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Showing papers on "Bending moment published in 1985"


Journal ArticleDOI
TL;DR: In this article, the possibilities of producing such a dipole moment are discussed in terms of contact electrification (or separating electrification) and piezoelectrification, and both possibilities are shown.
Abstract: To test the possibility of the emission of electromagnetic waves from rocks, experiments have been made to measure the electric field by using mainly granite samples that were struck together or struck by a hammer or a weight and were fractured by a bending moment. The wide-band (10 Hz to 100 kHz) waveforms of electric signals were digitally recorded. Roughly four kinds of signals have been observed: 30 kHz, 5 kHz, 10 Hz and, in addition, intermittent pulses. Using these measurements of the electric fields, the average electric dipole moment generated was estimated to be 10−14 C m. The possibilities of producing such a dipole moment are discussed in terms of contact electrification (or separating electrification) and piezoelectrification, and both possibilities are shown.

239 citations


Journal ArticleDOI
TL;DR: The strong mode preferences show by curvature-controlled flagellar models, in contrast to the weak or absent mode preferences shown by real flagella, therefore do not demonstrate the inapplicability of the moment-balance approach to real flaglla, but indicate a need to specify additional properties of real flageslla that are responsible for selecting particular operating points.

86 citations


Patent
04 Nov 1985
TL;DR: In this article, a system for reducing wing root bending moment load during aircraft maneuvers was proposed, which operates to reduce the lift on the outboard section of the wing by moving an outboard flap upward in response to commands calculated from aircraft parameters.
Abstract: A system for reducing wing root bending moment load during aircraft maneuvers. The system operates to reduce the lift on the outboard section of the wing by moving an outboard flap upward in response to commands calculated from aircraft parameters and a predetermined wing root bending moment load limit.

72 citations


Patent
Hwa-shan Ho1
23 Oct 1985
TL;DR: In this article, a method and apparatus for obtaining complete loading on a drill bit at the end of a drill string in a borehole employ at least three rosette strain gauges uniformly disposed on an instrument sub to measure torque and axial force on the sub, two bending moments in mutually perpendicular directions, and two shear forces in mutually parallel directions.
Abstract: A method and apparatus for obtaining complete loading on a drill bit at the end of a drill string in a borehole employ at least three rosette strain gauges uniformly disposed on an instrument sub to measure torque and axial force on the sub, two bending moments in mutually perpendicular directions, and two shear forces in mutually perpendicular directions. These measurements are used to obtain torque on bit, weight on bit, two side forces on the bit normal to each other, and two bending moments on the bit normal to each other which, in turn, can be used to control the bit movement.

67 citations


Journal ArticleDOI
TL;DR: In this article, a higher-order plate theory was used to analyze a complete double cantilever beam specimen and the effect of specimen geometry on energy release rate was investigated numerically.

62 citations




Journal ArticleDOI
J.K. Chen1, C.T. Sun1
TL;DR: In this article, a nine-node isoparametric quadrilateral element is developed to model laminated plates under initial deformation and initial stress according to the Mindlin plate theory and von Karman large deflection assumptions.

35 citations


Journal ArticleDOI
01 Jan 1985
TL;DR: For the free vibrations of a gravity-loaded clamped-free Euler-Bernoulli-beam (flexible pendulum) no exact analytical closed-form solutions are known in the literature as mentioned in this paper.
Abstract: For the free vibrations of a gravity-loaded clamped-free Euler-Bernoulli-beam (flexible pendulum) no exact analytical solutions are known in the literature. Approximate analytical closed-form solutions are determined by use of the Ritz-Galerkin method with gravity-free beam eigenfunctions in the series expansion. A comparison with experimentally obtained modal data on a heavy beam with strong gravity influence shows good agreement and justifies the necessity of modelling gravity effects. Since in many vibration problems of engineering one of both influences of gravity or flexural rigidity is dominating, further approximated solutions are determined by applying regular perturbation theory (influence of bending moment dominates) and singular perturbation theory by the method of the “matched asymptotic expansions” (influence of gravity dominates: heavy rope with small bending stiffness), which creates a boundary layer problem at the clamped end. Within a wide range of values of the perturbated parameters the lower eigenfrequencies agree well with the Ritz-Galerkin solutions.

35 citations


Journal ArticleDOI
TL;DR: In this article, the bending moments and shear forces that are induced in the members of the frame by the differential column shortening, taking into account the construction sequence and the sequential application of dead weight in the analysis, are dealt with.
Abstract: This paper deals with the bending moments and shear forces that are induced in the members of the frame by the differential column shortening, taking into account the construction sequence and the sequential application of dead weight in the analysis. Utilizing the substructuring techniques, the entire frame is analyzed by “one substructure at a time” approach in the reverse order of construction. Numerical examples of two high‐rise buildings clearly show the significance of the differential column shortening effects and the effectiveness of the proposed frame analysis technique in coping with the problem.

31 citations


Journal ArticleDOI
TL;DR: In this paper, the effect of wall flexibility on the behaviour of a propped embedded retaining wall was investigated and it was shown that for flexible walls of the sheet pile type the predicted bending moments are much lower than that given by the simple limit equilibrium type of design calculation.
Abstract: In this note numerical analysis has been used to investigate the effect of wall flexibility on the behaviour of a propped embedded retaining wall. It has been shown that for flexible walls of the sheet pile type the predicted bending moments are much lower than that given by the simple limit equilibrium type of design calculation. As the stiffness of the wall increases then so do the bending moments. For walls installed in low k0 (=0.5) soils the bending moments approach the limit equilibrium values as the wall stiffness increases. These results are in full agreement with the model tests of Rowe (1952). However, for stiff walls in high k0 (>1) soils the bending moments greatly exceed the limit equilibrium values. A similar trend is observed for the prop forces. The results imply that for a diaphragm or secant pile wall in stiff clay with a high k0 the bending moments and prop forces could exceed design values based on the limit equilibrium type of design calculations. Curves showing the variation in the ratios of: (a) maximum bending moment to that predicted by limit equilibrium; (b) the prop force to that predicted by limit equilibrium, with wall stiffness for various in situ k0 values are given. These may be useful for preliminary design. (TRRL)

Journal ArticleDOI
TL;DR: It appears that the hypoaxial and epiaxial muscles are capable of generating forces that are approximately equal, and Thrust delivered in the upstroke and downstroke may therefore be equal.
Abstract: Controversy has existed about the power stroke of cetacean locomotion. We therefore measured cross-sectional areas of the appropriate muscles of the tail and computed possible forces and bending moments. The muscle areas are approximately equal in size and a similar relationship holds for the caudal tendons. It appears that the hypoaxial and epiaxial muscles are capable of generating forces that are approximately equal. Thrust delivered in the upstroke and downstroke may therefore be equal.

Patent
15 Mar 1985
TL;DR: A tendon for prestressed concrete is described in this paper, where inorganic particles are formed with minute rugged surface portions on the outer surface of the tendon, the rugged surface portion being firmly adhered to concrete.
Abstract: A tendon for prestressed concrete wherein inorganic particles are coated on an outer surface of a rod made of fiber reinforced plastic through a plastic adhesive layer. The inorganic particles are formed with minute rugged surface portions on the outer surface of the tendon for prestressed concrete, the rugged surface portions being firmly adhered to concrete. The inorganic particles are coated on the whole outer surface of the tendon for prestressed concrete, on the fixed portions at both ends, or on the fixed portions at both ends and on a portion subjected to the maximum bending moment.

Journal ArticleDOI
TL;DR: In this paper, a two-dimensional plane-stress finite element model was used to determine the strain energy release rate of a crack in a circular cross-section of a bar.
Abstract: A bar of circular cross-section is modelled with two-dimensional plane-stress finite elements. The bar has a crack at its edge, the front of which is a circular arc. The ends of the bar remote from the crack are subjected to either an axial load or a bending moment in the plane of symmetry of the cracked section. The strain energy release rate of the crack is determined from a finite element model as the rate of change of elastic energy in the bar for successive positions of the circular arc crack front. The values of strain energy release rate so determined are found to be comparable with existing results obtained from three-dimensional finite element analyses. The effect of curvature is found to cause a reduction in the strain energy release rate compared to that for a straight fronted crack of the same maximum depth in a bar under the same loading conditions. The results obtained are superimposed to obtain strain energy release rates for the circular are crack edge subjected to a combined tensi...

Patent
24 Oct 1985
TL;DR: In this paper, the side surfaces of movable and stationary volute plates are sloped at an angle theta to increase bending moment of a volute plate and improve a sealing characteristic of working fluid.
Abstract: PURPOSE:To increase bending moment of a volute plate and improve a sealing characteristic of working fluid, by forming side surfaces of the movable and stationary volute plates to be sloped so as to form the volute plate in a tapered shape toward its point end CONSTITUTION:A scroll fluid machine provides its two volute plates 20, 22 to be formed in a tapered shape by increasing their thickness in a side of end plates 19, 21 a little larger than that of the point end part, that is, by forming both side surfaces of the volute plate to be sloped at an angle theta In this way, the two volute plates can be closely fitted further their clearance with each other can be accurately maintained even if bending moment acts on the volute plate while working fluid is compressed

Journal ArticleDOI
TL;DR: In this article, the authors investigated the harmonic flexural vibration of a rectangular plate with an arbitrarily located rectilinear crack and derived the square root singularities of the bending moment at the crack's tips.

Journal ArticleDOI
TL;DR: In this paper, an analytical model of dented tubular members is constructed using this model, an ultimate strength interaction relationship between axial force and biaxial bending moments is derived.
Abstract: An analytical model of dented tubular members is constructed. Using this model, an ultimate strength interaction relationship between axial force and biaxial bending moments is derived. The implementation of this interaction relationship to take account of denting and bending damage in the analysis of nonlinear behavior of tubular space frames by ISUM (the Idealized Structural Unit Method) is described. An experimental study of the behavior of dented members subjected to pure bending is reported. Comparison with theoretical predictions is presented.

Patent
24 Jun 1985
TL;DR: In this article, a floor construction comprising a concrete slab which is supported adjacent its edges of the slab is described, and a plurality of cellular raceways are embedded in the slab, and at least one intermittently bottomless trench runs across the raceways.
Abstract: This disclosure relates to a floor construction comprising a concrete slab which is supported adjacent its edges of the slab. A plurality of cellular raceways are embedded in the slab, and at least one intermittently bottomless trench runs across the raceways. The trench is located along a line where the bending moment on the slab is substantially zero. The construction further comprises a plurality of post-tensioned tendons which extend across the slab, underneath the trench and between the raceways.

Journal ArticleDOI
TL;DR: In this article, an analytical procedure for predicting thrust chamber life was developed, where the hot-gas wall ligaments separating the coolant and combustion gas are subjected to pressure loading and severe thermal cycling.
Abstract: An analytical procedure for predicting thrust chamber life is developed. The hot-gas wall ligaments separating the coolant and combustion gas are subjected to pressure loading and severe thermal cycling. The resulting stresses interact during plastic straining causing incremental bulging of the ligaments during each firing cycle. This mechanism of plastic ratcheting is analyzed and a method using a yield surface for combined bending and membrane loading is developed for determining the incremental permanent deflection and progressive thinning near the center of the ligaments. Fatigue and tensile instability are analyzed as possible failure modes. Results of the simplified analyses compare favorably with available experimental data and finite element analysis results for OFHC (Oxygen Free High Conductivity) copper. They are also in reasonably good agreement with experimental data for NARloy Z, a copper-zirconium silver alloy.

Journal ArticleDOI
TL;DR: In this article, the optimal design with respect to the variable thickness of an elastic beam with unilateral supports under the criterion of minimal value of the maximal stress is presented, and a dual formulation of the state problem in terms of bending moments is used and the convergence of some approximations proved.
Abstract: Optimal design with respect to the variable thickness of an elastic beam with unilateral supports under the criterion of minimal value of the maximal stress is presented in Part I. A dual formulation of the state problem (in terms of bending moments) is used and the convergence of some approximations proved.

Journal ArticleDOI
TL;DR: In this paper, the elastic behavior of a long flexible cylinder buried in an infinite elastic medium and acted on by uniform hoop compressions is examined, and a simplified solution is obtained, which can be used to accurately and efficiently determine the cylinder response.

Journal ArticleDOI
TL;DR: In this article, the von Karman-type non-linear bending of an unsymmetrically laminated angle-ply rectangular plate under lateral load has been analyzed for various high-modulus materials, aspect ratios, geometries of lamination and boundary conditions.
Abstract: This paper is analytically concerned with non-linear bending of an unsymmetrically laminated angle-ply rectangular plate under lateral load The plate edges are subjected to the varying rotational constraints A series solution satisfying the von Karman-type non-linear equations and the required boundary conditions of the plate is presented In the formulation the edge moments are replaced by an equivalent lateral pressure near the plate edges Governing equations are reduced to a set of algebraic equations Numerical results for maximum deflection, bending moment and inplane force of unsymmetric angle-ply plates are graphically presented for various high-modulus materials, aspect ratios, geometries of lamination and boundary conditions Present results are also compared with available data

01 Aug 1985
Abstract: A series of laboratory tests on model single piles and pile groups in sand is described The main objectives of the tests were to examine the "shielding" effect in laterally loaded pile groups, whereby the front piles carry a greater proportion of load than the rear piles The tests clearly showed this shielding effect and indicated that, as the load increased towards failure, the sign of the bending moment in the rear piles could even change Load cycling was found to influence bending moments in the piles, but to have little effect on pile shears Comparisons between measured and theoretical group deflections, moments, shears and axial forces, showed some measure of agreement, particularly if the theory incorporated pile-soil-pile interaction However, none of the existing theories was capable of allowing directly for the shielding effect Consequently, theoretical predictions of shear and moment distributions within laterally loaded pile groups will remain inaccurate until allowance for the shielding effect is made (Author/TRRL)

Book
01 Jan 1985
TL;DR: In this paper, fundamental concepts and principles resultant of Coplanar Force Systems Equilibrium of COPLANAR Force Systems Analysis of Structures Friction Concurrent Spatial Force Systems Center of Gravity and Centroids Area Moments of Inertia Simple Stresses Strains Strains Mechanical Properties of Materials Torsion of Circular Shafts Shear forces and Bending moments in Beams Stresses in beams Stams Stressed in Beam Design of Beams for Strength Deflections of Beam Statically Indeterminate Beams Combined Stresses Columns Connect
Abstract: Fundamental Concepts and Principles Resultant of Coplanar Force Systems Equilibrium of Coplanar Force Systems Analysis of Structures Friction Concurrent Spatial Force Systems Center of Gravity and Centroids Area Moments of Inertia Simple Stresses Strains Mechanical Properties of Materials Torsion of Circular Shafts Shear Forces and Bending Moments in Beams Stresses in Beams Design of Beams for Strength Deflections of Beams Statically Indeterminate Beams Combined Stresses Columns Connections

Journal ArticleDOI
TL;DR: In order to find the biomechanical principles which are realized in the upper jaw, the premaxilla, maxilla, palate and nasal skeleton of long-snouted vertebrates is seen as a "cantilever beam" in the sense of mechanics.
Abstract: In order to find the biomechanical principles which are realized in the upper jaw, the premaxilla, maxilla, palate and nasal skeleton of long-snouted vertebrates is seen as a "cantilever beam" in the sense of mechanics. This model is derived from the skull of crocodiles, but can also be applied to the skulls of pig, dog, or baboons. The shorter snouts of gorillas and chimpanzees are in cluded into the comparison. The external loads acting against the jaws are in side view the bite forces, in top view the horizontal components of the chewing forces or the resistence which occurs if the an imal has seized an object with its teeth and tries to move its head sideways. The magnitude of the ex ternal forces which can be applied to various teeth was calculated on the basis of the equilibrium of moments about the mandibular joint (side view) and about the occipital joint (top view). The external forces evoke shearing forces in the "beam", that is the upper jaw, which are distri buted over the entire cross sectional area. The shearing stresses are equal all over the length of the up per jaw. This element therefore seems to be a "body of equal strength" against the shearing forces. The above mentioned external forces also cause bending in two planes. Numerous details of jaw shape can be explained as traits which provide the necessary resistence against bending in side view. The ability of the cross sections to resist bending in one of the two planes increases occipitally faster than the bending moments do. Therefore, the bending stresses decrease from the tip to the base of the snout.


Journal ArticleDOI
TL;DR: In this article, a method for analysing the cyclic behavior of laterally loaded piles has been developed and applied to single vertical piles embedded in clay soils, and the analysis is used to simulate the increase in pile displacement, bending moments and gap development during each load cycle.

Dissertation
01 Jan 1985
TL;DR: In this article, an incremental approach is employed to derive the moment-curvature relationship and hence the peak moment for a ship's hull girder under vertical bending, and the results from an existing parametric study on the large deflection elasto-plastic behaviour of practical plates in compression with constrained edges are used as basic data.
Abstract: The aims of the research work presented in this thesis are to assess the effects of weld-induced residual stresses and initial imperfections on the collapse behaviour of a ship's hull girder, and to demonstrate the close correlation that exists between the hull's ultimate longitudinal strength and the maximum load-carrying capacity of its components under compressive loads. A theoretical method for evaluating the ultimate longitudinal strength of a ship's hull girder under vertical bending is described. The hull's midship cross-section is discretised into structural elements such as stiffened panels, plate elements and hard corners. Effects of buckling of compressive components are allowed for by incorporating the load-end shortening curves of unstiffened and stiffened plates into the hull strength analysis. An incremental approach is employed to derive the moment-curvature relationship and hence the peak moment for the hull girder. Curvature, rather than bending moment, increments are imposed on the hull girder to enable the post-collapse behaviour to be followed. Comparisons with tests on welded steel box girder models and other analytical methods show that the agreement is satisfactory. Prior to determining the vertical moment-curvature relationship for a hull, the load-end shortening curves need to be established for each stiffened panel forming the hull's mid-ship cross-section. An analytical method is developed to examine the large deflection elasto-plastic behaviour of stiffened panels under uniaxial compression. The method is based on a beam-column approach in which the longitudinally stiffened plating is treated as a series of beam-columns formed by the stiffeners and an associated width of plates. The beam-column model is continuous over three supports provided by transverse frames to take effect of interaction between adjacent spans into account. Dynamic Relaxation is employed to numerically solve the non-linear equilibrium equations. The strength contribution from the plating, allowing for buckling effects, is accounted for by using the plate average stress-strain curves. The load is applied through end displacements such that both the pre- and postcollapse behaviour can be traced. It is shown by comparisons with test results and other analytical methods that the present one satisfactorily predicts the behaviour of stiffened compression panels. A numerical method to generate the plate average stress-strain curves for the stiffened panel analysis is proposed. The results from an existing parametric study on the large deflection elasto-plastic behaviour of practical plates in compression with constrained edges are used as basic data. A simplified procedure is followed to interpolate the average stress-strain curve for the plate with parameters different from the standard cases. An analytical study on the ultimate strength behaviour of longitudinally framed frigate-type hulls is presented. Five naval frigates designed in the 1950's and 1960's are analysed by the present incremental approach. The derived load-end shortening curves for the stiffened panels and moment-curvature curves for the hull girders are presented. It is shown that the ultimate strength of longitudinally framed hulls is strongly influenced by the full-range behaviour of components under compressive loads in association with bending. In particular, the ultimate hull strengths are closely correlated with the maximum load-carrying capacities of the critical stiffened panels which are located in deck structures in the sagging condition and in bottom structures in the hogging condition. Two simple expressions for predicting the ultimate moment capacity of longitudinally stiffened hulls in the sagging and hogging conditions are proposed. They are based on the results of the numerical analysis for appropriate initial imperfections in the plate and stiffened panels. The ultimate bending moments of a variety of hull and box girders predicted by the strength formulae are compared with the numerical and experimental results. Satisfactory agreement is obtained which suggests that the proposed formulations could form the basis of an improved design method.

Journal ArticleDOI
TL;DR: In this article, a program was developed to simulate ship responses in bidirectional irregular waves and a statistical analysis of the simulated time history yielded a "theoretical distribution" of response amplitude.
Abstract: A program was developed to simulate ship responses in bidirectional irregular waves. Statistical analysis of the simulated time history yielded a "theoretical distribution" of response amplitude. Model experiments corresponding to the simulation were set upusing an elastic model of a bulk carrier in fully loaded condition and in two ballast conditions of the same displacement with different trim conditions. Comparisons were made between the simulation and the experiment on histograms of longitudinal bending moment and variations of significant values of the moments along the hull. Discussions cover effects of slamming and whipping on the bending moment; changes of response in relation to loading conditions; and, effects of heading angle in bidirectional waves.

Journal ArticleDOI
Kosuke Nagaya1
TL;DR: In this article, a method for solving problems of transient response in flexure due to general unidirectional dynamic loads of beams of variable cross section with tip inertias is presented.