Investigation of the equivalent material properties and failure stress of the re-entrant composite lattice structures using an analytical model

2021 ◽  
Vol 257 ◽  
pp. 113161
Author(s):  
Hossein Veisi ◽  
Amin Farrokhabadi
Keyword(s):  
Analytical Model ◽  
Material Properties ◽  
Failure Stress ◽  
Equivalent Material ◽  
Lattice Structures ◽  
Composite Lattice ◽  
Equivalent Material Properties

Analysis of Buffering Properties of Honeycomb Material

2012 ◽  
Vol 482-484 ◽  
pp. 1146-1149
Author(s):  
Ming Bo Yang ◽  
Jin Bao Chen ◽  
Fei Deng ◽  
Meng Chen
Keyword(s):  
Theoretical Analysis ◽  
Material Properties ◽  
Orthotropic Material ◽  
Soil Mechanics ◽  
Material Model ◽  
Lunar Soil ◽  
Equivalent Material ◽  
User Material Model ◽  
Honeycomb Material ◽  
Equivalent Material Properties

The buffering properties of honeycomb material are analyzed in the presented work. Theoretical analysis based on energy method is first presented, the buffering process of honeycomb material can be divided into three phases, honeycomb material can be equivalent to orthotropic material and the equivalent material properties are given. Being good at soil mechanics, Abaqus can simulate lunar soil very well. Using a constitutive model for honeycomb material, which is a built-in user material model, the presented work developed a honeycomb material simulation model and verified with a practical example. Now we can analysis the entire landing buffer process in Abaqus, which is a complement to existing analysis processes.

Effective Stress Ratio of Triangular Pattern Perforated Plates

2008 ◽  
Author(s):  
Naoto Kasahara ◽  
Hideki Takasho ◽  
Nobuchika Kawasaki ◽  
Masanori Ando
Keyword(s):  
Effective Stress ◽  
Material Properties ◽  
Constitutive Equations ◽  
Stress Ratio ◽  
Equivalent Material ◽  
Solid Materials ◽  
Perforated Plates ◽  
Non Linear ◽  
Effective Stress Ratio ◽  
Equivalent Material Properties

Tubesheet structures utilized in heat exchangers have complex perforated portions. For realistic design analysis, axisymmetric models with equivalent solid materials of perforated plate are conventionally adopted to simplify perforated area (figure1). Sec.III Appendix A-8000 (ASME 2004) provides elastic equivalent solid materials for flat tubesheets. Plastic properties were studied by Porowski et al. (1974), Gorden et al. (2002) and so on. Elevated temperature design of tubesheets requires plastic and creep properties in addition. The purpose of this study is to develop a general determination method of non-linear equivalent material properties for perforated plates and to confirm their applicability to both flat and spherical tubesheets. Main loadings of tubesheets in fast reactor heat exchanges are inner pressure and thermal stress at transient operations. Under above conditions, average stress of perforated area becomes approximately equi-biaxial. Therefore, average inelastic behaviors of various perforated plates subjected to equi-biaxial field were investigated by inelastic finite element method. Though above investigations, Authors clarified that perforated plates have their own effective stress ratio (ESR). ESR is a function of geometry and is independent from their materials. ESR can determine non-linear equivalent material properties of perforated plates for any kind of constitutive equations of base metals. For simplified inelastic analysis of perforated plates, the brief equations were proposed to determine equivalent plastic and creep material properties for perforated plates. It is considered that physical meaning of ESR is an effective stress ratio between perforated plates and equivalent solid plates. ESR is a function of geometry and is independent from constitutive equations. ESR can determine non-linear equivalent material properties for perforated plates from any kind of constitutive equations of base materials. Assumptions in ESR are von Mises’s equivalent stress-strain relationship and equi-biaxial loadings. Applicability of ESR was investigated through finite element analyses of various flat and spherical tubesheets.

A Method of Structure Analysis for Complex Small HAWT Composite Blade Design

2012 ◽  
Vol 591-593 ◽  
pp. 227-230
Author(s):  
Shih Fang Wei ◽  
Chung Yan Lin
Keyword(s):  
Structure Analysis ◽  
Material Properties ◽  
Composite Structures ◽  
Composite Layer ◽  
Equivalent Material ◽  
Unique Challenge ◽  
3D Shape ◽  
Composite Blade ◽  
Composite Layers ◽  
Equivalent Material Properties

The air contain very low density of energy, as a result the complex 3D shape blade is required for maximize the energy extraction. The blades of the wind turbine will suffer the tough nature environment. The complex 3D shape blade with thick composite layers creates unique challenge for the design and structure analysis. The equivalent property of a composite layer that contains multiple plies of laminates is often used in the analysis of the thick composite structures. This study focused on a methodology to calculating the equivalent material properties on the 3D blade with thick composite layers. The research applies reverse engineering method to sample the blade material in order to get the equivalent material properties of complex composite 3D blade. By doing this, an equivalent material properties of composite blade can be used in the finite element analysis. The result can also provide a guide line for stress and fatigue design of blade.

scholarly journals Influence of Boundary Conditions on the Simulation of a Diamond-Type Lattice Structure: A Preliminary Study

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Patrick Terriault ◽  
Vladimir Brailovski
Keyword(s):  
Boundary Conditions ◽  
Material Properties ◽  
Lattice Structure ◽  
Industrial Applications ◽  
Unit Cell ◽  
Equivalent Material ◽  
Unit Cells ◽  
Type Lattice ◽  
Diamond Type ◽  
Equivalent Material Properties

Emergent additive manufacturing processes allow the use of metallic porous structures in various industrial applications. Because these structures comprise a large number of ordered unit cells, their design using conventional modeling approaches, such as finite elements, becomes a real challenge. A homogenization technique, in which the lattice structure is simulated as a fully dense volume having equivalent material properties, can then be employed. To determine these equivalent material properties, numerical simulations can be performed on a single unit cell of the lattice structure. However, a critical aspect to consider is the boundary conditions applied to the external faces of the unit cell. In the literature, different types of boundary conditions are used, but a comparative study is definitely lacking. In this publication, a diamond-type unit cell is studied in compression by applying different boundary conditions. If the porous structure’s boundaries are free to deform, then the periodic boundary condition is found to be the most representative, but constraint equations must be introduced in the model. If, instead, the porous structure is inserted in a rigid enclosure, it is then better to use frictionless boundary conditions. These preliminary results remain to be validated for other types of unit cells loaded beyond the yield limit of the material.

scholarly journals Identification of representative anisotropic material properties accounting for friction and preloading effects: A contribution for the modeling of structural dynamics of electric motor stators

2016 ◽  
Vol 24 (2) ◽  
pp. 237-259 ◽  
Author(s):  
Pierre Millithaler ◽  
Émeline Sadoulet-Reboul ◽  
Morvan Ouisse ◽  
Jean-Baptiste Dupont ◽  
Noureddine Bouhaddi
Keyword(s):  
Dynamic Behavior ◽  
Structural Dynamics ◽  
Electric Motor ◽  
Material Properties ◽  
Anisotropic Material ◽  
Equivalent Material ◽  
Low Frequencies ◽  
Practical Applications ◽  
Steel Sheets ◽  
Equivalent Material Properties

Simulating the dynamic behavior and determining equivalent material properties for anisotropic models, superelements or structures subjected to preloads or friction remains a challenging issue. Amongst other practical applications, modeling interactions between the steel sheets in industrial magnetic cores of electric motor stators is a complex task, as it requires anticipating behavioral heterogeneities in the structure, and possibly represents significantly costly operations for performing modal or dynamic response simulations. In this article, a method for identifying equivalent material properties to anisotropic structures is developed, which is able to take into account the influence of preloads and friction on the material properties, later used in structural dynamics simulations. The proposed approach can be used with superelements, converting stiffness matrices into elasticity matrices. The method is first applied to a triclinic model, and recreates its elasticity matrix with little derivation. Then, an equivalent linear material is computed for a continuous structure under preloading. Compared at low frequencies, the vibration behavior of the preloaded structure and its equivalent effective media are in good agreement. The operation is repeated with a laminated stack under preloading. Again, the dynamic behavior of the equivalent structure shows good accuracy compared to the initial preloaded stack. Finally, the magnetic core of an electric machine stator is modeled with equivalent anisotropic material properties, accounting for friction and preload in the yoke's and the teeth's steel sheets. The simulation of the structure's low-frequency radial vibration modes is satisfying, and shows improvement compared to orthotropic properties.

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