A computer analysis of orientation devices for vibratory bowl feeders

Currently, vibratory bowl feeders are widely used in industry to feed small parts in assembly processes. The actual orientation of parts is achieved by various devices used in these feeders. However, each type of device performs only a limited function. The objective of this project was to develop a systematic approach which both analyses the geometrical and topological properties of parts designed in a CAD system and selects appropriate orientation devices to feed the designed parts.     

On the theoretical analysis of vibratory flame propagation

The condition is established under which the mutual effect between wave generation at a flame surface and periodic accelerations in the surrounding medium may become an essential feedback mechanism in the vibratory propagation of the flame along ducts.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 18, No. 5, pp. 924–926, May, 1970.     

On nonlinear stochastic vibratory systems with stiffness degradation

Summary In the paper a coupled response–degradation problem for a nonlinear vibrating system is analyzed. The analysis allows to account for the effect of stiffness degradation (during the vibration process) on the response and, in the same time, gives the actual stress values for estimation of damage accumulating in the system. The paper constitutes an extension of the approach (a sequential characterization of the degradation random process) presented in [4] to vibrating systems with nonlinear restoring term. Dedicated to Professor Franz Ziegler on the occasion of his 70th birthday     

Evaluation of WEDM performance characteristics of Inconel 706 for turbine disk application

Inconel 706 is a newly developed superalloy, which offers high mechanical strength alongwith easy fabricability thus making it suitable for turbine disk applications. Although Inconel 706 exhibits a substantial increase in stress rupture and tensile yield strength compared to other superalloys, its conventional machining yields poor surface finish and low dimensional accuracy of the machined components. Hence, wire electrical discharge machining (WEDM) of Inconel 706 has been performed and various performance attributes such as material removal rate (MRR), surface roughness (SR), recast surface, topography, microhardness, microstructural and metallurgical changes of the machined components have been evaluated. The experimental results revealed that servo voltage, pulse on time, and pulse off time greatly influence the MRR and SR. Due to high toughness of Inconel 706, no micro cracks were observed on the machined surface. Micro voids and micro globules are significantly reduced at low pulse on time and high servo voltage. But, there is a propensity of thick recast layer formation at high pulse on time and low servo voltage. EDAX analysis of recast surface exposed the existence of Cu and Zn which have migrated from the brass wire. The subsurface microhardness was changed to 80 μm due to significant thermal degradation.     

On the efficiency of a ducted nonstationary actuator disk

Summary In this article an actuator disk with a time-dependent normal load and surrounded by a shroud is discussed. Its efficiency is calculated as a function of its dimensions and frequency. Numerical results are given.     

On the theoretical and experimental conveying speed of granular bulk solids on vibratory conveyors

At hand of a simplified model, a theory has been developed in order to gain more insight in the complicated mechanism behind the functioning of vibratory conveyors in both, qualitative and quantitative sense. The theoretical results have been basely presented in one graph only, which forms a useful aid for design engineers and estimators. The theoretical results have been experimentally checked by means of two special designed conveyors, and by making use of the equipment of a laboratory of a major manufacturer in the field of bulk solids handling and transportation. The theory also covers the cases of inclined and declined transport. In this work, however, the latter has not been discussed since no experimental results were available yet for comparison.     

On the moment of a plane disk in a non-Newtonian fluid

Summary Exact analytic solution for the flow of non-Newtonian fluid of grade two generated by periodic oscillations of a plane disk is obtained. The velocity field and the moment of the frictional forces are calculated and the results are compared with those for Newtonian fluid. The moments caused by certain special oscillations are also discussed.     

Multi-scale study of particle flow in silos

The flow characteristics of solid particles in a silo were studied experimentally and theoretically. A multi-scale study of the particles flow was performed by means of discrete element method (DEM). The dependence of flow behaviors on the particles diameter distribution and silo geometry was analyzed to establish the spatial and statistical distributions of microdynamic variables related to flow and silo structures such as velocity, porosity, coordination number, and interaction forces between particles. The results show that the distribution of particle diameter has great effects on particles flow, and the mixing of multi-sized particles is propitious to granular flow. The geometry of silos has greater effects on granular flow than particle size distribution, and inserts can improve the flow behaviors of “funnel flow” type to “mass flow”. Linear equations can be used to describe the relationship between discharge rate and orifice size by G^2/5 vs. D_o for the same distribution of particles diameter. The flow structure of particles in the silos is spatially non-uniform, which is illustrated by spatial and statistical distributions of porosity and coordination number. Both porosity and coordination number are affected by the mode of particles packed, which is affected by the geometry of silos and particle size distribution. The distribution of contact forces between particles is spatially non-uniform too. In flat-bottomed silo, there are arched stress chains in the vicinity of the orifice under the “bridging action”, which disappeared in wedge-shaped hopper silo.     

Dynamic characteristics of vibratory gyroscopes

Although there have been test results on microgyroscope dynamic characteristics, quantitative results relating the dynamic properties to microgyro design and operating parameters are not yet available. In this paper, we study the dynamic characteristics of a vibrating wheel microgyroscope. In vibratory microgyroscopes, the mechanical structure is driven into oscillatory motion. Consequently, the angular velocity input to the sensor is multiplied by the periodic driven motion. In order to recover the angular velocity input from the sensor responses, a demodulation must by carried out. Therefore, the differential equation governing the gyro input and output is not time invariant. The frequency response for the time-variant linear system is obtained through the demodulated and low-pass filtered steady-state output to sinusoidal excitations. With further assumptions of large Q value and close frequency match between the driven mode and sense mode, we obtain a time invariant model for the microgyroscope which is much simpler to use in the design of the microgyroscopes.     

Investigation of vibratory bowl finishing

Although vibratory finishing has been in commercial use for over 40 years, relatively little fundamental information is known about the process, and industrial practice remains largely based on empiricism and trial and error. An experimental investigation into the vibratory bowl finishing process was conducted using material removal rate and surface roughness as the dependent variables. Bowl performance can best be described in terms of acceleration and depends primarily on the feed weights used, while bowl loading has a relatively minor effect. Furthermore, small changes in bowl loading resulting from normal media wear can be neglected. Results showed that material removal rates were constant over time for aluminium, brass and steel and were sensitive to hardness and bowl acceleration. Surface roughness saturated after a fixed period and was primarily a function of material composition. Surface roughness did not appear to be sensitive to bowl acceleration.     

Performance analysis of the disk modulo allocation method for concurrent accessing on multiple disk systems

Abstract

In this paper, we shall discuss the performance of the Disk Modulo allocation method which was proposed by Du and Sobolewski for Cartesian product files on multiple disk systems. A performance formula which can be used directly to evaluate the average response time to all possible partial match queries by using Disk Modulo allocation method is derived.     

Optimal vehicle-dispatch decisions for cement silos using a fuzzy multi-objective approach

In real dispatch problems for cement-silo trucks, input data or parameters, such as forecasting demand, resources, costs, and the objective function, are often imprecise or fuzzy because some information is incomplete, unavailable, or unobtainable. This work presents a novel fuzzy multi-objective linear programming (FMOLP) model that solves the cement-silo vehicle-dispatch problem in a fuzzy environment. This model is applied to solve multi-source, multi-product, multi-vehicle, and multi-ready-mixed-concrete (RMC) plant vehicle-dispatch problems with imprecise goals, input data, and parameters. This work elucidates the relationship between dispatch planning and RMC plants with a focus on the allocation of cement-silo trucks. This work uses a real cement study case to demonstrate the feasibility of the proposed model. The main contribution of this work is its fuzzy mathematical programming methodology for solving the cement-silo vehicle-dispatch problem in a fuzzy environment. The analytical results can help dispatchers analyse systematically the cost-effectiveness of vehicle-dispatch planning in practical applications.     

用振动剪切波强化工艺处理洗毛废水的试验研究

采用振动剪切波强化工艺(VSEP)和选用DS-5纳滤膜处理洗毛废水.结果表明,在操作压力1.4MPa、运行温度45～50℃,设备振幅12.7mm(1/2英寸)的条件下,在废水总固体浓度为37800～144000mg/L浓度范围内时,膜水通量为94.4～34.6L/(m2·h).对洗毛废水中COD、羊毛油脂和总固体TS的一次性去除率分别为98.5%,99.7%和94%.膜的清洗周期为5天左右,清洗后膜水通量恢复至膜初始水通量水平的90%以上.     

On the axisymmetric loading of an annular crack by a disk inclusion

This paper examines the axisymmetric elastostatic problem related to the loading of an annular crack by a rigid disk–shaped inclusion subjected to a central force. The integral equations associated with the resulting mixed–boundary–value problem are solved numerically to determine the load–displacement result for the rigid inclusion and the Mode II stress–intensity factors at the boundaries of the annular crack. The results presented are applicable to a wide range of Poisson's ratios ranging from zero to one half.     

On the dynamic strength of a disk with a central cylinder-conic opening

The problem of nonstationary dynamic behavior of a disk weakened by a central cylinder-conic opening under the action of suddenly applied loading is considered. Determining relations are given in the form of a system of integral equations in an arbitrary oblique coordinate system. A numerical solution has been obtained by using a hybrid difference scheme constructed on the basis of the method of flow correction. Our generalized versions of the S.K. Godunov method for the case of a nonorthogonal system of coordinates were used as basic schemes. The locations of maximum stresses that precede the appearance of plasticity zones have been determined for a particular elastic body. Translated from Problemy Prochnosti, No. 2, pp. 79–87, March–April, 1997.     

A review of vibratory gyroscopes

This paper describes the mechanical design of some vibratory rate gyroscopes. The principal commercial designs are identified and their operating principles are described. Only two designs based upon micromechanical methods of manufacture have been produced and these are still at an early stage of development. These designs are described and discussed     

A computer-aided framework for the selection and sequencing of orientating devices for the vibratory bowl feeder

Correct part orientation has been the key to many successful automation applications, and often vibratory bowls were used. Traditionally, the design and tooling of the vibratory bowls are limited to a group of skilled experts. In this paper a feature-based framework for the automatic selection and sequencing of orientating devices is presented. A direct link between part representation and the selection and sequencing of modular orientating devices is provided by a spatial technique, in place of traditional CAD representation. Also described is the classification of a part's orientating features and classification of orientating devices. These two classifications are integrated into a knowledge-based system that will automatically generate sequences of modular orientating devices.