Ngoc Nguyen Sy

• Doctor of Engineering
• Assistant Professor at Dongguk University

This paper proposes a simple yet accurate finite element (FE) formulation for the thermomechanical analysis of laminated composites and sandwich plates. To this end, an enhanced first-order shear deformation theory including the transverse normal effect based on the mixed variational theorem (EFSDTM_TN) was employed in the FE implementation. The pr...

This study introduces an efficient and versatile numerical approach for simulating passive/semi-active damping treatments on laminated structures composed of functionally graded carbon nanotube-reinforced composites (FG-CNTRC) plates. This novel approach integrates an isogeometric finite element formulation that leverages basic functions generated...

This study presents a novel approach for constitutive modeling of complex shell structures using a mixture of MITC3 and MITC4 and interface shell element formulation. It focuses on accurate viscoelastic analysis, considering time-dependent behavior such as creep and relaxation. By combining the advantages of MITC3 and MITC4 elements, along with int...

Over the past decades, numerous damage diagnosis techniques based on modal flexibility have been studied and developed for various types of structures, but rarely for structures made of functionally graded (FG) materials. This paper aims to present the extensive applicability of a modal flexibility sensitivity-based damage index termed as MFBDI for...

The paper presents an efficient numerical approach to deal with the hybrid damping vibration control of laminated functionally graded carbon-nanotube reinforced composite plates (FG-CNTRC) structures. In order to evaluate the damped response, a smoothed finite element model has been derived to simulate the laminated FG-CNTRC plate integrated with a...

This study focuses on the viscoelastic analysis of laminated composite shell structures under long-term creep mechanical loading. An advanced finite element technique named as cell/element-based smoothed discrete shear gap method (CS-DSG3) is employed to obtain the numerical solutions for both elastic and viscoelastic problems owing to its accuracy...

A multi-objective optimization approach for optimal smart damping treatment of functionally graded magneto-electro-elastic plate (FGMEE) structures is investigated in the present study. The finite element method is employed to analyze the vibration responses of the FGMEE plate with active constrained layer damping (ACLD) treatment patches consistin...

This paper proposed an effective numerical approach for free vibration analysis and optimal control of the porous functionally graded magneto-electro-elastic (PFGMEE) plates integrated with the active constrained layer damping (ACLD). Specifically, in order to analyze the free vibration characteristic of the PFGMEE plates based on the layer-wise sh...

An enhanced Lo–Christensen–Wu (LCW) theory is defined in the Laplace domain to predict the thermo-mechanical-viscoelastic behavior of long-term composite structures. The primary objective herein is to systematically extract the computational benefits of the conventional LCW and fifth-order zigzag model via the mixed variational theorem (MVT). Furth...

The tensile properties of fiber-reinforced polymer (FRP) rods in adhesively bonded anchorages are expected to be studied in detail. Therefore, the study aims to predict the failure modes and load-bearing capacity (load-capacity) of FRP rods subjected to direct tensile force. The cohesive zone models were employed to evaluate the interfacial bond be...

Recurrent neural network (RNN)-based accelerated prediction was achieved for the long-term time-dependent behavior of viscoelastic composite laminated Mindlin plates subjected to arbitrary mechanical and hygrothermal loading. Time-integrated constitutive stress-strain relation was simplified via Laplace transform to a linear system to reduce the co...

In the present study, recurrent neural network (RNN)-based accelerated prediction for the long-term time-dependent behavior of viscoelastic composite laminated Mindlin plates subjected to arbitrary mechanical and hygrothermal loading was achieved. For reducing computational storage, time-integrated constitutive stress-strain relation was simplified...

In this work, uncertainty in fiber angles, laminate dimensions, and constituent material properties of composite laminates is investigated to quantify their effects on the buckling load of different laminated composite plates, consisting of four composite plies. For stochastic buckling quantification, typical fourteen scenarios of randomness are in...

This paper aimed to use finite-element analysis to evaluate the seismic performance of self-centering devices, containing superelastic shape memory alloy (SMA) bars and their application. It should be noted that the devices could perform bending behaviors combining with tensions or compression. Cyclic performance of the devices under pulling and pu...

Surface functionalization is one of the useful techniques for modulating the mechanical and electronic properties of two-dimensional systems. In the present study, we investigate the structural, elastic, and electronic properties of hexagonal boron phosphide monolayer functionalized by Br and Cl atoms using first-principles predictions. Once surfac...

In the present study, the viscoelastic analysis is investigated for composite laminated plates using a smoothed finite element method called cell/element based smoothed discrete shear gap method. Moreover, the hygrothermal effects is considered on the viscoelastic responses of composite laminated plates. The first-order shear deformation theory is...

This paper proposes a method based on efficient higher-order zig-zag theory to analyze the viscoelastic response of doubly-curved laminated shell structures. In the general curvilinear coordinates, displacement fields are obtained by imposing a varying cubic displacement field on a varying linear zig-zag field. Then, the transverse shear stress-fre...

To predict the time-dependent behaviors of viscoelastic laminated composites, a three-node multilayered plate element is developed based on the efficient higher-order plate theory (EHOPT), which was originally proposed by Cho and Parmerter. With the help of the Laplace transform, the integral form of the constitutive equation in the time domain is...

An enhanced first-order shear deformation theory (EFSDT) is developed for linear viscoelastic analysis of laminated composite and sandwich plates. Improved strain energy expression of the conventional Reissner/Mindlin first-order shear deformation theory (FSDT) through strain energy transformation is derived in the Laplace domain by minimizing the...

An efficient higher-order plate theory for viscoelastic materials is developed to predict the time-dependent mechanical behaviors of composite laminates. In-plane displacement fields are constructed by superimposing a cubic varying displacement field on a linear zig-zag varying field. Time-dependent relaxation moduli have the form of Prony series,...

Viscoelastic behaviors of symmetric laminated composite shell are investigated based on efficient higher order shell theory (EHOST). The constitutive equation of linear viscoelastic materials in integral form is simplified by using Laplace transform. Moreover, the free top and bottom condition and continuity condition at interface layers can be app...

Time-dependent responses of composite plate are investigated based on efficient higherorder plate theory. The constitutive equation of linear viscoelastic materials, expressed as a Boltzmann superposition integral equation, is simplified by the convolution theorem of Laplace transformation. Hence, the computational resource can be saved significant...

In order to analysis time-dependent mechanical behavior accurately, an efficient higherorder plate theory is developed for viscoelastic laminated composite plates. In-plane displacement fields are obtained by superimposing a cubic varying displacement field on a zigzag linearly varying displacement. The time-dependent relaxation modulus has form of...

In this study, the linear viscoelastic response of a rectangular laminated plate is investigated. The viscoelastic properties, expressed by two basic spring-dashpot models, that is Kelvin and Maxwell models, is assumed in the range to investigate the influence of viscoelastic coefficients to mechanical behavior. In the present study, viscoelastic r...