Joint Arrangement Research Articles

Thermal deformation analysis of BGA package by digital image correlation technique

PurposeThe mismatch of the thermal expansion coefficients of the materials in multiplayer structure may induce serious stress concentrations in electronic packaging. Experimental evaluation of the thermal stresses and strains in those electronic composites is becoming significantly important for optimizing design and failure prediction of the electronic devices.Design/methodology/approachDigital image correlation (DIC) technique was utilized to obtain thermal deformation filed of a BGA package. With the help of white light to illuminate the cross section of the BGA package, the gray images were taken from the rough surface of the specimen, that offer a kid of carrier pattern for the DIC processing with statistical resemblance in gray distributions. By using the algorithm of correlation computation, the DIC searched the matching spots in a pair of those images in which the spot displacements were involved in between, to obtain the deformation fields of the package specimen caused by temperature changes.FindingsThe results show interesting strain distributions in the assembly. Both the horizontal displacement component and its normal derivative are strongly related to the arrangement of the solder joints in the bonding medium between the die and the ceramic substrate. The strain components in the middle region of the package are larger than those in the side regions where the strain relaxation may exist near the stress‐free boundaries. The shear strain components show special bands of parallel lines with identical amount over the chip‐package to sustain the shearing of the packed structure under thermal loading.Originality/valueThe DIC technique shows to be a useful tool for the thermal strain analysis of the electronic packaging devices. Not only provides it the whole field deformation of the assembly, but also maintains the surface pictures of the package without covering any fringes, which is important to compare the deformation field with the specimen surface to reveal the stain distribution related to the failure prediction of the materials.

Topological analysis of 6-joint serial manipulators and their inverse kinematic solutions

The 6-joint serial manipulators are thoroughly investigated from the viewpoint of their inverse kinematic solutions. To do this systematically, the manipulators are classified according to their joint arrangements and two topological concepts are introduced as type number and conjugacy. The conditions of validity are stated and the valid manipulators are further classified into four groups according to their type numbers as type-3, type-4, type-5, and type-6. The concept of conjugacy leads to a reduction in the number of manipulators to be investigated. The minimal conditions for the existence of analytical solutions are determined. The ways of obtaining analytical solutions are described for all typical samples of joint arrangement and type number classifications. If analytical solutions do not exist, then it is described how to obtain semi-analytical solutions of first, second, or at most third order. A kth order semi-analytical solution is such that the number of equations to be solved numerically can be reduced to k. Simplifications and manipulations of the kinematic equations both for their analytical or semi-analytical solutions and for the topological analysis of manipulators have been achieved by means of the numerous properties of the exponential rotation matrices.

Trust and Collaborative Planning Theory: The Case of the Scottish Planning System

The chief objective of this paper is to introduce trust as a new component of the collaborative planning theory and discuss its significance in respect of the newly introduced joint structure plan-making system in Scotland. To achieve this, we briefly discuss the main components of collaborative planning theory in the second section as its main protagonists have comprehensively discussed these aspects of collaborative planning theory elsewhere. Then we develop the indicators of trust in the third section. The fourth section outlines the newly introduced system of joint structure plan making in Scotland. It is in the fifth section that the trust indicators are applied to the system of joint structure plan making in Glasgow and the Clyde Valley, Scotland. The last section sums up the main conclusions. A new system of joint structure plan making was introduced in Scotland after the reorganization of local government in 1995. While this system exhibits some traces of collaborative planning, indications are that this joint arrangement could develop into a high trust partnership among the stakeholders involved jointly in the production of structure plans. Most of the trust indicators developed in this paper show positive results when applied to the case study. The stakeholders expect that high trust will result in better understanding among them leading to sustained collaboration. It is expected that as collaboration matures, trust will further develop. We have thus argued that both trust and collaboration reinforce each other. Collaboration is understood as willingness to work together to attain shared objectives through formalized horizontal organizational arrangements.

Fluid flow in discrete joint sets: Field observations and numerical simulations

The distribution of flow within conductive joint sets is influenced by the geometric arrangement of joints and the hydraulic properties of both joints and matrix. We use finite element simulations with an equivalent porous media joint representation to understand the distribution of flow through joints and porous matrix. Isolated joints in a porous media create characteristic flow perturbations in the matrix with reduced fluid potentials near the upstream joint tip, elevated potentials near the downstream tip, and flow shadows adjacent to the joint. In more complex joint systems, flow in any given joint is influenced by its proximity to other joints, resulting in characteristic enhancement or reduction of flow velocities. The permeability ratio (equivalent joint permeability divided by matrix permeability) plays a major role in determining the distribution of flow within complex joint systems. When the permeability ratio is <3.0 orders of magnitude, all joints are indirectly connected to the flow system through the matrix. As joint conductivity increases, flow becomes increasingly localized into directly connected joints. When the permeability ratio exceeds 6.5 orders of magnitude, significant flow occurs only in the directly connected joints. We compare these numerical results with field observations from an ancient reactive flow system now exposed at the Earth's surface. In the field, 32% of joints are associated with chemically altered halos. By explicitly representing mapped joint distributions in numerical simulations, we estimate that 32% of the joints would conduct significant volumes of fluid if joint permeability is 5 orders of magnitude greater than the matrix permeability. This corresponds to an in situ joint aperture of 2.3 mm, closely resembling the 1.8‐mm average joint aperture measured on the present‐day outcrop.

高カボルト接合された鋼板の破断形式と破断耐力

In order to investigate the effects of bolt-hole arrangement and edge distance of bolted joints on the ultimate tensile strength of joint plates and failure modes, we conduct tension tests of the steel plates jointed with high-strength bolts. We propose formulas to predict the ultimate strength of the joint plates for three failure modes: net section fracture, tearing fracture and end fracture. The experimental results confirm the validity of the formulas. In addition, the experimental results are compared with the design values specified in the "Standard for Limit State Design of Steel Structure (draft)" (Architectural Institute of Japan) and the "Load and Resistance Factor Design Specification for Structural Steel Buildings" (American Institute of Steel Construction). Furthermore, relationships between the failure modes and the geometric properties of the bolt-hole arrangements are clarified: In the tests, three types of steels of 400MPa-grade steel, 590MPa-grade and 780MPa-grade high-quality steels are adopted.

Kinematic passive correction of errors in active surface telescopes

The advancing requirements of instrumentation in astronomy have led to the development of telescopes with segmented active surfaces. In such telescopes, movable segments are controlled together to maintain the correct figure of the reflecting surface. This paper investigates telescope active surfaces by representing each movable segment as a three-degree-of-freedom parallel manipulator. In this representation, the performance of the active surface can be understood by investigating the small-motion workspace of the manipulator. The workspace is examined for two types of actuator mounting geometry which use only revolute and spherical (ball) joints. In the first geometry, the pin joints are located at the base and ball joints are used to connect to the segment. In the second case, the joint arrangement is reversed. Following the workspace investigation, the effects of the kinematics on the performance of an example surface are determined. The analysis reveals that placing all of the ball joint connections at the base provides a passive correction of uncontrolled degrees of freedom in the active surface, significantly improving telescope performance.

Performance of Nailed Gusset Joints in Ridged Timber Portals

Abstract The structural behaviour and performance of nailed plywood gusset knee joints of timber portal frames are investigated. An analytical study has shown, and experimental study has confirmed, that the behaviour of the joints in terms of strength and stiffness, distribution of stresses, and rotation of nail groups within the gusset haunches, is directly related to the joint’s component arrangements, plywood grain orientation and the dowel action of the nails. An empirical method is presented which permits calculation of the short-term ultimate strength of plywood gusset plates, for various component arrangements of the knee joints, based on the strain distribution along the critical section of the haunched gussets. It is shown that a considerable gain in ultimate strength and performance can be achieved if a correct joint configuration is used.

Spring equilibrator theory for static balancing of planar pantograph linkages

Static spring balancing theory for planar pantograph linkages is developed using a potential energy approach. Application of this theory achieves static balancing of pantograph linkages in a gravitational field throughout the full range of motion by guaranteeing perfect energy transfer between system gravitational and elastic potential energies. The general planar pantograph linkage is addressed by means of four pantograph types where each type represents a different revolute/prismatic joint arrangement. Equilibrator design for two of these pantograph types represents a first introduction of equilibrium theory to include linkages having prismatic pairs. Applications for walking machine leg design and for vertical plane selective compliance assembly robot design are discussed.

The joint African radiometric propagation measurement programme

AbstractThis paper summarizes the principal aspects of a major co‐operative radiowave propagation experiment that was designed to collect data for improving rain attenuation prediction models for tropical Africa. A pressing need for such data had previously been identified by Resolution 79 of the CCIR. In a unique joint arrangement with three African governments, INTELSAT, COMSAT, the U.S. Agency for International Development, the U.S. National Telecommunications and Information Administration and the U.S. Telecommunications Training Institute (USTTI) collaborated in setting up a Ku‐band radiometric measurement campaign in Cameroon, Kenya and Nigeria. A brief historical overview is given, together with the major technical parameters of the sites and the equipment installed there. The anticipated characteristics of the three locations are outlined with regard to meteorological and propagation conditions, and some preliminary indications of the results are presented based on an inspection of the early event data.

Anatomical and physiological organization of the swimmeret system of the spiny lobsterJasus lalandii as adaptive components of the tail flick

1. The swimmerets ofJasus lalandii, in contrast to those well known in the nephropid lobsters (e.g.Homarus) and astacurans (crayfish), do not display spontaneous antero-posterior beating, but are either apposed actively to the ventral surface of the abdomen, or rotated outward (Fig. 2). These movements are imposed by the geometrical arrangement of the bicondylar joints at the base of the swimmeret (Fig. 3), and involve contraction of either the remotor muscle, or the promotor-rotator muscles (Figs. 2, 3). Each swimmeret includes a short, thick blade-like exopodite that contains two antagonistic muscles, a large curler and a small adductor muscle (Fig. 3). Each swimmeret is innervated by 80 motor neurons (MNs) which are disposed in two clusters in the ganglion. 2. The modulation of the tonic discharge of the muscles which maintain the swimmeret position at rest (remotor and curler) has been studied in two situations: body rolling (Fig. 4) and walking activity (Fig. 5). In the female, in which the most anterior pair of swimmerets are biramous, both endopodite and exopodite curler muscles display the same responses to body rolling (Fig. 4). In all these situations no overt swimmeret movement occurs. 3. Nevertheless, rhythmicity exists inJasus, but it is limited to the gravid female when the swimmerets bear the eggs (Fig. 6). In contrast to other decapod Crustacea, this swimmeret beating is not metachronous (Fig. 6). 4. Movement monitoring (Fig. 7) and EMG recordings (Figs. 9, 10) have demonstrated the involvement of the swimmerets in the three phases of the tail flick response (preparation, flexion, extension). During the preparatory phase, in response to mechanical stimulation of the legs, the swimmerets open on the stimulated side (on both sides in the case of a symmetrical stimulation) (Fig. 7). During the rapid abdominal flexion of the tail flick all swimmerets open fully regardless of the stimulus (Figs. 7, 8). Two different units in the rotator muscle EMG are responsible for swimmeret opening during the preparatory and the flexion phases of the tail flick (Figs. 9, 10). 5. The curler muscle of the endopodite in the female displays antagonistic activities to that of the exopodite during tail flicks (Fig. 10). 6. Selective swimmeret blockage demonstrates that they contribute to the thrust efficacy in tail flicks. In particular they are responsible for the variation of the maximal force produced at its onset. This effect could be interpreted as a consequence of force redistribution by the swimmerets acting on water flow (produced by the tail fan). This mechanism implies a functional role for the swimmerets in righting and steering responses (Fig. 11).

Appropriate lengths between phalanges of multijointed fingers for stable grasping

AbstractAn appropriate arrangement of finger joints is very important since the stability of grasping an object greatly depends on that arrangement. Multijointed fingers can grasp an object with many points of contact each of which is pressed against the object as if wrapping up that object. The amount of the wrapped up area and the form of the finger when an object is grasped are therefore important factors for determining the stability of grasping. We propose the wrapping factor to be used for the evaluation of the stability of grasping by using these factors. We consider 28 models for the finger having three joints, and perform a simulation of their ability to grasp various shapes stably. Based on the simulation results, an appropriate arrangement of lengths between phalanges for a multijointed finger is presented.

Consideration of the effect of construction joints on the strength of massive reinforced-concrete components

1. When designing massive reinforced-concrete components and their elements it is necessary to take into account the presence of construction Joints between the blocks. 2. The developed design requirements imposed on elements of massive reinforced-concrete components having construction joints and the method of calculating the strength of inclined sections permit a rational arrangement of the construction joints, ensuring reliability and durability of the structures. 3. A differentiated approach to carrying out measures on the surface of blocks in conformity with the graph in Fig. 1 and indications in Table 1 is necessary. 4. The cost effectiveness of using the proposed solutions is expressed in a reduction of the cost of works: for components of the first group (Table 1), due to the elimination of technological and design measures on the surface of the blocks in the case of the arrangement of the joints within zone 1 (Fig. 1); for components of the second group (Table 1), due to the elimination of technological or design measurements on the surface of the blocks and also due to a savings of transverse reinforcement in the case of a rational arrangement of the construction joints and use of shortened reinforcement cages. 5. The proposed solutions permit an experimental and theoretical evaluation of the state of operating reinforced-concrete components on the basis of the strength of inclined sections in the zone of construction joints, which in certain cases effects a savings due to elimination of costly investigations and repair works. 6. It is expedient to introduce the given suggestions into the standards during their revision with respect to the calculation and design of massive reinforced-concrete components and their construction.

PETROLEUM EXPLORATION DEVELOPMENTS IN THE NORTHERN TERRITORY DURING 1982

Petroleum exploration areas under Northern Territory Administration to the end of 1982, can be split into three separate zones. Onshore exploration is administered under the Petroleum (Prospecting and Mining) Act; exploration in waters adjacent to the Northern Territory is administered by joint arrangement with the Commonwealth under the Petroleum (Submerged Lands) Act; offshore exploration in the Ashmore and Cartier Islands area is administered on behalf of the Commonwealth under the Petroleum (Submerged Lands) Act. Of course, on declaration of the amended Petroleum (Submerged Lands) Act, the Territorial Sea will become a fourth discrete area.

Use of the probabilistic method of calculating stability when designing rock slopes

1. At present rock slopes are usually designed on the basis of the most unfavorable (of those possible) arrangement of potential shear joints in the investigated mass and without consideration of the probability of the presence of joints of such orientation in it. 2. A new method is proposed here for calculating the stability of rock slopes based on the use of a statistical probabilistic method of processing the measurements of orientations of potential shear joints and taking as the criterion of stability of slopes their reliability value. 3. The practical use of the method when designing the rock slopes of foundation pits of the Southern Ukraine power complex showed the advantages and prospects of the probabilistic approach to estimation of the stability of masses. In particular, use of the method made it possible to design some steeper slopes, which as a whole for the complex will permit avoiding additional excavation of tens of thousands (potentially as much as 160,000) of cubic meters of rock. 4. The results of calculating slope stability for various values of the hydrostatic pressure indicate the need for special investigations (e.g., on an electrohydrodynamic analogue) to determine the shape of the line of seepage in masses and the expediency of refining this line during excavation works.

Anisotropic Skew Plates and Grids

A discrete element method of analysis for the bending of an anisotropic skew-plate-and-grid-beam system is presented. The distinguishing features are (1) The representation of an anisotropic skew-plate-and-grid system by a discrete element model consisting of a tridirectional arrangement of rig bars and elastic joints; and (2) the formulation of stress-strain and moment-curvature relations for the discrete element model using concepts of a continuum composed of interconnected fibers. The method allows free variation in stiffnesses, loads, and elastic supports at mesh points that are closely spaced. Concentrated and distributed loads and external couples in three directions are easily handled, and one-dimensional beams may be added in any of the three directions. Elastic supports may be either distributed or concentrated. A computer program has been written which utilizes the formulation. The results compare well with results from other methods and with experimental data. /ASCE/

Selecting the best expansion joint arrangement in forced circulation evaporator circuits

Selecting the best expansion joint arrangement in forced circulation evaporator circuits

Bewegungsmechanismus und gelenkrezeptoren der Antennen von Locusta migratoria L. (Insecta, orthoptera)

The morphological arrangement of the antennal joints and their significance for the complex antennal movements are investigated. Particular value is attached to the mechanoreceptors of the 2. segment because of their importance for the function of the antennae as air current sense organs.

The prediction of damping in nailed and glued wood structures

Improvement of damping of small amplitude vibrations can be obtained by properly optimizing glued and nailed joints. In this paper methods for accurately predicting such damping are developed which require simple tests on small specimens. The analytical predictions are confirmed by experiments on structural members. These results can lead to arrangements of joints which maximize the damping.

Design of Boundary Arch Dam

The design of a 360-ft high, thin, double-curvature arch dam is described. Reference is made to topographic and geologic conditions, to hydraulics and hydrology, site investigation and rock mechanics. The methods of analysis used for preliminary and final design are described, including the electric analogy simulation method of analysis. Reference is made to a study developed to analyze the stability of dam abutments containing two types of rock of different properties, numerous faults, and a large limestone erosion cavity immediately downstream of the arch abutments. Design and operation of are described of seven large sluice gates located 200 ft below the dam crest and a horizontally moving maintenance gate serving all the sluice openings under full reservoir head. Arrangement and grouting of gravel-filled contraction joints, dam cooling, instrumentation and various other details are also considered. The dam design allows for overtopping during flood season while partially completed.

Toward an international program of research on the handling of conflicts: introduction

ganized during 1957-58 through a joint arrangement between the Institute for Social Research and the Institute of Philosophy at the University of Oslo. This seminar grew out of an established tradition of co-operation between United States and Norwegian social scientists. For a decade now, United States social psychologists and sociologists have taken an active part in the planning and conducting of empirical and experimental research in Oslo.