3-D Finite element modelling of diamond pull-out failure in impregnated diamond bits

- The interfacial failure of impregnated diamond bits is analyzed.
- The critical force for initiation of interface de-bonding between the diamond and the matrix is determined.
- Cohesive zone modelling technique is used to simulate the failure at the interface.
- Factors that have significant influence on the retention capacity of diamond particle are studied.

In this study, the finite element and cohesive zone technique are used to analyse the failure mechanisms of impregnated diamond bits. The bit consists of diamond particles randomly distributed within a metal matrix. Investigations are carried out using a three-dimensional numerical model of a single diamond particle embedded in a metal matrix. This study is mainly focused on the interfacial debonding behaviour between the diamond particle and the matrix for an assessment of diamond retention capacity of these drilling bits. A zero thickness surface based cohesive zone modelling technique is used to simulate the failure at the interface. In order to validate the present model, few example problems are solved by the model and the results obtained are compared with the published results which show a good performance of the model. The effects of diamond particle shapes, orientations and the interface properties on the retention capacity of diamond particles in the bit are studied by conducting a parametric study.

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