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Showing papers on "Flexural rigidity published in 1989"


Journal ArticleDOI
TL;DR: In this paper, the effects of bow flare on deck wetness and the asymmetry of the vertical wave bending moment were investigated in both regular and irregular waves for models with two kinds of bow flares.
Abstract: Model tests were conducted in both regular and irregular waves for models with two kinds of bow flare form. The purpose of the tests was to obtain information on the effects of bow flare on deck wetness and the asymmetry of the vertical wave bending moment. The model was made of synthetic resins so as to simulate the bending rigidity of a full scale ship. The measured results are analysed as to the intensity of impact pressure in the bow, the frequency of the deck wetness, and the asymmetry of the bending moment.

72 citations


Journal ArticleDOI
TL;DR: The analysis of a beam-column using stability functions as an alternative to the stress stiffness matrix is discussed in this article, in terms of member length, cross-sectional properties, axial force, and the end moments.
Abstract: Members carrying both axial force and bending moment are subjected to an interaction between these effects. The analysis of a beam-column using stability functions as an alternative to the stress stiffness matrix is discussed. Explicit expressions for stability functions for three-dimensional beam-columns, in terms of member length, cross-sectional properties, axial force, and the end moments, are derived. The effect of flexure on axial stiffness and the effect of axial force on flexural stiffness and stiffness against translation are considered in the derivation of stability functions. The effect of axial force on torsional stiffness and the effect of torsional moment on axial stiffness are neglected. The nonlinear stiffness matrix of a three-dimensional beam-column using the stability functions is presented by modifying the linear elastic stiffness matrix for a beam-column (which includes the effect of shear deformations) available in the literature. A numerical example showing the calculation of stability functions for a given beam-column is also presented.

59 citations


Journal ArticleDOI
TL;DR: In this paper, an inverse elastic flexural model for foreland basins has been developed and applied to southeastern Sicily, where the lithosphere is assumed to act as an elastic plate of finite lenght (L) and constant flexural rigidity (D ).

46 citations


Journal ArticleDOI
TL;DR: In this article, the authors investigated the importance of fabric overfeed in the sewing operations during tailoring and showed how fabric bending rigidity, formability, shear and hygral expansion are important in clothing manufacture.
Abstract: In Part 1 of this series of papers, we investigated the importance of fabric overfeed in the sewing operations during tailoring. It was also shown how fabric bending rigidity, formability, shear and hygral expansion are important in clothing manufacture. The present paper is concerned with the measurement and experimental study of seam balance, breaking elongation and bending properties of seams. The aim is to evaluate quantitatively the consumption of sewing thread and the relationship between the degree of fabric overfeed during sewing and the curvature of the seam in the garment. Balanced seams have much higher breaking elongation and more symmetrical bending properties than unbalanced seam structures. A natural curvature and curling couple result from fabric overfeed during sewing. The value of the curvature is time‐dependent because of fabric viscoelastic effect and also depends on the level of fabric overfeed, the tensile and longitudinal compressive module of the component fabrics and the structure of the seamed composite. The natural curvature of the seam may be derived quantitatively from the relative lengths of overfeed fabrics using a modified theory for a bimetallic themostatic strip.

23 citations


Patent
06 Mar 1989
TL;DR: In this paper, a rigidity control system for a variable rigidity structure incorporating variable-rigidity elements, such as braces, for making the connecting condition with the frame variable between the locked and unlocked conditions for example, where the vibration of a structure caused by external vibrational forces of an earthquake, wind or the like is attenuated by varying the rigidity of the structure.
Abstract: The present invention contemplates a rigidity control system for a variable rigidity structure incorporating variable rigidity elements, such as braces, for making the connecting condition with the frame variable between the locked and unlocked conditions for example, in which the vibration of a structure caused by external vibrational forces of an earthquake, wind or the like is attenuated by varying the rigidity of the structure. The rigidity control of the present invention imitates the tension and relaxation of a muscle in the self-balancing function of a living body. The vibrational condition of a frame is considered to be separately four conditions, i.e., the process of increasing the deformation in one direction, the process of decreasing the deformaton following thereafter, the process of increasing the deformation in the opposite direction and the process of decreasing the deformation following thereafter. Continuous responses are detected by sensors and the structure is set to be in the rigid condition in the deformation increasing process to restrain the excessive deformation of the building frame while the structure is set to be in the resilient condition in the deformation decreasing process to continuously vary the rigidity of the frame, whereby the resonance of the frame with seismic motion or the like is avoided to attenuate the vibration.

20 citations


Journal ArticleDOI
TL;DR: In this article, changes in shape of the Michigan Basin during the Phanerozoic are determined using depths to formation tops from 480 wells, using a one-dimensional finite-difference thermal model in which a 142 km plate is temporarily heated from below.

17 citations


Journal ArticleDOI
TL;DR: In this article, a stiffened coupled structural wall with a strong beam located along the building height is designed and the results are given in terms of two dimensionless structural parameters: the relative flexural rigidity of the strong beam and the effectiveness of the lintel beams.
Abstract: Design charts are presented for the design of a stiffened coupled structural wall with a strong beam located somewhere along the building height. The analysis is based on a continuous medium approach with the deflection at the top. The couple due to the axial force in the walls and the shear force in the laminae are presented in the form of graphs. The variations of the couple due to the axial force in the walls and the laminar shear along the structural height are also presented to permit the curtailment of reinforcements where appropriate for achieving economy. The results are given in terms of two dimensionless structural parameters: one is the relative flexural rigidity of the strong beam, and the other is a measure of the effectiveness of the lintel beams. The application of the design charts is illustrated by determining the deflections and the internal forces of a typical 20-story building.

16 citations


Journal ArticleDOI
TL;DR: In this paper, a method of analysis based on the continuum approach is derived for investigating the beneficial effect of a stiffening beam, which may be positioned somewhere along the structural height, on laterally loaded coupled shear walls.
Abstract: A method of analysis (based on the continuum approach) is derived for investigating the beneficial effect of a stiffening beam, which may be positioned somewhere along the structural height, on laterally loaded coupled shear walls. It is shown that the incorporation of a stiffening beam into coupled shear walls will reduce considerably the maximum shear force in the lintel beams and the base moment in the walls and the top drift of the structure. It was found that stiffening beam should be positioned at a level about 0.4 of the structural height for achieving the greatest reduction in the maximum shear force in the lintel beams and about 0.5 of the height for achieving the minimum top deflection, depending on the flexural stiffness of the lintel beams.

15 citations



Journal ArticleDOI
TL;DR: In this paper, a theoretical analysis of composites under longitudinal compression is presented, based on the instability of different types of fibers on a common elastic foundation of the matrix material, and it is shown that a synergistic effect in compressive strength can be realized through fiber hybridization.

11 citations


Journal ArticleDOI
TL;DR: In this article, a practical method for calculating the flexural rigidity of reinforced concrete members under short-time loading is proposed, and extensive comparisons of the calculated defelections have been made with the results of 434 tests of actual beams, providing final confirmation of the validity of the proposed method.
Abstract: A practical method for calculating the flexural rigidity of reinforced concrete members under short-time loading is proposed. This method has been developed and refined to achieve both simplicity in use and a representation of actual behavior that is as realistic as possible. Extensive comparisons of the calculated defelections have been made with the results of 434 tests of actual beams, providing final confirmation of the validity of the proposed method.

01 Jan 1989
TL;DR: The results of an analytical and experimental study on the behavior of simple and double diagonal crossbracings in vertical stiffening trusses and in built-up open web beams are presented and discussed in this paper.
Abstract: The results of an analytical and experimental study on the behavior of simple and double diagonal cross-bracings in vertical stiffening trusses and in built-up open web beams are presented and discussed. Simple design expressions for the evaluation of the effective length of the compression members are presented. It is shown that the transverse stiffness provided by the tension members depends upon the flexural stiffness of the tension member and upon the ratio of the compression force to the tension force. A limited experimental study shows that the proposed equations slightly underestimate the transverse stiffness and overestimate the effective length factor.

Journal ArticleDOI
TL;DR: In this article, the thermally induced vibrations of a simply supported orthotropic rectangular plate are studied and the generalized bending rigidity for an orthotropic plate is shown to have a significant effect on the vibrational behavior.

Patent
31 Jan 1989
TL;DR: In this paper, an optical device is used to measure the bending length and bending rigidity of a piece of fabric and detect when a plane is intersected by an edge over which the piece of material passes.
Abstract: An apparatus (10) to measure the bending length and bending rigidity of a piece of fabric, the apparatus includes a generally planar surface (12) upon which the piece of material is moved, the surface terminates at one end with an edge (14) over which the piece of material passes. An optical device (18) defines a plane extending downwardly from the edge (14) at approximately 41.5° and detects when that plane is intersected. The length of material which has passed over the edge (14) provides an indication of the bending length and bending rigidity of the piece of fabric.

Journal ArticleDOI
TL;DR: Estimates of the contribution of the band to cellular rigidity are made based on the measurements of the structural properties of the isolated band to provide the cell with a large resistance to indentations at the rim and to large extensions, while maintaining a high degree of flexibility in small extensions or flexure.
Abstract: The marginal band is a bundle of microtubules residing at the periphery of nucleated erythrocytes of nonmammalian vertebrates and some invertebrates. Marginal bands from erythrocytes of the newt (Notopthalmus viridescens) were isolated from the cells as intact structures by treatment with detergent and either mild protease or high salt. Isolated bands were subjected to mechanical testing by stretching the band between a glass microhook and a calibrated glass fiber. The deflection of the fiber provided a measure of the force on the band. The flexural rigidity of the band was determined from measurements of the band deformation as a function of applied force. Bands isolated with either of two proteases (pepsin or elastase) or with high salt exhibited elastic behavior with a flexural rigidity of approximately 9.0 X 10(-12) dyn.cm2. Treatment of bands with chymopapain caused an increase in band rigidity and inelastic behavior. Estimates of the contribution of the band to cellular rigidity are made based on the measurements of the structural properties of the isolated band. The band provides the cell with a large resistance to indentations at the rim and to large extensions, while maintaining a high degree of flexibility in small extensions or flexure.

Journal ArticleDOI
TL;DR: In this article, the use of experimental modal analysis to obtain the dynamic mechanical properties of spirally wound paper tubes is investigated, based on experimentally measured natural frequencies in the free-free mode of transverse vibration, tube flexural stiffness properties are predicted using three beam theories: Euler-Bernoulli beam theory, Timoshenko beam theory for isotropic materials, and Timoshenkobeam theory for anisotropic materials.
Abstract: The use of experimental modal analysis to obtain the dynamic mechanical properties of spirally wound paper tubes is investigated. Based on experimentally measured natural frequencies in the free-free mode of transverse vibration, tube flexural stiffness properties are predicted using three beam theories: Euler-Bernoulli beam theory, Timoshenko beam theory for isotropic materials, and Timoshenko beam theory for anisotropic materials.

Patent
22 Mar 1989
TL;DR: In this article, the upper part of a vehicle body was formed by a roof structure, which set bending rigidity in its lengthwise directional section higher in the width direction central part than that in the other part of the roof structure.
Abstract: PURPOSE: To attain a reduced weight while obtaining a structure of sufficient pressure resistance by forming the upper part of a vehicle body by a roof structure setting bending rigidity in its lengthwise directional section about the horizontal axis higher in the width direction central part than that in the other part of the roof structure. CONSTITUTION: A roof structure 30 of a rolling stock, connected to a side structure 1 through a pole plate 31 and a side plate 32, is constituted of a mold member (roof outer plate) 33 integrally extruding a rib-provided plate arranged in the lengthwise direction of a vehicle body and a rafter 34 mounted along a rib end part in a lower surface of this roof outer plate 33. Now in order to reduce stress generated by bending moment generated in the central part of the roof structure 30 when an internal pressure is applied, bending rigidity of the structure, including the roof outer plate 33 and the rafter 34, is set larger than that in the other part. For instance, by increasing the height in the vehicle body width central part of the rafter 34, the bending rigidity of the roof structure 30 is increased. COPYRIGHT: (C)1990,JPO&Japio

Journal ArticleDOI
TL;DR: In this paper, the estimation of spacially dependent flexural rigidity coefficients in Kirchhoff models using an output least-squares method in H2 regularization is discussed and the regularity of optimal estimators is studied and these properties are used to develop an approximation theory.

Patent
01 Jul 1989
TL;DR: In this article, the flexural rigidity of the protrusion part of a scroll shape is set to approximately the same value as that of a machining tool to improve the squareness of the shape with a base surface.
Abstract: PURPOSE: To sharply improve squareness of a scroll shape with a base surface by a method wherein flexural rigidity of the protrusion part of the scroll shape is set to approximately the same value as that of a machining tool. CONSTITUTION: A blade 3 in a scroll shape protruded from a base surface 2 at right angles is integrally formed to a scroll compressor 1 being a work. An end mill 4 applying finish machining on the inner and outer surfaces of the blade 3 is disposed in a direction extending at right angles with the base surface 2, and a flexural rigidity F1 of the end mill 4 is set to approximately the same value as flexural rigidity F2 in a direction extending at right angles with the base surface of the blade 3. When finish machining is applied on the side of the blade 3 by using the end mill 4, the scroll compressor 1 is mounted to a milling machine and a finish cutting work is effected in a state that the end mill 4 is pressed against the side of the blade 3. In this case, a bending amount of the blade 3 is offset with a bending amount of the end mill 4. As a result, squareness of the scroll shape with the base surface 2 is sharply improved. COPYRIGHT: (C)1991,JPO&Japio

Journal ArticleDOI
TL;DR: In this article, a rational method of analysis is proposed for the calculation of creep deflections of reinforced concrete beams under sustained service loads, which introduces the use of a fictitious modulus relating, for a given section under bending, the initial stress in concrete with the final strain after a period of sustained load.
Abstract: A rational method of analysis is proposed for the calculation of creep deflections of reinforced concrete beams under sustained service loads. The method introduces the use of a fictitious modulus relating, for a given section under bending, the initial stress in concrete with the final strain after a period of sustained load. The requirements of strain compatibility and equilibrium of a section are used, in conjunction, to determine the position of neutral axis and strain and stress distributions after creep. The long‐term flexural rigidity of the member, (EI), is determined from a knowledge of a new neutral axis and a new modular ratio and is used to calculate the final deflections. The approach for calculating long‐term deflections is similar to the current American Concrete Institute (ACI) procedure for calculating short‐term deflections. The accuracy of the analysis is verified by comparison with several experimental measurements of beam deflections. The result is good correlation between the theoret...


Journal ArticleDOI
TL;DR: The rigidity and strength of an adhesive lap joint, where one end of a beam is bonded to a base by an interface parallel to the axis of the beam and a bending load is applied, have been examined theoretically and experimentally as discussed by the authors.
Abstract: The rigidity and the strength of an adhesive lap joint, in which one end of a beam is bonded to a base by an interface parallel to the axis of the beam and a bending load is applied, have been examined theoretically and experimentally. the deformations of the adhesive joint and the stresses caused in the adhesive layer were analyzed using the finite element method. Then, the rigidity and the strength of the joint were calculated. They coincided well with the experimental results. Effects of the dimensions of the bonded part of the beam, the thickness and Young's modulus of the adhesive layer on the rigidity and the strength of the joint were clarified. It was observed that the value of the rigidity of the adhesive joint was independent of the loading directions and was almost constant, and that the rigidity of the adhesive joint was greater than that of the bolted joint.

Patent
03 Oct 1989
TL;DR: In this paper, a car structure is composed of a side structure 1 forming a side face, a roof structure 10 forming an upper part and a lower part, and a framing structure 20.
Abstract: PURPOSE:To make light and rigid a car structure suitable particularly for a car running at a high speed by installing a high rigidity member arranged in the car body longitudinal direction at the joint of structure component members. CONSTITUTION:A car structure is composed of a side structure 1 forming a side face, a roof structure 10 forming an upper part and a lower part, and a framing structure 20. FRM members (high rigidity member) 31, 41 having higher Young's modulus than the material to the structure component members are installed at the joint part of the side structure 1, roof structure 10, framing structure 20 with one another, i.e. near the boundaries. When the car body is assumed as a beam, higher Young's modulus and provision of the abovementioned FRM in the position good apart from the neutral axis of this beam strengthens the bending rigidity, i.e. the vertical bending rigidity dominant over the comfort in getting on the car, whereby the car body can be made light and its high rigidity be accomplished.

Patent
26 Jan 1989
TL;DR: In this paper, the authors propose to facilitate the exchange of a deformation member due to an earthquake or the like and the quantitative evaluation of member rigidity by detachably fixing a connecting structure installed at the lower end of deformation absorbing sections to an anchor bolt for a foundation section mounted into a ground.
Abstract: PURPOSE: To facilitate the exchange of a deformation member due to an earthquake or the like and the quantitative evaluation of member rigidity in case of deformation by detachably fixing a connecting structure installed at the lower end section of a deformation absorbing section to an anchor bolt for a foundation section mounted into a ground CONSTITUTION: Plasticizing members (deformation absorbing sections) 5, 5 are arranged at the specified places of the first layer F of the building structure A under the state, in which connecting members 6 and connecting structures 7 are fitted previously at upper and lower end sections and unitized Upper end sections are attached to braces 14, 14, in which one ends are installed to beams 2, while being screwed to anchor bolts 9 projected from a footing beam 4 through the structures 7, and clamped in specified tension and fixed detachably onto the footing beams 4 The structures 7 and the bolts 9 are formed so as to be made sufficiently more rigid than the members 5, and the rigidity of the members 5 can be evaluated quantitatively by determining the flexural rigidity of the structures 7, the axial rigidity of the bolts 9 and elastic force

Patent
09 Oct 1989
TL;DR: In this paper, the bending rigidity of multiple transport members forming the composite transport pipe is different and has large asymmetry respectively as much as possible, and the twisting pitch of them is set to the integer ratio against the winding length to one winding drum.
Abstract: PURPOSE:To make a composite transport pipe easy to be bent at the time of thermal expansion and mitigate the ejection stress on a unit at the end section side by forming the composite transport pipe so that the bending rigidity of multiple transport members forming the composite transport pipe is different and has large asymmetry respectively as much as possible. CONSTITUTION:Heat transport members 10 and 10' and a power cable 20 are formed in a lengthy shape and integrated with control line members 30 and 30' via an inclusion 101, a sheath 102 is formed on the periphery. The bending rigidity of the members 10 and 10' and the bending rigidity of the power cable 20 are made different to have large asymmetry as much as possible. The twisting pitch of them is set to the integer ratio against the winding length to one winding drum for the storage or transportation of a composite transport pipe, thus the composite transport pipe is made easy to be bent at the time of thermal expansion. The life of the composite transport pipe of heat and electric energy can be lengthened, and the ejection stress on a unit installed at the end section side is mitigated.

Journal ArticleDOI
TL;DR: In this article, the nonlinear large deformation equations are formulated and solved by perturbation and numerical integration, and the problem is governed by a nondimensional parameter K representing the relative importance of aerodynamic drag to flexural rigidity.
Abstract: The nonlinear large deformation equations are formulated and solved by perturbation and numerical integration. The problem is governed by a nondimensional parameter K representing the relative importance of aerodynamic drag to flexural rigidity. For large K, phenomena such as nonuniqueness, instability, and hysteresis may occur

Patent
28 Jul 1989
TL;DR: In this paper, a reinforcing material 7 is inserted in a core inside space with being obliquely inclined as being shown in a figure, for example, the diaphragm is caused to be the honey comb structure, for which skin materials 4a and 4b are fit to both sides of a honey comb core material 4c and united.
Abstract: PURPOSE:To obtain the noise absorption equipment of large noise absorbing force to effectively cause diaphragm quantity to be small by causing a reinforcing material to be much more in a peripheral part in honey comb structure to be composed of a core, for which the reinforcing material is added in a core material, and the other core. CONSTITUTION:The diaphragm is caused to be the honey comb structure, for which skin materials 4a and 4b are fit to the both sides of a honey comb core material 4c and united. In this structure, a reinforcing material 7 is inserted only to a core 4d in an outer circumference part. The reinforcing material 7 is stretched in a core inside space with being obliquely inclined as being shown in a figure, for example. The quality of the material of the core material 4c is formed by a paper and synthetic resin, etc., in addition to aluminum and concerning the quality of the material of the skin material 4a and reinforcing material 7, the same formation is obtained. Thus, by arranging the core 4d, to which the reinforcing material 7 is inserted, in the outer circumference part where reaction is concentrated when bending force is added, bending rigidity is effectively made large and as a result, the diaphragm quantity can be made small to the bending rigidity. Then, the noise absorption equipment of large noise absorbing quantity can be obtained.

Patent
15 Feb 1989
TL;DR: In this paper, the upper chord material of an un-bonded type concrete filled steel pipe, the lower chord material 2 of PC strands and the post materials 3 of PC wires connecting the materials 1, 2.
Abstract: PURPOSE: To reduce cost by bridging the upper chord material of a concrete filled pipe between foundation sections in an arched shape, connecting the upper chord material by a lower chord material bridged on the lower side and a post material and introducing compression axial force to the upper chord material and tensile force to the lower chord material respectively. CONSTITUTION: The frame is composed of the upper chord material 1 of an un-bonded type concrete filled steel pipe, the lower chord material 2 of PC strands and the post materials 3 of PC wires connecting the materials 1, 2. Hat type metal fittings 8 projected from foundation sections 7 are inserted into a steel pipe 4 and abutted and borne to infilled concrete while the ends of the material 2 are fixed by introducing tensile force by fixtures 12 in bearing sections at both ends of the material 1. The bending-back force of the post materials 3 by the tensile force of the material 2 is introduced to compressive force by its own weight of the material 1, and the flexural rigidity of the material 1 is increased. Accordingly, since sufficient rigidity is obtained by a small cross section, a steel material is decreased, and construction cost can be reduced.

Journal ArticleDOI
TL;DR: In this paper, the influence of the diaphragm flexural rigidity on the clinical load of a thin-walled column loaded by uniform compression is examined, and the problem has been solved approximately by applying an energy method.
Abstract: The influence of the diaphragm flexural rigidity on the clinical load of a thin-walled column loaded by uniform compression is examined. The problem has been solved approximately by applying an energy method. The results of numerical calculations are presented in graphical form.

Journal ArticleDOI
TL;DR: In this paper, a simplified moment-curvature relationship is proposed for rapid nonlinear analysis of continuous girder bridges, and numerical examples clarify effects of the level of prestressing and the pattern of cracking on redundant forces under service load conditions.
Abstract: In designing statically indeterminate structures of partially prestressed concrete under service load conditions, it is reasonable to take into account the reduction of flexural rigidity due to cracking for computing redundant forces.In this paper, experiments are conducted to clarify flexural deformation of partially prestressed concrete beams, and a simplified moment-curvature relationship is proposed for rapid nonlinear analysis of continuous girder bridges.Furthermore numerical examples clarify effects of the level of prestressing and the pattern of cracking on redundant forces under service load conditions.