In-Plane Stiffness and Yield Strength of Periodic Metal Honeycombs

2004 ◽  
Vol 126 (2) ◽  
pp. 137-156 ◽  
Author(s):  
A.-J. Wang ◽  
D. L. McDowell
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Relative Density ◽  
Cell Types ◽  
Elastic Stiffness ◽  
Honeycomb Structures ◽  
Initial Yield ◽  
Cell Structures ◽  
Plane Anisotropy ◽  
Different Cell Types

In-plane mechanical properties of periodic honeycomb structures with seven different cell types are investigated in this paper. Emphasis is placed on honeycombs with relative density between 0.1 and 0.3, such that initial yield is associated with short column compression or bending, occurring prior to elastic buckling. Effective elastic stiffness and initial yield strength of these metal honeycombs under in-plane compression, shear, and diagonal compression (for cell structures that manifest in-plane anisotropy) are reported as functions of relative density. Comparison among different honeycomb structures demonstrates that the diamond cells, hexagonal periodic supercells composed of six equilateral triangles and the Kagome cells have superior in-plane mechanical properties among the set considered.

Effect of Tempering Temperature on Microstructure, Texture and Mechanical Properties of a High Strength Steel

2014 ◽  
Vol 4 (3) ◽  
pp. 33-49 ◽  
Author(s):  
Pradipta Kumar Jena ◽  
K. Siva Kumar ◽  
A.K. Singh
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Mechanical Behavior ◽  
High Strength Steel ◽  
High Strength ◽  
Tempering Temperature ◽  
Plane Anisotropy ◽  
Microstructures And Mechanical Properties

This work describes the microstructure, texture and anisotropy in mechanical behavior of a high strength steel in various tempered conditions. The microstructures and mechanical properties change considerably with varying tempering temperatures. The material exhibits low in-plane anisotropy and low anisotropic index in terms of yield strength and elongation with increase in tempering temperature. The anisotropy of the material displays similar behavior to that of the yield strength.

scholarly journals Dual Graded Lattice Structures: Generation Framework and Mechanical Properties Characterization

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1528
Author(s):  
Khaled G. Mostafa ◽  
Guilherme A. Momesso ◽  
Xiuhui Li ◽  
David S. Nobes ◽  
Ahmed J. Qureshi
Keyword(s):  
Mechanical Properties ◽  
Relative Density ◽  
Lattice Structure ◽  
Cell Types ◽  
Functionally Graded ◽  
Unit Cell ◽  
Lattice Structures ◽  
Unit Cells ◽  
Mechanical Properties Characterization ◽  
Graded Lattice

Additive manufacturing (AM) enables the production of complex structured parts with tailored properties. Instead of manufacturing parts as fully solid, they can be infilled with lattice structures to optimize mechanical, thermal, and other functional properties. A lattice structure is formed by the repetition of a particular unit cell based on a defined pattern. The unit cell’s geometry, relative density, and size dictate the lattice structure’s properties. Where certain domains of the part require denser infill compared to other domains, the functionally graded lattice structure allows for further part optimization. This manuscript consists of two main sections. In the first section, we discussed the dual graded lattice structure (DGLS) generation framework. This framework can grade both the size and the relative density or porosity of standard and custom unit cells simultaneously as a function of the structure spatial coordinates. Popular benchmark parts from different fields were used to test the framework’s efficiency against different unit cell types and grading equations. In the second part, we investigated the effect of lattice structure dual grading on mechanical properties. It was found that combining both relative density and size grading fine-tunes the compressive strength, modulus of elasticity, absorbed energy, and fracture behavior of the lattice structure.

scholarly journals Design Optimization of Lattice Structures under Compression: Study of Unit Cell Types and Cell Arrangements

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 97
Author(s):  
Kwang-Min Park ◽  
Kyung-Sung Min ◽  
Young-Sook Roh
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Relative Density ◽  
Lattice Structure ◽  
Density Ratio ◽  
Cell Types ◽  
Unit Cell ◽  
Structure Characterization ◽  
Optimized Design ◽  
Lattice Structures

Additive manufacturing enables innovative structural design for industrial applications, which allows the fabrication of lattice structures with enhanced mechanical properties, including a high strength-to-relative-density ratio. However, to commercialize lattice structures, it is necessary to define the designability of lattice geometries and characterize the associated mechanical responses, including the compressive strength. The objective of this study was to provide an optimized design process for lattice structures and develop a lattice structure characterization database that can be used to differentiate unit cell topologies and guide the unit cell selection for compression-dominated structures. Linear static finite element analysis (FEA), nonlinear FEA, and experimental tests were performed on 11 types of unit cell-based lattice structures with dimensions of 20 mm × 20 mm × 20 mm. Consequently, under the same relative density conditions, simple cubic, octahedron, truncated cube, and truncated octahedron-based lattice structures with a 3 × 3 × 3 array pattern showed the best axial compressive strength properties. Correlations among the unit cell types, lattice structure topologies, relative densities, unit cell array patterns, and mechanical properties were identified, indicating their influence in describing and predicting the behaviors of lattice structures.

Simulation of Spatial Strain Inhomogeneities in Lithium-Ion-Cells Due to Electrode Dilation Dependent on Internal and External Cell Structures

2020 ◽  
Author(s):  
Fabian Ebert ◽  
Markus Spielbauer ◽  
Maximilian Bruckmoser ◽  
Markus Lienkamp
Keyword(s):  
Energy Density ◽  
Lithium Ion ◽  
Cell Types ◽  
Post Mortem ◽  
Lithium Ion Cells ◽  
Cell Material ◽  
Cell Structures ◽  
Cell Energy ◽  
Simulation Results ◽  
Different Cell Types

Electrochemical-mechanical interactions, in particular pressure-induced ones, have been identified to be a cause for lithium-plating in lithium-ion cells. Mechanically-induced porosity inhomogeneities in the separator layers due to electrode expansion during charging especially lead to cell internal balancing currents and can cause localized plating. To identify cell-format and cell-material dependent mechanical weak spots, a layer-resolved mechanical simulation of different cell types and cell-material combinations is presented in this work. The simulation results show distinctive layer strain patterns for different cell-types that coincide with localized lithium-plating found in post-mortem cells. Additionally, the effects of cell bracing in battery modules is investigated and a method to mitigate the increased layer strain due to bracing counterforces is proposed that also increases cell energy density for hardcase-type automotive cells.

scholarly journals Simulation of Spatial Strain Inhomogeneities in Lithium-Ion-Cells Due to Electrode Dilation Dependent on Internal and External Cell Structures

2021 ◽  
Author(s):  
Fabian Ebert ◽  
Markus Spielbauer ◽  
Maximilian Bruckmoser ◽  
Markus Lienkamp
Keyword(s):  
Energy Density ◽  
Lithium Ion ◽  
Cell Types ◽  
Post Mortem ◽  
Lithium Ion Cells ◽  
Cell Material ◽  
Cell Structures ◽  
Cell Energy ◽  
Simulation Results ◽  
Different Cell Types

Electrochemical-mechanical interactions, in particular pressure-induced ones, have been identified to be a cause for lithium-plating in lithium-ion cells. Mechanically-induced porosity inhomogeneities in the separator layers due to electrode expansion during charging especially lead to cell internal balancing currents and can cause localized plating. To identify cell-format and cell-material dependent mechanical weak spots, a layer-resolved mechanical simulation of different cell types and cell-material combinations is presented in this work. The simulation results show distinctive layer strain patterns for different cell-types that coincide with localized lithium-plating found in post-mortem cells. Additionally, the effects of cell bracing in battery modules is investigated and a method to mitigate the increased layer strain due to bracing counterforces is proposed that also increases cell energy density for hardcase-type automotive cells.

Effect of Tempering Temperature on Microstructure, Texture and Mechanical Properties of a High Strength Steel

2017 ◽  
pp. 1690-1702
Author(s):  
Pradipta Kumar Jena ◽  
K. Siva Kumar ◽  
A.K. Singh
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Mechanical Behavior ◽  
High Strength Steel ◽  
High Strength ◽  
Tempering Temperature ◽  
Plane Anisotropy ◽  
Microstructures And Mechanical Properties

This work describes the microstructure, texture and anisotropy in mechanical behavior of a high strength steel in various tempered conditions. The microstructures and mechanical properties change considerably with varying tempering temperatures. The material exhibits low in-plane anisotropy and low anisotropic index in terms of yield strength and elongation with increase in tempering temperature. The anisotropy of the material displays similar behavior to that of the yield strength.

The ultra-structure of the developing eye of Drosophila

1960 ◽  
Vol 153 (951) ◽  
pp. 155-178 ◽  
Keyword(s):  
Nuclear Envelope ◽  
Cell Types ◽  
Pigment Cells ◽  
Cell Organelles ◽  
Ultra Structure ◽  
Cell Structures ◽  
Cone Cells ◽  
Different Types ◽  
Different Cell Types ◽  
First Time

A description is given of the ultra-structure of the eye of Drosophila melanogaster during its development from the imaginal bud of the late larva till it attains its final form in the adult. Six markedly different types of cells develop out of the apparently uniform epithelium of the imaginal bud; namely, cone cells, retinula cells, primary pigment cells, secondary and basal pigment cells, two [inner and outer] types of hair-nerve cells. In each type of cell there is a characteristic form of cytoplasmic double-membrane structure [endoplasmic reticulum] which reaches its highest development at or just before the time at which the characteristic cell structures are being formed. In most types of cell there are indications of the participation of the nucleus, or nuclear envelope, in cell differentiation, these indications being different in the different cell types. In retinula cells and also in inner hairnerve cells there is evidence suggesting that the outer layer of the nuclear envelope may give rise directly to cytoplasmic double membranes. Several cell organelles are described for the first time, in particular the rhabdomere vesicular spheroids and the cone cell granules. In the formation of the rhabdomeres by the retinula cells, the first stages in the deposition of this structure are carried out by the plasma membrane on the cells. The presence of an eighth retinula is confirmed. The implications of the observations for our general understanding of cell activities during differentiation is briefly discussed; work already in progress with various mutants is expected to reveal new facts of interest in this connexion.

scholarly journals Mechanical Response of Hollow Metallic Nanolattices: Combining Structural and Material Size Effects

2015 ◽  
Vol 82 (7) ◽  
Author(s):  
L. C. Montemayor ◽  
J. R. Greer
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Relative Density ◽  
Size Effects ◽  
Scaling Laws ◽  
Tube Wall ◽  
Three Dimensional ◽  
Cellular Solids ◽  
Tube Wall Thickness ◽  
Strength And Stiffness

Ordered cellular solids have higher compressive yield strength and stiffness compared to stochastic foams. The mechanical properties of cellular solids depend on their relative density and follow structural scaling laws. These scaling laws assume the mechanical properties of the constituent materials, like modulus and yield strength, to be constant and dictate that equivalent-density cellular solids made from the same material should have identical mechanical properties. We present the fabrication and mechanical properties of three-dimensional hollow gold nanolattices whose compressive responses demonstrate that strength and stiffness vary as a function of geometry and tube wall thickness. All nanolattices had octahedron geometry, a constant relative density, ρ ∼ 5%, a unit cell size of 5–20 μm, and a constant grain size in the Au film of 25–50 nm. Structural effects were explored by increasing the unit cell angle from 30 deg to 60 deg while keeping all other parameters constant; material size effects were probed by varying the tube wall thickness, t, from 200 nm to 635 nm, at a constant relative density and grain size. In situ uniaxial compression experiments revealed an order of magnitude increase in yield stress and modulus in nanolattices with greater lattice angles, and a 150% increase in the yield strength without a concomitant change in modulus in thicker-walled nanolattices for fixed lattice angles. These results imply that independent control of structural and material size effects enables tunability of mechanical properties of three-dimensional architected metamaterials and highlight the importance of material, geometric, and microstructural effects in small-scale mechanics.

Effect of Defect on Elastic-Plastic and Creep Behavior of Cellular Materials

2007 ◽  
Author(s):  
Amin Ajdari ◽  
Hamid Nayeb-Hashemi ◽  
Paul K. Canavan
Keyword(s):  
Mechanical Properties ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Yield Strength ◽  
Creep Behavior ◽  
Cellular Materials ◽  
Hexagonal Structure ◽  
Cellular Solids ◽  
Element Analysis ◽  
Honeycomb Structures

Cellular solids, such as foams, are widely used in engineering applications. In these applications, it is important to know their mechanical properties and the variation of these properties with the presence of defects. Several models have been proposed to obtain the mechanical properties of cellular materials. However, some of these models are based on idealized unit cell structures, and are not suitable for finding the mechanical properties of cellular materials with defects. Furthermore, the creep response changes in cellular solids when the exposed temperature is higher than 1/3 of the material’s melting temperature. The objective of this work is to understand the effect of missing walls and filled cells on mechanical and creep behavior of both the regular hexagonal and non-periodic Voronoi structures using finite element analysis. The finite element analysis showed that on average the non periodic structures have inferior mechanical properties compared to that of the regular hexagonal structures with the same relative density. The yield stress of Voronoi structures had a mean of 27% lower compared to that of the hexagonal structure with the same relative densities. Defects, introduced by removing cell walls at random locations, caused a sharp decrease in the effective mechanical properties of both Voronoi and periodic hexagonal honeycombs. However, our results indicated that elastic properties of Voronoi Structures are more sensitive to missing walls when compared to those of regular honeycomb structures. The yield strength of Voronoi and regular honeycombs exhibited the similar sensitivity to cell wall removal. For creep analysis, the results suggest that removal of struts dramatically increases the creep rate. In the case of filled cells, regular honeycomb structures showed less sensitivity to the defect compared to Voronoi structures. The overall elastic modulus of the structure increased by 11% when 5% of cells were filled in regular hexagonal honeycombs while for Voronoi structure it had more significant effect (22% increase). The results also show that filled cell did not have a significant effect on yield strength of the regular and Voronoi structures.

Force/Torque Field Generation to Obtain Local Properties within Soft Hydrogels

2007 ◽  
Author(s):  
Uday Chippada ◽  
Bernard Yurke ◽  
David I. Shreiber ◽  
Rene Schloss ◽  
Xue Jiang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cell Types ◽  
Biological Applications ◽  
Cellular Behavior ◽  
Closed Form Solutions ◽  
Matrix Deposition ◽  
A Cell ◽  
The Media ◽  
Local Properties ◽  
Different Cell Types

Soft media like hydrogels are used as substrates for cellular engineering of different cell types and the stiffness of these media plays an important role in the cellular behavior like adhesion, proliferation, matrix deposition and differentiation. The global mechanical properties of such substrates were previously calculated using spherical beads embedded in micro-liter samples and then deflecting them by a magnetic manipulator [1]. Knowing the force and the displacement the elastic modulus was evaluated using closed form solutions. However in the context of our studies for biological applications there are circumstances where the local elastic properties of the hydrogel play an important role. For example in the vicinity of a cell, the cell will distort the gel and the modulus of elasticity of the surface may get altered, particularly if the gel is non-linear and if the distortions are substantial. In order to measure these local properties a four magnet manipulator based on Amblard, et al [2] was built, which is capable of applying large forces on micron sized particles embedded in the media.

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