent fracture properties of adhesive interface involving large-scale yielding

“…In order to bond the propellant and insulation, an adhesive consisting of 92.9% HTPB binder and 7.1% isophorone diisocyanate was mixed as shown in a previous study. [2] Two kinds of experiments, DCSB tests and UT tests, are carried out to determine the fracture energy and adhesive strength of the composite propellant/insulation interface. They provide the estimated values of the CZM parameters, cohesive energy and cohesive strength.…”

“…It should be noted that in this work, the initial stiffness is determined by matching the initial slope of the numerical load vs. displacement curve to the experimental one, as suggested in one previous work. [2] 4.2. Inverse analysis A numerical analysis was performed by modeling the same DCSB specimens as those used in the experiments.…”

“…Recently, Gain et al [29] took the full-field displacement field instead of global response as the input of the inverse analysis and extracted the objective cohesive shape using NelderMead algorithm. In order to keep the amount of computational work in the numerical simulation reasonable, Zhou et al [2] proposed a new method that integrated the CBT and inverse analysis to establish the interfacial parameters. Except those inverse analysis methods, other methods that combined the experimental and computational work are developed as well.…”

“…Previous experimental observations indicate that the large-scale yielding (LSY) phenomenon is commonly in adhesively bonded interface during loading. [1][2][3] Consequently, many theoretical and numerical work were done to investigate the LSY. The crack tip field for LSY was characterized in the analytic way.…”

Review of the Adhesively Bonded Interface in a Solid Rocket Motor

“…In the cohesive law, the traction increases with the opening displacement up to a threshold, then the traction will decrease along with the increasing displacement. In this way, the degradation in performance caused by the damage or yield of materials on the crack tip can be modeled.Zhou et al[86] first investigated the debonding simulation of the propellant/insulation interface with two kinds of CZM: bilinear law and an improved exponential law. The bilinear law is given as follows: subscript n and t represent the normal and tangential behaviors, T denotes the traction, and are the separation and characteristic length parameter, respectively.…”