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Transition from Crack-Type to Spall-Type Failure Mode in Interfacial Debonding Under Tensile Loading

Meng Wang¹, Jay Fineberg², Alan Needleman^3,*

1 Institute of Advanced Structure Technology, Beijing Institute of Technology, Beijing, 100081, China
2 The Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem, 9190500, Israel
3 Emeritus, Brown University, Providence, RI, RI 02912, USA

* Corresponding Author: Alan Needleman. Email:

The International Conference on Computational & Experimental Engineering and Sciences 2025, 33(4), 1-1. https://doi.org/10.32604/icces.2025.011000

Abstract

Brittle materials fail by means of rapid cracks. At their tips, tensile cracks dissipate elastic energy stored in the surrounding material to create newly fractured surfaces, precisely maintaining 'energy balance' by exactly equating the energy flux with dissipation. Using energy balance, fracture mechanics perfectly describes crack motions; accelerating from nucleation to their maximal speed of cR, the Rayleigh wave speed. A tensile crack speed greater than cR is generally considered impossible [1]. Recently, a new mode of tensile crack propagation faster than cR that is not incorporated in classical fracture mechanics has been predicted in lattice models and observed in fracture experiments on brittle hydrogels under high applied stretch [2,3]. In this talk, we present a distinct mechanism that facilitates tensile fracture beyond cR. We conducted experiments and numerical simulations on an elastic plate with a weak interface under remote dynamic tensile loading [4]. The cohesive constitutive law, which describes the relationship between normal tractions and opening displacement jumps, was applied across the weak interface. Various cohesive properties were examined. A transition from sub-Rayleigh to super-Rayleigh crack propagation, or alternatively to spall-like separation, was observed during the debonding process. The results reveal that a characteristic length scale, associated with the cohesive properties, governs the transition between different debonding modes.

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