Pin Support Research Articles

等分布荷重を受ける屋根型単層円筒ラチスシェルの耐力評価法に関する研究

The present paper discusses on elastic buckling load and ultimate strength of reticulated cylindrical roofs under uniform lateral loads in the case of two boundary conditions of simple support and pin support. First, classical buckling load under a uniform lateral load is newly derived mathematically based on a simple approximation, followed by comparison with the linear elastic buckling loads calculated using FEM analysis. The comparison is performed to find approximate relations between the classical buckling loads and the FEM linear buckling loads for simple support and pin support. Second, elastic buckling loads are investigated based on FEM analysis considering geometrical imperfections, followed by derivation of formula for imperfection sensitivity which enables engineers to evaluate elastic buckling loads with hand calculation. Third, elastic plastic buckling loads are investigated based on FEM analysis also considering geometric imperfection, and the imperfection sensitivity of elastic plastic buckling loads is formulated mathematically. Finally, an estimation procedure for elastic plastic buckling loads is proposed based on the elastic buckling loads and the imperfection sensitivity for elastic plastic buckling loads in the two cases of boundary conditions.

Determination of load transfer in reinforced concrete solid slabs by finite element computer analysis

According to the ACI building code, the concrete slab can be divided into two types depending on the ratio of the long side to the short side. Regarding the results of the ratio, the concrete slab can be divided as one-way and two-way slabs. The main objective of this paper is to study the stress or moments distribution in solid slab panel in its two directions and compare with ACI code assumption that the load is transferred mainly in short direction and most of the load is transferred in one direction only if the ratio of the longer span to the shorter span is greater than one. This will be discussed by analyzing one panel of solid slab using the computer software SAP2000. Two types of panels will be used; the first one a panel that is supported simply on its four sides and the second panel is supported only by four pin supports and beams. This paper shows that the gravity load on the slab is transferred to long and short direction. This means that one-way concrete solid slab doesn't exist and all concrete solid slabs work as a two-way concrete slab.

Modeling and Analysis of Support Pin for Brake Spider Fixture by Fem Using Ansys Software

A fixture is designed and built to hold, support and locate every component to ensure that each is drilled or machined with accuracy and manufactured individually. A fixture can be designed for a particular job. A brake spider includes a spider body with a central opening and a slot for receiving a camshaft and bracket assembly. The brake spider is attached to axle housing via the central opening. The form to be used depends on the shape and requirement of the work piece to be machined. In the existing fixture, used for modeling brake spider component, only five components were machined per hour. In the present work, detailed study of brake spider component is carried out and design is modified to increase the productivity. The new fixture design is carried out by using CATIA V5 modeling software and it is critically evaluated for the failure of support pin component, by finite element method (FEM) using ANSYS software. This modified design is adapted in the fabrication of fixture and is tested for its productivity. It is found that there is a considerable enhancement in the productivity to seven components per hour with required accuracy.

Design for Pin Steel Bearings with Huge Horizontal Carrying Capability

The bearing in the roof of railway station is usually assumed three-dimensional fixed pin support. Good load-supporting, rotate and back-moving capacities are needed in the bearing design as well as durability. And the most prominent problem is how to bear so huge horizontal load in limited architecture space. Traditional spherical bearing couldn’t sustain huge horizontal loading because of excessive stress concentration induced by point-to-surface contact between upper and base plates. In this paper, a new economical steel hinged bearing form is developed to use surface contact to improve horizontal force carrying capacity. By FEM software ANSYS, nonlinear analyses are performed on bearing models to obtain necessary design results. Comparison between new and traditional bearings shows that new steel bearing is much more reasonable and economic.

Dynamics of a clapper-to-bell impact

Church bells are exposed to severe loading conditions during ringing, which results in different damage modes due to material wear, fatigue loading, material deficiencies, different clapper-to-bell layouts, etc. As part of the activities of an EU-funded project called Maintenance and Protection of Bells (PROBELL), experimental investigations and finite-element simulations of the local contact between the clapper and the bell were carried out to study the wear-related damage to bells. First a simplified model was built to assess under the laboratory-controlled conditions the consequences of the repetitive impacts between a spherical body made from steel and a flat block made from bronze. After the results of the finite-element simulations for a simplified model were in reasonable agreement with the measured data a full-scale finite-element model for simulating the repetitive clapper-to-bell strokes was built. The simulations with the full-scale model were performed for variations of the parameters that influence the structural behaviour of the bell and the clapper: the clapper material, the clapper mass, the relative impact velocity of the clapper, the shape of the clapper, the clapper's pin support, the clapper's impact angle, the clapper's guide accuracy, the bell's sound-burp thickness and the coefficient of friction between the clapper and the bell. The agreement between the simulated and the measured results and the relation between the local stress–strain state and the damage to the bell in the contact area are discussed.

On the effect of local boundary condition details on the natural frequencies of simply-supported beams: Eccentric pin supports

Pinned supports, or simple supports, are boundary conditions frequently encountered in the analysis of beams, plates, and shells. Simply supported boundary conditions can be modeled as restricting the lateral motion of the structure but freely allowing rotation at the boundaries. The literature to date has treated simple supports as though they are solely pinned at the mid-plane of the structure; however, the present study investigates the effects of eccentric pinned supports on the natural frequencies of beam structures. A COMSOL finite element model is created to investigate the changes in the natural frequencies of a beam structure with respect to the through-thickness location of the pin supports. Through this study it is found that the natural frequencies are significantly influenced by pin support eccentricity. For the beams considered in this article, it is seen that moving the pin supports from the mid-plane to the bottom edge raises the first natural frequencies by over 55%, regardless of beam length. To verify the COMSOL finite element model results, a Rayleigh–Ritz approximate solution for the natural frequencies is also obtained. To capture pin eccentricity, a novel cross-sectional geometry is proposed that incorporates fictitious material through the beam thickness. This fictitious material approach is completely compatible with the existing literature pertaining to the analysis of thin beams. The natural frequencies are confirmed to be strong functions of pin eccentricity, with the Rayleigh–Ritz results matching the COMSOL results to well within 4%. From this study it can be concluded that the through-thickness location of pin supports are significant and must be specified.

Extraction of artificial boundary frequencies for damage identification

This paper introduces some recent progress in a study which is aimed at incorporating the so-called artificial boundary condition (ABC) frequencies for damage identification. The ABC frequencies are those corresponding to the natural frequencies of the system with additional pin supports, but may be extracted from specially configured incomplete frequency response function matrix of the original structure without the need of physically imposing the additional supports. A particular focus of this paper is placed on the actual extraction of such frequencies from physical experiments and the associated data processing and analysis. Results will demonstrate that it is possible to extract the first few ABC frequencies for a variety of boundary conditions with 1-2 artificial pin supports in a beam or a slab structure.

Modification of the edge crack torsion specimen for mode III delamination testing. Part II – experimental study

Experimental studies of carbon/epoxy edge crack torsion specimen have been conducted using a specially designed twist test fixture. Of particular concern was verification of the recommendations expressed in the analytical part of this study (Part 1), where it was suggested that overhang (sections of specimen laying outside of the loading and support pins) in the x- and y-directions should be minimized, and fracture testing at longer delamination lengths should be avoided. The experimental test results verified that the specimens with the smallest overhang produced the most consistent delamination toughness data, GIIIc. Specimens with large overhangs exhibited high apparent GIIIc values at long delamination lengths. This was most likely due to nonuniform loading and associated nonuniform delamination extension.

Peak Offset Times as an Indication of Stress Relaxation During Tableting on a Rotary Tablet Press

During powder compaction on a Manesty Betapress, peak pressures, Pmax, are reached before the punches are vertically aligned with the centres of the upper and lower compression roll support pins. The interval between the time taken to reach this alignment and the time to reach Pmax is defined as the peak offset time, t(off). The duration of t(off) depends on the ability of the compacted powder to relieve stress and is an indication of the predominant mechanisms of particle deformation during consolidation. Thus, at a given Pmax, short t(off) values are characteristic of materials that consolidate mainly by brittle fracture while longer values indicate an increase in plastic flow. On the Betapress, the decrease in stress during t(off) occurs under conditions approaching constant strain and t(off) therefore, is an indirect measure of stress relaxation. Stress relaxation, and hence t(off), decreases with increase in Pmax due to the reduction in the porosity of the compact and consequent restriction of plastic flow into the void spaces. In addition to Pmax, the effects of variables such as punch head geometry, press speed and formulation on t(off) are reported.

ANALYSIS OF ULTIMATE STRENGTH OF REINFORCED CONCRETE ARCHES

Ultimate strength of wide roof-type shallow arches of reinforced concrete is discussed for pin support at both ends under vertical loads. The method considers the effects of not only initial geometric imperfections but also the tensile strength of concrete. The effect of sectional shape is included; a flat plate section and a curved section like a spherical surface. The results reveal that the ultimate strength of curved section is larger than that of flat section, the ultimate strength under uniform load is not reduced so much only if there are no geometric imperfection, however, the ultimate strength is largely reduced due to geometric imperfections and anti-symmetric vertical loads, and this tendency is much amplified in case of no concrete tensile strength, and followed by a suggestion that strength against earthquake forces should be studied for shallow arches to be built in area with high seismicity.

Entire Contact Design Theory for High Performance Drum Brake

Drum brake is a braking part which is widely used on heavy truck. The distribution and dimension of contacting pressure and contacting area between friction linings and brake drum have important influence on braking performance. Entire contact theory in this article was found based on the conditions that the outside radius of linings was equal to the inside radius of drum. The relation between the corresponding points on contact surface and the angle which lining rotated around support pin axis was calculated based on entire contact theory. The radial deformation, pressure distribution, contact area of linings and the brake performance were analyzed in the condition of entire contact theory.

P‐64: New Drying Process without Pin‐Mura for Ink‐Jet Alignment Layer Printing of Large‐Sized LCDs

AbstractA new drying process has been developed for ink‐jet alignment layer printing technology of large‐Sized LCDs. The system can prevent pin‐mura which was easily appeared in conventional drying process by optimizing independent X‐Z and Y‐Z directionally movable support pins with a single hot‐plate and an exhaust system. This development enabled us to mass‐produce >40″ LCD‐TV panels with high efficiency in our factory.

Application of Experimental and Finite Element Modal Analysis in Development of a Novel Solder Joint Inspection Systems

Inspection of flip chip solder joints has been a crucial process in the electronics manufacturing industry to reduce manufacturing cost, improve yield, and ensure product quality and reliability. New inspection techniques are urgently needed to fill in the gap between available inspection capabilities and industry requirements of low-cost, fast-speed, and highly reliable inspection systems. The laser ultrasound inspection system under development aims to provide a solution that can overcome some of the limitations of current inspection techniques. This research project is based on laser ultrasound and interferometric techniques. A pulsed laser generates ultrasound on the chip's surface, and the entire chip is excited into structural vibration. An interferometer is used to measure the vibration displacement of the chip's surface at several points, and solder joints with different qualities cause different vibration responses. By analyzing the surface vibration responses, defects in solder joints may be detected and/or classified. In this paper, a broadband laser pulse is used for dynamic excitation of the chip before its vibration signature is analyzed. Experimental modal analysis extracts and estimates the modal information (mode frequencies and mode shapes) from raw vibration signals. Multiple-point surface responses are scanned with an interferometer under repeated laser pulse excitation. Spectral estimation on the raw vibration signals gives dominant-mode frequencies. The corresponding vibrational patterns are obtained by reconstructing the scanned grids using the decomposed signals at each mode frequency. Because we are interested only in the transverse vibration on the chip's surface, and because the chip's length and width are much larger than its thickness, it can be modeled as a rectangular plate with pin supports. Modal analysis by finite element modeling is applied to devices with and without defects. The objectives are to identify the differences of mode frequencies and mode shapes between good chips and chips with defects and to identify measurement points that show maximum difference in the presence and absence of defects.

Vibration of Tensioned Beams with Intermediate Damper. I: Formulation, Influence of Damper Location

Exact analytical solutions are formulated for free vibrations of tensioned beams with an intermediate viscous damper. The dynamic stiffness method is used in the problem formulation, and characteristic equations are obtained for both clamped and pinned supports. The complex eigenfrequencies form loci in the complex plane that originate at the undamped eigenfrequencies and terminate at the eigenfrequencies of the fully locked system, in which the damper acts as an intermediate pin support. The fully locked eigenfrequencies exhibit “curve veering,” in which adjacent eigenfrequencies approach and then veer apart as the damper passes a node of an undamped mode shape. Consideration of the evolution of the eigenfrequency loci with varying damper location reveals three distinct regimes of behavior, which prevail from the taut-string limit to the case of a beam without tension. The second regime corresponds to damper locations near the first antinode of a given undamped mode shape; in this regime, the loci bend b...

Computer Modeling of Restrained Reinforced Concrete Slabs in Fire Conditions

This paper describes the computer modeling of axially restrained, one-way reinforced concrete slabs in fire conditions. The study was carried out for slabs with pin supports and slabs with rotationally restrained supports. A single span, 5 m slab, carrying a uniformly distributed load was analyzed using a special purpose, nonlinear finite element program, SAFIR. The study for pin-supported slabs considered the effects of the position of the thrust force at the supports and different axial restraint stiffnesses. The effects of axial restraint on slabs with rotationally restrained supports were also investigated. The analyses found that the behavior of pin-supported slabs is very sensitive to the position of the thrust force at the end supports and the axial restraint stiffnesses. Slabs with rotationally restrained supports are predicted to have much better fire resistance than equivalent pin-supported slabs due to moment redistribution. The behavior of rotationally restrained slabs in fire conditions is less sensitive to the different axial restraint stiffnesses than pin supported slabs.

Influence of wafer chucking on focus margin for resolving fine patterns in optical lithography

The fabrication of ULSI devices requires a wide focus margin. A newly developed vacuum pin chuck has been used to decrease the margin reduction caused by wafer chucking. This paper describes the influences of pin support and back-surface waviness on site flatness during clamping. Pin support reduces the effect of dust, but degrades the site flatness. It is shown that the deformation between pins with a 2-mm pin-pitch chuck for an 8″ standard wafer is negligibly small, but the back-surface waviness of the etched wafer degrades the site flatness by 0.05 μm in a 30-mm-square field. Reducing the vacuum pressure and polishing for a short time only slightly improves the site flatness. Therefore, it is difficult to use the present type of etched wafers and it is necessary to reduce wavinesses onvinesses on both sides of wafers for next-generation lithography of 0.13 μm.

Bending and buckling of superconducting partial toroidal field coils

Based on the theory of curved beams and the Biot–Savart law, a new theoretical model for magnetoelastic bending and buckling of superconducting toroidal field coils is developed and corroborated numerically. In contrast to the existing models, this model incorporates in-plane deformation of the coil. A semi-analytical approach is used to obtain the solution to the coupled problem. In order to validate the model and associated solution method, the experiment of Miya et al., 1982 is modeled. The theoretical predictions of the critical current of coils with none or one pin support are shown to be in excellent agreement with the published experimental data. It is also shown that the in-plane deformation has a significant influence on the critical current.

Instability of Superconducting Partial Torus with Two Pin Supports

Further theoretical analysis is presented on the instability of superconducting magnets. A three-coil superconducting partial torus with two pin supports is described by a nonlinear theoretical model, which is composed of the theory of curved beams and the Biot-Savart law. A semianalytical and seminumerical program is used to obtain the solution to the nonlinear boundary-value equations of the coil. The influence of the location of two pin supports on the critical current is investigated in detail. The numerical results show that the deformation procedure can be well simulated by the theoretical model, and the critical current values of magnetoelastic stability of the coil are in good agreement with the existing experimental data.

Slab behavior and approximation of transverse strain increase due to the change of support conditions from rigid to elastic supports

When existing multiple simple span bridges are converted into a continuous span in order to increase the load carrying capacity by connecting each opposite ends of the simple beams, the rigid support conditions (pin and roller supports) have to be changed to elastic supports in order to absorb and distribute the energy of large horizontal motion due to earthquake loading. However, it may overlook the development of additional stress in the transverse direction of the slab due to the relative vertical displacement of the elastic support. In this study, a simple span bridge specimen of 1/6 scale is tested and analyzed by the use of F.E.M. to investigate strain increase in the transverse direction of the slab when the rigid supports are replaced by the elastic supports. Both test and analytical results exhibit a notable increase of transverse stress throughout the whole feasible range of the vertical support stiffness.

Imperfectly constrained planer impacts — a coefficient-of-restitution model

A simple coefficient-of-restitution model is proposed for the impact of a rigid body, constrained by an imperfect pin support, with a rigid barrier. The collision process is represented by two phases. In the first phase, the rigid body impacts the barrier with negligible influence from the support. The next phase is characterized by an impact between the rigid body and the imperfect pin support. This second phase commences when the impact with the barrier ceases. Both moving and stationary barriers are considered. For a moving barrier, energy can be added to the rigid body due to the work done by the friction force exerted by the moving barrier. Such a result is not predicted with the usual constrained impact formulation. Impact with a stationary barrier is characterized by continuous slip, slip reversal, or slip followed by stick. A ‘constrained’ coefficient of restitution is presented for these partially-constrained impacts.