Showing papers on "Flexural rigidity published in 1977"
TL;DR: In this article, it was shown that the isostatic response function for the continental United States, computed by Lewis & Dorman (1970), is incompatible with any local compensation model that involves only negative density contrasts beneath topographic loads.
Abstract: Summary. Using the techniques of linear and quadratic programming, it can be shown that the isostatic response function for the continental United States, computed by Lewis & Dorman (1970), is incompatible with any local compensation model that involves only negative density contrasts beneath topographic loads. We interpret the need for positive densities as indicating that compensation is regional rather than local. The regional compensation model that we investigate treats the outer shell of the Earth as a thin elastic plate, floating on the surface of a liquid. The response of such a model can be inverted to yield the absolute density gradient in the plate, provided the flexural rigidity of the plate and the density contrast between mantle and topography are specified.
If only positive density gradients are allowed, such a regional model fits the United States response data provided the flexural rigidity of the plate lies between 1021 and 1022 N m. The fit of the model is insensitive to the mantle/ load density contrast, but certain bounds on the density structure can be established if the model is assumed correct. In particular, the maximum density increase within the plate at depths greater than 34 kin must not exceed 470 kg m−3; this can be regarded as an upper bound on the density contrast at the Mohorovicic discontinuity.
The permitted values of the flexural rigidity correspond to plate thicknesses in the range 5–10 km, yet deformations at depths greater than 20 km are indicated by other geophysical data. We conclude that the plate cannot be perfectly elastic; its effective elastic moduli must be much smaller than the seismically determined values. Estimates of the stress-differences produced in the earth by topographic loads, that use the elastic plate model, together with seismically determined elastic parameters, will be too large by a factor of four or more.
213 citations
TL;DR: In this paper, the energy analysis of woven-fabric mechanics is extended by considering the pure bending behavior of the plain-weave structure as a generalization of the tensile deformation.
Abstract: The energy analysis of woven-fabric mechanics developed in Part I of this series is extended by considering the pure-bending behaviour of the plain-weave structure as a generalization of the tensile deformation. The boundary conditions for the plain-weave fabric in bending are evaluated, and the ratio of fabric bending rigidity per thread to yarn bending rigidity is computed for a range of fabric structures of different values of weave crimp and degree of set by introducing inequality constraints on the curvature or control variable, a concept borrowed from optimal-control theory. The theoretical results for fabric bending rigidity are compared with experimental work reported by previous workers, and the theoretical shape of the yarn axis in a bent fabric is computed for different fabric curvatures. A comparison of the theoretical results computed by means of optimal-control theory for plain-weave, plain-knitted, and 1 × 1 rib-knitted structures is presented in terms of the following parameters expressed ...
47 citations
Journal Article•
TL;DR: In this paper, the structural behavior of bolted cast iron segments has been investigated under simple, known loading conditions, and the conclusions drawn are that the modulus of flexural rigidity of the segments is changed by variation in the applied bending movement, and also with variation in uniform pressure on the back of the segment.
Abstract: The structural behavior of bolted cast iron segments has been investigated under simple, known loading conditions. This knowledge was required to help ascertain the structural behavior of segments in actual tunnels where complex loading conditions exist. One of two kinds of segment studied was an experimental segment of unusual proportions. Some structural properties of tunnel segments for which evidence had previously been inconclusive were clearly displayed by these experimental segments. Among the conclusions drawn are that the modulus of flexural rigidity of the segments is changed by variation in the applied bending movement, and also with variation in uniform pressure on the back of the segment. The joints between segments do not always behave as simple butt joints.
14 citations
TL;DR: The storage and loss shear moduli, G' and G'', have been measured for dilute solutions of paramyosin from the clam Mercenaria mercenaria in water and glycerol--water mixtures containing potassium chloride and phosphate buffer.
Abstract: The storage and loss shear moduli, G' and G'', have been measured for dilute solutions of paramyosin from the clam Mercenaria mercenaria in water and glycerol--water mixtures containing potassium chloride and phosphate buffer The Birnboim--Schrag multiple-lumped resonator was used in the frequency range from 150 to 8100 Hz; the concentration range was 07 to 2 X 10(-3) g/mL and the temperature range was 00 to 60 degrees C The intrinsic moduli were obtained by extrapolation to infinite dilution When compared with predictions of Yamakawa for a rigid cylindrical molecule, they agreed at low frequencies but diverged at high frequencies Excellent agreement was obtained with calculations for a hybrid model whose relaxation times are attributed to rigid-body end-over-end rotation together with some internal modes of motion, probably flexural The rotational relaxation time agreed rather well with that determined by DeLaney and Krause from electrical birefringence measurements From the ratio of the rotational to the longest flexural relaxation time, the flexural rigidity and Young's modulus of the paramyosin molecule were estimated by relations derived by Wada and collaborators; the modulus was 12 X 10(10) dyn/cm2
13 citations
TL;DR: In this article, the critical speed of force on a sandwich beam is always greater than that on an elastic beam of identical mass per unit length and flexural rigidity, and depends on its geometric and shear parameters.
12 citations
TL;DR: In this article, the effects of various weight ratios, flexural rigidity ratios and length ratios between the blades and shrouds on the frequencies of vibration of a shrouded blade packet are investigated.
Abstract: The free-vibration characteristics of shrouded blade packets are studied using the finite-element method. The effects of various weight ratios, flexural rigidity ratios and length ratios between the blades and shrouds on the frequencies of vibration of the blade packet are investigated.It is shown that the vibration characteristics of a multibladed packet can be predicted with reasonable accuracy from the inference diagram of a two-bladed packet.The theory developed can be easily adapted for more complex blade packet configurations. The results presented for the frequencies of vibration are compared with experimental results and show good agreement with those of other investigators.
12 citations
TL;DR: In this article, a non-linear theory for the inelastic stability of laterally unsupported steel I-beams is presented, which is based on a general nonlinear theory.
10 citations
Patent•
25 Jan 1977
TL;DR: In this article, a belt for high speed transmission with high tensil but low bending rigidity is presented. But this belt is not suitable for high-speed transmission with low bending stiffness.
Abstract: PURPOSE:To obtain belt for high speed transmission with high tensil but low bending rigidity.
3 citations
TL;DR: In this article, tensile creep tests were performed on annealed commercially pure aluminum specimens in order to measure the dominant elevated temperature dislocation processes, and it was concluded that the strain hardening increased static stiffness and decreased internal damping during early creep, and the dynamic modulus remained essentially constant at the elastic value during creep.
Abstract: Tensile creep tests conducted at 200 C were performed on annealed commercially pure aluminum specimens in order to measure the dominant elevated temperature dislocation processes. Testing consisted of applying small lateral loads to measure flexural stiffness, and vibrating the specimens laterally in order to measure dynamic modulus and internal damping. It was concluded that (1) the strain hardening increased static stiffness and decreased internal damping during early creep, and (2) the dynamic modulus remained essentially constant at the elastic value during creep. These results imply that primary creep may constitute a mechanism of recovery of dislocatory disorder induced by yielding the material during loading, and that the inelastic modulus utilized as a mathematical concept in several creep buckling theories is not a directly measurable material property.
2 citations
TL;DR: In this paper, the dynamic response of a rectangular membrane to external time-dependent loading is investigated for the case when bending rigidity is small, using singular perturbation techniques and multiple time scales.
Abstract: The dynamic response of a rectangular membrane to external time-dependent loading is investigated for the case when bending rigidity is small. Using singular perturbation techniques and multiple time scales, solutions are constructed up to order e, where e measures a small bending rigidity. The perturbation procedure is counterchecked using an example whose exact solution can be found.
2 citations
TL;DR: In this article, the effect of transverse loading on the abrasive disk was investigated by means of static flexural tests on randomly oriented disks and the failure load was predicted from considerations of beam theory and was found to agree well with experimental data.
Abstract: This paper deals with a study of the flexural behavior of thin, fiber-reinforced, resinoid abrasive disks. During use, these disks generally encounter a much higher ratio of flexural or bending stress to rotational stress than do straight grinding wheels. Material characteristics such as flexural modulus of elasticity, flexural strength, and flexural strain to fracture were evaluated for specimens machined from the disks at known orientations of each layer of fiber reinforcement. The effect of transverse loading on the abrasive disk was investigated by means of static flexural tests on randomly oriented disks. The failure load was predicted from considerations of beam theory and was found to agree well with experimental data.
Patent•
22 Dec 1977
TL;DR: In this article, aggregates and synthetic resin foams are filled between a plurality of fiber sheets imprengated with a synthetic resin which are laminated on the surfaces of a molded product of fiber-reinforced synthetic resin foam.
Abstract: PURPOSE:Aggregates and synthetic resin foams are filled between a plurality of fiber sheets imprengated with a synthetic resin which are laminated on the surfaces of a molded product of fiber-reinforced synthetic resin foam These components are adhered firmly to form an integrated composite struactural material having higher surface strength, compression strength, flexural stiffness in lowe costs
01 Jan 1977
TL;DR: Flexural rigidity can be used as a significant criterion for quantifying the handling characteristics of surgical sutures.
Abstract: The flexural rigidity of four sizes of fourteen different types of sutures were measured using Peirce's ring loop method. The suture materials were ranked according to the lowest value of flexural rigidity. This ranking strongly correlated (r=0.93) with the ranking of handling characteristics obtained thru a survey of practicing surgeons. Thus flexural rigidity can be used as a significant criterion for quantifying the handling characteristics of surgical sutures.
Patent•
01 Nov 1977
TL;DR: In this paper, the construction method of a high safety underground system low temp liquid reservoir with flexural rigidity by a part made of steel that uses a steel sheet pile, which is first driven, as a strength part material as it is, that a connecting part is joint-sealed by a steel plate for closing, and concrete wall is formed as the inner layer of the sheet pile.
Abstract: PURPOSE:To present the construction method of a high safety underground system low temp liquid reservoir with flexural rigidity by a part made of steel that uses a steel sheet pile, which is first driven, as a strength part material as it is, that a connecting part is joint-sealed by a steel plate for closing, and that concrete wall is formed as the inner layer of the sheet pile.