Browsing by Subject "boundary element method"

Now showing 1 - 4 of 4

Access status: Open Access ,
A new BEM for modeling and simulation of 3T MDD laser-generated ultrasound stress waves in FGA smart materials
(Wydawnictwa AGH, 2021) Fahmy, Mohamed Abdelsabour
The goal of this study is to present a new theory known as the three-temperature memory-dependent derivative (MDD) of ultrasound stress waves in functionally graded anisotropic (FGA) smart materials. It is extremely difficult to address the difficulties related to this theory analytically due to its severe nonlinearity. As a result, we suggest a new boundary element method (BEM) to solve such equations. The suggested BEM technique incorporates the benefits of both continuous and discrete descriptions. The numerical results are visually represented to demonstrate the impacts of MDD three temperatures and anisotropy on the ultrasound stress waves in FGA smart materials. The numerical findings verify the proposed methodology's validity and accuracy. We may conclude that the offered results are useful for comprehending the FGA smart materials. As a result, our findings contribute to the advancement of the industrial applications of FGA smart materials.
Access status: Open Access ,
Analysis of effective properties of piezocomposites by the subregion BEM-Mori-Tanaka approach
(2011) Dziatkiewicz, Grzegorz
Recently, many approaches have been proposed to estimate the effective properties of composites. The most typical are: the self-consistent method and the Mori-Tanaka method. However, they are restricted to simple geometries of phases. Also for complex constitutive laws the analytical results are complicated. On the other hand, the combination of numerical methods and these approaches gives an efficient computational scheme for estimating effective properties of composite materials. In this paper the hybrid subregion boundary element method (BEM) and Mori-Tanaka approach is implemented to solve coupled field equations of linear piezocomposites in the unit cell approach and then to determine the effective properties. To obtain the BEM fundamental solutions, the Stroh formalism is used. The numerical examples demonstrate an effectiveness of the BEM-Mori-Tanaka approach.
Access status: Open Access ,
Elastic properties of composites reinforced by wavy carbon nanotubes
(2011) Górski, Radosław
In the paper the prediction of the elastic Young modulus of single-walled carbon nanotubes (CNTs) and the elastic properties of composites reinforced by straight or wavy CNTs is presented. The properties are evaluated by numerical methods. Nanotubes are modeled and analyzed by the finite element method (FEM). The specific atomistic nature of CNTs is taken into account by using a linkage between molecular and continuum mechanics. The methodology consists in replacing the discrete molecular structure of a CNT with a space-frame FE model by equating the molecular potential energy and the elastic strain energy of both models subjected to small elastic deformations. A three-dimensional frame is further substituted with a one-dimensional beam which represents the reinforcement in a representative volume element (RVE) of the considered composite. The properties of the nano-composite are determined by modeling and analyzing RVEs using the coupled boundary and finite element method (BEM/FEM). A two-dimensional matrix is modeled by the BEM and CNTs by the FEM using beam elements. The waviness and shape of a single fiber or multiple aligned nanotubes on the properties of the nanocomposite are investigated. Sinusoidal or arbitrary shapes of the reinforcement are considered. The influence of volume fraction of the reinforcement and the fiber/matrix Young's modulus ratio on the elastic properties of the composite is also studied.
Access status: Open Access ,
Modelling of stress state of elastic medium containing perfectly and imperfectly bonded thin inclusions and overlays
(2011) Sulim, Georgij T; Pasternak, Âroslav Mihajlovič
This study considers modelling of two-dimensional stress state of solids containing thin elastic inclusions. In modeling the coupling principle for continua of different dimension is utilized. Basing on the model of inclusion under the perfect contact three other models of imperfect contact are developed. The simplest one is a model of thin inclusion, which is completely delaminated at certain segments. Two other models take into account a smooth contact between inclusion and a solid, and also a contact with friction. The developed models are easy to introduce into the used boundary element approach. The model of inclusion, completely debonded at one face, is also used in modeling of solids with thin elastic overlays or stringers.