Somnath Bhattacharya

Mixed-mode fatigue crack growth analysis of functionally graded materials by XFEM

The present study investigates the fatigue life of a functionally graded material (FGM) made of aluminum alloy and alumina (ceramic) under cyclic mixed mode loading. The fatigue lives of aluminum alloy, FGM and an equivalent composite (having the same composition as of FGM) are compared for a major edge crack in the rectangular domain. The extended finite element method is used to simulate the fatigue crack growth under plane strain conditions. Various discontinuities such as minor cracks, holes and inclusions of arbitrary sizes are randomly located in the domain along with the major edge crack. Paris law is used to evaluate the fatigue life of the aluminium alloy, FGM and equivalent composite.

Fatigue-life estimation of functionally graded materials using XFEM

The present work deals with the fatigue crack growth simulation of alloy/ceramic functionally graded materials (FGMs) using extended finite element method (XFEM). Various cases of FGM containing multiple inhomogeneities/discontinuities along with either a major edge or a center crack are taken for the purpose of simulation. The fatigue life of the FGM plate is calculated using Paris law of fatigue crack growth under cyclic loading. The effect of multiple inhomogeneities/discontinuities (minor cracks, holes/voids, and inclusions) on the fatigue life of cracked FGM plate is studied in detail. These simulations show that the presence of inhomogeneities/discontinuities in the domain significantly influences the fatigue life of the components.

Fatigue Crack Growth Analysis of Functionally Graded Materials by EFGM and XFEM

The present work investigates the fatigue life of a functionally graded material (FGM) made of aluminum alloy and alumina (ceramic) under cyclic mixed mode loading. Both element free Galerkin method (EFGM) and extended finite element method (XFEM) are employed to simulate and compare the fatigue crack growth. Partition of unity is used to track the crack path in XFEM while a new enrichment criterion is proposed to track the crack path in EFGM. The fatigue lives of aluminum alloy, FGM and an equivalent composite (having the same composition as of FGM) are compared for a major edge crack and center crack in a rectangular domain. The proposed enrichment criterion not only simulates the crack propagation but it also extends the applicability and robustness of EFGM for accurate estimation of fatigue life of component.

Numerical simulation of elastic plastic fatigue crack growth in functionally graded material using the extended finite element method

ABSTRACT In the present work, the extended finite element method has been used to simulate the fatigue crack growth problems in functionally graded material in the presence of holes, inclusions, and minor cracks under plastic and plane stress conditions for both edge and center cracks. Both soft and hard inclusions have been implemented in the problems. The validity of linear elastic fracture mechanics theory is limited to the brittle materials. Therefore, the elastic plastic fracture mechanics theory needs to be utilized to characterize the plastic behavior of the material. A generalized Ramberg-Osgood material model has been used for modeling purposes.

Analysis of interface crack in piezoelectric materials using extended finite element method

ABSTRACT In the present work, static impermeable crack at interface of piezoelectric materials is analyzed using an extended finite element method. An edge crack and center crack at the interface of PZT-5H and PZT-4 for k-class singularity of piezoelectric materials have been analyzed under mechanical and electromechanical loadings. Enrichment functions for k-class are used for determining the asymptotic fields near the crack tip. KI and KIV are determined using the interaction integral. The effect on fracture parameters of major crack due to minor cracks, holes, and combination of minor cracks and holes has been investigated. The variation in intensity factors with elastic field and electric displacement has been analyzed.