Showing papers on "Deflection (engineering) published in 1988"
TL;DR: In this paper, the Young's moduli and the yield strengths of thin-film materials that comprise the beams are determined using simple beam theory and the load-deflection data, the measured mechanical properties are compared to those obtained by indenting similar thin films supported by their substrate.
Abstract: The mechanical deflection of cantilever microbeams is presented as a new technique for testing the mechanical properties of thin films. Single-layer microbeams of Au and SiO2 have been fabricated using conventional silicon micromachining techniques. Typical thickness, width, and length dimensions of the beams are 1.0,20, and 30 μm, respectively. The beams are mechanically deflected by a Nanoindenter, a submicron indentation instrument that continuously monitors load and deflection. Using simple beam theory and the load-deflection data, the Young’s moduli and the yield strengths of thin-film materials that comprise the beams are determined. The measured mechanical properties are compared to those obtained by indenting similar thin films supported by their substrate.
380 citations
293 citations
195 citations
191 citations
TL;DR: In this paper, the problem of an orthotropic cantilevered plate subjected to a uniformly distributed end load is solved by the Rayleigh-Ritz energy method, and the result is applied to laminated composite, double-cantilevered specimens to estimate the effect of crack tip constraint on the transverse curvature, deflection and energy release rate.
Abstract: The problem of an orthotropic cantilevered plate subjected to a uniformly distributed end load is solved by the Rayleigh-Ritz energy method. The result is applied to laminated composite, double cantilevered specimens to estimate the effect of crack tip constraint on the transverse curvature, deflection and energy release rate. The solution is also utilized to determined finite width correction factors for fracture energy characterization tests in which neither plane stress nor plane strain conditions apply.
95 citations
TL;DR: In this article, the effect of the probe beam radius on the amplitude of optical beam deflection was investigated in air at frequencies around 10 kHz and in liquids around 100 Hz, and it was shown that for certain values of the modulation frequency and probe beam surface distance, the amplitude exhibits a sharp minimum and its phase varies drastically.
Abstract: Important effects of the finite size of the probe beam occur in optical beam deflection experiments when the probe beam radius is of the order of magnitude of the thermal diffusion length. The calculation of this effect is checked by experiments in air at frequencies around 10 kHz and in liquids around 100 Hz. In this last case, for certain values of the modulation frequency and of the probe beam‐sample surface distance, the amplitude of the deflection exhibits a sharp minimum and its phase varies drastically.
81 citations
TL;DR: In this article, the authors evaluated the fracture energy of single-edge-notched beams in three-point bending in concrete and showed that fracture energy, traditionally presented as a material property, depends upon the specimen size and configuration.
Abstract: Three test series of single-edge-notched beams in three-point bending are conducted to evaluate the fracture energy of concrete. The fracture energy is determined from the area under the complete load: load-point deflection diagram. The nonlinear fictitious crack model is implemented in a finite-element analysis showing good agreement with the experimental data. By varying the notch depth and the beam depth it is shown that the fracture energy, traditionally presented as a material property, depends upon the specimen size and configuration. This is atributed to the energy dissipation in the process zone which is not accounted for in the analytical model.
64 citations
TL;DR: In this article, the von Karman plate theory was used to analyze composite laminates under in-plane and transverse loadings, and the governing equations were reduced to linear differentia with nonlinear boundary conditions yielding a simple solution procedure.
Abstract: Linear laminated plate theory is shown to be inadequate for analysis of asymmetric composite laminates, even in the small deflection range. The von Karman plate theory was used to analyze composite laminates under in-plane and transverse loadings. For cylindrical bending problems, the governing equations were reduced to linear differentia} equations with nonlinear boundary conditions yielding a simple solution procedure. Cross-plied laminates were used as examples.
61 citations
TL;DR: In this article, the posibuckling behavior of simply supported rectangular plates under uniaxial compresion is investigated and the effects of initial imperfections are also studied.
Abstract: In this paper, applving perturbation method to von Karman nonlinear large deflection equations of plates by taking deflection as perturbation parameter, the posibuckling behavior of simply supported rectangular plates under uniaxial compresion is investigated. Two types of in-plane boundary conditions are now considered and the effects of initial imperfections are also studied. It is found that the theoretical results are in good agreement with experiments.
56 citations
Patent•
12 Jan 1988
TL;DR: A deflection device attachable to a vehicle lap/shoulder seat-belt below the door post anchorage, free of any attachment to fixed structure of the vehicle, to shorten the length of the shoulder belt portion and dispose it across the chest of a smaller seat occupant such as a child is described in this paper.
Abstract: A deflection device attachable to a vehicle lap/shoulder seat-belt below the door post anchorage, free of any attachment to fixed structure of the vehicle, to shorten the length of the shoulder belt portion and dispose it across the chest of a smaller seat occupant such as a child. The attachment prevents relative movement between the shoulder belt portion and the vertical run of the seatbelt located below the door post anchorage.
54 citations
Patent•
19 Jan 1988
TL;DR: In this article, a liquid distributor for a gas-liquid contact column, which liquid distributor comprises a plurality of elongated distributors extending across the general cross section of a gas liquid contact column and secondary distributing troughs located on each side of the distributor, is described.
Abstract: A liquid distributor for a gas-liquid contact column, which liquid distributor comprises a plurality of elongated distributors extending across the general cross section of a gas-liquid contact column, and secondary distributing troughs located on each side of the distributor, the secondary distributor troughs containing a deflection plate having an upper section and a lower section and a support plate which connects the deflection plate and spaces the deflection plate apart from the liquid distributor, the support plate having large openings for the upward passage of a gas and smaller openings located near the intersection of the support plate with the deflection plate to permit the liquid splashing from the orifices of the liquid distributor against the deflection plate to flow downwardly against the wall surface of the lower portion of the deflection plate and to be distributed through multiple drip points on the lower edge of the deflection plate in the lower portion of the gas-liquid column.
Patent•
30 Aug 1988
TL;DR: In this article, a single-wire drying group in a paper machine is disclosed including a plurality of drying cylinders whose axes are situated in a substantially common plane, a drying wire carrying a web between successive drying cylinders, one or more deflection rolls, each situated between a pair of successive driers, and a blow box has a wall which defines a gap space with the incoming run of the web-carrying wire and a gas flow is directed through the gap space to induce an under pressure on the incoming runs to fix the web on the drying wire.
Abstract: A single-wire drying group in a paper machine is disclosed including a plurality of drying cylinders whose axes are situated in a substantially common plane, a drying wire carrying a web between successive drying cylinders, one or more deflection rolls, each situated between a pair of successive drying cylinders and wherein the web-carrying drying wire has an incoming run from a drying cylinder to a deflection roll whereupon the drying wire runs over a deflection sector of the deflection roll and then to a subsequent drying cylinder. A blow box has a wall which defines a gap space with the incoming run of the web-carrying wire and a gas flow is directed through the gap space to induce an under pressure on the incoming run to fix the web on the drying wire. The deflection roll has a perforated shell in the perforations of which an underpressure is maintained to ensure that the web remains in contact with the outer surface of the drying wire as the drying wire travels over the deflection or closed sector of the deflection roll.
TL;DR: In this paper, a linear analysis for bending and vibration of sandwich plates consisting of an orthotropic core and unbalanced laminated face plates is presented, and a solution method is proposed through the principle of minimum total potential energy.
TL;DR: In this article, the effect of large deflection term becomes pronounced even in the "small deflection" range and the apparent laminate bending rigidity depends on the direction of deflection.
Abstract: Static and dynamic behaviors of unsymmetric cross-ply laminates in cylindrical bending are investigated using von Karman large deflection theory. Due to the presence of bending- extension coupling, the effect of the large deflection term becomes pronounced even in the "small deflection" range. Further, the apparent laminate bending rigidity depends on the direction of deflection. It is also found that in free vibration at small amplitudes, large deflection theory may yield frequencies lower than linear theory.
TL;DR: In this article, a simple finite element formulation is presented for evaluating the thermal postbuckling behavior of rectangular plates, in the form of linear thermal loads and ratios of nonlinear to linear thermal load for various values of the central deflection and for three sets of boundary conditions.
TL;DR: In this paper, an extended analysis of previous experimental work (Takizawa, 1985) is made using the dispersion relation for flexural free waves in a floating ice sheet, a diagram that predicts the critical speed, at which the ice deflection is amplified markedly, is presented.
Abstract: An extended analysis of previous experimental work (Takizawa, 1985) is made. Using the dispersion relation for flexural free waves in a floating ice sheet, a diagram that predicts the critical speed, at which the ice deflection is amplified markedly, is presented. An understanding of the group velocity provides one explanation for the question why two waves appear in front of and at the rear of the load. The two-dimensional deflection patterns obtained in the experiment are compared with the existing theoretical results. At high speeds the ice beneath the load is found not to be depressed but somewhat elevated. It is shown that viscous damping has substantial effects on the ice deflection profile. The wave number curves, which give the two-dimensional wave patterns, are also examined, and the results verify that a one-dimensional model quite adequately describes the wave characteristics in Takizawa's experiment.
Journal Article•
TL;DR: In this article, the AASHTO Guide for the Design of Pavement Structures, subgrades and granular base layers are evaluated by the resilient modulus test, which is a measure of a material's deflection behavior.
Abstract: In the 1986 AASHTO Guide for the Design of Pavement Structures, subgrades and granular base layers are evaluated by the resilient modulus test. Inclusion of the resilient modulus test was prompted by the need for a rational evaluation method. Resilient modulus is a measure of a material's deflection behavior. Since pavement life and surface deflection are strongly related, resilient modulus is a fundamental and rational material property that needs to be included in pavement design. The effects of variations in subgrade resilient modulus on various design parameters and on the AASHTO design thickness are examined. The seasonal variations of subgrade resilient modulus with moisture fluctuation and freezing and thawing are discussed; and methods for selecting a single design resilient modulus are examined. However, resilient modulus does not measure all of the material properties that can influence pavement behavior. Consequently, resilient modulus should not be the only property used in selecting a pavement material or in judging the material's structural contribution to the pavement.
TL;DR: The ultimate lateral resistance and the groundline lateral deflection under working loads of freestanding single model piles and small pile groups, of various materials and different embedded leng... as mentioned in this paper.
Abstract: The ultimate lateral resistance and the groundline lateral deflections under working loads of freestanding single model piles and small pile groups, of various materials and different embedded leng...
24 Apr 1988
TL;DR: A method of deflection analysis for a general serial manipulator which considers end- effector, gravity, and inertial loads is described, and a description of the generalized end-effector spring is presented.
Abstract: A method of deflection analysis for a general serial manipulator which considers end-effector, gravity, and inertial loads is described. The conceptualized manipulator can have many degrees of freedom and be of the most general geometry. The analysis returns end-effector error based on a quasistatic approach. Thus, small oscillations (due to vibrations) are ignored and the inertial loads are considered applied loads. A kinematic analysis based on geometric influence coefficients is used to obtaining resultant joint loads. A flexibility analysis sufficient to describe general link deformation is performed to yield the local link deformations. These local values are transformed to end-effector deflections through the use of the kinematic influence coefficients as a first order approximation. End-effector deflection due to flexibilities in the joint actuators is addressed. A description of the generalized end-effector spring is presented. >
TL;DR: In this article, the authors introduced the mechanical deflection of cantilever microbeams as an experimental technique for measuring the strength and stiffness of thin films, which utilizes conventional integrated circuit (IC) fabrication to process the samples, a Nanoindenter to deflect the cantilevers mechanically, and simple elastic beam theory to analyze the data.
Abstract: The present authors recently introduced the mechanical deflection of cantilever microbeams as an experimental technique for measuring the strength and stiffness of thin films.[1] The technique utilizes conventional integrated circuit (IC) fabrication to process the samples, a Nanoindenter to deflect the cantilever beams mechanically, and simple elastic beam theory to analyze the data. This paper will review the technique and describe some of its current applications.
TL;DR: In this paper, the stability of heavy columns which are subjected to an axial load and may be restrained by several elastic braces or internal supports is investigated by minimizing the generalized Rayleigh quotient subject to some equality constraints on the deflection curve, imposed by the presence of lateral restraints.
Patent•
28 Apr 1988
TL;DR: In this paper, an apparatus and method for measuring the gap, tram, deflection, and wear of rotating grinding plates is presented. Butler et al. used inductive sensors mounted in a recessed manner inset from the surface of a first grinding plate and located opposite recessed nonwear surfaces of a second grinding plate, thereby providing data by which plate gap and plate wear may be derived.
Abstract: An apparatus and method for measuring the gap, tram, deflection, and wear of rotating grinding plates (4) wherein inductive sensors (24) are mounted in a recessed manner inset from the surface (12) of a first grinding plate (2) and located opposite recessed nonwear surfaces (30) of a second grinding plate (4), thereby providing data by which plate gap and plate wear may be derived. A plurality of such sensors (24) provide data by which plate tram and/or deflection may be deduced.
TL;DR: In this article, the exact dynamic stiffness coefficients for an axially loaded Timoshenko member embedded in an elastic medium are given and used for finding the natural frequencies of plane or space frames.
Patent•
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TL;DR: In this paper, a cable tree in a motor vehicle door can be easily removed by pressing a water deflection film onto the cable tree, which is already present in the door.
Abstract: In a motor vehicle door (1) having a plurality of electrical consumers (2, 3, 5), the said consumers are connected by means of conducting films (6-11) which are pressed onto a water deflection film (12) which is already present This means that the awkward process of laying a cable tree in the motor vehicle door (1) can be dispensed with
TL;DR: In this article, a stiffness matrix and nodal load vector of a beam element on a two-parameter elastic foundation is developed for concentrated loads, concentrated moments, and linearly distributed forces.
Abstract: A stiffness matrix and nodal load vector of a beam element on a two‐parameter elastic foundation is developed for concentrated loads, concentrated moments, and linearly distributed forces. The formulation is based on the exact solution of the differential equation governing displacements. Numerical analysis shows that the accuracy of the results using this beam element is independent of element refinement. The beam‐element also can be easily coupled with two‐dimensional frame analysis to investigate superstructure‐foundation‐soil interaction. The numerical results for a two‐dimensional frame supported on a beam on elastic foundation indicate that the second parameter not only introduces continuity to the deflection pattern of the foundation, but also affects the distribution of stresses in the elements at the column‐foundation junctions.
06 Jun 1988
TL;DR: In this article, a comparison of polysilicon microstructure deflection behavior for doping and annealing conditions is presented and discussed using a Linnik interferometer.
Abstract: Polysilicon micro-cantilever beams and doubly-supported beams are fabricated and conditioned with phosphorus doping and high-temperature anneal cycles to assess the effects of process history and geometry on polysilicon microstructure rigidity. Using a Linnik interferometer, deflection trends for series of beams are measured and compared for several process conditions. Two bending moments can induce beam deflection: the first due to the beam boundary support, and the second due to stress nonuniformity through the beam thickness. A comparison of polysilicon microstructure deflection behavior for doping and annealing conditions is presented and discussed. >
Patent•
02 Sep 1988
TL;DR: In this paper, a parallelogram-like load cell structure that deflects in response to application of the force to be measured, and a pair of force-sensitive crystal resonators, attached to cantilever sensor beams forming part of the structure for sensing the deflection of the load cell, are used to measure the force applied to the structure.
Abstract: Apparatus for measuring force, useful in a weighing scale for example, includes a parallelogram-like load cell structure that deflects in response to application of the force to be measured, and a pair of force-sensitive crystal resonators, attached to cantilever sensor beams forming part of the structure for sensing the deflection of the load cell structure. The two resonators are attached to the sensor beams such as to be placed in tension and compression, respectively, upon deflection of the structure and thereby cause their vibration frequency to increase and decrease, respectively, with increases in applied force. The difference between the two frequencies, which varies substantially linearly with changes in applied force and is inherently digital in nature, is used as a measure of the force applied to the load cell structure.
TL;DR: In this paper, a fast-beam deflection technique is used to investigate the transient behavior of a laser-induced surface plasma generated by CO2laser pulses of 2kW average power near an aluminum surface in various protective gas atmospheres, with a typical pulse energy of 3.3×10−2 J, a pulse repetition rate of 60 kHz, and an average peak power per pulse of 30 kW.
Abstract: A fast‐beam deflection technique is used to investigate the transient behavior of a laser‐induced surface plasma generated by CO2‐laser pulses of 2‐kW average power near an aluminum surface in various protective gas atmospheres, with a typical pulse energy of 3.3×10−2 J, a pulse repetition rate of 60 kHz, and an average peak power per pulse of 30 kW, corresponding to an intensiy of 6×1012 W/m2. As a laterally probing beam, a cw 10‐W CO2 laser is used, whose beam is focused into a small volume in front of the surface. The electrons of the laser‐induced plasma passing this volume diffract the cw CO2 laser beam, and the resulting beam deflection is determined by means of a partially absorbing CaF2 wedge in connection with a fast infrared detector. The evaluation of beam deflection 0.15 cm above the surface renders a maximum electro density of 2×1023 m−3 for a surrounding argon atmosphere and 0.7×1023 m−3 for pure helium. Additives of O2 reduce the attainable electron density even more. No plasma can be detec...