bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Temperature on Physical and Optical Properties of Photoelastic Materials
Authors: Lee G. H. , Armstrong C. W. 
Published: February 2021

Abstract
This paper reports the results of tension tests, to determine the suitability for photoelastic work, of five samples of Bakelite and two of Marblette at temperatures between 32 and 140 F. These results show the variation, of Young’s modulus, Poisson’s ratio, stress-optical coefficient, and strain-optical coefficient with temperature. Stress-strain curves of the materials are also given showing the relative amounts of creep. The effect of heat-treatment on Marblette is shown by tests before and after annealing.
Rubber Mountings
Authors: Downie Smith J. F. 
Published: February 2021

Abstract
This paper deals with static deflections of rubber mountings. An equation has been developed which correlates all the available data on plain rectangular slabs under compression loading. Data are given showing how closely this equation checks experimentation, and examples are solved, giving the method of using this equation and also the use of a chart simplifying the calculations. Additional data are given on other shapes of compression mountings.
The deflections of shear-type mountings are shown to agree with theory. Combination shear-compression units have also been tested.
Data are given showing the variation of hardness on the durometer A scale with change of temperature. At room temperature moduli of elasticity for compression and for shear are related with durometer hardness number, and the equations of these curves are derived.
A New Relationship for Use in the Design of Machine Columns
Authors: Clapp W. H. 
Published: February 2021

Abstract
The author discusses the requirements of an ideal formula for determining the stresses in machine columns and points out the fact that although the secant formula meets several of these requirements the relationships are so involved that it has always been necessary to use one of several empirical equations because of the uncertainty regarding the probable eccentricity of the load. The author describes a relationship which makes the secant formula usable and presents a universal chart adapted to the solution of problems of steel columns having any type of cross section when subjected to axial loading.
An Improved Method for Calculating Free Vibrations in Systems of Several Degrees of Freedom
Authors: Dudley Winston M. 
Published: February 2021

Abstract
In 1934 two English investigators (1) published a method for calculating the various modes and frequencies of vibration of a system having several degrees of freedom. Their method, which is based on matrices, greatly shortens the time spent in obtaining numerical solutions in many important problems, notably those with immovable foundations. In this paper is presented a new theorem which (a) makes possible a further reduction of nearly one half in the time required, so that solutions up to 20 deg or more of freedom are now practical and (b) makes it then possible to determine the motion of the system after any initial disturbance in a few minutes, instead of several hours as required by older methods. It is useful in the latter respect whether the modes have been determined by matrix methods, or not.
Although the paper gives simpler proofs than any previously published, knowledge of the matrix theory is not required in using the method. Problems are analyzed by a tabular process, in which an ordinary computing machine helps greatly. Comments based on computing experience are given. A simple numerical example has been given elsewhere (1).
Efficient Algorithm for Automatic Support Structure Generation in Layered Manufacturing
Authors: Hur Junghoon , Lee Kunwoo 
Published: February 2021

Abstract
Stereolithography is a process used to rapidly produce polymer components directly from a computer representation of a part. There are several considerations to be made for the efficient use of the process. Especially, the necessity of support structures, which prevent the part from warping, sagging, or parachuting and toppling as the elevator moves up and down in the resin, is one concern. After solidification, the support structures must be removed in the end. Thus the more the support structures, the more it increases the finishing operations. Especially for a complicated part, the removal operations may be difficult, take so much time, and even reduce the accuracy of the product. It is, therefore, important to efficiently generate the support structure for each part geometry. This paper proposes a algorithm to automatically generate the support structure focused on accuracy, efficiency, convenience, and generation speed. Besides, we can exactly determine an optimal build-up direction for the minimum volume of support structures.
A Workbench Architecture for Object Oriented Handling of Features
Authors: Horváth Imre 
Published: February 2021

Abstract
This paper is devoted primarily to the presentation and discussion of a novel architecture, called workbench, that facilitates application of system independent feature objects in various stages of mechanical design process. The motivation behind the development of this non-traditional architecture for advanced CAD/CAE systems lies in the necessity to (a) separate application oriented feature entities from the geometric modeling kernel, (b) increase the level of integration of functioning modules by supporting parallel processing and intercommunication, finally, (c) extend the scope of near-future systems to conceptual design in order to increase their influence on the technical and economic value of products. First, the paper gives an overview on the related research. Then, it presents the workbench architecture that consists of four main fundamental modules that are integrated, simultaneously active, and communicating. The library manager taxonomically classifies, retrieves and activates the existing feature-objects. The libraries of feature-objects contain generic entities for procedural modeling in conceptual design, shape design, manufacturing process planning, assembly planning, or other applications. The pool is an intermittent store of feature-instances that have been produced by procedural modeling based on the feature-object programs. The workspace provides graphical interactive tools for manipulation and positioning of, and composition with feature-instance geometries. The paper also discusses some implementation aspects.
Integration of Real IT-Applications in Virtual Manufacturing Systems
Authors: Gausemeier Jürgen , von Bohuszewicz Oskar , Gehnen Gerrit , Grafe Michaei 
Published: February 2021

Abstract
Modeling of automated manufacturing systems under conditions approaching reality by means of Virtual Reality technology is part of the Virtual Model Enterprise Project. It encompasses especially the integration of real information technology (IT) like CAD/CAM, PPS, or manufacturing control systems in the virtual environment, alongside the structural and functional reproduction of manufacturing systems.
The integration of real IT-applications in a virtual environment requires the realization of a data interface between VR-software and the IT-applications as well as the development of a suitable user interface to control the Application from within a Virtual Environment.
This contribution shows, in the case of the integration of a manufacturing control system in the existing production area of the Virtual Model Enterprise, how the previously described problems could be solved. Through the integration of the production management system, it is possible to apply the functionality of the manufacturing control to the virtual production and transport systems. This functionality encompasses the detailed planning of the tasks as well as the control and supervision of the virtual systems. The user is able to directly follow the process of the production tasks through the immediate visualization of the work process.
A New Viewfactor Algorithm Specific for Rectangular Enclosures
Authors: Collado F. J. , Marín J. M. , Minguijón R. 
Published: February 2021

Abstract
A new viewfactor algorithm valid for any pair of rectangles with all their edges lying parallel to some coordinate axis is presented in this paper. The new procedure is based on the projected contour method, making the best use of the simplicity of this geometry with many engineering applications. The main advantage of the new algorithm compared with other well known procedures, as the Mitalas-Stepheson one, is the great economy of execution time (almost three times faster) without loss of accuracy. Then, for more complicated cases with obstructions solved with clipping methods, where it is necessary to work out a large amount of contour integrals, the potential economy of CPU time is evident. Finally, a FORTRAN 77 subroutine coding the new algorithm is supplied.
Using VR for Design and Manufacturing Applications: A Feasibility Study
Authors: Angster S. , Gowda S. , Jayaram S. 
Published: February 2021

Abstract
Virtual Reality has been used for several years by architects to bridge the gap between their vision of the product and the finished product. Many of these applications use VR on a completed design and allow minor modifications to the design in the VR environment. This paper presents a feasibility study which was conducted to evaluate the accuracy of VR systems when used for conceptual design and in general, for engineering applications. A truck cab interior was modeled in a virtual environment and several ergonomic tests were performed in this virtual environment. The same tests were performed in a physical prototype of the truck cab and results of the two tests were compared. The virtual reality hardware and software systems used, the design evaluation scenario and the results of the tests are presented.
Modeling of Particulate Contamination in Tungsten Low Pressure Chemical Vapor Deposition
Authors: Busnaina Ahmed A. , MacGibbon Bruce S. 
Published: February 2021

Abstract
Chemical vapor deposition processes are one of the most used techniques for depositing thin films in the semiconductor-microelectronics and opto-electronic industries. Particulate contamination of the substrate during these CVD processes can be detrimental to the product yield. Due to the temperature gradients present in the CVD reactor, thermophoresis has a direct impact on the amount of particulate deposition on the substrate. The thermophoretic force is the force that arises from asymmetrical interactions of a particle with the surrounding gas molecules due to a temperature gradient. CVD processes can take place in hot and cold wall reactors, with varying substrate temperatures. This array of thermal boundary conditions results in a variety of temperature gradients and thermophoretic forces on the particle. There are other forces also acting on the particles in the CVD environment such as the Brownian force, drag, and gravity. The effect of thermophoresis on the particle transport and deposition in the reactor is examined. Different particle concentrations and sizes is considered in the reactor. The motion of these particles according to the thermal gradients in the reactor is examined. The behavior of these particles under different thermal conditions is studied.
Spacetime Optimization for Assembly Process Design Associated With Manual Lifting
Authors: Chang Chienchi , Brown Don R. , Bloswick Donald S. 
Published: February 2021

Abstract
This research develops a computer-aided system for health professionals which helps them to prevent injury related to manual lifting by workers in a manufacturing operation. The heart of the system is a computer program which prescribes the motion that a given person should follow while lifting an object according to different conditions. The system compares the prescribed path to the true motion data taken from a motion tracking system so the health professional can make suggestions on how the person should modify his/her movement.
The prescribed motion is generated with a new technique called spacetime optimization. The health professional describes the simplified characteristics of the human subject such as sex, height, weight, and harmful conditions that the subject should avoid, such as maximum low back stress or shoulder stress. He/she also describes the task involved, such as the starting and ending positions of the load, its shape and weight, and the positions of any intermediate obstacles in the path. The spacetime optimization engine generates the path that the person should follow in order to minimize the harmful conditions according to an objective function and constraints.
In this research, two dimensional dynamic human models are used and a graphical user interface is added to this system to display and compare the motion between real motion and simulation models.
Involute Gear Pumps Versus Lobe Pumps: A Comparison
Authors: Mimmi Giovanni C. , Pennacchi Paolo E. , Savi Carlo G. 
Published: February 2021

Abstract
In previous studies we have considered several types of positive displacement rotary pumps and deeply analyzed the generation of the flow rate and the design limits. This has been done in order to evaluate the main performance indexes: one of these, the flow rate irregularity, is related to the possibility that the pump becomes a source of vibration and noise. A second index is the specific flow rate, related to the delivery capacity of the pump.
In this paper, following our previous researches, we analyze internal involute gear pumps and internal lobe pumps, that have similar way to operate but different performances.
The design parameters and the way to optimize the performances are summarized for both cases. Finally a comparison between the two types of pumps is proposed, along with some optimum design cases.
The R&D of the Business Process Related Services of the Integrating Infrastructure
Authors: E Mingcheng , Cha Jianzhong , Dong Ming 
Published: February 2021

Abstract
Through analyzing the function requirements of the Business Process Related Services of the Integrated Infrastructure, this paper has studied the implementation strategy of BPRS by means of Object-Oriented method, matrix theory and Petri Net(PN) technology. Moreover, it has provided a system structure of BPRS based on Intelligence Engineering theory.
An Octree Algorithm for Dynamic Interference Detection Using Space Partitioning
Authors: Yu Yongxiang , Wu Minghua , Zhou Ji 
Published: February 2021

Abstract
This paper presents an octree algorithm for collision and interference detection using space partitioning technique. The technique greatly reduces the computation time consumed in dynamic collision detection during simulation progress. The simulated objects are represented in hierarchically decomposed octrees. Under this technique, the checking space can be partitioned according to the geometric dependence of two octrees, so that the relations (overlap or separate) among the nodes in the octrees can be determined directly. Since heuristic calculation is excluded from the algorithm, the time consumption for collision detection is greatly reduced.
Motion of Top Feed Mechanism of an Industrial Sewing Machine
Authors: Muramatsu N. 
Published: February 2021

Abstract
This study considered the motion of the top feed mechanism on lockstitch industrial sewing machines with alternating foot top feed and drop feed. The results obtained are as follows.
(1) The bounce phenomena of presser foot Ⓔ and walking foot Ⓖ is a spring reaction of said parts induced by the restoring force of feed dog Ⓕ or throat plate Ⓗ.
(2) The effects of the constituent factors that cause bouncing are as follows:
a. As the rotating speed increases and bouncing gradually increases, resonance occurs in the proximity of 1800 r/min.
b. There are certain ranges where the bounce of presser foot yp2 and walking foot yw1 decreases intermittently but sharply due to the uniformity in lightness of the mass mi (i = 1 to 7) of all constituent parts.
c. The bounce phenomena of yp2 decreases in direct proportion to the reduction of spring constant k1, of throat plate Ⓗ. On the other hand, that of yw1 shows minimal fluctuation.
Effective Design Methods of Wide Robust Structures
Authors: Hiroyasu Tomoyuki , Yamakawa Hiroshi 
Published: February 2021

Abstract
A structure, whose characteristics are less modified by any changes of external forces, boundary conditions and productive errors, has advantages for its practical use. This character is called robustness. In the consecutive study (Yamakawa and Miyashita, 1991), the authors studied the structural design with robustness and proposed a new structural concept called “Robust Structure.” Robust structural design is more useful when the structures are designed in the upper flow of the design process than in the lower flow. Robust structures can be designed by minimizing the sensitivities of the reference function relative to the variable parameters. However, the sensitivities provide only the local information even when their values are evaluated. Therefore, it is not clarified whether robust structure designed by the sensitivities has wide robustness or not. To conquer this problem, this paper shows robust structural design method using the fuzzy sets. In this method, the variable parameters are shown with fuzzy sets and then obtain the wide robustness. It is also pointed out that robust structural design using sensitivities can design wide robust structure in certain cases. Because robust structural design using fuzzy sets needs a lot of numerical iterations, it is important to figure out the effective design method of wide robust structures. In this paper, an idea is proposed how to design wide robust structures. The numerical examples designed by two different methods using sensitivities and fuzzy sets are shown. Further more, the proposed idea is discussed with these examples.
Two-Dimensional Sub-Micron Interferometric Detection of Geometric Translation Errors
Authors: Pegna Joseph , Hilaire Thierry P. , Clément André 
Published: February 2021

Abstract
In earlier papers [2][3] we showed how accurate position measurement and error propagation is completely characterized by a measurement plan. Among the various position sensor designs of interest, we pointed out that some spatially unresolved measurement plans are of particular value. Because the measurement plan is invariant for some degrees of freedom of the system, they offer an unusually large depth of field. The case in point is a measurement plan designed to capture the five components of motion errors for machine elements in translation. This paper focuses on the design of an optical sensor that makes this measurement plan feasible. High resolution translational error measurements over large depth of field were achieved due to a novel interferometer system. Design, implementation and testing are disclosed in this paper. The interferometer features the detection of transverse two-dimensional displacements in one measurement with a resolution of 80 nanometers over a depth of field up to one meter. The main originality of this interferometer is that it does not use wavelength, but rather the geometry of the fringe pattern to derive measurements. Thus the sensor was demonstrated to remain accurate under environmental variation that normally plague other interferometers. It is expected that this novel sensor design can refine resolution of precision machinery down to about 100 nm/m without the extent of environmental constraints and cost usually affiliated with the technology.
An Investigation Into the Performance of Cantilever Hook Type Integral Attachment Features
Authors: Luscher Anthony F. 
Published: February 2021

Abstract
Cantilever hook features are commonly molded into plastic parts as a inexpensive method of assembling several parts without separate fasteners. Insertion force, insertion dynamic strain, and retention force represent the critical performance data needed to design a cantilever hook for given loading conditions. This paper explores the performance of this feature under both insertion and retention using numerical and experimental methods.
A finite element model using contact and friction surface elements was used to simulate the actual insertion and retention processes of hooks. The design space for a hook was explored by using a design of experiments approach. Sensitivity information was obtained by tabulating main effects and interactions. For the goal of minimizing insertion force and maximizing retention strength, a balanced design was found which was sensitive to differing factors. Based on this data, generalized design rules for designing hooks were formulated.
Thermal Analysis of a New Metal-Deposition Rapid Prototyping Process
Authors: Worth Ronald K. , Barkan Philip 
Published: February 2021

Abstract
Rapid prototyping with solid free-form fabrication (SFF) is a key innovation that makes it possible to rapidly produce physical parts directly from a CAD model. Recent research focuses on SFF systems which directly fabricate metal parts. This paper introduces the Stanford Solid Plotter (SSP), a new SFF system that forms prototypes using metal-deposition. Since many critical problems in metal deposition relate to heat transfer issues, the main focus of the paper is on key aspects of the thermal behavior of the SSP part fabrication process, namely the deposition, freezing and cooling of a workpiece. Predictions from a finite difference heat transfer model are used to improve both the precision and strength of actual workpieces made with the SSP. Lab experiments using thermocouples confirm the behavior of the finite difference model.
Axiomatic Design Applied to Manufacturing Systems Design
Authors: Vallhagen Johan 
Published: February 2021

Abstract
In earlier work, the axiomatic design theory has been analyzed for applications on product design and the production processes that pertain to it, where parts manufacture and assembly take place in flexible and automatic manufacturing systems. The conclusion is that the original model cannot handle the manufacturing aspects in a satisfactory manner.
This report proposes an expansion of the axiomatic design model, with a life-cycle approach as take-off. The expansion of the model consists of the introduction of a so-called Manufacturing World with different spaces, where various types of processes and support functions can be developed in agreement with the axiomatic principles. The spaces and their relationships have been defined along with explanations of work procedures. An explanatory example is given.