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Showing papers on "Flexural rigidity published in 1975"


Journal ArticleDOI
TL;DR: In this paper, simple models for the flexure of the lithosphere caused by the load of the Great Meteor seamount have been determined for different assumed values of the effective flexural rigidity.
Abstract: Simple models for the flexure of the lithosphere caused by the load of the Great Meteor seamount have been determined for different assumed values of the effective flexural rigidity of the lithosphere. The models utilize a new method for determining the flexure of the lithosphere caused by a three-dimensional load. The gravity effect of the models has been computed and compared with observed free-air anomalies in the vicinity of the seamount. Computations show that the observed free-air anomalies can be most satisfactorily explained for an assumed effective flexural rigidity of the lithosphere of about 6 x 1029 dyn cm. This value, which is similar to other values determined for loads of different ages, suggests that the oceanic lithosphere is rigid enough to support applied loads for periods of time of at least several tens of millions of years. A basic postulate of the modern concept of plate tectonics is that a strong rigid outer layer of the earth (the lithosphere) overlies a weaker layer (the asthenosphere). The assumption that lithospheric plates act as rigid units for up to a few hundreds of millions of years is implicit in the reconstruction of

133 citations


Book ChapterDOI
TL;DR: Torsional and flexural fatigue tests were performed on both uniaxial and crossplied graphite-epoxy materials at temperatures of 24 and 74 C in environments of air and water as discussed by the authors.
Abstract: Torsional and flexural fatigue tests were performed on both uniaxial (0 deg) and crossplied (plus or minus 45 deg) graphite-epoxy materials at temperatures of 24 and 74 C in environments of air and water. The results of the torsion testing showed that the number of cycles required to cause an initial decrease in stiffness as well as the rate of stiffness loss was a function of temperature and environment; the most significant losses were noted for tests at the higher temperature in water. The torsional fatigue specimens were subsequently tested in four-point bending to determine the effect of torsional damage on longitudinal properties. This damage caused changes in the flexural stiffness, failure stress, and failure energy, depending on the stress and environmental histories. The flexural fatigue tests also showed a significant effect of water (at 24 C) on the material behavior. These results are compared with the results of previous investigations and are discussed in terms of proposed damage mechanisms.

15 citations


Journal ArticleDOI
K. Arin1
TL;DR: In this article, an infinite stringer partially bonded to a plate through a layer of adhesive is considered, and the effect of the stringer's bending rigidity on the stress intensity factor at the tip of the crack is illustrated.

11 citations





Journal ArticleDOI
TL;DR: In this article, Young's modulus of metal outer layer/viscoelastic core/metal outer layer about neutral axis is used to measure the strength of a cantilever beam.
Abstract: = breadth of beam = Young's modulus = real part of complex Young's modulus of damping material = effective (complex/real) flexural rigidity of beam = Young's modulus of metal outer layer/viscoelastic core = resonant frequency in nth mode (Hz) = factor by which centrifugal loading exceeds unit gravity = thickness of wall = second moment of area of viscoelastic core/metal outer layer about neutral axis = length of beam = time dependent load per unit length = time = axial coordinate along beam, with root as origin = transverse displacement of point on beam = nondimensional parameter = loss factor of composite beam /damping material ** = first eigenvalue of cantilever beam ( ~ 12.36) = effective mass per unit length of composite beam = density of damping material/metal outer layers = resonant frequency at zero rotational speed = resonant frequency (rad/sec)

2 citations


01 Jan 1975
TL;DR: In this article, the flexural rigidity of reinforced concrete members is determined in the calculation of the deflection, and the results of tests carried out by the Cement & Concrete Assoc.
Abstract: The article examines the problem of determining the flexural rigidity EI in the calculation of the deflection of reinforced concrete members. It is shown that EI varies with the magnitude of bending moment due to the increasing propagation of cracks. Tests have shown that the difference between measured and calculated stresses in such members is due to the presence of cracks and the effect of the concrete between the cracks. So that a realistic prediction of deformation can be made, the tension stiffening effect of the concrete must be considered and specified in terms of strain reduction of the reinforcement due to the concrete action. The results of tests carried out by the Cement & Concrete Assoc, are used to evaluate factors expressing the efficiency of concrete in resisting tension and the average position of neutral axis. Graphs are given to compare test results with calculated deflection values. /TRRL/

2 citations


Journal ArticleDOI
TL;DR: In this article, a direct iterative numerical method is presented for predicting the post-local-buckling response of thin-walled continuous structures, where nonlinearities due to local buckling and nonlinear material properties are accounted for by the nonlinear moment-curvature relations of the section derived with the aid of effective width concept.

2 citations