Publications

Finite Element Simulation of the Laser Shock Peening Process on 304L Stainless Steel

This study investigates the effects of Laser Shock Peening (LSP) on residual stress distribution and surface deformation using a Finite Element Method (FEM) model. LSP is a surface treatment process that generates compressive residual stress by applying high-energy laser pulses over nanosecond timescales. The study aims to analyze the impact of key parameters, specifically laser spot overlap rate and power density, on the induced residual stress and surface deformation. A Design of Experiment (DOE) approach was used to systematically vary these parameters. These simulations were performed using the ANSYS Explicit Dynamics FEM with a Johnson-Cook material model to capture the nonlinear constitutive behavior. The research analyzes the distribution of residual stress and surface deformation caused by LSP. Increasing laser spot overlap and power density leads to higher compressive residual stress and surface deformation, revealing two distinct behavioral outcomes: either deep compressive stress with minimal deformation or a transition from compressive to tensile stress followed by significant surface deformation and a subsequent return to compressive stress. The results demonstrate strong agreement with existing experimental data presented in the literature. This study contributes novel insights into the interaction between LSP parameters and their effects on material properties, with implications for understanding LSP techniques in practical applications. The triangular pulse model and dual-overlap analysis offer a novel simulation strategy for optimizing LSP parameters in stainless steel.

The role of strain rate response on transfer layer formation during sliding

Understanding the stress corrosion cracking resistance of laser shock surface patterned austenitic stainless-steel weld joints

Surface texturing by indirect laser shock surface patterning for manipulated friction coefficient

Studies on Friction and Formation of Transfer Layer in HCP Metals

Surface texture plays an important role as it predominantly controls the frictional behavior and transfer layer formation at the contacting surfaces. In the present investigation, basic studies were conducted using inclined pin-on-plate sliding tester to understand the role of surface texture of hard material on coefficient of friction and transfer layer formation when sliding against soft materials. HCP materials such as pure Mg and pure Zn were used as pins while 080 M40 steel was used as plate in the tests. Two surface parameters of steel plates — roughness and texture — were varied in the tests. Tests were conducted in ambient conditions under both dry and lubricated conditions. The morphologies of the worn surfaces of the pins and the formation of transfer layer on the counter surfaces were observed using a scanning electron microscope. It was observed for both the pin materials that the occurrence of stick-slip motion, the transfer layer formation and the value of coefficient of friction as well as its two components, namely, adhesion and plowing, depend primarily on surface texture. The effect of surface texture on coefficient of friction was attributed to the variation of plowing component of friction for different surfaces. Both the plowing component of friction and amplitude of stick-slip motion were highest for the surface texture that promotes plane strain conditions while these were lowest for the texture that favors plane stress conditions at the interface.

Studies on friction and transfer layer: role of surface texture

Distance-controlled direct ink writing of titanium alloy with enhanced shape diversity and controllable porosity

Self-Lubricating Polymer Matrix Composites

Smart manufacturing approach to manufacture bulk nanocrystalline aluminum for lightweight applications

Fundamentals of Engineering Surfaces

Influence of Grain Boundary Character on Dopants Segregation in Nanocrystalline Aluminum

Assessing the tribo-corrosion resistance of surface nanostructured stainless-steel

Mechanical, physical and tribological characterization of nano-cellulose fibers reinforced bio-epoxy composites: An attempt to fabricate and scale the ‘Green’ composite

Subsurface deformation and the role of surface texture—A study with Cu pins and steel plates

ROLE OF SURFACE TEXTURE ON FRICTION AND TRANSFER LAYER FORMATION WHEN PURE ALUMINUM PINS SLID AT VARIOUS NUMBERS OF CYCLES ON STEEL PLATES

In the present investigation, various kinds of textures, namely, unidirectional, 8-ground, and random were attained on the die surfaces. Pins made of aluminum were then slid against steel plates for various numbers of cycles using a pin-on-plate reciprocating sliding tester. It was observed that the friction and transfer layer formation depended on the die surface textures. Under lubricated conditions, the friction decreased for unidirectional and 8-ground surfaces but increased for random surfaces as a function of cycles. Under dry conditions, the friction increased with increasing number of cycles for all kinds of surfaces. In the tests, the friction was always highest when sliding was perpendicular to the unidirectional textures and was lowest for the random textures under both dry and lubricated conditions. The difference in friction values between these two surfaces decreased with increasing number of cycles. The variation in the friction was attributed to the change in texture of the surfaces during sliding.

A Brief Review of Fly Ash as Reinforcement for Composites with Improved Mechanical and Tribological Properties

Experimental and numerical analysis of helical-wedge rolling process for producing steel balls

Disruptive Manufacturing of Oxide Dispersion-Strengthened Steels for Nuclear Applications: Advances, Challenges, and Future Prospects

Oxide dispersion-strengthened (ODS) steels are emerging as leading candidate materials for next-generation nuclear reactor components due to their exceptional resistance to creep, fatigue, and irradiation, combined with high strength at elevated temperatures. This paper investigates the microstructural mechanisms underpinning these superior properties, with a particular focus on the critical role of nano-oxides in enhancing performance. Various manufacturing techniques, including powder metallurgy and additive manufacturing, are reviewed to assess their impact on the structural and mechanical properties of ODS steels. Recent case studies on their application in nuclear environments highlight the potential of ODS steels to significantly extend component longevity without necessitating major reactor redesigns. Nevertheless, further research is necessary to assess their reliability under extreme environmental conditions and to determine optimal, scalable manufacturing processes for large-scale production.