Contemporary Research in Engineering Science Batra, Romesh C.

Fatigue failures occur in aerospace,marine,nuclear structures and automobile com­ ponents from initiation and propagation of cracks from holes,scratches or defects in the material. To design against these failures, crack propagation life and fracture strength need to be accurately predicted. It is reported in the literature, that these failures often initiate as surface cracks, corner cracks and cracks emanating from fastner holes. Such cracks are with elliptic or nearly elliptic in shapes. The deviation from elliptic shape is due to varying constraint effect along the crack front. Even in situations, when the cracks are through the thickness of the material, there would be thicknesswise variation of constraint effects leading to three dimensional nature of crack growth. Accurate predictions of the crack growth in these cases by numerical methods can be made only by solving three-dimensional boundary value problems. Empirical relationships have been developed [1] based on Linear Elastic Fracture Mechanics over years describing fatigue crack growth response. Some of these empirical relationships required modifications in the later stages, to meet the design applications. The Crack closure phenomenon discovered by Elber[2, 3] during the crack growth phase is mainly attributed to the local material yielding near the crack tip and the consequent residual plastic wake behind the crack tip. It helped considerably in understanding several aspects of fatigue crack growth and rewrite these relations.

Prediction of Damage Evolution in Continuous Fiber Metal Matrix Composites Subjected to Fatigue Loading.- FE Analysis of Fracture with Debonding in Ceramic/Metal Joint.- Analyses of Oxide Layer Cracking Patterns of MA956 and MA956/Sapphire Composite Systems.- Elastic Material with Systems of Growing or Closing Cracks: Tangential Stiffness.- Generalized Dundurs Parameters and the Bimateriai Anisotropic Interfacial Crack.- A Comparative Study on Three BEM Approaches for Dynamic Elastoplastic Analysis.- Effective Elastoplastic Behavior of a Class of Two-Phase Composites with a Polycrystal-Like Microstructure.- The T*-Integral: Definition and Use for Predicting Damage Accumulation and Fracture.- Numerical Simulation of the Super Boom Problem.- From Shakedown Theory to Fatigue Fracture of Ductile Materials.- Computation of Stress Intensities for Edge Delamination in a Laminated Composite Strip Under Generalized Plane Deformation.- Accuracy of Finite Element Solutions for Flexible Beams Using Corotational Formulation.- Static and Free Vibration Analysis of Composite Plates and Shells Using a Flat Shell Element.- Three-Dimensionai Elasticity Solution for the Buckling of Moderately Thick Orthotropic Columns.- Optimum Structural/Control Design with Robustness Constraints.- Fracture Analysis of a SiC Particle Reinforced Aluminum Alloy.- Case Studies in Aircraft Structural Integrity.- Self-Propagating Synthesis Route to High Performance Ceramic Materials.- Present-day Computing Environment.- Vorticity Transport, Dynamical Systems and Bifurcation Analysis in Hydrodynamic Stability.- Shape Optimization of Ceramics/Metal Joint Based on Reliability.- Multi-Domain Modeling of Delaminated Stiffened Composite Shells.- A Unified Derivation of Explicit Expressions for Transient Asymptotic Solutions of Dynamically Propagating Cracks Under the Mode I, II and III Unsteady State Conditions.- A Reinvestigation of Stress-Intensity Factors for Surface and Corner Cracks in Three-Dimensional Solids.- On the Role of Microcracking in the Dynamic Fracture of Polymethylmethacrylate.- Relaxation Models for Normal Stresses in Turbulent Shear Flows.- Finite Element Analysis of Engine Rotor Failure and Containment.- Three-Dimensional Elastic-Plastic Finite Element Analysis of Crack Closure in CT Specimen.- Effect of MSD on Large Damage Residual Strength.- Two Dimensional Channel Flow with Uniform Boundary Suction or Source.- Creep Modeling for Composite Structures.- Incremental Damage Theory for Metal Matrix Composites.- Three-Dimensional Solutions for Free Vibrations of Initially-Stressed Thermoelectroelastic Multilayered Plates.- On the Penalty Method of Stokes Equations and Biphasic Mixture Model of Soft Hydrated Tissues.- Elasto-Plastic Analysis of Rigid Frames Under Cyclic Loading Using Minimum Residual Displacement Method.- A Neural Network-Based Finite Element Method on Parallel Processors.- Equations for the Extension and Flexure of Relatively Thin Thermopiezoelectric Plates Subjected to Large Electric Fields.- An Expansion Series for Solving Improper Cylindrical Functions Occurring in Subsonic, Supersonic and Transonic Kernel Formulation.