Stress wave propagation in 1-D and 2-D media using Smooth Particle Hydrodynamics method

Liu, Z.S.,Swaddiwudhipong, S.,Koh, C.G. Techno-Press 2002 Structural Engineering and Mechanics, An Int'l Jou Vol.14 No.4

The paper involves the study on the elastic and elasto-plastic stress wave propagation in the 1-D and 2-D solid media. The Smooth Particle Hydrodynamics equations governing the elastic and elasto-plastic large deformation dynamic response of solid structures are presented. The proposed additional stress points are introduced in the formulation to mitigate the tensile instability inherent in the SPH approach. Both incremental rate approach and leap-frog algorithm for time integration are introduced and the new solution algorithm is developed and implemented. Two examples on stress wave propagation in aluminium bar and 2-D elasto-plastic steel plate are included. Results from the proposed SPH approach are compared with available analytical values and finite element solutions. The comparison illustrates that the stress wave propagation problems can be effectively solved by the proposed SPH method. The study shows that the SPH simulation is a reliable and robust tool and can be used with confidence to treat transient dynamics such as linear and non-linear transient stress wave propagation problems.

Understanding the electromechanical admittance of piezoelectric transducers collocated on a finite beam from the perspective of wave propagation

SAGE Publications 2014 Journal of intelligent material systems and struct Vol.25 No.17

<P>This article analytically investigates the electromechanical admittance of piezoelectric transducers collocated on a finite beam from the perspective of wave propagation. First, the analytic solutions are derived for flexural waves induced by piezoelectric transducers collocated on an infinite beam. Then, the concept of a flexural wave group is used to express the analytic solutions for flexural waves reverberating on a finite beam. Detailed formulation is presented to describe the evolution of resonance of a beam and the corresponding electromechanical signatures induced by flexural wave groups. The validity of the proposed formulation has been demonstrated through a proof-of-concept numerical simulation providing more rigorous physical insight on the relevance between the flexural wave groups and the electromechanical signatures within the relatively low-frequency range.</P>

Response of orthotropic Kelvin modeling for single-walled carbon nanotubes: Frequency analysis

Hussain, Muzamal,Naeem, Muhammad N.,Tounsi, Abdelouahed Techno-Press 2020 Advances in nano research Vol.8 No.3

In this paper, modified Kelvin's model has been used to analyze the orthotropic vibration frequencies of single walled carbon nanotubes with clamped-clamped and clamped-free boundary conditions. For this system the governing equation is developed with wave propagation approach. Armchair, zigzag and chiral structures are considered for the vibrational analysis to investigate the effect of different modes, in-plane rigidity and mass density per unit lateral area. Throughout the computations, on decreasing the length-to-diameter ratios, the frequencies of said structure increases. In addition, by increasing three different value of in-plane rigidity resulting frequencies also increase and frequencies decrease on increasing mass density per unit lateral area. The results generated using computer software MATLAB to furnish the evidence regarding applicability of present model and also verified by available published literature.

Vibration analysis of submerged thin FGM cylindrical shells

Muhammad Nawaz Naeem,Madiha Gamkhar,Shahid Hussain Arshad,Abdul Ghafar Shah 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.3

This study gives a brief work on vibration characteristics of cylindrical shells submerged in an incompressible fluid. The shell is presumed to be structured from functionally graded material. The effect of the fluid is introduced by using the acoustic wave equation. Love’s first order thin shell theory is utilized in the shell dynamical equations. The problem is framed by combining shell dynamical equations with the acoustic wave equation. Fluid-loaded terms are associated with Hankel function of second kind. Wave propagation approach is employed to solve the shell problem. Some comparisons of numerical results are performed for the natural frequencies of simply supported-simply supported, clamped-clamped and clamped-simply supported boundary conditions of isotropic as well as functionally graded cylindrical shells to check the validity of the present approach. The influence of fluid on the submerged functionally graded cylindrical shells is noticed to be very pronounced.

Size dependent dynamic bending nonlocal response of armchair and chiral SWCNTs based on Flügge model

Hussain, Muzamal Techno-Press 2022 Advances in concrete construction Vol.13 No.6

In present study, the nonlocal Flügge shell model based is utilized to investigate the vibration characteristics of armchair and chiral single-walled carbon nanotubes with impact of small-scale effect subjected to two boundary supports. The wave propagation approach is employed to determine eigen frequencies for armchair and chiral tubes. The fundamental frequencies scrutinized with assorted aspect ratios by varying the bending rigidity. The raised in value of nonlocal parameter reduces the corresponding fundamental frequency. It is investigated with higher aspect ratio, the boundary conditions have a momentous influence on vibration of CNT. It is concluded that frequencies would increase by increasing of the bending rigidity. Solutions of the frequency equation have determined by writing in MATLAB coding.

Vibration of sumberged functionally graded cylindrical shell based on first order shear deformation theory using wave propagation method

Farahani, Hossein,Barati, Farzan Techno-Press 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.53 No.3

This paper focuses on vibration analysis of functionally graded cylindrical shell submerged in an incompressible fluid. The equation is established considering axial and lateral hydrostatic pressure based on first order shear deformation theory of shell motion using the wave propagation approach and classic Fl$\ddot{u}$gge shell equations. To study accuracy of the present analysis, a comparison carried out with a known data and the finite element package ABAQUS. With this method the effects of shell parameters, m, n, h/R, L/R, different boundary conditions and different power-law exponent of material of functionally graded cylindrical shells, on the frequencies are investigated. The results obtained from the present approach show good agreement with published results.

Vibration of sumberged functionally graded cylindrical shell based on first order shear deformation theory using wave propagation method

Hossein Farahani,Farzan Barati 국제구조공학회 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.53 No.3

This paper focuses on vibration analysis of functionally graded cylindrical shell submerged in an incompressible fluid. The equation is established considering axial and lateral hydrostatic pressure based on first order shear deformation theory of shell motion using the wave propagation approach and classic Flügge shell equations. To study accuracy of the present analysis, a comparison carried out with a known data and the finite element package ABAQUS. With this method the effects of shell parameters, m, n, h/R, L/R, different boundary conditions and different power-law exponent of material of functionally graded cylindrical shells, on the frequencies are investigated. The results obtained from the present approach show good agreement with published results.

Nonlocal vibration of DWCNTs based on Flügge shell model using wave propagation approach

Sehar Asghar,Muhammad N. Naeem,Muzamal Hussain,Abdelouahed Tounsi 국제구조공학회 2020 Steel and Composite Structures, An International J Vol.34 No.4

In this article, free vibration attributes of double-walled carbon nanotubes based on nonlocal elastic shell model have been investigated. For this purpose, a nonlocal Flügge shell model is established to observe the small scale effect. The wave propagation is employed to frame the governing equations as eigenvalue system. The influence of nonlocal parameter subjected to different end supports has been overtly examined. A suitable choice of material properties and nonlocal parameter been focused to analyze the vibration characteristics. The new set of inner and outer tubes radii investigated in detail against aspect ratio and length. The dominance of boundary conditions via nonlocal parameter is shown graphically. The results generated furnish the evidence regarding applicability of nonlocal shell model and also verified by earlier published literature.

Numerical study for nonlocal vibration of orthotropic SWCNTs based on Kelvin's model

Hussain, Muzamal,Naeem, Muhammad N.,Tounsi, Abdelouahed Techno-Press 2020 Advances in concrete construction Vol.9 No.3

This research deals with the study of the orthotropic vibrational features of single-walled carbon nanotubes according to Kelvin's model and to check the accuracy of the models, the results have been compared with earlier modeling/simulations. Obtaining rough approximations of the natural frequencies of CNTs using continuum equations are still a common procedure, even at high harmonics. The effects of different physical and material parameters on the fundamental frequencies are investigated for zigzag and chiral single-walled carbon nanotubes invoking Kelvin's theory. By using nonlocal Kelvin's model, the fundamental natural frequency spectra for two forms of single-walled carbon nanotubes (SWCNTs) have been calculated. The influence of frequencies with nonlocal parameters and bending rigidity are investigated in detail for these tubes. Computer software MATLAB is utilized for the frequencies of SWCNTs and current results shows a good stability with comparison of other studies.

Nonlocal effect on the vibration of armchair and zigzag SWCNTs with bending rigidity

Hussain, Muzamal,Naeem, Muhammad Nawaz,Tounsi, Abdelouahed,Taj, Muhammad Techno-Press 2019 Advances in nano research Vol.7 No.6

Vibration analysis of carbon nanotubes (CNTs) is very essential field owing to their many promising applications in tiny instruments. In current study, the Eringen's nonlocal elasticity theory with clamped-clamped and clamped-free end conditions is utilized for the vibration analysis of armchair and zigzag SWCNTs. The Fourier method is utilized to solve the ordinary differential equation. The motion equation for this system is developed using a novel wave propagation method. Complex exponential functions have been used and the axial model depends on BCs that has been described at the edges of CNTs. The behavior of different nonlocal parameters is considered to find the vibrational frequency of SWCNTs. It is exhibited that the effect of frequencies against aspect ratio by varying the bending rigidity. It has been investigated that by increasing the nonlocal parameter decreases the frequencies and on increasing the aspect ratio increases the frequencies for both the tubes. To generate the fundamental natural frequencies of SWCNTs, computer software MATLAB engaged. The numerical results are validated with existing open text. Since the percentage of error is negligible, the model has been concluded as valid.