Computational Mechanics
Fracture Mechanics
Composite Structures
Additive Manufacturing
Structural Health Monitoring
Thesis:
Ph.D. Thesis:
Title: Robust Finite Element Implementation of Damage-based Cohesive Zone Models: Application to Composite Delamination and Hydrofracturing of Glaciers
Advisor: Prof. Ravindra Duddu
Brief Description: We present a stabilized finite element method that generalizes Nitsche’s method for enforcing stiff anisotropic cohesive laws with different normal and tangential stiffness. For smaller values of cohesive stiffness, the stabilized method resembles the standard method, wherein the traction on the crack surface is enforced as a Neumann boundary condition. Conversely, for larger values of cohesive stiffness, the stabilized method resembles Nitsche’s method, wherein the cohesive law is enforced as a kinematic constraint. We present several numerical examples, in two-dimensions, to compare the performance of the stabilized and standard methods. Our results illustrate that the stabilized method enables accurate recovery of crack-face tractions for stiff isotropic and anisotropic cohesive laws; whereas, the standard method is less accurate due to spurious traction oscillations. Also, the stabilized method could mitigate spurious sensitivity of load–displacement results to displacement increment in mixed-mode fracture simulation, owing to its stability and accuracy.
M.Tech Thesis:
Title: Efficiency of Mode Shape-based Methods in Structural Damage Localization
Advisor: Prof. Samit Ray Chaudhuri
Brief Description: In this work, I have investigated the efficiency of the fundamental mode shape, higher mode shape and torsional mode shape in damage localization by performing numerical and experimental studies. I have done some analytical formulation for better understanding of the efficiency of the higher mode shapes in localizing damage. I found that the efficiency of the higher mode shapes is dependent upon the location of damage. So, to circumvent this problem I have proposed a wavelet-based approach for damage localization in a structure. In addition to that, I have carried out a simulation study to find out the efficiency of mode shape-based approach in localizing damage at multiple locations of a structure.