The significance of the elastic modulus of wood cell walls obtained from nanoindentation measurements

2004 ◽  
Vol 35 (11) ◽  
pp. 1345-1349 ◽  
Author(s):  
W. Gindl ◽  
T. Schöberl
Keyword(s):  
Elastic Modulus ◽  
Cell Walls

Quasi-static and dynamic nanoindentation to determine the influence of thermal treatment on the mechanical properties of bamboo cell walls

Holzforschung ◽  
2015 ◽  
Vol 69 (7) ◽  
pp. 909-914 ◽  
Author(s):  
Yanjun Li ◽  
Liping Yin ◽  
Chengjian Huang ◽  
Yujie Meng ◽  
Feng Fu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Thermal Treatment ◽  
Cell Walls ◽  
Loss Modulus ◽  
Treatment Temperature ◽  
Dry Density ◽  
Bamboo Fibers ◽  
Tan Δ ◽  
Dynamic Nanoindentation

Abstract Bamboo was thermally treated at 180°C and 200°C, and the micromechanical properties of its cell walls were investigated by means of quasi-static and dynamic nanoindentation experiments. With increasing treatment temperatures, the average dry density and mass of the bamboo decreased, whereas the already reduced elastic modulus at 180°C of the fiber cell walls did not change, but the hardness showed increasing tendencies. Dynamic nanoindentation revealed reduced storage modulus $({E'_{\rm{r}}})$ and loss modulus $({E''_{\rm{r}}}\,)$ for the thermotreated bamboo cell walls compared with the untreated bamboo fibers in all frequency regions. Moreover, ${E'_{\rm{r}}},{\rm{ }}{E''_{\rm{r}}},$ and loss tangent (tan δ) of treated bamboo decreased with increasing treatment temperature.

scholarly journals Change in Micromechanical Behavior of Surface Densified Wood Cell Walls in Response to Superheated Steam Treatment

Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 693
Author(s):  
Elin Xiang ◽  
Rongfeng Huang ◽  
Shumin Yang
Keyword(s):  
Elastic Modulus ◽  
Creep Resistance ◽  
Cell Walls ◽  
Superheated Steam ◽  
Untreated Wood ◽  
Fiber Cell ◽  
Steam Treatment ◽  
Densified Wood ◽  
Relative Crystallinity ◽  
Fiber Cell Wall

The combination of surface densification and superheated steam treatment is an effective method to improve the mechanical properties and dimensional stability of low-density wood. The objective of the current work is to evaluate the effects of superheated steam treatment on the micromechanical behavior of surface densified wood. The microstructure, chemical composition, cellulose crystalline structure, and micromechanical behavior of surface densified wood under different superheated steam pressures were investigated. Results indicated that both 0.1 MPa and 0.3 MPa superheated steam treatments increased the elastic modulus and hardness of fiber cell walls in surface densified wood. However, the average creep ratio and maximum creep compliance J(50) of surface densified wood under 0.3 MPa decreased by 41.59% and 6.76%, respectively, compared with untreated wood. The improvement of elastic modulus, hardness and creep resistance of surface densified wood treated with superheated steam was associated with the increase of relative crystallinity (CrI) and crystalline size. In addition, 0.3 MPa superheated steam treatment displayed a better effect on the enhancement of the elastic modulus, hardness, and creep resistance of the fiber cell wall than 0.1 MPa superheated steam treatment.

scholarly journals Determination of the Effects of Superheated Steam on Microstructure and Micromechanical Properties of Bamboo Cell Walls Using Quasi-Static Nanoindentation

Forests ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1742
Author(s):  
Tiancheng Yuan ◽  
Xiaorong Liu ◽  
Youming Dong ◽  
Xinzhou Wang ◽  
Yanjun Li
Keyword(s):  
Elastic Modulus ◽  
Cell Walls ◽  
Superheated Steam ◽  
Lignin Content ◽  
Crystallinity Index ◽  
X Ray Diffraction ◽  
Untreated Sample ◽  
X Ray ◽  
Micromechanical Properties

In this paper, quasi-static nanoindentation was applied for investigating the influence of superheated steam on microstructure and micromechanical properties of Moso bamboo cell walls. The changes of mico-morphology, chemical composition, cellulose crystallinity index, micro-mechanical properties of bamboo were analyzed via scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR), and nanoindentation. As expected, the content of hemicellulose and cellulose showed a downward trend, whereas the relative lignin content increased. Elastic modulus and hardness of the cell wall increased compared with that of the untreated sample. The elastic modulus and hardness of bamboo increased from 11.5 GPa to 19.5 GPa and from 0.35 GPa to 0.59 GPa. Furthermore, results showed that the creep resistance positively correlated to treatment severity.

scholarly journals Protocol for mapping the spatial variability in cell wall mechanical bending behavior in living leaf pavement cells

2021 ◽  
Author(s):  
Wenlong Li ◽  
Sedighe Keynia ◽  
Samuel A. Belteton ◽  
Faezeh Afshar-Hatam ◽  
Daniel B. Szymanski ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cell Wall ◽  
Elastic Modulus ◽  
Cell Walls ◽  
Turgor Pressure ◽  
Plant Cell Walls ◽  
Pavement Cells ◽  
Elastic Bending ◽  
Entire Thickness ◽  
Bending Behavior

AbstractAn integrated, experimental-computational approach is presented to analyze the variation of elastic bending behavior in the primary cell wall of living Arabidopsis thaliana pavement cells and to measure turgor pressure in the cells quantitatively under different osmotic conditions. Mechanical properties, size and geometry of cells and internal turgor pressure greatly influence their morphogenesis. Computational models of plant morphogenesis require values for wall elastic modulus and turgor pressure but very few experiments were designed to validate the results using measurements that deform the entire thickness of the cell wall. Because new wall material is deposited from inside the cell, full-thickness deformations are needed to quantify relevant changes associated with cell development. The approach here uses laser scanning confocal microscopy to measure the three-dimensional geometry of a single pavement cell, and indentation experiments equipped with high magnification objective lens to probe the local mechanical responses across the same cell wall. These experimental results are matched iteratively using a finite element model of the experiment to determine the local mechanical properties, turgor pressure, and cell height. The resulting modulus distribution along the periclinal wall is shown to be nonuniform. These results are consistent with the characteristics of plant cell walls which have a heterogeneous organization. This research and the resulting model will provide a reference for future work associated with the heterogeneity and anisotropy of mechanical properties of plant cell walls in order to understand morphogenesis of the primary cell walls during growth and to predict quantitatively the magnitudes/directions of cell wall forces.One sentence summaryThe distribution of elastic modulus of the periclinal cell walls of livingArabidopsis epidermis is nonuniform as measured by bending the entire thickness of the wall.HighlightsExperimental characterization of the spatial distribution of elastic bending behavior across the periclinal wallQuantification of the turgor pressure of the living plant epidermal cells validated with osmotic treatmentsQuantification of the effect of cell geometry on the measured mechanical responseGraphical abstract

scholarly journals Equivalent Elastic Modulus of Asymmetrical Honeycomb

2011 ◽  
Vol 2011 ◽  
pp. 1-10
Author(s):  
Dai-Heng Chen ◽  
Kenichi Masuda
Keyword(s):  
Elastic Modulus ◽  
Coordinate System ◽  
Cell Walls ◽  
Elastic Moduli ◽  
Relative Displacement ◽  
Regular Hexagon ◽  
Relative Deformation ◽  
Direction Parallel ◽  
Minimum Compliance ◽  
Honeycomb Cell

The equivalent elastic moduli of asymmetrical hexagonal honeycomb are studied by using a theoretical approach. The deformation of honeycomb consists of two types of deformations. The first is deformation inside the unit, which is caused by bending, stretching, and shearing of cell walls and rigid rotation of the unit; the second is relative displacement between units. The equivalent elastic modulus related to a direction parallel to one cell wall of the honeycomb is determined from the relative deformation between units. In addition, a method for calculating other elastic moduli by coordinate transformation is described, and the elastic moduli for various shapes of hexagon, which are obtained by systematically altering the regular hexagon, are investigated. It is found that the maximum compliance and the minimum compliance of elastic modulus in one rotation of the coordinate system vary as the shape of the hexagon is changed. However, takes a minimum and takes a maximum when the honeycomb cell is a regular hexagon, for which the equivalent elastic moduli are unrelated to the selected coordinate system, and are constant with .

Mechanical characterisation of wood-adhesive interphase cell walls by nanoindentation

Holzforschung ◽  
2006 ◽  
Vol 60 (4) ◽  
pp. 429-433 ◽  
Author(s):  
Johannes Konnerth ◽  
Wolfgang Gindl
Keyword(s):  
Elastic Modulus ◽  
Cell Walls ◽  
Urea Formaldehyde ◽  
Wood Adhesive ◽  
Interphase Cell ◽  
Adhesive Bonds ◽  
Resorcinol Formaldehyde ◽  
Interphase Region ◽  
Mechanical Characterisation ◽  
Penetration Behaviour

Abstract The elastic modulus, hardness, and creep factor of wood cell walls in the interphase region of four different adhesive bonds were determined by nanoindentation. In comparison with reference cell walls unaffected by adhesive, interphase cell walls from melamine-urea-formaldehyde (MUF) and phenol-resorcinol-formaldehyde (PRF) adhesive bonds showed improved hardness and reduced creep, as well as improved elastic modulus in the case of MUF. In contrast, cell walls from the interphase region in polyvinylacetate (PVAc) and one-component polyurethane (PUR) bonds showed more creep, but lower elastic modulus and hardness than the reference. Considering the different cell-wall penetration behaviour of the adhesive polymers studied here, it is concluded that damage and loss of elastic modulus to surface cells occurring during the machining of wood is recovered in MUF and PRF bond lines, whereas damage of cell walls persists in PVAc and PUR bond lines.

Evaluation of elastic modulus and hardness of crop stalks cell walls by nano-indentation

2010 ◽  
Vol 101 (8) ◽  
pp. 2867-2871 ◽  
Author(s):  
Yan Wu ◽  
Siqun Wang ◽  
Dingguo Zhou ◽  
Cheng Xing ◽  
Yang Zhang ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Cell Walls ◽  
Nano Indentation

scholarly journals The Bulk Elastic Modulus and the Reversible Properties of Cell Walls in Developing Quercus Leaves

2006 ◽  
Vol 47 (6) ◽  
pp. 715-725 ◽  
Author(s):  
Takami Saito ◽  
Kouichi Soga ◽  
Takayuki Hoson ◽  
Ichiro Terashima
Keyword(s):  
Elastic Modulus ◽  
Cell Walls ◽  
Bulk Elastic Modulus

In-Plane Stiffness of Additively Manufactured Hierarchical Honeycomb Metamaterials With Defects

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Kazi Moshiur Rahman ◽  
Zhong Hu ◽  
Todd Letcher
Keyword(s):  
Elastic Modulus ◽  
Manufacturing Process ◽  
Cell Walls ◽  
Second Order ◽  
Plastic Behavior ◽  
Manufacturing Defects ◽  
First Order ◽  
Large Structures ◽  
Overall Performance ◽  
Current Engineering

Cellular metamaterials are of interest for many current engineering applications. The incorporation of hierarchy to cellular metamaterials enhances the properties and introduces novel tailorable metamaterials. For many complex cellular metamaterials, the only realistic manufacturing process is additive manufacturing (AM). The use of AM to manufacture large structures may lead to several types of manufacturing defects, such as imperfect cell walls, irregular thickness, flawed joints, partially missing layers, and irregular elastic–plastic behavior due to toolpath. It is important to understand the effect of defects on the overall performance of the structures to determine if the manufacturing defect(s) are significant enough to abort and restart the manufacturing process or whether the material can still be used in its nonperfect state. In this study, the performance of hierarchical honeycomb metamaterials with defects has been investigated through simulations and experiments, and hierarchical honeycombs were shown to demonstrate more sensitivity to missing cell walls than regular honeycombs. On average, the axial elastic modulus decreased by 45% with 5.5% missing cell walls for regular honeycombs, 60% with 4% missing cell walls for first-order hierarchical honeycomb and 95% with 4% missing cell walls for second-order hierarchical honeycomb. The transverse elastic modulus decreased by about 45% with more than 5.5% missing cell walls for regular honeycomb, about 75% with 4% missing cell walls for first-order and more than 95% with 4% missing cell walls for second-order hierarchical honeycomb.

scholarly journals Paws, pads and plants: the enhanced elasticity of cell-filled load-bearing structures

2015 ◽  
Vol 471 (2178) ◽  
pp. 20150107 ◽  
Author(s):  
L. Angela Mihai ◽  
Khulud Alayyash ◽  
Alain Goriely
Keyword(s):  
Cell Wall ◽  
Elastic Modulus ◽  
Cell Walls ◽  
Large Strain ◽  
Strain Energy Function ◽  
Material Design ◽  
Wall Material ◽  
Solid Core ◽  
Internal Cell ◽  
Wide Range

Paws, fat pads and plants share a remarkable structure made up of closed cells with elastic cell walls capable of supporting large loads and deformations. A key challenge is to understand how the function of these structures is enhanced by their geometric and material design. To do so, we compare different elastic models operating in large strain deformation when the cells are empty or filled with an incompressible liquid or solid core. We demonstrate theoretically, for three different cell geometries, that the elastic modulus in a direction associated with the change of curvature in the cell wall (i) is greater when the cell is filled; (ii) increases as the internal cell pressure increases; and (iii) increases also as the thickness of the cell wall increases or when the wall is multi-layer. As these results do not depend on the choice of the strain-energy function describing the cell-wall material, they are valid for a wide range of structures made from different elastic materials. For multiple cells deforming together due to external forces, the increase in elastic modulus of the cell walls under increasing core pressure is found numerically throughout the structure.

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