Cell Wall Length Research Articles

Effect of Cell Geometry on the Energy Absorption of Honeycombs Under In-Plane Compression

This study examines the energy absorption capabilities of cellular honeycombs subjected to in-plane compression. ABAQUS nonlinear finite element analysis is used and cellular honeycombs with different cell geometries are considered. Simulation results are validated against previously published results for 30 deg cellular honeycombs. For various cell angles, comparison of simulation results for full-size honeycombs and their single-cell analogs suggest that the energy absorption can be accurately determined using the single-cell model. Results indicate that for cells with equal wall length, the specific energy absorption capability increases with increasing cellular honeycomb angle. A cell wall length study shows that the specific energy absorption (energy absorption per unit mass) is higher for cells with shorter vertical walls. A cell wall thickness study shows that increasing wall thickness increases the specific energy absorption. A vertical wall thickness study shows that the vertical walls should be thick enough not to buckle, but no thicker, providing the maximum energy absorption for minimum weight. A detailed analysis of cell deformation for different honeycombs and an insight of the underlying physics behind the differences in energy absorption capabilities observed for the different honeycombs are also presented.

Evaluation of Compressive Densification Strain of Paper Honeycombs

The significance of the compressive densification strain to the evaluation of energy absorption properties is analyzed. The evaluation equation of compressive densification strain of paper honeycombs is modeled by introducing the instantaneous and relative density of paper honeycombs. The results of many experiments of paper honeycombs with different structure factors show how geometry aspects of hexagonal paper honeycombs, e.g. the thickness and length of honeycomb cell-wall and the drawing ratio of hexagonal honeycomb, affect the compressive densification strain of the paper honeycombs. With the increase of cell-wall thickness, the densification will reduce; with the increase of cell-wall length, the densification will increase; with the increase of thickness-length ratio of cell-walls, the densification will reduce; with the increase of drawing ratios, the densification will reduce; when the drawing ratio is 1, the compression densification is up to the maximum. The experiment results agree with the evaluation equation, and when the instantaneous and relative density is almost 0.39, the densification appears. The evaluation equation applied to the five-layer corrugated paperboard shows it also can be used for other structure honeycomb materials. The equation is universal.

Presumable role of plasmodesmata in floral signal transduction in shoot apical meristems of rudbeckia and perilla plants

The number of plasmodesmata was calculated per 1 μm of cell wall length in the central and medullar zones of shoot apical meristems (SAM) in the course of floral transition in a long-day (LD) plant Rudbeckia bicolor Nutt. and a short-day plant Perilla nankinensis Lour. Under the day length unfavorable for flowering (control), the numbers of plasmodesmata differed in the central and medullar zones of SAM, which produce the reproductive organs and stems, respectively. Besides, the numbers of plasmodesmata in the central zone of perilla SAM considerably differed between the anticlinal and periclinal cell walls of the first and second cell layers. Following the photoperiodic induction (PI) with eight LD in rudbeckia and twelve SD in perilla favorable for floral transition, the numbers of plasmodesmata considerably increased in the anticlinal and periclinal cell walls of the first and second cell layers of the central zone; meanwhile in the medullar zone, the numbers of plasmodesmata dropped down following PI. These data show that floral transition presumably involves the activation of cell-to-cell interactions and enhances the signal transduction in SAM.

Transverse shape analysis of xylem ground tissues by Fourier transform image analysis II: cell wall directions and reconstruction of cell shapes

Cell wall directions of tracheids in transverse sections of Agathis sp. and Cryptomeria japonica and fiber bodies in Magnolia obovata were quantified by Fourier transform image analysis (FTIA). Three kinds of information about cell shapes were determined from the angular distribution functions of the net map-power spectrum pattern (NM-PSP): (1) the peak angle expresses the most frequent cell wall direction, (2) the area of the peak is indicative of cell wall length, and (3) the dispersion of the peak indicates the fluctuation of cell wall orientation. Fluctuations were expressed as the standard deviation (σ) by the use of statistical analysis. Cell wall directions in Agathis, that is, directions of the tangential and radial walls (three orientations were detected) were 0° (σ = 7°), 59° (12°), 91° (9°), and 122° (12°), respectively. Pentagonal and hexagonal models were reconstructed as cell shape models in a calculated ratio of 60 : 40. On the other hand, directions were 0° (5°), 76° (12°), 89° (5°), and 102° (12°) in a calculated ratio of 45 : 55 in Cryptomeria. Fiber bodies were extracted in Magnolia and their wall directions were 0° (5°), 50° (7°), 90° (6°), and 131° (7°), respectively. The ordinary accumulated image analysis (OAIA) was checked at the same time in Agathis, and indicated that FTIA could be used as a method of reconstruction of cell shape.

Parameters affecting energy absorption and deformation in textile composite cellular structures

Cellular structures currently applied in various engineering fields are mainly made of metals and papers. To engineering design textile composite cellular structures, in this paper, comparisons of various essential structural parameters affecting energy absorption and deformation are carried out. These parameters include the opening angle, the cell-wall length, the cell-wall thickness, the bonded cell-wall length, and the bonded cell-wall thickness. The structure geometries are created by in-house computer package which exports IGES files. Two-dimensional finite element analyses are conducted by MSC.Marc Mentat 2001 which imports these IGES files to numerical calculation. Orthotropic mechanical properties of the textile composite cellular structure laminate are applied for the finite element analyses. It is found that the opening angle, the cell-wall length and the cell-wall thickness affect significantly energy absorption and deformation. Strain energy density concentrations appear very seriously around the cell corners during quasi-static impact.