Seyed Mohammad Hossein Hosseini

Numerical Investigation of the Thermal Properties of Irregular Foam Structures

The thermal properties of irregular open-cell and closed-cell metal foams are investigated via numerical simulation. The influence of relative density and cell irregularity on the thermal conductivity and thermal expansion of the foam structure is determined. It is concluded that the effective thermal conductivity of the foam structure depends linearly on the relative density, whereas no dependence on the degree of irregularity is observed. The effective thermal expansion coefficient of the foam structure is constant for the range of parameters considered.

Numerical Prediction of the Effective Thermal Conductivity of Open- and Closed-Cell Foam Structures

This paper investigates the thermal properties of metallic open-cell and closed-cell foam structures in space filling and non-space filling configurations. In both, i.e. open-cell and closed-cell structures, a linear trend depending on the relative density has been reported. However the closed-cell structures compared to open-cell ones have a higher thermal conductivity for the same relative density.

Numerical simulation of thermal and mechanical properties of sintered perforated hollow sphere structures (PHSS)

This paper investigates the thermal and mechanical properties of a new type of hollow sphere structures. For this new type, the sphere shell is perforated by several holes in order to open the inner sphere volume and surface. The effective thermal conductivity of perforated sphere structures in several kinds of arrangements, i.e. primitive cubic (PC), body‐centered cubic (BCC), face‐centered cubic (FCC) and hexagonal (Hex) unit cell models, is numerically evaluated for different hole diameters. In addition, mechanical properties of sintered perforated hollow sphere structures also have been evaluated for a unit cell in a PC arrangement with different hole diameters. The results are compared to classical configurations without perforation. In the scope of this study, three‐dimensional finite element analysis is used in order to investigate unit cell models. When the relative density decreases the heat conductivity also decreases. A linear behavior was found for the heat conductivity of different hole diame...

Numerical Prediction of the Effective Thermal Conductivity of Perforated Hollow Sphere Structures

This paper investigates the thermal properties of a new type of hollow sphere struc- tures. For this new type, the sphere shell is perforated by several conical holes in order to open the inner sphere volume. The effective thermal conductivity of perforated sphere structures in a primitive cubic arrangement is numerically evaluated for different material combinations and compared to sphere structures without perforation.

Numerical Simulation of Perforated Hollow Sphere Structures (PHSS) to Investigate Mechanical Properties

This paper investigates the uniaxial mechanical properties of a new type of hollow sphere structures. For this new type, the sphere shell is perforated by several holes in order to open the inner sphere volume and surface. The mechanical properties, i.e. elastic properties and initial yield stress, of perforated hollow sphere structures in a primitive cubic arrangement are numerically evaluated for different hole diameters and different sphere wall thicknesses.

Damping Boundary Conditions for a Reduced Solution Domain Size and Effective Numerical Analysis of Heterogeneous Waveguides

In the current chapter we focus on the development of numerical methods to reduce the computational effort of finite element (FE)-based wave propagation analysis and to enable the modelling of heterogeneous cellular structures. To this end, we take two different approaches: (1) implementation of damping boundary conditions to reduce the solution domain, and (2) development of methodologies to approximately capture the heterogeneities of cellular sandwich materials. The main advantage of our approach is seen in the fact that it can be implemented in commercial FE software in a straightforward fashion. Using these approaches we can study the interaction of guided waves with heterogeneous and cellular microstructures with a significantly reduced numerical effort. By means of parametric studies we then extract important variables that influence the behavior of elastic waves in sandwich panels.

Temperature Dependence of Elastic Properties of Aluminum Foam Structures

The temperature dependence of mechanical properties of aluminum foams has been investigated. Youngs modulus and Poissons ratio have been determined from simulations of a unidirectional tensile test using a finite element model of aluminum foam networks. The Youngs modulus of the network structure for different relative densities and foam cell regularity factors have been plotted over temperature. It has been found that the Youngs modulus decreases with increasing temperature, whereas the Poissons ratio remains constant. This trend has been observed for various foam structures of different sizes, relative densities and network irregularities.