Sondipon Adhikari

Sondipon Adhikari
University of Glasgow | UofG · James Watt School of Engineering

PhD
Structural dynamics, probabilistic methods, and computational mechanics

About

649
Publications
126,630
Reads
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14,149
Citations
Introduction
Professor Adhikari holds the position of Professor of Engineering Mechanics at the James Watt School of Engineering of the University of Glasgow. He received his PhD in 2001 as a Jawaharlal Nehru Memorial Trust scholar at the Trinity College of the University of Cambridge.
Additional affiliations
October 2021 - October 2021
University of Glasgow
Position
  • Professor
Description
  • Professor Adhikari's research stands on three fundamental footing - structural dynamics, probabilistic methods, and computational mechanics. His research works use these basic principles to understand cutting-edge multiscale and multidisciplinary problems in applied science and engineering. Specific research areas include uncertainty quantification in computational mechanics, dynamics of complex systems, inverse problems for linear and non-linear dynamics, and vibration energy harvesting.
November 2012 - present
The American Institute of Aeronautics and Astronautics
Position
  • Associate Fellow
April 2007 - September 2021
Swansea University
Position
  • Chair
Education
October 1997 - September 2000
University of Cambridge
Field of study
  • Engineering
July 1995 - July 1997
Indian Institute of Science
Field of study
  • Engineering

Publications

Publications (649)
Article
This paper proposes an analytical stochastic spectral dynamic stiffness method (SSDSM) for free and forced vibration analysis of plate built-up structures subject to uncertain viscoelastic boundary or connection conditions (BCs or CCs). First, a recently developed spectral dynamic stiffness (SDS) theory for broadband vibration analysis of plate bui...
Article
This paper proposes two significant developments of the Wittrick–Williams (W–W) algorithm for an exact wave propagation analysis of lattice structures based on analytical dynamic stiffness (DS) model for each unit cell of the structures. Based on Bloch’s theorem, the combination of both the DS and the W–W algorithm makes the wave propagation analys...
Article
Stiffness matrices of beams with stochastic distributed parameters modelled by random fields are considered. In stochastic finite element analysis, deterministic shape functions are traditionally employed to derive stiffness matrices using the variational principle. Such matrices are not exact because the deterministic shape functions are not deriv...
Article
The closed-form analytical expression of the objective function of a single degree of freedom system with the tuned mass damper, subjected to Gaussian white noise and Kaimal forcing spectrum, is derived implementing the H 2 optimization technique. To illustrate the procedure, a wind turbine tower with and without the tuned mass damper, subjected to...
Conference Paper
2-D lattice structures have gained significant attention in the last few decades. Extensive analytical and experimental studies have been conducted to determine the elastic properties of the lattice structures. Further, the variation in the elastic properties of the passive lattice structures by changing various dimensional parameters and geometry...
Preprint
Wave propagation characteristics of an elastic bar coupled at one end with a single degree of freedom, bi-stable, essentially nonlinear snap-through element are considered. The free end of the bar is subjected to sinusoidal excitations. A novel approach based on Multiple Time Scales and Harmonic Balance Method has been proposed to analytically inve...
Article
Full-text available
The architected mechanical metastructures have garnered significant research attention for various engineering applications due to their remarkable mechanical properties and unique deformation behavior. The lattice-based micro-structured materials have shown enhanced mechanical properties and the ability to control wave propagation, making them ide...
Article
We theoretically investigate the bandgap formation in an Euler–Bernoulli beam-based metastructure with periodically attached double negative 3-dof local resonators. The idiosyncratic physical phenomena found in mechanical metamaterials, such as negative stiffness and mass, are introduced in the attached local resonator to design the double negative...
Article
Full-text available
This paper proposes an efficient and reliable eigenvalue solution technique for analytical stochastic dynamic stiffness (SDS) formulations of beam built-up structures with parametric uncertainties. The SDS formulations are developed based on frequency-dependent shape functions in conjunction with both random-variable and random-field structural par...
Article
Full-text available
Offshore structures are exposed to cyclic loading and thereby at risk of fatigue failure, especially at the welded joints between trusses in offshore jacket foundations. In this paper, an optimization framework for welded joints considering fatigue damages is presented. The framework can be used to optimize the orientation and location of welds con...
Article
Uncertainties need to be taken into account in the dynamic analysis of complex structures. This is because in some cases uncertainties can have a significant impact on the dynamic response and ignoring it can lead to unsafe design. For complex systems with uncertainties, the dynamic response is characterised by the eigenvalues and eigenvectors of t...
Article
Full-text available
Carbon-based nanostructures are receiving increasing attention over the past two decades due to their unprecedented multi-functional features. However, the macro-scale structural applications of these nanostructures have not yet come to full fruition due to the involvement of complex multi-scale computations and manufacturing. Recently, the researc...
Article
This paper introduces the concept of negative stiffness inertial-amplifier-base-isolators to achieve enhanced broadband vibration control. Three physically different novel isolators, namely inertial amplifier base isolator (IABI), negative stiffness inertial amplifier base isolator (NSIABI), and negative stiffness base isolator (NSBI), are achieved...
Chapter
Parametric excitation is introduced to amplify the external harmonic excitation and extend the capabilities of a nonlinear piezoelectric energy harvester device. To investigate the efficiency of the parametrically amplified energy harvester, the time responses of the voltage and power are computed using the state space formulation. It is assumed th...
Chapter
Parametric excitation is introduced to amplify the external harmonic excitation and extend the capabilities of a nonlinear piezoelectric energy harvester device. To investigate the efficiency of the parametrically amplified energy harvester, the time responses of the voltage and power are computed using the state space formulation. It is assumed th...
Preprint
Metadamping is the phenomenon of either enhanced or diminished intrinsic dissipation in a material stemming from the material's internal structural dynamics. It has been previously shown that a locally resonant elastic metamaterial may be designed to exhibit higher or lower dissipation compared to a statically equivalent phononic crystal with the s...
Article
A novel method for characterising and propagating system uncertainty in structures subjected to dynamic actions is proposed, whereby modal shapes, frequencies and damping ratios constitute the random quantities. The latter, defined in the modal subspace rather than the full geometrical space, reduce the number of the random variables and the size o...
Article
Full-text available
The stochastic behaviour of materials and loading is of great importance for buckling and analysis of prestressed beam and frame structures. In this paper, the stochastic stiffness and stress stiffness matrices are developed for stochastic analysis and buckling analysis. The bending rigidity and the buckling load are modelled as stochastic fields....
Conference Paper
Full-text available
Honeycomb lattice structures are lightweight and have high strength to weight ratio. Hence, such structures have gathered a significant amount of attraction over the last decade. Many experimental and analytical studies have been carried out to determine the in-plane elastic properties of these lattice structures. Once manufactured, it is impossibl...
Article
We propose an analytical framework to understand the mechanics and quantify the essential elastic properties of two-dimensional hexagonal lattices with curved elements. Generalised closed-form expressions for the in-plane Young’s moduli and Poisson’s ratios are obtained. It is of utmost importance to develop physics-based efficient computational mo...
Article
A large number of studies have been reported in literature to analyse various parameters that influence the Poisson's ratios of multi-functional lattice materials. However, the major limitation in such lattices is that once the lattice is manufactured , the Poisson's ratios and other elastic properties become fixed corresponding to the particular l...
Article
Full-text available
Harnessing the concept of inertial amplification, an inertial amplifier coupled base isolator (IABI) is proposed in this paper. The seismic performance, in terms of story drift, base shear reduction, of this proposed inertial amplifier coupled base isolator has been compared with that of the classical base isolator (CBI) and inerter-based isolation...
Article
The current design method of ultimate capacity of beam string structure (BSS) is mainly based on the fixed load ratio (FLR) criterion, seldom considers the effect of the random load ratio (RLR) on bearing capacity. This paper compared the coefficient of variation (COV) of bearing capacity obtained by RLR criterion with that obtained by the FLR crit...
Article
Stiffness matrices of beams embedded in an elastic medium and subjected to axial forces are considered. Both the bending and the axial deformations have been incorporated. Two approaches for deriving the element stiffness matrix analytically have been proposed. The first approach is based on the direct force–displacement relationship, whereas the s...
Article
Full-text available
Piezoelectric vibration energy harvesters have demonstrated the potential for sustainable energy generation from diverse ambient sources in the context of low-powered micro-scale systems. However, challenges remain concerning harvesting more power from low-frequency input excitations and broadband random excitations. To address this, here we propos...
Article
The in-plane mechanics of two-dimensional heterogeneous hexagonal lattices are investigated. The heterogeneity originates from two physically realistic considerations: different constituent materials and different wall thicknesses. Through the combination of multi-material and multi-thickness elements, the most general form of 2D heterogeneous hexa...
Article
Full-text available
We demonstrate that the consideration of material uncertainty can dramatically impact the optimal topological micro‑structural configuration of mechanical metamaterials. The robust optimization problem is formulated in such a way that it facilitates the emergence of extreme mechanical properties of metamaterials. The algorithm is based on the bi‑di...
Article
Periodic structures attenuate wave propagation in a specified frequency range, such that a desired bandgap behaviour can be obtained. Most periodic structures are produced by additive manufacturing. However, it is recently found that the variability in the manufacturing processes can lead to a significant deviation from the desired behaviour. This...
Article
Inertial amplification has been utilized in phononic media as a mechanism for the generation of large band gaps at low subwavelength frequencies. A unique feature in an inertial-amplification band gap is that it may exhibit two coupled peaks in the imaginary wavenumber portion of its band diagram. This unique double-attenuation band gap has been sh...
Article
Elastic instability such as the buckling of cellular materials plays a pivotal role in their analysis and design. Despite extensive research, the quantifi- cation of critical stresses leading to elastic instabi- lities remains challenging due to the inherent nonlinearities. We develop an analytical approach considering the spectral decomposition of...
Article
An enrichment scheme based upon the Neumann expansion method is proposed to augment the deterministic coefficient vectors associated with the polynomial chaos expansion method. The proposed approach relies upon a split of the random variables into two statistically independent sets. The principal variability of the system is captured by propagating...
Preprint
The present paper aims to develop governing equation of motion for in-plane dynamics of Micropolar-Cosserat composite models with damping. Constitutive model of linear elastic damping system is formulated for an anisotropic domain fiber-reinforced composite panels (FRCP); undergoing large macro as well as micro geometric deformations. The air dampi...
Article
Vibration energy harvesting is an emerging technology that enables electric power generation using piezoelectric devices. The prevailing approach for characterization of the energy-harvesting capacity in these devices is to consider a finite structure operating under forced vibration conditions. Here, we present an alternative framework whereby the...
Article
For large-span hybrid roof structures, the construction uncertainties of cable tension usually have significant influences on the roof's mechanical performance and should be considered in reliability evaluation. An effective approach to quantify uncertainties of cable tensions and evaluate structural reliability is proposed to carry out the studies...
Article
This paper proposes the methodology to carry out the analysis of Bloch wave propagation in an array of vertically aligned and elastically connected structural elements such as beams, strings, plates, or other slender structures. The suggested approach is based on the Galerkin approximation and Floquet-Bloch theorem used in defining the eigenvalue p...
Article
Full-text available
Elastic mechanical metamaterials are the exemplar of periodic structures. These are artificially designed structures having idiosyncratic physical properties like negative mass and negative Young’s modulus in specific frequency ranges. These extreme physical properties are due to the spatial periodicity of mechanical unit cells, which exhibit local...
Article
Topological phononic crystals in the mechanical setup became a topic of great interest owing to their applicability in various engineering systems such as waveguides or vibration isolation devices. If such systems are composed of elastic structures, they are usually characterized by a bulkedge correspondence where the geometrical and material prope...
Article
Full-text available
The present paper aims to develop governing equation of motion for in-plane dynamics of Micropolar-Cosserat composite models with damping. Constitutive model of linear elastic damping system is formulated for an anisotropic domain fiber-reinforced composite panels (FRCP); undergoing large macro as well as micro geometric deformations. The air dampi...
Article
Full-text available
Offshore wind turbines are a complex, dynamically sensitive structure due to their irregular mass and stiffness distribution, and complexity of the loading conditions they need to withstand. There are other challenges in particular locations such as typhoons, hurricanes, earthquakes, sea-bed currents, and tsunami. Because offshore wind turbines hav...
Article
An analytical stochastic dynamic stiffness formulation is developed for the dynamic analysis of damped membrane structures with parametric uncertainties. First, the exact general solution of a biaxially taut membrane in the frequency domain is derived, which is used as the frequency-dependent shape function. Both the material properties and the ten...
Article
Highly compressible and stretchable lattice materials are perfectly suitable to be exploited in a range of cutting edge engineering applications such as low band-gap acoustic metamaterials, vibration absorbers, soft robotics, stretchable electronics and stent devices. Physics-based understanding and efficient computational methods are of paramount...
Article
Dynamic response analysis of wind turbine towers plays a pivotal role in their analysis, design, stability, performance and safety. Despite extensive research, the quantification of general dynamic response remains challenging due to an inherent lack of the ability to model and incorporate damping from a physical standpoint. This paper develops a f...
Article
Full-text available
Recent research has shown that large-scale Internet of Things (IoT)-based load altering attacks can have a serious impact on power grid operations such as causing unsafe frequency excursions and destabilizing the grid’s control loops. In this work, we present an analytical framework to investigate the impact of IoT-based static/dynamic load alterin...
Article
Free and forced bending vibration of damped nonlocal nano-beams resting on an elastic foundation is investigated. Two types of nonlocal damping models, namely, strain-rate-dependent viscous damping and velocity-dependent viscous damping are considered. A frequency-dependent dynamic finite element method is developed to obtain the forced vibration r...
Article
To reduce the computational cost of assembled stochastic linear structural dynamic systems, a three-staged reduced order model-based framework for forward uncertainty propagation was developed. First, the physical domain was decomposed by constructing an equivalent reduced order numerical model that limited the cost of a single deterministic simula...
Preprint
This paper communicates an analytical study on computing the natural frequencies and in-plane deflections caused by static forces in the panel walls using Euler-Bernoulli, Timoshenko, Timoshenko and Goodier, Couple-stress, and Micropolar-Cosserat theory. The study highlights the formulation of the transfer matrix via the state-space method in the s...
Article
Full-text available
A generic analytical framework is proposed to obtain the dynamic elastic moduli of lattice materials under steady-state vibration conditions. The dynamic deformation behaviour of the individual beam elements of a lattice is distinct from the behaviour under a static condition. This leads to a completely different global deformation pattern of the l...
Article
Full-text available
This paper communicates an analytical study on computing the natural frequencies and in-plane deflections caused by static forces in the panel walls using Euler-Bernoulli, Timoshenko, Timoshenko and Goodier, Couple-stress, and Micropolar-Cosserat theory. The study highlights the formulation of the transfer matrix via the state-space method in the s...
Article
This paper characterizes the stochastic dynamic response of periodic structures by accounting for manufacturing variabilities. Manufacturing variabilities are simulated through a probabilistic description of the structural material and geometric properties. The underlying uncertainty propagation problem has been efficiently carried out by functiona...
Conference Paper
Parametric excitation is introduced to amplify the external harmonic excitation and extend the capabilities of a nonlinear piezoelectric energy harvester device. To investigate the efficiency of the parametrically amplified energy harvester, the time responses of the voltage and power are computed using the state space formulation. It is assumed th...
Article
Full-text available
This paper presents a machine learning assisted efficient, yet comprehensive characterization of the dynamics of coronaviruses in conjunction with finite element (FE) approach. Without affecting the accuracy of prediction in low-frequency vibration analysis, we have proposed an equivalent model for the FE analysis, based on which the natural freque...
Article
This paper investigates the elastic wave propagation, mode veering, and in-plane vibration of pre-stressed hexagonal lattice embedded in an elastic medium and composed of axially loaded Timoshenko beams with attached point masses. The frequency band structure of the lattice system is obtained by solving the corresponding eigenvalue problem based on...
Article
Robust design optimization (RDO) of large-scale engineering systems is computationally intensive and requires significant CPU time. Considerable computational effort is still required within conventional meta-model assisted RDO frameworks. The primary objective of this article is to minimize further the computational requirements of meta-model assi...
Book
This book comprises select proceedings of the National Conference on Advances in Structural Technology (CoAST 2019). It brings together different applied and technological aspects of structural engineering. The main topics covered in this book include solid mechanics, composite structures, fluid-structure interaction, soil-structure interaction, st...
Article
Full-text available
Continuous demand for the improvement of mechanical performance of engineering structures pushes the need for metastructures to fulfil multiple functions. Extensive work on lattice-based metastructure has shown their ability to manipulate wave propagation and producing bandgaps at specific frequency ranges. Enhanced customizability makes them ideal...
Article
An efficient semi-numerical framework is used in this paper to analyze the dynamic model of an axially moving beam with a nonlinear attachment composed of a nonlinear energy sink and a piezoelectric device. The governing equations of motion of the system are derived by using the Hamilton’s principle with von Karman strain-displacement relation and...
Article
Full-text available
Two-dimensional lattices are ideal candidate for developing artificially engineered materials and structures across different length-scales, leading to unprecedented multi-functional mechanical properties which can not be achieved in naturally occurring materials and systems. Characterization of effective elastic properties of these lattices is ess...
Article
Digital twin technology has a huge potential for widespread applications in different industrial sectors such as infrastructure, aerospace, and automotive. However, practical adoptions of this technology have been slower, mainly due to a lack of application-specific details. Here we focus on a digital twin framework for linear single-degree-of-free...
Preprint
Full-text available
Recent research has shown that large-scale Internet of Things (IoT)-based load altering attacks can have a serious impact on power grid operations such as causing unsafe frequency excursions and destabilizing the grid's control loops. In this work, we present an analytical framework to investigate the impact of IoT-based static/dynamic load alterin...
Article
Digital twin technology has significant promise, relevance and potential of widespread applicability in various industrial sectors such as aerospace, infrastructure and automotive. However, the adoption of this technology has been slower due to the lack of clarity for specific applications. A discrete damped dynamic system is used in this paper to...
Article
Full-text available
This article proposes the concept of anisotropy tailoring in multi-material lattices based on a mechanics-based bottom-up framework. It is widely known that isotropy in a mono-material lattice can be obtained when the microstructure has an isotropic geometry. For example, regular hexagonal lattices with a unit cell comprised of six equal members an...
Article
This paper investigates electromagnetic energy harvesting based on vibration energy extraction from the vibration of a bluff body elastically connected with an additional nonlinear oscillator and subjected to fluid flow and base excitation. The mechanical part is modeled as a system of two coupled oscillators where a combination of harmonic base ex...
Article
Full-text available
Two-dimensional (2D) materials are crucially important nanomaterials because of their exciting multi-functional properties. However, a single layer of 2D materials may not have a certain property adequately, or multiple application-specific properties simultaneously to the desired and optimal level. For mitigating this lacuna, a new trend has emerg...
Article
Full-text available
Mechanical coupling in similar energy harvesters has the potential to enhance their broadband harvesting capability. However, often the performance of one harvester dominates the other, and the coupling transfers energy from the high frequency harvester to the low frequency harvester, thus reducing the capability of the high frequency harvester. He...
Article
The steady-state response of a nonlinear piezoelectric energy harvester subjected to external and parametric excitation is investigated based on the Mathieu-Duffing nonlinear oscillator model. The parametric excitation is introduced to amplify the external harmonic excitation and extend the capabilities of the nonlinear piezoelectric energy harvest...
Article
Nano and micromechanical mass sensing using cantilever oscillators of different length-scales has been an established approach. The main principle underpinning this technique is the shift in the resonance frequency caused by the additional mass in the dynamic system. While the mass of an object to be sensed is useful information, some idea about th...
Article
Structural vibrations are very common in aerospace and mechanical engineering systems, where dynamic analysis of modern aerospace structures and industrial machines has become an indispensable step in their design. Suppression of unwanted vibrations and their exploitation for energy harvesting at the same time would be the most desirable scenario....
Preprint
Full-text available
Digital twin technology has a huge potential for widespread applications in different industrial sectors such as infrastructure, aerospace, and automotive. However, practical adoptions of this technology have been slower, mainly due to a lack of application-specific details. Here we focus on a digital twin framework for linear single-degree-of-free...
Article
Moire pattern arises from the lattice mismatch between two different nanosheets. The discovery of the Moire pattern has resulted in breakthrough properties in 2D carbon-based nanostructures such as graphene. Here we investigate the impact of a Moire pattern on mechanical properties of bi-layer 2D nanosheets. In particular, buckling instability of 2...