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Showing papers on "Deflection (engineering) published in 2002"


Journal ArticleDOI
TL;DR: The classical problem of the deflection of a cantilever beam of linear elastic material, under the action of an external vertical concentrated load at the free end, is analyzed in this paper.
Abstract: The classical problem of the deflection of a cantilever beam of linear elastic material, under the action of an external vertical concentrated load at the free end, is analysed We present the differential equation governing the behaviour of this physical system and show that this equation, although straightforward in appearance, is in fact rather difficult to solve due to the presence of a non-linear term In this sense, this system is similar to another well known physical system: the simple pendulum An approximation of the behaviour of a cantilever beam for small deflections was obtained from the equation for large deflections, and we present various numerical results for both cases Finally, we compare the theoretical results with the experimental results obtained in the laboratory

241 citations


Journal ArticleDOI
TL;DR: In this paper, the superprism effect allows wide-angle deflection of the light beam in a photonic crystal (PC) by a slight change of the wavelength or the incident angle.
Abstract: The superprism effect allows wide-angle deflection of the light beam in a photonic crystal (PC) by a slight change of the wavelength or the incident angle. In this paper, we discuss such light deflection outside the PC, which is expected when the output end of the PC is tilted against the input end. The analysis of the dispersion surfaces indicates a deflection angle of /spl plusmn/50/spl deg/ in a two-dimensional PC composed of triangular lattice airholes by changing the incident angle by /spl plusmn/2/spl deg/ or the wavelength by /spl plusmn/2%. Light deflections inside and outside the PC are numerically demonstrated by the finite difference time-domain method. It displays not only the main output beam but also many diffracted waves, which satisfy the wavevector conservation condition. These waves are sufficiently suppressed and an almost collimated output beam is realized by a flat interface.

159 citations


Journal ArticleDOI
TL;DR: In this article, an experimental study and theoretical analyses on the monotonic and fatigue performance in bending of a polyvinyl alcohol (PVA) fiber-reinforced engineered cementitious composite (ECC) overlay system is investigated.

154 citations


Journal ArticleDOI
TL;DR: In this paper, a model for a cantilever beam with end moment acting in the opposite direction as the end force was presented, which may or may not cause an inflection point.
Abstract: The analysis of compliant mechanisms is often complicated due to the geometric nonlinearities which become significant with large elastic deflections. Pseudo rigid body models (PRBM) may be used to accurately and efficiently model such large elastic deflections. Previously published models have only considered end forces with no end moment or end moment acting only in the same direction as the force. In this paper we present a model for a cantilever beam with end moment acting in the opposite direction as the end force, which may or may not cause an inflection point. Two pivot points are used, thereby increasing the model's accuracy when an inflection point exists. The Bernoulli-Euler beam equation is solved for large deflections with elliptic integrals, and the elliptic integral solutions are used to determine when an inflection point will exist. The beam tip deflections are then parameterized using a different parameterization from previous models, which renders the deflection paths easier to model with a single degree of freedom system. Optimization is used to find the pseudo rigid body model which best approximates the beam deflection and stiffness. This model, combined with those models developed for other loading conditions, may be used to efficiently analyze compliant mechansims subjected to any loading condition.

136 citations


Journal ArticleDOI
TL;DR: In this article, the structural behavior of hybrid reinforced-concrete beams with hybrid fiber-reinforced polymer (FRP)-steel reinforcements is analyzed, and the results of an experimental and theoretical investigation are presented and discussed.
Abstract: The paper analyzes the structural behavior of concrete beams reinforced with hybrid fiber-reinforced polymer (FRP)-steel reinforcements. The analysis refers to concrete beams reinforced with FRP rebars placed near the outer surface of the tensile zone, with low cover thickness values, and steel rebars placed at the inner level of the tensile zone, with high cover thickness values, able to protect the steel from the corrosion. Such reinforcement allows one to optimize the structural behavior of beams and guarantees a good level of ductility and rigidity. Results of an experimental and theoretical investigation are presented and discussed. Significant features of the structural behavior regarding deflection, curvature, ductility, crack width, and spacing are pointed out. Ultimate and serviceability conditions are examined, highlighting the influence of mechanical and geometrical parameters affecting the behavior of hybrid reinforced-concrete beams.

134 citations


Journal ArticleDOI
TL;DR: In this paper, the authors investigated rectangular two-beam microelectromechanical thermal actuators and provided a method for their optimization, which consisted of two asymmetric parallel arms, one thin and one wide.
Abstract: This article investigates rectangular two-beam microelectromechanical thermal actuators and provides a method for their optimization. The thermal actuators investigated consisted of two asymmetric parallel arms,one thin and one wide. Under an electric current load, the thin arm heats and expands more than the wide arm, thereby bending the entire structure. Simplified models of the heat transfer mechanisms are used to determine the temperature profile. From the thermal expressions for expansion of the arms, equations are derived to predict the deflection as well as the buckling loads. Measurements of the actuator deflection as a function of voltage are presented. Design guidelines are introduced for optimization of a thermal actuator.

128 citations


Patent
18 Jan 2002
TL;DR: In this paper, a deflection element span is provided, as-fabricated, curved in one of the two stable positions and in a mechanically unstressed condition along the length of the span.
Abstract: A bistable structure provided by the invention is characterized as including a deflection element that has mechanically constrained end points and a compliant span between the end points that is substantially free to deflect between two stable positions when a force is applied at a point along the span. The deflection element span is provided, as-fabricated, curved in one of the two stable positions and in a mechanically unstressed condition along the length of the span. The as-fabricated curve of the deflection element span includes a curve maxima at a point along the span length that is at least about 1/4 of the span length from the end points of the span. The deflection element span is constrained to substantially prohibit development of a second bending mode that is characteristic for the span as the element deflects between the stable positions.

118 citations


Journal ArticleDOI
TL;DR: In this article, an exact solution for multi-layered filament-wound composite pipes under pure bending was presented, and detailed stress-strain responses and deflection was investigated using the present analytical method.

109 citations


Patent
23 Jul 2002
TL;DR: In this article, a flexible surface on which formed deflection sensors detect the deflection of the surface is used to yield information regarding the locations and magnitudes of forces deflecting the surface.
Abstract: An input device has a flexible surface on which are formed deflection sensors. The flexible surface can be deformed against an adjacent resilient layer. The deflection sensors detect the deflection of the surface. Electronic circuits for processing signals from the deflection sensors to yield information regarding the locations and magnitudes of forces deflecting the surface may be deposited all, or in part on the flexible surface. The input device may be combined with a display to yield a touch-sensitive display suitable for use in a wide range of applications.

107 citations


Journal ArticleDOI
TL;DR: In this paper, an efficient mesh-free formulation based on the first-order shear deformation theory (FSDT) is presented for the static analysis of laminated composite beams and plates with integrated piezoelectric layers.
Abstract: An efficient meshfree formulation based on the first-order shear deformation theory (FSDT) is presented for the static analysis of laminated composite beams and plates with integrated piezoelectric layers. This meshfree model is constructed based on the element-free Galerkin (EFG) method. The formulation is derived from the variational principle and the piezoelectric stiffness is taken into account in the model. In numerical test problems, bending control of piezoelectric bimorph beams was shown to have the efficiency and accuracy of the present EFG formulation for this class of problems. It is demonstrated that the different boundary conditions and applied actuate voltages affects the shape control of piezolaminated composite beams. The meshfree model is further extended to study the shape control of piezo-laminated composite plates. From the investigation, it is found that actuator patches bonded on high strain regions are significant in deflection control of laminated composite plates.

104 citations


Journal ArticleDOI
TL;DR: In this paper, an experimental study of reinforced concrete beams strengthened in flexure and shear using externally epoxy-bonded bidirectional carbon fiber fabric is presented. But the difference between the two series related to the amount of internal stirrups and concrete strength.
Abstract: This paper presents results obtained from an experimental study of reinforced concrete beams strengthened in flexure and shear using externally epoxy-bonded bidirectional carbon fiber fabric. Two series of 3 large-scale concrete beam models were built and tested under 4-point bending. The beams of the 2 series were internally reinforced with high-tensile steel for both shear and flexure. One beam for each series was used as a control beam without external reinforcement. The difference between the 2 series related to the amount of internal stirrups and concrete strength. To study effects of external composite reinforcement, variations in the number of layers applied and in the external end arrangements were made. One type of external reinforcement consisted of 2 layers of fabric bonded to the tension face of the beam and partly extended up to the vertical sides. The second arrangement consisted of 4 layers of fabric and supplementary end anchorages. The composite reinforcement led to an increase both in the load-carrying capacity at ultimate and flexural stiffness as compared with control beams. Significant reductions in deflection, curvature, and structural ductility were observed.

Journal ArticleDOI
TL;DR: In this article, the authors deal with the plane problem of the hydroelastic behavior of floating plates under the influence of periodic surface water waves, in which the coupled hydrodynamics and structural dynamics problems are solved simultaneously.
Abstract: The paper deals with the plane problem of the hydroelastic behaviour of floating plates under the influence of periodic surface water waves. Analysis of this problem is based on hydroelasticity, in which the coupled hydrodynamics and structural dynamics problems are solved simultaneously. The plate is modeled by an Euler beam. The method of numerical solution of the floating-beam problem is based on expansions of the hydrodynamic pressure and the beam deflection with respect to different basic functions. This makes it possible to simplify the treatment of the hydrodynamic part of the problem and at the same time to satisfy accurately the beam boundary conditions. Two approaches aimed to reduce the beam vibrations are described. In the first approach, an auxiliary floating plate is added to the main structure. The size of the auxiliary plate and its elastic characteristics can be chosen in such a way that deflections of the main structure for a given frequency of incident wave are reduced. Within the second approach the floating beam is connected to the sea bottom with a spring, the rigidity of which can be selected in such a way that deflections in the main part of the floating beam are very small. The effect of the vibration reduction is quite pronounced and can be utilized at the design stage.

Patent
Masatsugu Kametani1, Kenjiro Yamamoto1, Taku Ninomiya1, Osamu Yamada1, Katsuhisa Ike1 
23 Sep 2002
TL;DR: In this article, a digital deflection control scheme is employed in which the deflection scanning signal and correction are all calculated digitally in a deflection controller for deflecting and controlling a charged particle beam irradiated onto a subject to be inspected.
Abstract: In order that the deflection scanning position can be corrected at a time point within a period for fetching information from a subject to be inspected and improvements in accuracy of chip comparison inspection and an inspection near the wafer outer periphery where distortion is large can be assured by correcting the inspection position and biased distortion at a high speed with high accuracy, a digital deflection control scheme is employed in which the deflection scanning signal and correction are all calculated digitally in a deflection controller for deflecting and controlling a charged particle beam irradiated onto a subject to be inspected and the digital value is sequentially converted into an analog value by a time-series train of digital control signal to form a deflection scanning waveform.

Journal ArticleDOI
TL;DR: In this article, full-scale measurement data observed on the Akashi-Kaikyo Bridge during strong typhoons were analyzed, and power spectral density and spatial correlation of longitudinal velocity fluctuations were analyzed.

Journal ArticleDOI
TL;DR: In this article, an actuator that uses the volume expansion related to the solid-to-liquid phase transition of paraffin wax has been fabricated and evaluated, which can be used as a thermal switch.
Abstract: An actuator that uses the volume expansion related to the solid-to-liquid phase transition of paraffin wax has been fabricated and evaluated. The actuator consists of a ring-shaped paraffin cavity confined by two joint silicon diaphragms with rigid centers. When the paraffin is melted, the resulting hydrostatic pressure deflects the joined rigid centers in one direction only. The magnitude of the deflection is primarily a function of the geometrical relation between the two diaphragms, giving the opportunity to tailor the behavior of the actuator in a large range. Conventional IC-processing techniques have been used to fabricate a prototype with a width of 68 mm and a thickness of 825 μm. The prototype attained a maximum deflection of ca. 90 μm. Loaded with 3 N it still exhibits a deflection of ca. 75 μm. The device can be used as a thermal switch.

Journal ArticleDOI
Jinling Yang1, Oliver Paul1
TL;DR: In this article, the bulge test is successfully extended to the determination of the fracture strength of thin films by accurately describing the deflection profile of the loaded long membranes, including the prestress and bending stiffness of the membrane material into the load-deflection response.
Abstract: The bulge test is successfully extended to the determination of the fracture strength of thin films by accurately describing the deflection profile of the loaded long membranes. The model includes the prestress and bending stiffness of the membrane material into the load-deflection response. The feasibility of this method is demonstrated with LPCVD silicon nitride films with maximum strengths between 10.8 GPa and 11.7 GPa.

Patent
06 Dec 2002
TL;DR: In this paper, a modular, integrated stop assemblies magnify sensor substrate deflection by use of opposed concave (Belleville) springs are used in direct contact with the substrate to accommodate ±Z axis deflection and Mx/My moment angular rotation.
Abstract: Automotive load cells having centralized, multi-axis, loose tolerance overload/limit stops provide improved strain gauge response. The modular, integrated stop assemblies magnify sensor substrate deflection by use of opposed concave (Belleville) springs are used in direct contact with the substrate to accommodate ±Z axis deflection and Mx/My moment angular rotation. A flanged guide member on the load stud permits a wide range of geometries. The substrate is thickened around the load stud hole and the outboard support bolt holes. Hollow rivets assist in design modularity. Strain gauges are placed at the yield zones symmetrically with respect to the X axis. The substrate hole Mx/My gap is larger than the stop bracket hole to insure a positive stop for Mx/My moments prior to yield. The inventive multi-axis stop assembly is used in any type load cell, including rectangular, thinned, notched, necked/dogbone, or cantilever substrates with any strain gauge layout configuration.

Journal ArticleDOI
TL;DR: In this article, an attempt was made to determine the strain and the stresses generated by the growth of an oxide film using several approaches: an experimental one by means of deflection tests and modeling using either a recently developed creep analysis or a finite element simulation.
Abstract: An attempt was made to determine the strain and the stresses generated by the growth of an oxide film using several approaches: an experimental one by means of deflection tests and modeling using either a recently developed creep analysis or a finite-element simulation A new deflection apparatus was developed and NiO growth studied during the early stages of oxidation of a Ni80Cr20 alloy at 900°C, since many microstructural, kinetics and mechanical data are available for this system The comparison of experiments and modeling indicate that the oxide layers are mostly subjected to compressive stresses when NiO is growing and the stress level and evolution clearly show that viscoplastic strain occurs in both the substrate and the oxide during oxidation The comparison between the two modeling approaches with experiment leads to good agreement and suggests that the compressive-growth stresses derive from the lateral expansion of the fraction of new oxide that is formed within the oxide layer

Journal ArticleDOI
TL;DR: In this article, the authors used model simulations of plumes beneath Africa to predict the magnitude and direction of seismic anisotropy caused by lateral flow of hot plume material beneath and around a cratonic keel.
Abstract: Abstract Lithosphere that formed in Archaean and possibly early Proterozoic time is thicker, more buoyant, and geochemically distinct from lithosphere that formed after about 2.3 Ga. Mantle xenolith and seismic data indicate that some cratonic roots, or ‘keels’, extend to depths of c. 250 km, compared with normal continental lithosphere of thickness 150 km or less; yet many cratons have experienced uplift, dyking and kimberlite emplacement, suggesting interactions with hot, rising asthenosphere referred to as mantle plumes. Plumes supply additional heat to the base of the lithospheric plates, whose base can be heated and entrained in the flow (thermal erosion). How have these cratonic keels persisted despite their interactions with mantle plumes? The geometry of cratonic keels during their interactions with mantle plumes is a critical factor controlling keel preservation. To a laterally spreading plume head, cratonic keels appear as major obstacles, and the hot, buoyant plume material ponds beneath thinner lithosphere. Our model simulations show that deep keels deflect mantle plume material and that steep gradients at the lithosphere-asthenosphere boundary between Archaean keels and ‘normal’ lithosphere will focus flow, leading to localized adiabatic decompression melting. Plume processes can lead to a reduction in the breadth of a cratonic root where the plume rises beneath the craton, regardless of the initial breadth of the craton. Where the plume rises beneath a craton the hot plume material will spread laterally beneath the keel and attain thicknesses of tens of kilometres. This transfers heat to the base of the lithosphere and could generate small volumes of melt at considerable depth, depending on the composition of the lower lithosphere. We have used model simulations of plumes beneath Africa to predict the magnitude and direction of seismic anisotropy caused by lateral flow of hot plume material beneath and around a cratonic keel. The shear-wave splitting in our models is greatest at the edge of the cratonic keel, and its azimuth is parallel to the plume flow direction.

Journal ArticleDOI
TL;DR: In this paper, the authors proposed the use of operational deflection shapes (ODS) for structural damage detection, which are the actual vibration displacement or velocity patterns of a structure that is vibrating in the steady state condition due to a specific structural loading.

Patent
24 May 2002
TL;DR: In this article, the authors describe a spatial light modulator with a micromirror and one or more deflection limiting mechanisms, and a process for fabrication therefor, where the mirror support structure has a deflection stopping mechanism that limits the tilt angle of the reflective plate.
Abstract: A spatial light modulator having a micromirror and one or more deflection limiting mechanisms, and a process for fabrication therefor. In one embodiment, the mirror support structure has a deflection stopping mechanism that limits the tilt angle of the reflective plate. Alternatively, a deflection stopping mechanism can be provided separate from the mirror support structure. The deflection stopping mechanism can be used in conjunction with one or more additional stopping mechanisms such as the abutment of a portion of the reflective plate against the substrate upon which it was constructed and/or abutment of the micromirror on a surface or structure of the circuit substrate.

Journal ArticleDOI
TL;DR: In this article, an element free Galerkin (EFG) method is presented for buckling analyses of isotropic and symmetrically laminated composite plates using the classical plate theory.
Abstract: An element free Galerkin (EFG) method is presented for buckling analyses of isotropic and symmetrically laminated composite plates using the classical plate theory. The shape functions are constructed using the moving least squares (MLS) approximation, and no element connectivity among nodes is required. The deflection can be easily approximated with higher-order polynomials as desired. The discrete eigenvalue problem is derived using the principle of minimum total potential energy of the system. The essential boundary conditions are introduced into the formulation through the use of the Lagrange multiplier method and the orthogonal transformation techniques. Since the dimension of the eigenvalue problem obtained by the present method is only one third of that in the conventional finite element method (FEM), solving the eigenvalue problem in the EFG is computationally more efficient compared to the FEM. Buckling load param-eters of isotropic and symmetrically laminated composite plates for different boundary conditions are calculated to demonstrate the efficiency of the present method.

Journal ArticleDOI
TL;DR: In this article, a closed-form solution of beam on viscoelastic subgrade subjected to moving loads is proposed by using the theory of linear partial differential equation to express the deflection of the beam in terms of the Green's function.

Journal ArticleDOI
TL;DR: In this article, a laminated piezoelectric bimorph actuator with a graded compositional distribution of PZT and Pt was fabricated, and its deflection characteristics were evaluated.

Journal ArticleDOI
TL;DR: In this paper, the eigenfunctions of Green's function for the transient temperature distribution of a plate made of functionally graded materials (FGMs) were derived from the continuity conditions of the temperature and the heat flux at interfaces.
Abstract: Green's function approach is adopted for analyzing the deflection and the transient temperature distribution of a plate made of functionally graded materials (FGMs). The governing equations for the deflection and the transient temperature are formulated into eigenvalue problems by using the eigenfunction expansion theory. Green's functions for solving the deflection and the transient temperature are obtained by using the Galerkin method and the laminate theory, respectively. The eigenfunctions of Green's function for the deflection are approximated in terms of a series of admissible functions that satisfy the homogeneous boundary conditions of the plate. The eigenfunctions of Green's function for the temperature are determined from the continuity conditions of the temperature and the heat flux at interfaces.

Patent
27 Jun 2002
TL;DR: In this article, a rotatable drilling shaft deflection assembly for a drilling direction control device of the type consisting of a rotating drilling shaft and a housing for supporting a length of the drilling shaft for rotation therein is presented.
Abstract: A drilling shaft deflection assembly for a drilling direction control device of the type comprising a rotatable drilling shaft and a housing for supporting a length of the drilling shaft for rotation therein The deflection assembly is contained within the housing and is axially located between a first support location and a second support location for bending the drilling shaft between the first support location and the second support location The deflection assembly includes a deflection mechanism for imparting lateral movement to the drilling shaft to bend the drilling shaft, a deflection actuator for actuating the deflection mechanism in response to longitudinal movement of the deflection actuator, and a deflection linkage mechanism between the deflection mechanism and the deflection actuator for converting longitudinal movement of the deflection actuator to lateral movement of the drilling shaft

Journal ArticleDOI
TL;DR: In this paper, the plane strain theory of transversely isotropic bodies was used to study a piezoelectric cantilever actuator and to determine the density distribution profile.
Abstract: We have used the plane strain theory of transversely isotropic bodies to study a piezoelectric cantilever. In order to find the general solution of a density functionally gradient piezoelectric cantilever, we have used the inverse method (i.e. the Airy stress function method). We have obtained the stress and induction functions in the form of polynomials as well as the general solution of the beam. Based on this general solution, we have deduced the solutions of the cantilever under different loading conditions. Furthermore, as applications of this general solution in engineering, we have studied the tip deflection and blocking force of a piezoelectric cantilever actuator. Finally, we have addressed a method to determine the density distribution profile for a given piezoelectric material.

Journal ArticleDOI
TL;DR: In this article, the free vibration of a flexible thin plate placed into a circular hole and elastically connected to the rigid bottom slab of a circular cylindrical container filled with fluid having a free surface is studied.

Patent
20 Sep 2002
TL;DR: In this paper, a mask is detected and corrected to ensure a good projection of a mask pattern by using an arithmetic operation unit, which uses the detection result supplied from the mask-deflection detection system so to calculate the magnitude of the deflection.
Abstract: Any deflection of a mask is detected and corrected to ensure a good projection of a mask pattern. When a mask suffers a deflection due to some reasons such as the gravity and/or thermal expansion, the deflection is detected by a mask-deflection detection system and the detection result is supplied to an arithmetic operation unit. The arithmetic operation unit uses the detection result supplied from the mask-deflection detection system so to calculate the magnitude of the deflection, and then calculate a pneumatic-pressure control value for controlling the pneumatic-pressure within a mask-deflection correction unit. The pneumatic-pressure control value is supplied to a pneumatic-pressure control unit, which controls the pneumatic pressure within the air chamber of the mask-deflection correction unit such that the deflection of the mask may be corrected.

Journal ArticleDOI
TL;DR: In this paper, the authors developed advanced, yet design-oriented ultimate strength expressions for stiffened panels subject to combined axial load, in-plane bending and lateral pressure, and classified the collapse patterns of a stiffened panel into six groups.
Abstract: This paper develops advanced, yet design-oriented ultimate strength expressions for stiffened panels subject to combined axial load, in-plane bending and lateral pressure. The collapse patterns of a stiffened panel are classified into six groups. It is considered that the collapse of the stiffened panel occurs at the lowest value among the various ultimate loads calculated for each of the collapse patterns. The panel ultimate strengths for all potential collapse modes are calculated separately, and are then compared to find the minimum value which is then taken to correspond to the real panel ultimate strength. The post-weld initial imperfections (initial deflection and residual stress) are included in the developed panel ultimate strength formulations as parameters of influence. The validity of the developed formula is confirmed by comparing with the mechanical collapse tests and nonlinear FEA. A comparison of the present method is also made with theoretical solutions from the Det Norske Veritas classification society design guideline. Important insights developed are summarized.