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**A new three-dimensional interface finite element to simulate fracture in composites.**
*(English)*
Zbl 1119.74609

Summary: A new three-dimensional quadratic interface finite element is developed. The element is made up by two 6-noded triangular surfaces which initially lie together and connect the faces of adjacent quadratic tetrahedra, the only elements supported by automatic meshing algorithms. The element is introduced within the framework of implicit analysis and large displacements, and can include any traction-separation law at the interface. It is aimed at simulating damage by particle fracture and interface decohesion in composites by the numerical simulation in three-dimensions of a representative volume element which reproduces the microstructure. The element was validated by comparison with previous results of sphere-matrix decohesion obtained in two-dimensional, axisymmetric conditions. In addition, a new control technique is presented to obtain the whole load-displacement curve at a reasonable computational cost when progressive damage throughout the model (due to the simultaneous development of multiple cracks) leads to severe numerical instabilities. The potential of the new element and the control technique were checked in simulations including sphere fracture in composites made up of random distribution of elastic spheres within an elasto-plastic matrix.

### MSC:

74S05 | Finite element methods applied to problems in solid mechanics |

74R99 | Fracture and damage |

74E30 | Composite and mixture properties |