The cohesive law for the particle/matrix interfaces in high explosives

Development of an image-based numerical model for predicting the microstructure–property relationship in alumina trihydrate (ATH) filled poly(methyl methacrylate) (PMMA)

“…The model calculations are outlined in the Appendix and the interfacial strength was estimated at approximately 200 MPa. This is the same order of magnitude as the value of 119 MPa obtained using the method by Tan et al (2005b). Williams's model assumes the composites are only toughened by the debonding of the particles, whilst in reality, there are other toughening mechanisms including crack pinning, deflection and blunting.…”

“…The parameters needed in the cohesive zone model have been determined experimentally using the methodology outlined in Tan et al's work (Tan et al 2005b). For the definition of the interface behaviour in the numerical simulation, the initial linear stiffness of the interface, k σ , the cohesive strength, σ int max and the cohesive fracture energy release rate, γ int , need to be determined.…”

“…Using the calculated value of φ f N α N as 0.5, the value of the macroscopic cohesive stress, σ , is given by (Tan et al 2005b):…”

“…According to Tan et al (2005b), the normal traction stress on the interface equals the value of σ f N . Since the relatively bigger particles debond first (Jung et al 2000) and the values of α N converge to the value α N ≈ 2.4 at large particle diameter (see Fig.…”

“…In addition to the experiments outlined above, compact tension tests were also performed in order to characterise the properties of the interface between the ATH particle and the PMMA matrix in accordance of the method proposed by Tan et al (2005b). Since the same coupling agent was used in all the composites, CT tests were only performed on three replicates of composite C. The tests were performed according to the ISO 13586 standard (ISO 2000) on an Instron 3369 system fitted with a 5 kN load cell, at a crosshead motion rate of 10 mm/min.…”