Topic
Flexural rigidity
About: Flexural rigidity is a research topic. Over the lifetime, 3829 publications have been published within this topic receiving 56780 citations.
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TL;DR: The measurements rule out the possibility that chromosome stretching and bending elasticity are principally due to a stiff central core region and are instead indicative of an internal structure, which is essentially homogeneous in its connectivity across the chromosome cross-section.
Abstract: The bending rigidities of mitotic chromosomes isolated from cultured N. viridescens (newt) and Xenopus epithelial cells were measured by observing their spontaneous thermal bending fluctuations. When combined with simultaneous measurement of stretching elasticity, these measurements constrain models for higher order mitotic chromosome structure. We measured bending rigidities of B approximately 10(-22) N. m(2) for newt and approximately 10(-23) N. m(2) for Xenopus chromosomes extracted from cells. A similar bending rigidity was measured for newt chromosomes in vivo by observing bending fluctuations in metaphase-arrested cells. Following each bending rigidity measurement, a stretching (Young's) modulus of the same chromosome was measured in the range of 10(2) to 10(3) Pa for newt and Xenopus chromosomes. For each chromosome, these values of B and Y are consistent with those expected for a simple elastic rod, B approximately YR(4), where R is the chromosome cross-section radius. Our measurements rule out the possibility that chromosome stretching and bending elasticity are principally due to a stiff central core region and are instead indicative of an internal structure, which is essentially homogeneous in its connectivity across the chromosome cross-section.
68 citations
TL;DR: In this paper, the effects of hollow glass microsphere fillers and the addition of short fibre reinforcements on the mechanical behaviour of epoxy binding matrix composites were studied, and the results showed that flexural and compressive stiffness, maximum compressive stresses, fracture toughness and impact absorbed energy decrease significantly with increasing filler content.
Abstract: This paper presents the results of an investigation into the effects of hollow glass microsphere fillers and of the addition of short fibre reinforcements on the mechanical behaviour of epoxy binding matrix composites. Properties like flexural stiffness, compressive strength, fracture toughness and absorbed impact energy, were studied. The specimens were cut from plates produced by vacuum resin transfer moulding having a microsphere contents of up to 50% and with fibre reinforcement up to 1.2% by volume. The tests performed with unreinforced composites show that flexural and compressive stiffness, maximum compressive stresses, fracture toughness and impact absorbed energy decrease significantly with increasing filler content. However, in terms of specific values, both flexural and compressive stiffness and impact absorbed energy increase with microsphere content. The addition of glass fibre produces only a slight improvement in the flexure stiffness and fracture toughness, while increasing significantly the absorbed impact energy. In contrast, the addition of a small percentage of carbon fibres produces an important improvement in both fracture toughness and flexure stiffness, when hybrid composites with 0.9% carbon fibre are compared to unreinforced foam, but did not improved absorbed impact energy.
67 citations
20 Feb 1980
TL;DR: In this article, the effects of flexural rigidity and sag of a cable are taken into account for field measurement of cable tension during the construc tion of cable system bridges such as an arch bridge stiffened with inclined cables.
Abstract: The vibration method is usually used for field measurement of cable tension during the construc tion of cable system bridges such as an arch bridge stiffened with inclined cables or a cable-stayed bridge. Practical formulas for the vibration method are proposed herein taking the effects of flexural rigidity and sag of a cable into account. The formulas are based on the approximate solutions of high accuracy for the equation of inclined cable with flexural rigidity. Cable tensions are easily estimated by these formulas using measured natural frequencies of low-order modes. The practical formulas presented herein are applicable to various cables, regardless of length and tension as far as the vibration of first- or second-order mode is measurable. As to a very long cable that cannot be easily excited artificially, a formula is presented by using natural frequencies of high-order modes obtained from stationary microvibrations. The accuracy is confirmed through comparison of the values obtained by practical formulas with measured values and calculated values by the finite element method.
67 citations
TL;DR: In this article, an attempt is made to investigate the Poisson effect in modified couple stress microbeam models by use of available experimental data of an epoxy micro-cantilever.
67 citations
TL;DR: In this paper, the authors presented accurate numerical calculations of the natural frequencies for elastic rectangular plates of variable thickness with various combinations of boundary conditions The thickness variation in one or two directions of the plate is taken in polynomial form.
66 citations