Transfer functions in the linear dynamic system theory are applied to characterize dynamic mechanical properties of viscoelastic materials. Correlation between transfer functions and typical rheological models and fractional derivative ones are briefly introduced. The transfer function of a rheological model may be expressed in terms of multiplication of factored polynomials. The frequency–response

Aerogel is studied numerically using a one-dimensional two-phase flow equations system. A hyperbolic and conservative two-phase flow model is applied to a mixture of porous media containing nanofluids. The application of non-equilibrium mixture behavior between phases is adopted and promoted in this current investigation. By establishing mixture conservation balance laws, finite volume techniques using

In this research contribution, the static behavior and failure mechanisms are developed for a three-dimensional (3D) printed dogbone, auxetic structure and sandwich composite using acoustic emissions (AEs). The skins, core and whole sandwich are manufactured using the same bio-based material which is polylactic acid reinforced with micro-flax fibers. Tensile tests are conducted on the skins and the

The central cracked Brazilian disk (CCBD) specimen is one of the most favored samples to measure the combined mode fracture resistance of brittle materials. The T-stress in this sample has a great influence on the experimental results, which are extensively used in fracture criteria for evaluating the fracture behavior of CCBD specimens for different materials. Due to the errors in geometric dimension

Rijke tube is a benchmark model widely used in thermo-acoustic community. As an alternative to existing modeling methods, this work proposes a modified Fourier series solution for modal characteristic analyses of a one dimensional (1D) thermo-acoustic system. The proposed modeling framework allows the consideration of arbitrary impedance boundaries owing to the special feature of the Fourier expansion

This paper is devoted to superharmonic and subharmonic behavior investigation of imperfect functionally graded (FG) cylindrical shells with external FG spiral stiffeners under large amplitude excitations. The structure is embedded within a generalized nonlinear viscoelastic foundation, which is composed of a two-parameter Winkler–Pasternak foundation augmented by a Kelvin–Voigt viscoelastic model with

The spacecraft with large flexible space structures may be subject to the thermally induced vibration (TIV) due to the rapidly changed solar heat flux when it enters and leaves the eclipse, which would lead to certain spacecraft failure. This paper reports a laboratory experiment that aims to study the impact of transient characteristics of heat flux on the ground experiment of TIV. In the experiments

In this study, vibration analysis of single-walled carbon nanotube (SWCNT) has been carried out by using a refined beam theory, namely one variable shear deformation beam theory. This approach has one variable lesser than a contractual shear deformation theory such as first-order shear deformation theory (FSDT) and acts like classical beam approach but with considering shear deformations. The SWCNT

This paper studies the dynamic viscoelastic response of functionally graded (FG) thick 2D cantilever and simply supported beams under dynamic pulse load, for the first time. A point load applied at a specific spatial point is described as a time-pulse sinusoidal load. Two-dimensional plane-stress constitutive equation is exploited to describe the local stress–strain relation through the beam. The gradation

In this paper, free and forced vibrations of nanocomposite beams reinforced by 3D graphene foam (3D-GrF) are studied. Different distributions of 3D-GrF in the beam thickness direction are considered. In accordance with the rule of mixture, the effective Young’s modulus, Poisson’s ratio and mass density of the 3D-GrF reinforced beams are predicted. Based on the Timoshenko beam theory, the governing

In this work, fluid–structure interaction (FSI) simulations, as well as non-FSI ones, are conducted to study the behavior of a functionally graded (FG) pH-sensitive micro-valve. The FEM analysis of the hydrogel is performed in ABAQUS while the fluid domain is analyzed in ANSYS fluent. To investigate the FSI and FG effects, both FSI and non-FSI simulations are performed for pH-sensitive micro-valve

This paper presents the postbuckled configurations of simply supported and clamped-pinned nanorods under self-weight based on elastica theory. Numerical solution is considered in this work since closed-form solution of postbuckling analysis under self-weight cannot be obtained. The set of nonlinear differential equations of a nanorod including the effect of nonlocal elasticity are investigated. The

This paper aims at investigating a two-dimensional flow over the rod-airfoil as a simple component of an aircraft using URANS equations. The prediction of the flow-induced noise is performed using F-WH analogy. Since Vortex’s periodic production is the main cause of the noise mechanism, by reducing its effect on the airfoil leading edge, the acoustic propagation reduces as well. To control flow and

For the first time, a two-dimensional (2D) piezoelasticity-based analytical solution is developed for free vibration analysis of axially functionally graded (AFG) beams integrated with piezoelectric layers and subjected to arbitrary supported boundary conditions. The material properties of the elastic layers are considered to vary linearly along the axial (x) direction of the beam. Modified Hamiltons

Based on the Gurson–Tvergaard–Needleman (GTN) model, a constitutive relationship considering both the effects of strain hardening and hydrostatic stress for porous shape memory alloys (SMAs) is proposed. To capture the relationship between microscopic and mesoscopic behaviors, a representative volume element (RVE) containing an array of spherical voids is presented. In this paper, an approximate solution

Certain shape memory alloys (SMAs) are considered to be good absorbents of hydrogen atoms (e.g., NiTi). However, upon the absorption of hydrogen atoms, SMAs exhibit deteriorated effects of superelasticity and shape memory mechanisms. In this paper, we have developed a coupled model, based on experimental results, that demonstrates the effects of hydrogen diffusion on NiTi SMAs. The proposed model has

Two-dimensional (2D) representative volume element (RVE) has been widely used to simulate the effective behaviors of the materials with aligned pores. In this paper, the anisotropy indexes are defined for the 2D RVE model to quantitatively evaluate the extent of anisotropy of the model. A normalized procedure is then proposed to compute the effective moduli of the RVE models, which can further minimize

The propagation of surface waves of symmetric and anti-symmetric families is investigated in a generalized thermoelastic plate. Frequency equations of such surface waves are derived and deduced for the cases of long compressional, flexural and Rayleigh waves. The existence of two modes of vibration is discussed. Numerically and analytically, the phase speeds and attenuations of these waves are computed

Since lightweight and energy-absorbing materials have an effective role in occupant safety during accidents, the use of hybrid aluminum–composite tubes and their optimum designs are of great importance in the crashworthiness. In this study, finite element simulation and multi-objective optimization of a hybrid aluminum–composite tube are performed under axial crushing to investigate the effect of metal

This paper presents a novel approach for improving the reliability and driving capability of piezoelectric actuators by developing braided fiber piezoelectric composite (BFPC) actuators. The nonlinear analysis of laminated beams integrated with the BFPC actuators under electric load is presented. According to Timoshenko beam theory and von Kármán nonlinear geometric relation, the strain components

Based on the reproducing kernel particle method (RKPM) and the radial basis function (RBF), the radial basis reproducing kernel particle method (RRKPM) is presented for solving geometrically nonlinear problems. The advantages of the presented method are that it can eliminate the negative effect of diverse kernel functions on the computational accuracy and has greater computational accuracy and better

In recent years, the demand for control of sound power and radiation patterns in personal messaging, calls, automotive entertainment, and gaming has brought a new interest in the audio world. The aim of this paper is to investigate the feasibility of producing the sound waves in the audible range and directing them in the desired listening zone by electrostatic micro-speakers. Therefore, a capacitive

A study is made to investigate the compression behavior of different nested tube systems made of mild steel under lateral compression. The nested tube systems including stacked groups of circular, rectangular and square tubes are built for application in narrow compressive zones. The deformation mode of these systems is observed and their lateral compression behavior are identified. The desirable stepwise

Arteries often demonstrate geometric variations such as elliptic and eccentric cross sections, stenosis, and tapering along the longitudinal axis. Effects of these variations on the mechanical stability of the arterial wall have not been investigated. The objective of this study was to determine the buckling behavior of arteries with elliptic, eccentric, stenotic, and tapered cross sections. The arterial