A Floquet-Based Bar-Spring Model for the Dynamic Modulus of Bioinspired Composites With Arbitrary Staggered Architectures

2019 ◽  
Vol 86 (9) ◽  
Author(s):  
Wen Xie ◽  
Yanan Yuan ◽  
Zuoqi Zhang

Staggered architectures widely seen in load-bearing biological materials provide not only excellent supporting functions resisting static loading but also brilliant protecting functions attenuating the dynamic impact. However, there are very few efforts to unveil the relationship between staggered architectures and damping properties within load-bearing biological and bioinspired materials, while its static counterpart has been intensively studied over the past decades. Here, based on the Floquet theory, we developed a new generic method to evaluate the dynamic modulus of the composites with various staggered architectures. Comparisons with the finite element method results showed that the new method can give more accurate predictions than previous methods based on the tension-shear chain model. Moreover, the new method is more generic and applicable for two- and three-dimensional arbitrarily staggered architectures. This method provides a useful tool to understand the relationship between micro-architecture and damping property in natural load-bearing biological materials and to facilitate the architectural design of high-damping bioinspired composites.

2017 ◽  
Vol 88 (9) ◽  
pp. 1026-1037 ◽  
Author(s):  
Ge Wu ◽  
Duan Li ◽  
Pengpeng Hu ◽  
Yueqi Zhong ◽  
Ning Pan

In this paper, a new method was proposed to establish the relationship between three-dimensional (3D) foot shapes and their two-dimensional (2D) foot silhouettes, through which a complete 3D foot shape can be predicted by simply inputting its two 2D silhouettes. 3D foot scans of 80 participants were randomly selected as the training set, and those of another 20 participants were used as the testing set. Elliptical Fourier analysis (EFA) and principle component analysis (PCA) were adopted to parameterize the 3D foot shapes. A linear regressive model was then developed to predict the 3D foot shape with the foot silhouettes. Experiment results indicated individual 3D foot shape can be predicted with a mean error between 1.21 and 1.27 mm, which can provide enough accuracy for the fit evaluation of footwear.


1974 ◽  
Vol 25 (5) ◽  
pp. 803 ◽  
Author(s):  
WT Williams ◽  
LA Edye

The analysis of three-dimensional data sets has received considerable attention in ecology, but relatively little in agriculture, in which such data sets are equally common. A model has recently been proposed for the (sites x species x times) case in marine ecology; it can be regarded as based either on Euclidean distance or on the analysis of variance. The model is recapitulated in outline, its properties are somewhat extended, and its application to agronomic experiments is discussed. A brief account is given of the use of the model in the analysis of two real-life agronomic experiments. Finally, the relationship of such methods to those of classical statistics is briefly discussed.


2018 ◽  
Vol 89 (8) ◽  
pp. 1582-1592
Author(s):  
Keshuai Liu ◽  
Yi Zhou ◽  
Weilin Xu

This study reports a numerical analysis on embeddable and locatable spinning systems. The finite element method is used to quantify the relationship between the tension and twist of staple strands and the spinning parameters. The model was constructed using the three-dimensional beam element, which is capable of simulating the stretching, bending and torsion behavior of the filament and the staple strand. It was found that the staple strand shares far less load (around 13.8%) than the filament during the spinning process. The twist is mainly distributed on the composite yarns and less on other zones. The pretension of the filament, the filament–strand distance ratio, the twist of the composite yarn and the material fed-in velocity were investigated for their influence on the tension and twist of the staple strand. Numerical predictions showed that higher filament tension and filament–strand ratio lead to less load and more twist on the staple strand. This is beneficial in producing stronger and smoother yarns and avoiding end breakages. It was also determined that strand tension and twist increase with an increase in composite yarn twist and a decrease in material fed-in velocity.


This chapter reviews emerging Shape Grammar research, categorising it into three themes: design analysis and generation, automated design and generative algorithms, and algebraic Shape Grammars. The first theme consists of theoretical Shape Grammar approaches, two-dimensional architectural design, three-dimensional architectural design, urban design, and design in art and engineering. The second theme addresses four alternative perspectives to grammatical approaches based on design automation, procedural modelling, genetic algorithms, and other algorithmic generation and evaluation methods. The last theme examines research using algebraic shape descriptions and operations. The purpose of this chapter is to provide a critical summary of recent trends in Shape Grammar research and an overview of the relationship between grammatical and generative systems in architecture.


2012 ◽  
Vol 548 ◽  
pp. 123-127
Author(s):  
Xiao Tuo Li ◽  
Xin Yu Fan ◽  
Ying Dan Zhu ◽  
Juan Li

A three-dimensional computational model based on the finite element method was developed to predict the thermal properties of randomly distributed multi-walled carbon nanotube (MWCNT)/polymer composites. The numerical results agree very well with the experimental data for MWCNT/epoxy composites with the MWCNT loading below ~10 vol% at the interfacial thermal resistance of ~1.0×10-8 m2K/W, which may give insight into the relationship between the thermal behavior of MWCNT-matrix interfaces and the thermal conductivity of composites. This model is also a useful tool to evaluate the effects of MWCNT-matrix interfacial thermal resistance, volume fraction, thermal conductivity and diameter of MWCNTs on the thermal conductivity of other types of MWCNT/ polymer composites.


2021 ◽  
Vol 2021 ◽  
pp. 1-6
Author(s):  
Tao Su ◽  
Gang Ouyang

With the continuous development of social economy, people’s aspiration for architecture is getting higher and higher. Designing more functional and aesthetically pleasing interior styling products is increasingly important research. Relying on the multimedia three-dimensional hybrid algorithm, the mathematical modeling of the relationship between visual comfort and chromaticity is modeled in this paper, to construct an economical and practical interior architectural design model that takes into account color comfort perception, that is, complete “design, conversion, editing and repair, and semantic and coordinate supplement” and other chain construction to realize usable interior architectural design models. The simulation experiment results show that the model based on the multimedia 3D hybrid algorithm has high practicability.


1957 ◽  
Vol 24 (3_Suppl) ◽  
pp. S207
Author(s):  
A. Klopper

Abstract The changes in view on the significance and amount of urinary pregnanediol in the menstrual cycle are reviewed; in particular the effects of the discovery that the adrenals in both sexes normally contribute to the urinary pregnanediol. Pregnanediol excretion during the menstrual cycle was studied by means of a new method of assay (Klopper et al., 1955) and the results applied to present day concepts of the growth and duration of the corpus luteum. The relationship between pregnanediol excretion and ovulation or the onset of menstrual bleeding was studied. A new view is put forward on the influence of age and parity on the production of progesterone by the corpus luteum.


2020 ◽  
Vol 46 (3) ◽  
pp. 175-181
Author(s):  
Marcelo Bighetti Toniollo ◽  
Mikaelly dos Santos Sá ◽  
Fernanda Pereira Silva ◽  
Giselle Rodrigues Reis ◽  
Ana Paula Macedo ◽  
...  

Rehabilitation with implant prostheses in posterior areas requires the maximum number of possible implants due to the greater masticatory load of the region. However, the necessary minimum requirements are not always present in full. This project analyzed the minimum principal stresses (TMiP, representative of the compressive stress) to the friable structures, specifically the vestibular face of the cortical bone and the vestibular and internal/lingual face of the medullary bone. The experimental groups were as follows: the regular splinted group (GR), with a conventional infrastructure on 3 regular-length Morse taper implants (4 × 11 mm); and the regular pontic group (GP), with a pontic infrastructure on 2 regular-length Morse taper implants (4 × 11 mm). The results showed that the TMiP of the cortical and medullary bones were greater for the GP in regions surrounding the implants (especially in the cervical and apical areas of the same region) but they did not reach bone damage levels, at least under the loads applied in this study. It was concluded that greater stress observed in the GP demonstrates greater fragility with this modality of rehabilitation; this should draw the professional's attention to possible biomechanical implications. Whenever possible, professionals should give preference to use of a greater number of implants in the rehabilitation system, with a focus on preserving the supporting tissue with the generation of less intense stresses.


1990 ◽  
Vol 18 (4) ◽  
pp. 216-235 ◽  
Author(s):  
J. De Eskinazi ◽  
K. Ishihara ◽  
H. Volk ◽  
T. C. Warholic

Abstract The paper describes the intention of the authors to determine whether it is possible to predict relative belt edge endurance for radial passenger car tires using the finite element method. Three groups of tires with different belt edge configurations were tested on a fleet test in an attempt to validate predictions from the finite element results. A two-dimensional, axisymmetric finite element analysis was first used to determine if the results from such an analysis, with emphasis on the shear deformations between the belts, could be used to predict a relative ranking for belt edge endurance. It is shown that such an analysis can lead to erroneous conclusions. A three-dimensional analysis in which tires are modeled under free rotation and static vertical loading was performed next. This approach resulted in an improvement in the quality of the correlations. The differences in the predicted values of various stress analysis parameters for the three belt edge configurations are studied and their implication on predicting belt edge endurance is discussed.


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