Nelson Muthu

• Doctor of Philosophy, IITB-Monash Research Academy
• Professor (Assistant) at Indian Institute of Technology Guwahati

This study explores the structural behavior of 3D-printed concrete (3DPC) walls through numerical simulations, with a focus on the impact of interfaces between printed layers. The numerical analysis is performed in ABAQUS®, with the concrete damage plasticity (CDP) model used to represent the printed layers, while cohesive zone modelling (CZM) is a...

Rubber-like materials that are commonly used in structural applications are modelled using hyperelastic material models. Most of the hyperelastic materials are nearly incompressible, which poses challenges, i.e., volumetric locking during numerical modelling. There exist many formulations in the context of the finite element method, among which the...

This study aims to determine the cohesive zone model (CZM) parameters for predicting the mixed-mode delamination of carbon fiber/epoxy composites reinforced with hydroxyl functionalized multi-walled carbon nanotubes (MWCNTs). The cohesive strengths of the composite laminate are measured through cross-tension and short beam shear (SBS) tests for ope...

The present work examines the fabrication and numerical modelling of honeycomb core sandwich sheets utilizing Friction Stir Spot Welding (FSSW) techniques as prospective substitutes for adhesive-bonded structures. Here, the sandwich sheet contains AA5052-H32 skins and AA3003 honeycomb core. Two strategies, FSSW with disc insert (FSSW_D) and FSSW wi...

A modified element‐free Galerkin (EFG) method that combines the Heaviside enrichment and diffraction method is used to study crack propagation problems by employing a cohesive zone model (CZM) with an exponential traction separation law (TSL). The generalized displacement control method (GDCM) is adopted to solve the nonlinearity arising during the...

This work is an attempt to study the feasibility of the friction stir spot welding (FSSW) of the sandwich sheet with honeycomb core and examine the effect of rotational speed on plunge load, torque, and lap-shear test performance. While keeping all other parameters constant, the plunge load decreases with the increase in the rotational speed of the...

The current study is concerned with the effect of friction stir welding (FSW) on the mechanical properties of aluminium alloy (AA1100). The FSW process was carried out using two rotational speed values—1100 rpm and 1500 rpm at a constant weld speed of 98 mm/min. The standard tensile and fracture (compact tension) specimens were prepared and subject...

Although the 3D-printed plate lattices have higher stiffness and strength than the strut lattices, the difficulty in fabricating the plate microlattices limited their potential application. The plate lattices require holes in the plates to remove the powder trapped inside, but introducing holes in plates in a lattice could reduce stiffness and stre...

The primary objective of the proposed work was to present a theoretical and computational procedure to predict the effective elastic properties of a periodic honeycomb structure. In the theoretical framework, the effective orthotropic elastic properties were determined using the strain-energy approach. Whereas in the computational procedure, a homo...

The present work is concerned with the study of interface crack using the extrinsic cohesive zone model (CZM) that nullifies the crack tip stress singularity. A semi-analytical procedure combining the generalized crack opening displacement solution and the finite element (FE) result is shown to estimate the traction-separation law (TSL) parameters....

A novel metamaterial lattice composite structure inspired by the particle reinforced composite materials was designed by combining the platePlate microlatticeand strut-microlatticeStrut microlattice topologies to achieve high stiffness. The previously published literature has shown that the plate latticePlate microlattice exhibits much higher stiff...

In order to mitigate the greenhouse gas emission level largely in the atmosphere the best possible solution is storing the CO2 in deep saline confined aquifers having impermeable caprock material on the top. However, such deep sedimentary rocks in the presence of water and brine saturation undergo degradation in their mechanical properties – elasti...

Predicting failure in composite materials under service loading conditions has been challenging due to the non-uniform mechanical properties arising from the composite fabrication process. Including these uncertainties in the analysis becomes critical. The probabilistic approach plays a vital role in making the design less conservative and anticipa...

In this work, both theoretical framework and computational modelling were used to estimate the in-plane elastic properties of the periodic re-entrant honeycomb. The strain-energy approach on the basis of the second theorem of Castigliano was extended to determine all the in-plane material properties in the theoretical framework. A suitable represen...

Influenza like pandemics are a severe threat to any established health care system as many thousands of patients would need emergency ventilator support during the acute respiratory failure stage, and this quickly overloads the existing facilities. The present article addresses the design and development of a human breathing assist machine (ventila...

An analytical method for determination of dimensions of longitudinal crack in monolithic beams, based on frequency measurements, has been extended to model L and inverted T cracks. Such cracks including longitudinal crack arise in beams made of layered isotropic or composite materials. A new formulation for modelling cracks in bi-material beams is...

The microstructure of composite materials is often distinguished by the size, shape and distribution of the reinforcing constituents. Various analytical, semi-analytical and computational approaches have been developed to determine their effective properties and to study the evolution of damage in these materials. The finite element method (FEM) ha...

A multiple crack weight technique with a level set method is proposed to model multiple cracks using a coarse meshfree nodal discretization. A new level-set structure is presented to handle multiple cracks and their propagation using the maximum tangential principal stress criterion. The level sets are updated with respect to the new crack tip posi...

A detailed study of bi-material composites, using meshless methods (MMs), is presented in this paper. Firstly, representative volume elements (RVEs) for different bi-material combinations are analysed by the element-free Galerkin (EFG) method in order to confirm the effective properties of heterogeneous material through homogenization. The results...

In this paper, a micromechanical model is presented, using the element-free Galerkin (EFG) method, to simulate the propagation of the damage, based on linear elastic fracture mechanics. The first case study involves precise modelling of a static crack with a crack tip normal to a bi-material interface. The stress intensity factor (SIF) obtained fro...

In this work, a novel approach to predict the path of crack propagation through particle-reinforced composites is presented. Simulations are based on the Element-Free Galerkin (EFG) method and linear elastic fracture mechanics (LEFM). A modified interaction integral, suitable for heterogeneous materials, was used to obtain the stress intensity fact...

In this paper, a new approach for extracting stress intensity factors (SIFs) by the extended element-free Galerkin method, through a crack closure integral (CCI) scheme, is proposed. The CCI calculation is used in conjunction with a local smoothing technique to improve the accuracy of the computed SIFs in a number of case studies of linear elastic...

This paper describes the computation of stress intensity factors (SIFs) for cracks in functionally graded materials (FGMs) using an extended element-free Galerkin (XEFG) method. The SIFs are extracted through the crack closure integral (CCI) with a local smoothing technique, non-equilibrium and incompatibility formulations of the interaction integr...

This paper describes the computation of stress intensity factors (SIFs) for cracks in functionally graded materials (FGMs) using an extended element-free Galerkin (XEFG) method. The SIFs are extracted through the crack closure integral (CCI) with a local smoothing technique, non-equilibrium and incompatibility formulations of the interaction integr...