• Fracture Mechanics as Applied to Bi-Material Interfaces

• Damage Detection and Residual Life Assessment of Structures

• Fracture Behavior of Cracked Beam-Columns

• Failure Analysis of Laminated Composite Structures

 

 

 

 

 

 

 

 

Fracture Mechanics as Applied to Bi-Material Interfaces

Studies on crack propagation at the interface of dissimilar materials have been carried out. This is done in order to

• determine the fracture properties such as fracture toughness and fracture energy of concrete-concrete cold jointed interface.

• develop analytical tools using the contour integration and weight function methods for evaluating the mode I and mode II stress intensity factors.

• assess the shear friction factor of safety of gravity dams at the interface of concrete superstructure and rock foundation.

• evaluate the strength of concrete-concrete cold lift joints in large structures such as dams, nuclear containment vessels etc.,

• study the effect of heat of hydration in mass concrete structures on cracking phenomenon

• study the delamination process in different bi-material systems and composites

 

 

Damage Detection and Residual Life Assessment of Structures

A method for damage detection and assessment is developed using the concepts of inverse method and fracture mechanics The objectives are to detect, locate and quantify any damage that has occurred within a beam during its service using displacement measurements taken at some arbitrary points along it.

Studies on residual life assessment of plain and reinforced concrete members are done using fatigue and fracture mechanics conceptS. This includes the study of fatigue crack growth as a function of time, and the effects of crack propagation on structural strength. The residual life is determined in terms of the number of applied load cycles the beam can withstand before reaching the critical crack length.

The fatigue life of concrete is estimated using a method that correlates between fracture mechanics and damage mechanics. Two models, one based on the conventional strength of materials approach and the other based on global energy equivalence are proposed for correlating the fracture based on discrete crack and damage based on effective elastic moduli for concrete under fatigue loading. The objective is to relate discrete crack length obtained using fracture mechanics theory to the isotropic scalar damage parameter of damage mechanics and vice versa.

 

 

Fracture Behavior of Cracked Beam-Columns

The fracture behavior of cracked beam-columns with different eccentricities and subjected to axial and lateral loads is studied using a cracked beam-column element.

 

Failure Analysis of Laminated Composite Structures

In this work, a fracture mechanics based finite element technique is being developed to assess the damage in composite hardware such as rocket motor case and pressure bottles that has undergone pressure cycles in order to estimate their residual life and assess their potential for reuse.