Showing papers on "Deflection (engineering) published in 1979"

Ultrasonic imaging using arrays

Abstract: An analysis is presented of the two general types of arrays-the direct imaging array and the phased array. These are analyzed over three levels of approximation: geometric optics, steady-state sinusoidal diffraction, and wide-band diffraction. Systems are studied which provide electronic deflection and focusing. In addition, systems are considered which exhibit high resolution in both lateral dimensions.

Analysis of massless elastic chains with servo controlled joints

Abstract: The lumping approximation used frequently for dynamic analysis of distributed parameter systems is facilitated for a class of flexible systems by a technique using 4 × 4 coordinate transformation matrices to account for the deflection of elastic elements under load. This approach is used to develop the linear equations of spatial motion for a system of two rigid masses connected by a chain with an arbitrary number of massless beams and controlled joint rotations.

Group Factors for Pile-Deflection Estimation

Abstract: A series of solutions is presented for group settlement, lateral deflection and rotation ratios, for a variety of pile-group configurations, spacings, and stiffnesses and for both a homogeneous soil and a soil when modulus increases linearly with depth. These solutions have been obtained from an elastic analysis and may be applied to the appropriate single-pile deflections to obtain the group response. Some typical solutions are presented to indicate the effects of pile-head condition and pile batter on the group factors, and then an illustrative example is given to demonstrate the use of the solutions for a practical problem.

The Interaction between a Uniformly Loaded Circular Plate and an Isotropic Elastic Halfspace: A Variational Approach

Abstract: The axially symmetric flexural interaction of a uniformly loaded circular plate resting in smooth contact with an isotropic elastic halfspace is examined by using an energy method. In this development the deflected shape of the plate is represented in the form of a power series expansion which satisfies the kinematic constraints of the plate deformation. The flexural behavior of the plate is described by the classical Poisson-Kirchhoff thin plate theory. Using the energy formulation, analytical solutions are obtained for the maximum deflection, the relative deflection, and the maximum flexural moment in the circular plate. The results derived from the energy method are compared with equivalent results derived from numerical techniques. The solution based on the energy method yields accurate results for a wide range of relative rigidities of practical interest.

Cross-section behaviour and ductility in composite beams.

Abstract: Ductility in cross-section behaviour is a necessary requirement for plastic design. It is also a desirable condition in all design since ductile structures give warning of impending collapse. The chief aim of this paper is to define the conditions required for a composite beam to exhibit ductile sagging behaviour. The variations in the elastic and inelastic response of a composite beam in sagging bending are studied. The effects of material properties, geometry, residual stresses and interface slip are all examined. From a wide range of cross-sections, the form of a standard moment-curvature curve is determined. Simple analytical expressions are derived which give an approximate but quite accurate prediction of the form of the complete curve throughout the elastic and inelastic range. The criterion which determines whether a beam is ductile or strain-softening is deduced directly from this simple analysis. The ductility criterion developed here is shown to be accurate and is very simple to apply. It is not very restrictive on designs and enables the designer to achieve a ductile design quickly. (a) This report is also issued as Australian Road Research Board Internal Report Air 076-11. /TRRL/

On the measurement and calculation of vertical track modulus

Abstract: This paper presents the results of a series of tests and analyses directed towards the characterization of the track structure under vertical loads. It also presents and evaluates different analytical techniques for the calculation of the vertical track modulus. In a series of tests at the Association of American Railroads's Track Structures Dynamic Test Facility, the response of the track was obtained by monitoring track deflection under increasing vertical loads. This load and deflection data was then used to calculate vertical track modulus, track stiffness and track compliance. Three widely used techniques were utilized to calculate the vertical modulus. The results of the tests indicate that the modulus of the track is related to the level of loading; thus identical track can give different modulus values for different load levels. Of the three different techniques used to calculate track modulus, the beam-on-elastic-foundation technique was found to be the most applicable to field measurements since it requires a minimum number of track deflection values.

Agricultural dispensing mechanism

Abstract: A mechanism for dispensing seed or fertilizer, etc., for agricultural row crop implements such as seed drills and precision planters, comprises a resilient rotatable roller which cooperates with a flat vertical glass dispensing plate to dispense seed or fertilizer from a hopper through a nip between the plate and the roller. The roller is of unfoamed polyurethane formed with a honeycomb of axially extending recesses defining a relatively thin outer deflection band of the roller. The recesses give the roller the uniform and high degree of flexibility needed to accommodate a wide range of seed sizes while retaining the durability, consistency of physical characteristics and suitability for precision moulding, of unfoamed polyurethane.

Constant moment weigh scale with floating flexure beam

Abstract: A weigh scale apparatus in which forces caused by the applied load are transformed into moments of opposite sense and applied to opposite ends of a substantially rigid beam. Deflection of the beam is measured by centrally disposed strain gage resistors to produce an electrical signal quantity proportional to the applied load. The conversion of applied load to moments of opposite sense is accomplished by a pair of spaced parallel pivot members which are suspended by straps between the load receiving pan and the base such that the pivots tend to rotate in opposite directions. The beam is mechanically connected between the pivots such that it is subjected to the bending moment over substantially its entire length. A split scale device is provided by a composite pan, one portion of which is connected to the pivots directly and another portion of which is connected to the pivots through long lever arms to provide moment multiplication. A vibrator device for dithering the pivots is provided. .Iadd.

Slope and curvature measurement by a double-frequency-grating shearing interferometer: A shearing interferometer is presented which is capable of the direct independent measurement of all components of the first and second derivatives of deflection of reflecting plate models. The wavefront shearing is provided by a double-frequency grating

Abstract: This paper describes a shearing interferometer capable of the direct measurement of the slopes and curvatures of reflecting plates. The wavefront shear is produced by a double-frequency grating which is simply a grating containing two closely spaced frequencies. The first-order waves associated with each frequency form the interferogram, the contours of which are related to the model's slope or curvature depending upon system arrangement and recording procedure.

Elastically deformed reflectors

Abstract: Spherically-shaped dish and cylindrically-shaped trough reflectors are produced by the deflection of a thin reflective element within its elastic range of stress. A spherical or cylindrical shape is produced by including a pure bending moment stress pattern in the reflective element. This is accomplished by clamping the edges of the reflective element to a rigid frame which is precisely dimensioned relative to the dimensions of the reflective element. Preferably, the surface of the frame which engages and supports the reflective element is tangent to the desired radius of curvature of the reflector. Close control of the dimensions insures that no compressive or tensile stresses are induced in the element by forces from the support surfaces, such forces tending to push the edges of the reflective element toward or away from each other.

An integral equation method for the analysis of magnetic deflection yokes

Abstract: An integral equation method is developed for the computer modeling of the magnetic fields produced by color television deflection yokes. Saddle or toroidal yokes with either radial or nonradial winding distributions can be analyzed using this new technique. The integral equation method is shown to yield magnetic field calculations that are at least as accurate as those produced by conventional finite‐difference analysis. In most cases computer algorithms using the integral equation approach have been found to be more computationally efficient than existing finite‐difference programs.

Analysis of Curved, Prestressed, Segmental Bridges

Abstract: A method for the time-dependent analysis of curved, concrete box-girder bridges with nonprismatic cross section has been developed. The bridge can consist of precast segments, cast-in-place segments or any other form of staged or conventional construction. Time-dependent effects allowed for are creep and shrinkage of concrete, changes in material properties, temperature variations, and relaxation of prestressing steel. A computer program was developed to carry out the analysis. Input consists of a description of the bridge geometry, prestressing tendon details, material data, environmental data, and the construction sequence. Results are plotted for two examples. In the first, the axial stress of a curved bridge is compared with experimental results. In the second, the deflection history of a segmentally erected bridge is compared to experimental results.

Bridge section composite and method of forming same

Abstract: A low cost, structurally superior bridge and fabrication method are described which take maximum advantage of the compressive strength of concrete, and the tensile strength of steel, to give a bridge structure having the lowest allowable depth-to-span ratio and good dead load/live load ratios, as well as minimum deflection under impacting, moving concentrated loads. The bridge is most preferably shop cast in sections which include lowermost, substantially planar structural metallic plates (e.g., 5/16" thick self-rusting steel) of length and width dimensions substantially equal to that of the sections; a separate layer of concrete is then composited to each plate, preferably by means of upstanding studs secured to the plate and embedded within the concrete. Monolithic bridge sections are thus formed which can be transported to the bridge site, erected and connected, typically by welding the respective section plates together at regular intervals. All necessary bridge sections are preferably cast simultaneously on a single bed, so that field construction of the bridge is facilitated and the sections have guaranteed match. It is estimated that bridge superstructures in accordance with the invention can be constructed for a cost significantly less than that of conventional bridge superstructure.

Heated controlled deflection roll

Abstract: A controlled deflection roll is disclosed comprising a stationary support and a rotatable hydraulically supported roll shell. There is also provided heating of the hydraulic liquid which is infed to the controlled deflection roll by a pump device. The pressure line of the pump device is connected by means of a heat exchanger with a return flow line. Connected after the heat exchanger is a cooling device having a temperature regulator. In the pressure line there is arranged following the heat exchanger a heating device. The return flow line is connected by means of an overflow valve with a container for hydraulic medium which is fed to a heating device for the controlled deflection roll.

A method of analysis for horizontally embedded anchors in an elastic soil

Abstract: SUMMARY A general method is presented for the analysis of horizontally embedded anchors in an elastic soil. Provision is made in the analysis for the consideration of anchor shape, layer depth, anchor-soil interface condition, breakaway of the anchor from the underlying soil and interaction between groups of anchors. Application of the analytical technique is illustrated for strip and circular anchors, and these solutions are presented in the form of influence charts which may be used directly in hand calculations to predict the elastic load deflection behaviour of anchor plates for a wide variety of material and geometric conditions. INTRODUCfION Although the behaviour of anchor plates at working loads is of considerable practical importance, previous investigations into the eleastic load-deflection behaviour of horizontal anchors have been restricted to the case of a fully bonded, perfectly flexible or infinitely rigid anchor resting in either an elastic half -space (Fox 1) or within an infinite elastic mass (Selvadurai2). In this paper, an analytical technique will be presented for the analysis of an anchor of general shape buried at a depth h below the surface of an isotropic elastic soil layer (with elastic modulus E and Poisson's ratio II) which extends a further distance D below the anchor plate. The anchor plate itself may be either perfectly flexible or rigid while the anchor-soil interface may be either smooth or rough. In addition, provision is made for slip between anchor and soil as well as breakaway of the anchor from the underlying soil.

Convertible bowling alley

Abstract: In an improved bowling alley resilient or non-resilient deflection means are removably disposed along both sides of the lane bed for preventing balls from dropping into the gutters of the bowling alley. Exemplary deflection means of the invention are tubes, springs, elastic bands removably disposable in the gutters and conveniently storable elsewhere when removed.

Method of and device for implanting ions in a target

Abstract: In a method of implanting ions in a target, an ion beam is directed onto the target by means of an electrostatic deflection system where the beam describes a pattern over the target dependent on voltage variations on two mutually perpendicular sets of deflection plates. One of the sets of deflection plates is subjected to a varying voltage difference and the other set of deflection plates is subjected to a constant voltage difference so that the ion beam describes a straight line on the target, while at the end of the beam stroke a fixed voltage difference is superimposed on the plates having a constant voltage difference and the variation in the voltage difference is reversed in the plates having a varying voltage difference in such manner that lines described consecutively by the ion beam are always parallel and are situated at a fixed distance from each other.

Deflection unit for a color television display tube

Abstract: A deflection unit for a color television display tube 1 having a field deflection coil 8 and a line deflection coil 7, in which the line deflection coil is formed by two diametrically oppositely positioned coil portions which, on the side adjacent the tube's screen, have a flared end 17 having a profile with a path length 22 which is longer than the path length 23 of the contour of the outer surface of the tube, so that raster defects are smaller than when the profile of the flared ends conforms to the contour of the tube surface.

Traffic guide employable as a median barrier and road edge barrier

Abstract: A traffic guide provision is described with a twosided profile to be employed as a median barrier of roads or with a onesided profile to be employed as road edge barrier wherein the profile is provided with a substantially vertical lower side face (1), via run-up edge (2) followed by an inclined towards the outside running run-up face (3) and above a deflection strip (4) staggered towards the outside relative to the run-up edge (2) and acting upon a vehicle below the automobile body.

Optimal design of multi-purpose beam-columns

Abstract: The paper deals with the optimal design of an elastic pinended member of given volume that is to serve as a beam for a part of its design life and as a column for the rest. The optimal design can be interpreted in two ways. Firstly, it is the design that has the maximum Euler buckling load in column action, subject to a prescribed maximum deflection as a beam. Secondly, it is the design that has the least deflection as a beam under a midspan concentrated load, subject to a minimum permissible Euler buckling load in column action. The effectiveness of the optimal design is judged by comparing it with a prismatic bar of the same volume.

Scanning beam deflection system and method

Abstract: A scanning beam deflection system and method utilizes a beam scanning device for producing rays diverging from a central axis of a beam of charged particles and a deflection magnet assembly for deflecting the scanning beam substantially 270° within an evacuated deflection chamber such that the deflected scanning beam exits an offset beam window in the deflection chamber and has rays diverging from the central axis of the deflected scanning beam at substantially the same angle as the diverging rays produced by the beam scanning device. The system and method is particularly useful for irradiating internal surfaces of hollow articles with the deflection chamber and deflection magnet assembly disposed along an axis of symmetry of the object.

Deflection device for safety belts

Abstract: Deflection device for a safety belt which, at one end region, is rolled up in an automatic wind-up device, and is provided at the other end with a lock. An in-between-portion of the belt is routed over a fixed rounded deflection bar. The part of the device which serves for securing it, and the deflection crossbar which has rounded bends at least in the region of the deflection crossbar is formed by a metal stamping.

High dynamic response mass rate fluid flow sensor

Abstract: A restrained turbine high dynamic response mass rate of fluid flow sensor for applications to air flow sensing in internal combustion engine fuel controls. The turbine rotor vanes impart an angular momentum change to the fluid in passing through the turbine vanes and signals are generated corresponding to the resulting reaction forces, these signals combined with signals corresponding to the fluid temperature and downstream pressure to yield mass rate of flow output signals. Variations of the turbine rotor support configurations include a friction free flexural restraint comprised of radial webs which may also act as stator vanes, secured to the turbine hub. In several embodiments, reaction forces are sensed by measuring the reactive torque imposed on the turbine rotorand the flexural restraint supporting the rotor provides a rigid support for absorbing the radial and axial forces while being compliant to torque. In these embodiments, the torque is measured either by allowing limited deflection against the resilience of the flexure and measuring the deflection, or by rigidly resisting angular deflection and measuring the reaction force with a force sensing transducer. In a torque sensing embodiment, a nonlinear spring opposes the angular deflection of the turbine rotor to produce an angular deflection decreasing with increasing flow rates to vary the relationship of the output signals of the sensor in relation to the mass flow rate.