Showing papers on "Flexural rigidity published in 1997"

Flexural rigidity of Fennoscandia inferred from the postglacial uplift

Abstract: The Earth's response to glacial loading/unloading offers exceptional promise for the study of the physical properties of the lithosphere. In particular, tilting of paleoshorelines is very sensitive to the lithosphere rigidity. To determine the flexural rigidity, the isostatic response to deglaciation in Fennoscandia is modeled using an Earth model with a layered mantle viscosity overlain by an elastic lithosphere. The flexural rigidity and asthenosphere viscosity is allowed to vary to get a match between theoretical and observed present rate of uplift and tilting of paleoshorelines. Five different ice thickness models are used. For a relatively thin ice (2500 m in central areas) the resulting flexural rigidity is more or less uniform over Fennoscandia, with a value of 1023 N m (elastic thickness te ≈ 20 km). This is regarded as minimum for the flexural rigidity of central Fennoscandia. The pattern of the present rate of uplift and the tilts of the paleoshorelines of the area also sets an upper bound of the flexural rigidity, 2.5 × 1025 N m (te ≈ 110 km) in more central areas of Fennoscandia. The flexural rigidity at the western coast of Norway does not seem to exceed 1023 N m (te ≈ 50 km). The most likely glacier model gives a flexural rigidity of 1023 N m (te ≈ 20 km) at the Norwegian coast, increasing to above 1024 N m (te ≈ 50 km) in central parts of Fennoscandia.

The effect of sedimentary cover on the flexural strength of continental lithosphere

Abstract: The factors that control the flexural rigidity — or effective elastic thickness (EET) — of continental lithosphere have been extensively studied over the past two decades. Using EET estimates derived from the analysis of topography, basin structures and gravity anomalies, several authors1,2,3,4,5 have shown that crustal thickness, geothermal gradient, strain rate, rheology and plate curvature all affect the flexural strength of continents. Recognition that certain combinations of these parameters result in a significant reduction of flexural strength caused by decoupling of the crust and the upper mantle3,5 has been a critical step in understanding why many continental areas have estimated EETs that are thin compared with the total mechanical thickness of the continental lithosphere5. Here we develop a semi-analytical model of the EET through a parametrization of the yield stress envelope6,7 that includes the effects of crust–mantle decoupling. We perform a detailed comparison of EET estimates at foreland basins and mountain belts to values predicted by our model and find that, to predict the EET estimates successfully, we need to take into account the effect of the sediment cover and to use a strong plagioclase-controlled rheology. The effect of sediment cover is to weaken the lithosphere because of the lower density of sediments relative to crystalline crust5,8,9 and by thermally insulating the lower crust9,10,11.

Apparatus for measuring the flexural stiffness of moved laminar-shaped material

Abstract: An apparatus for measuring the flexural stiffness of a moving laminar-shaped material web is disclosed that guides the material web over two stationary guide rollers and a deflecting roller. The deflecting roller rides on the material web and deflects the material web for a predetermined distance. A force-measuring device attached to the deflecting roller measures the force exerted by the material web. An actuator movably attached to the force-measuring device is actuated periodically to move the deflecting roller into the material web whereby the force related to the additional periodic deflection is measured by the force-measuring device and evaluated to determine the flexural stiffness of the material web. In a second embodiment of the present invention, the actuator is not used and the deflecting roller includes an eccentric cross-section which imparts on the material web a periodic deflection of the web.

Method for manufacturing a solar cell module having photovoltaic cell sandwiched between covering materials

Abstract: A method for manufacturing a solar cell module including a photovoltaic cell between a surface covering material and a back-surface covering material is disclosed that includes the steps of sequentially laminating a member elastically deformable in the direction of the thickness and a member having a flexural rigidity on the surface covering material and/or the back-surface covering material, and providing an external pressure to the member having the flexural rigidity to cover the photovoltaic cell with the surface covering material and the back-surface covering material. According to the above-described manufacturing method, by providing the member elastically deformable in the direction of the thickness, it is possible to prevent deformation and breakage of the photovoltaic cell and rupture of the covering materials. Furthermore, by utilizing a property such that hardness changes in accordance with an amount of deformation, possesed by the member which is deformed in the direction of the thickness, foaming of a foamed member can be homogenized. In addition, since the pressure is provided via the member having the flexural rigidity, the surfaces of the covering materials of the solar cell module are not deformed more than the amount of deformation of the member which is elastically deformed in the direction of the thickness. As a result, large undulation does not occur in the solar cell module.

On-Line Measurement of Fabric Bending Behavior Part I: Theoretical Study of Static Fabric Loops

Abstract: In order to develop an on-line system to characterize fabric bending rigidity, four potential loop shapes are proposed. Loop shapes are chosen such that they can be formed under dynamic conditions. Results from theoretical models of these loops show the nature of the response of loop shapes to varying fabric bending behaviors. Two candidate loop shapes are identified for further investigation under nonlinear and dynamic conditions.

Influence of steel fibers and compression reinforcement on deflection of high-strength concrete beams

Abstract: The paper presents an experimental and theoretical study on immediate and long-term deflections of high-strength concrete beams. Twelve beams with 85 MPa (12,300 psi) compressive strength and having tension and compression rebars and steel fibers were tested. The experimental results show that the addition of fibers increases the flexural rigidity of the beams, thus reducing the immediate and total long-term deflections under sustained service load. The beneficial effect of the compression reinforcement in controlling the long-term deflection is observed in beams without fibers. However, for beams having steel fibers and compression reinforcement, the behavior depends on the amount of the two types of reinforcement, and their excessive amount may have an inauspicious effect on the long-term deflection. A method is presented for computing the effective moment of inertia of fibrous concrete beams, and a modification is suggested to the long-term multiplier of the ACI Code to include the effect of fibers and high-strength concrete.

Semi-rigid behaviour of connections in precast concrete structures

Abstract: Multi-storey precast concrete skeletal structures are assembled from individual prefabricated components which are erected on-site using various types of connections. In the current design of these structures, beam-to-column connections are assumed to be pin jointed. This current research work focuses on the flexural behaviour of the beam-to-column connections and their effect on the behaviour of the global precast concrete frame. The experimental work has involved the determination of moment-rotation relationships for semi-rigid precast concrete connections both in full scale connection tests and smaller isolated joint tests. This has been done using the so called "component method" in which the deformation of various parts of the connection and their interfaces are summated, and compared with results from full scale sub-frame connection tests. The effects of stress redistribution, shear interaction etc. are taken of by linear transformation in the results from the full scale tests, enabling parametric equations to be formulated empirically in order to describe the semi-rigid behaviour. Eight full scale column-beam-slab assemblages were tested to determine the (hogging) moment-rotation behaviour of double (balanced loading) and single sided in-plane connections. Two of the most common types of connection were used, the welded plate and the billet type. Proprietary hollow core slabs were tied to the beams by tensile reinforcing bars, which also provide the in-plane continuity across the joint. The strength of the connections in the double sided tests was at least 0.84 times the predicted moment of resistance of the composite beam and slab. The strength of the single sided connections was limited by the strength of the connection itself, and was approximately half of that for the double sided connection, even though the connection was identical. The secant stiffness of the connections ranged from 0.7 to 3.9 times the flexural stiffness of the attached beam. When the connections were tested without the floor slabs and tie steel, the reduced strength and stiffness were approximately a third and half respectively. This remarkable contribution of the floor strength and stiffness to the flexural capacity of the joint is currently neglected in the design process for precast concrete frames. Measurements of the extent of damaged zones near to the connection in full scale tests showed that, unlike steel connections, semi-rigid behaviour in precast concrete does not occur at a single nodal position. In general the double sided connections were found to be more suited to a semi-rigid design approach than the single sided ones. Analytical studies were carried out to determine empirical design equations for column effective length factors β in unbraced and partially braced precast concrete frames. The main variables were the relative flexural stiffness α of the frame members, and the relative linear rotational stiffness Ks of the connection to that of an encastre beam. The variation of β factors with Ks and α are presented graphically and in the form of design equations similar to those currently used in BS 8 110. The change in the response of a structure is greatest when 0 2 the changes in the behaviour are so small that they may be ignored within the usual levels of accuracy associated with stability analysis. This is an important finding because the experiments have found Ks to be generally less than 2 for typical sizes of beam. The results enable designers to determine β factors for situations currently not catered for in design codes of practice, in particular the upper storey of a partially braced frame. A design method is proposed to extend the concrete column design approach in BS 8110 and EC2, whereby the strength and semi-rigid stiffness of the connection enables column bending moments to be distributed to the connected beams. However, the suitability of each type of connection towards a semi-rigid design approach must be related to the stiffness and strength of the frame for which it is a part.

NMR Study of Collective Motions and Bending Rigidity in Multilamellar System of Lipid and Surfactant Bilayers

Abstract: Abstract The frequency dependence of the longitudinal proton spin relaxation time T1 was measured by field-cycling and standard NMR techniques at different temperatures in the liquid crystalline lamellar phases of bilayer systems, composed of lipids, nonionic surfactants, and lipid-surfactant mixtures. We show by our data analysis, comparing various motional models such as layer undulations (LUs) and relaxation by translational diffusion mediated reorientations (TR), that collective layer undulations with their typical T1~ν behaviour determine the low frequency T1 dispersion in both unoriented and glass plate-oriented bilayer systems. The angular dependence of the T1 dispersion for the oriented bilayer system supports these findings and provides a more critical analysis of the two dimensional self-diffusion than in unoriented samples. The evaluated fitting parameters of the LU model allows, together with the measured second moment of the proton NMR signal for the lipid, calculation of the bending rigidity ϰc for these bilayers at different levels of hydration. The obtained values of ϰc turn out to be too large compared with the literature. However, using recent LU models (B. Halle) which include the obvious couplings between neighbouring bilayers at low Larmor frequencies, the corrected ϰc of the fully hydrated membrane systems are comparable to those obtained from the standard videooptical experiments. Therefore proton spin relaxation measure-ments at low Larmor frequencies with the field-cycling technique are a suitable means to determine the bending rigidity ϰc of model membrane systems at low hydrations and of systems containing surfactants.

Effects of Foil Bending Rigidity on Spacing Height Characteristics of Hydrostatic Porous Foil Bearings for Web Handling Processes

Abstract: In this paper, the effects of foil bending rigidity on the spacing height characteristics of hydrostatic foil bearings with a hollow porous shaft for web handling processes are analyzed by the finite width bearing theory. In the analysis, in order to save computation time and to improve the convergence of solutions, the two-dimensional modified Reynolds equation considering the added flow through porous shaft is reduced to an ordinary differential equation based on the weighted residual method. The reduced Reynolds equation and elastic equation for the foil are discretized by the finite difference method and solved numerically by the iterative technique. The numerical solutions for the pressure and film thickness distributions between foil and shaft are obtained for a wide range of bearing width-to-diameter ratio under various combinations of foil bending rigidity and foil wrap angle, and the spacing height characteristics of the foil bearings are examined theoretically.

Stresses in a partially coated optical glass fiber subjected to the ends off-set

Abstract: A simple formula based on the elementary beam theory is obtained for the evaluation of the maximum bending stress in an optical glass fiber whose ends are clamped and experience lateral off-set. We consider a situation when the fiber is partially coated and/or partially metallized, and therefore its flexural rigidity is not constant along its span. The obtained formula can be helpful in the analysis and design of optical glass fibers and optical interconnects structures of the type in question.

Cyclic Behavior of Steel-Fiber Mortar Overlaid Concrete Beams

Abstract: A study was carried out to investigate the cyclic behavior of steel-fiber cement-mortar overlaid concrete beams at various stress levels. Two different volume fractions of steel fibers were selected for the present study. The concrete-beam specimens used in this study were tested simply supported with a point load at midspan. Two different types of bonding conditions were studied. The deterioration in the flexural rigidity of the test specimens after being subjected to a predetermined number of load cycles was evaluated. The test specimens were subjected to 100,000 cycles of loading under a maximum load of 45, 55, and 65% of the ultimate static load. Static loading tests to failure after 100,000 cycles of applied load showed that some of the beams loaded up to 65% of ultimate static failure strength failed by partial or complete delamination of the overlay. The results of the experimental tests are summarized and discussed in this paper.

Method for measuring flexural rigidity and tension of tensioned cable

Abstract: PROBLEM TO BE SOLVED: To provide a method by which the flexural rigidity of a cable can be measured easily with high accuracy and the tension of the cable can be calculated without conducting any preliminary experiment in laying the cable even when the length of the cable reaches hundreds of meters. SOLUTION: The flexural rigidity 5 of a tensioned cable 1 is found by giving an impact to the cable 1 and detecting 2a the vibration of an arbitrary part of the cable 1, and then, performing frequency analyses 3 and 4 on the detected vibration and finding the rigidity 5 from a plurality of characteristic frequencies existing in a frequency area where the influence of the flexural rigidity become dominant of the analyzed results. Or, the flexural rigidity of the cable 1 is calculated from a plurality of number-of-vibration data by performing frequency analysis for finding a transfer function from the ratio between the vibrations detected at two points on the cable 1 and reading the number of vibrations indicating the maximum or minimum value of an obtained frequency response function and, at the same time, selecting the plurality of number-of-vibration data of an area where the influence of the flexural rigidity becomes dominant.

Torsion beam type suspension

Abstract: PROBLEM TO BE SOLVED: To prevent strength deterioration at a connection part, and improve durability of a suspension by providing a fragile part to reduce stress concentration at the connection part of a torsion beam with a trailing arm at a part other than the connection part SOLUTION: A suspension comprises a pair of trailing arms 10 which are disposed to be apart from each other in a vehicle width direction, and pivotally supported on a car body at a front end part for supporting a wheel to be rotatable, and a torsion beam 12 extended in the vehicle width direction and integrally connected to the trailing arms 10 by weld parts 36 at both ends The tortion beam 12 is provided with a cutout 38 as a torsional rigidity reducing part to partially reduce torsional rigidity of it at a position apart from the weld part 36, and the trailing arm 10 is provided with a dent 40 as a flexural rigidity reducing part to partially reduce flexural rigidity in a width direction of it between the weld part 36 and a rear end part COPYRIGHT: (C)1998,JPO

The Influence of Plying on the Tenacity, Breaking Extension, and Flexural Rigidity of Air-jet-spun Yarn

Abstract: (1997). The Influence of Plying on the Tenacity, Breaking Extension, and Flexural Rigidity of Air-jet-spun Yarn. The Journal of The Textile Institute: Vol. 88, Issue 1, Parts 1 and 2, pp. 76-78.

Frp structural angle

Abstract: PROBLEM TO BE SOLVED: To make lightweight an FRP structural angle having two or more kinds of reinforcing fibers including carbon fiber, secure corrosion resistance and the closure of a bolt joint and prevent damage by aligning at least some of carbon fibers along the longitudinal direction of the shape. SOLUTION: This FRP structural angle is formed into a layered structure consisting of a CFRP part 2, made from carbon fibers aligned in its longitudinal direction LD and a resin, and an FRP part 3 made from glass fibers other than carbon fibers. The carbon fibers are appropriately distributed over its cross section, and carbon-fiber-containing parts in tow units are dispersed into a checkered pattern to obtain the respective FRP structural angles 1 for structures, for buildings, and for construction. In this case, the carbon fibers are 5 to 50vol% of all the reinforcing fibers, and the tensile elasticity of the carbon fibers is from 180 to 300GPa. Further, the carbon fibers have a tensile strength of 2,400 to 6,000MPa, and the number of filaments is 30,000 to 240,000 carbon-fiber bundles. Flexural rigidity is 0.1 to 1,000kN.m on a U-shaped cross section, and on an I-shaped cross section height is 30 to 300mm and flexural rigidity 0.5 to 3,500kN.m .

Socket for mounting package and mount structure of package using the same

Abstract: A socket for mounting a package has a socket body on which the package is mounted and a plurality of contacts which are integrated in the socket body. The socket has a flexural rigidity which is smaller than a flexural rigidity of a substrate on which the socket is to be mounted.

Analysis of crosstie track in lateral plane using new track equations

Abstract: The analysis of a crosstie railroad track in the lateral plane has traditionally been based on the theory of a beam on an elastic foundation, in which the bending rigidity of the track structure is assumed to be twice the rigidity of a single rail, and the ballast resistance is represented by a linear Winkler foundation with modulus k. The traditional analysis ignores the contribution of the ties and rail-tie fasteners to the bending stiffness of the track and the nonlinearity of the ballast resistance. In the present paper the analysis of an infinitely long crosstie track subject to a concentrated lateral load is presented. The analysis is based on the new track equations derived by Kerr and Zarembski in 1981. These equations explicitly account for the contribution of the rails, ties, and fasteners to the bending stiffness of the track. A bilinear approximation is assumed in modeling the lateral resistance due to the ballast. A closed form solution for the track deflection is obtained using the new equat...

Damping skeleton construction

Abstract: PROBLEM TO BE SOLVED: To promote damping efficiency by providing a beam having high bending rigidity equipped with a damper restoring the bending deflection of a core to a skeleton having the core in the vertical direction. SOLUTION: A building 1 is constituted of a cylindrical core wall 2 as an earthquake resisting wall and the circumferential skeleton 3. The skeleton 3 is constituted of the circumferential columns 4, circumferential beams and middle beams 6 constructed between the columns, beams and wall 2. Strut members 7, lattice members 8 and lattice members 9 as unbonded brace dampers are assembled between the highest floor section and up and down beams 6 of the intermediate floor, and the highest floor truss 10 and intermediate floor truss 20 are formed. In the case of an earthquake, the trusses 10 and 20 yield bending restoration to the wall 2, and the horizontal displacement of the wall 2 is controlled to keep it's balance. In that case, external force inputted to the trusses 10 and 20 is damped with the lattice members 9, and the whole cross section of the trusses 10 and 20 is plasticized to absorb vibration energy. By the constitution, the high damping effect can be displayed, and the cross section of a skeleton constituent can be reduced to curtail cost. COPYRIGHT: (C)1998,JPO

Response to doubling of MJS yarns produced with varying nozzle pressure

Abstract: The effects of nozzle pressure and doubling twist on the properties of polyester-viscose two-fold MJS yarn have been investigated and the properties of two-fold MJS yarn have been compared with those of ring-spun yarn. Tensile properties, abrasion resistance, S3 value, unevenness and imperfections improve after doubling in MJS yam and the extent of improvement is greater than that in ringspun yarn. Again, after doubling, increase in flexural rigidity is less than that in ring-spun yam. Tenacity, breaking elongation and abrasion resistance show optimum values at a particular level of doubling twist, whereas flexural rigidity, hairiness index and S3 value gradually decrease with the increasing doubling twist. The above parameters are also affected by the characteristics of single yam produced with different nozzle pressure combinations. Two-fold MJS yarn (with 4.1 tpcm) which are made from single yarns produced under nozzle pressure combination of 2.5 kg cm "? (N1l/3.5 kg ern-2 {N2lappears to be most suitable for weaving.

Shear strength enhancement type reinforcing method for existing reinforced concrete column

Abstract: PROBLEM TO BE SOLVED: To enhance the earthquake resistance of an existing reinforced concrete column as a whole with high efficiency by enhancing flexural rigidity at the center of the column, and enhancing shear strength at the ends of the column, i.e., near upper- and lower-story slabs. SOLUTION: An existing reinforced concrete column 9 firmly held between upper- and lower-story slabs 10, 11 is surrounded at its center by a new reinforced concrete body 1 for reinforcement, and is surrounded and reinforced, at its upper and lower ends located near the upper- and lower-slabs 11, 12, by band steel plates 2 for reinforcement. The column can thus be prevented from decreasing in length and allowed to have enhanced shear strength. Also, fire resistance and overall rigidity can be enhanced by surrounding with ordinary concrete 8 the outer peripheries of the band steel plates for reinforcement.

Liner for unvulcanized rubber member

Abstract: PROBLEM TO BE SOLVED: To compactly wind a rubber member and to prevent the rubber member from being deformed during storing by strengthening the bending rigidity in the width direction of a liner prepd. by covering one face or both faces of a woven fabric woven with warps and wefts with a non-sticky outer skin layer to the bending strength in the longitudinal direction by a specified ratio. SOLUTION: A liner 1 for an unvulcanied rubber member is prepd. by covering the surface of a woven fabric woven with wefts in the width direction and warps in the longitudinal direction with a non-sticky outer covering layer 3 and the back surface with a non-sicky outer covering layer 4. In addition, the bending rigidity of the liner 1 in the width direction is made at least 1.4-fold of the bending rigidity in the longitudinal direction. The material of the woven fabric is a multifilament yarn or a monofilament yarn consisting of an org. fiber or an inorg. fiber and the required rigidity ratio is obtd. by adjusting the denier and the density of the wefts and the warps. In addition, as the non- sticky outer covering layer, a silicone resin or a fluororesin with a proper stretchability and flexibility is pref.

Method for determining bending point of golf club, golf club shaft with features expressed by the method, and golf club equipped with the golf club shaft

Abstract: PROBLEM TO BE SOLVED: To match measured characteristics of a golf club with a feeling in a swing by judging characteristics including bending point of the shaft by curvature distribution calculated from data of measurement of the distribution of bending moment loaded on a shaft in a swing and bending rigidity distribution. SOLUTION: The grip side of a shaft 2 is fixed by a fixing part 11. Bending moment is applied loaded on the tip end part of the shaft 2 by a torque sensor 12. A laser sizer 13 is moved from a measuring part 11 side to the tip end side. A flexure curve and an outer shape Dere measured and inputted into CPU. A load is inputted from the torque sensor 12. Then the flexure curve of the shaft center axis is calculated. CPU circular-approximates by the least square method to calcualte the curvature radius on which binding moment acts and the center to calculate the curvature distribution. CPU also calculates the bending moment from the load and the distance from the load to complete. The CPU calculates the bending rigidity distribution of the shaft 2. COPYRIGHT: (C)1999,JPO

Wheel and its parts

Abstract: The present invention discloses a wheel with large bending rigidity and less rolling resistance. It is a solid wheel with high-modulus skeleton or an inflated wheel with large-bending rigidity skeleton inside its inner tube.

Steering device for automobile

Abstract: PROBLEM TO BE SOLVED: To prevent the generation of flutter by arranging one of yokes, which form an adjustable joint, substantially vertical in relation of the flat surface, which includes a pair of shafts connected by the adjustable joint, at the time of straight line traveling of a vehicle, and providing a low rigidity member in the shaft side having the yoke. SOLUTION: When the steering angle at the time of straight line traveling of a vehicle is zero, an output shaft side yoke 33 provided in an output shaft 25 is arranged nearly vertical in relation to the flat surface S1, which includes an intermediate shaft 24 and the output shaft 25. A yoke 32 of the intermediate shaft side is necessarily formed nearly parallel with the flat surface $1. The generated moment M is applied to a rubber coupling 40 at a low bending rigidity so as to generate the bending deformation, and the equivalent torsion rigidity of the rubber coupling 40 is thereby reduced. Rotational oscillation of a pinion is absorbed by the rubber coupling 40 so as to prevent the generation of flutter.