bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparing Designs: A Graphical Diff for Digital Mockups
Authors: Heisserman Jeff
Published: February 2021

The design and manufacture of aircraft require management of a product that is both large and complex, with as many as live million parts, tens of gigabytes of geometric data, multiple functional systems, manufacturing plans, assembly sequences, and maintenance and operational information. The access and manipulation of the data by the designers is essential to developing an efficient and competitive product. In developing and manufacturing these products, there are a number of situations where there is a need to compare designs.

In this paper, we describe the problem of comparing and merging different versions of a design, discuss criteria for determining differences, and present novel and efficient algorithms for their computation.

We have developed facilities for computing the differences between complex assembly structures with large amounts of geometric data, and for interactively visualizing these differences. These facilities have been implemented in our Genesis generative design system.
Designing for Feature Preservation and Build Improvement in Fused Deposition Manufacture
Authors: Jamalabad Vikram R. , Gasdaska Charles J. , Chard Jeffrey A.
Published: February 2021

A common problem facing designers utilizing Solid Freeform Fabrication techniques is the divergence between expected designs and obtained components. The causes range from processing issues (warpage and shrinkage) to discretization issues (reduction of 3-D components to 2-D or 1-D tool path plans). This problem is further compounded when post-processing issues (binder removal and sintering) are added on for applications like ceramic and metal part manufacture. Utilizing the build procedure to ensure that the part is built as expected is useful in reducing the time to manufacture. In addition, the preservation of features and resolution of feature conflict can be addressed. In this paper we specifically look at the toolpath generation procedures for Fused Deposition to extract information regarding the loss or alteration in original features. Further, we use this information to preserve, alter or resolve features. Due to the build procedures, the problems are inherently 2-dimensional in nature.
Web-Based, User-Friendly Design and Virtual Fabrication for Layered Manufacturing
Authors: Higgins Kathryn B. , Langrana Noshir A.
Published: February 2021

Layered Manufacturing is a valuable tool for efficient and concurrent engineering. In order to maximize its effectiveness, a web-based user-friendly virtual design and fabrication system has been developed using a systematic knowledge-based approach. The large amount of information available on layered manufacturing has been organized into a modular format. Tables and appendices organize hardware and software information for the different methods. A linked dictionary defines unfamiliar terminology. Java applets allow users to create an individualized engineering specification for their part. Recommendations regarding machines and materials are made based on this input. Tutorials guide the LM build process from initial design through selection of build parameters. This comprehensive knowledge base will expose the individual to various rapid prototyping concepts, and should reduce the build iterations required to successfully build parts. The web pages concentrate mainly on stereolithography and fused deposition modeling, but provide introduction to other technologies. Due to the quickly developing nature of the RP industry, information changes periodically. With the modular structure, as new materials and technologies become available, their information can be easily added to the existing knowledge base. Industry feedback on the web site development is facilitated via an online guestbook.
Multimedia-Based Active Tutors: A New Approach to Teaching Design for Manufacturing
Authors: Poli Corrado , Grosse Ian , Woolf Beverly
Published: February 2021

This paper describes multimedia based manufacturing tutors currently under development at the University of Massachusetts Amherst. The purpose of these tutors to assist the user in better visualizing and understanding the relationship between part design and the ease or difficulty of creating the tooling needed to produce the part. Evaluation of these tutors by both freshman and junior engineering students is discussed as well. A finite element analysis tutor, also under development, is briefly described.
Evaluation of Mechanical Product Architecture Using Interaction Graphs to Model Part Connectivity and Joint Strength
Authors: Steiner Mark W.
Published: February 2021

Product performance, variety, manufacturability, logistics and life cycle ultimately depend upon product architecture. Product architecture includes both the foundations and building blocks upon which a mechanical system is conceived. It is a key element of Design for Manufacture (DFM). Until recently relatively little work has been done to fully understand these ramifications. A first step toward this goal is to better quantify the attributes of product architecture for mechanical assemblies. Using interaction graphs and the mathematics of graph theory, this paper proposes metrics for evaluating product architecture. These metrics can be developed from information derived from the geometric design domain based upon part connectivity and joint strengths.
Process Capability Database Usage in Industry: Myth vs. Reality
Authors: Tata Melissa , Thornton Anna C.
Published: February 2021

Process capability data (PCD) is used during design to assess manufacturability, allocate tolerances, and evaluate robustness. Process capability databases (PCDBs)1 have been developed by many design/manufacturing industries to capture their process capability and communicate it to the entire organization. While these databases are being used to monitor quality, they are not being effectively utilized by design.

A survey of design and manufacturing companies was used to determine both how PCD is being used and the barriers preventing design from fully utilizing PCD. Two key barriers were identified: lack of a company-wide vision for PCD usage and poor communication between manufacturing and design. Management support, training, database population, common databases, and common indexing schemes were identified as solutions to these barriers.
State-of-the-Art Report on Design for Manufacturing
Authors: van Vliet J. W. , van Luttervelt C. A. , Kals H. J. J.
Published: February 2021

Often the designer has insufficient information and knowledge to effectively consider manufacturability aspects of the product design. To improve the efficiency of the product realisation process, i.e. to save time and costs, Design for Manufacturing-support must be offered in an effective way. Elements of DFM that must be considered for DFM support are identified in this literature study. The key towards effective computer based DFM support is integration of these elements, for which an architecture is proposed in this paper.
Use of Screw Theory to Detect Multiple Conflicting Key Characteristics in Complex Mechanical Products
Authors: Whitney Daniel E. , Mantripragada Ramakrishna , Adams Jeffrey , Cunningham Timothy
Published: February 2021

Complex mechanical products, such as automobiles and airplanes, must satisfy many customer requirements, commonly called Key Characteristics (KCs). Such products have many separate parts, all of which must cooperate to deliver these requirements. In many cases there are more requirements than degrees of freedom available to meet them all independently, requiring prioritization. This problem is called KC conflict. In a highly complex product, such conflicts can be difficult to detect during design. This paper defines this problem and shows how screw theory can be used to detect and potentially correct it.
Real and Perceived Limitations to Decision Based Design
Authors: Thurston Deborah L.
Published: February 2021

Decision based design shows great promise in improving the design process, but is not a panacea. The design problem of interest here is tradeoffs between conflicting objectives, particularly under uncertainty. The focus is on multiattribute utility theory. This paper describes several real limitations to utility analysis in the context of engineering design, and attempts to clear up several common misconceptions about it. The real limitations are in the initial configuration and analytic design phases, and in overcoming difficulties in group decision making. The major misconceptions relate to independence conditions, the functional form and assessment biases.
Differential Entropy As a Measure of Information Content in Axiomatic Design
Authors: Jahangir Ebad , Frey Dan
Published: February 2021

Axiomatic design theory aims to put the design process on a more scientific footing and is based on two axioms, viz., the independence axiom and the information axiom. Several quantitative measures to determine the degree of independence between functional requirement have been defined in the past and their use illustrated through numerous examples. However, very little work exists on quantifying information content of a design. In this paper, we outline the existing measures of information content and propose a more general quantitative measure. This measure is based on the concept of entropy from information theory. The case of discrete as well as differential entropy is examined in the context of axiomatic design. Differential entropy is proposed as a measure of information content. A case study is presented which demonstrates and compares the use of quantitative measures of information content in a design. It is shown that differential entropy offers a more general measure of information content in a design than Sun’s information measure or Taguchi’s signal-to-noise ratio and, therefore, may serve as a decision criterion in engineering design.
Constrained Shape Scaling of Trimmed NURBS Surfaces
Authors: Zhang Pifu , Zhang Caiming , Cheng Fuhua (Frank)
Published: February 2021

A method to scale and deform a trimmed NURBS surface while holding the shape and size of specific features (trimming curves) unchanged is presented. The new surface is formed by scaling the given surface according to the scaling requirement first; and then attaching the (original) features to the scaled NURBS surface at appropriate locations. The attaching process requires several geometric operations and constrained free-form surface deformation. The resulting surface has the same features as the original surface and same boundary curves as the scaled surface while reflecting the shape and curvature distribution of the scaled surface. This is achieved by minimizing a shape-preserving objective function which covers all the factors in the deformation process such as bending, stretching and spring effects. The resulting surface maintains a NURBS representation and, hence, is compatible with most of the current data-exchange standards. Test results on several car parts with trimming curves are included. The, quality of the resulting surfaces is examined using the highlight line model.
Quantitative Selection of Inspection Plans
Authors: Chen Tony J. , Thornton Anna C.
Published: February 2021

Quality improvement methods such as robust design, statistical process control (SPC), and inspection have received significant attention over the past decade. Despite the plethora of research, there is very little work that describes how to allocate quality control methods in a complex system. This paper focuses on how to choose an inspection plan to remove the most variation at the lowest cost. This paper describes how to quantitatively allocate inspection locations in a complex assembly using a combination of modeling, simulation, and simulated annealing. It demonstrates the functionality of the theory using an example from the aircraft industry. The model provides three improvements over current methods: 1) methods to optimize both inspection limits and inspection locations, 2) the ability to mix both rework and scrap, 3) explicit calculation of the probability distributions for each point in the assembly.
A Product Platform Concept Exploration Method for Product Family Design
Authors: Simpson Timothy W. , Maier Jonathan R. A. , Mistree Farrokh
Published: February 2021

Today’s highly competitive, global marketplace is redefining the way companies do business. Many companies are being faced with the challenge of providing as much variety as possible for the market with as little variety as possible between products in order to maintain economies of scale while satisfying a wide range of customer requirements. Developing a family of products — a group of related products derived from a common product platform — provides an efficient and effective means to realize sufficient product variety to satisfy a range of customer demands. In this paper the Product Platform Concept Exploration Method (PPCEM) is presented, providing a Method that facilitates the synthesis and Exploration of a common Product Platform Concept that can be scaled into an appropriate family of products. As an example, the PPCEM is employed to design a family of universal electric motors that are also compared against a benchmark group of individually designed motors. The focus in this paper, however, is on the PPCEM and not on the results, per se.
Transforming Functional Solutions Into Physical Solutions
Authors: Liu Y. C. , Chakrabarti A. , Bligh T. P.
Published: February 2021

The problem addressed is an issue of developing physical embodiments from a set of spatial configurations. These configurations are generated by a software program, FuncSION, for generating a wide range of concepts for mechanical design problems in conceptual design.

The method for transforming functional solutions to physical embodiments, consists of three steps: (1) to develop the relationships between each functional element and its physical embodiments, (2) to build the rule for ensuring interface compatibility between any two connecting objects, and (3) to develop reasoning procedures to replace each functional element in a spatial configuration with all its possible physical embodiments. Using this method, alternative physical embodiments for this spatial configuration can be found.

The outcome of the method is the presentation of physical embodiments, which leads to an improved visualisation of the spatial configurations, and an increase in the number of possible concepts.
Estimating Target Values in Preliminary Design: An Automotive Case Study
Authors: Brackin Patricia , Colton Jonathan
Published: February 2021

Estimation modules have been developed for use with the House of Quality. These estimation modules are used to predict the performance of a proposed design based on the values of the Engineering Characteristics. This, paper describes the development of modules for an automotive case study. Specifically, modules for weight, price, acceleration time, and fuel economy are given. Comparison of estimated values to actual values show an average percent difference of less than 10%.
Design Team Roles
Authors: Wilde Douglass J.
Published: February 2021

Methods used at Stanford to construct prize-winning student design teams are now available publically on a web site coded by graduate assistant Mike McNelly. Information supplied by the user is interpreted as interests in various roles a team member might assume. Then the site helps the user find potential team mates having different interests — the Stanford team construction strategy. The article shows how the team roles were developed from Jung’s Personality Theory.
Modeling Dependencies in Engineering Design
Authors: Wang Kai-Lu , Jin Yan
Published: February 2021

Collaborative engineering design involves coordination among designers. While coordination in most cases entails explicit communication between designers, the real reason for designers to coordinate with each other is not for communication but for resolving engineering dependencies. In the field of collaborative engineering research, various computer models and tools have been developed to facilitate communication among designers aiming to improve their communication efficiency for coordination. We argue that in order to provide effective and purposeful coordination support, one must understand how engineering dependencies evolve and propagate in different phases, of design, from problem definition, conceptual design, to detail design. In our research on collaborative design, we take a dependency-based approach, i.e., to explicitly capture and manipulate dependencies and create design processes and support tools based on explicit understanding of underlying dependencies. The long term goal of our research is to develop a dependency-based coordination framework that consists of a formal model of engineering dependencies and coordination mechanisms, mapping between the dependencies and coordination methods, and guidelines and procedures for dependency-based work process design and management. This paper describes our current status of developing a formal model of engineering dependencies.
Introducing a Use Perspective in Product Design Theory and Methodology
Authors: Warell Anders V.
Published: February 2021

In this paper it is argued that methods are needed for the design of a larger variety of product aspects than is feasible with mechanical engineering design methodology of today. Design methods found within the European schools of design are inadequate for the design of products other than machine systems of transforming character. The reason for this is that the underlying theories only describe the nature of ‘operand-transforming’ technical systems, and that the description of the process and function systems are too narrowly defined to be useful for the design of ‘non-transforming’ products, or for products where the human is involved as an active user.

The paper takes as the standpoint that the functional language, in accordance with established foundation in engineering design theory, is a successful means to treat usability aspects of human-product systems. An extended process modeling view based on product life-phase thinking including a ‘use-process’ is presented, focusing the attention towards the use, and not merely the workings, of the product. Also, extended definitions of a number of concepts are proposed, and function-classes of the human-product system, leading to a more generally applicable use of functions as a modeling tool when describing products, is introduced. The proposed functional language is illustrated in a product case example.
Educational Interactive Multimedia Software: Can it Effectively Teach Engineering Concepts?
Authors: Reamon Derek T. , Sheppard Sheri D.
Published: February 2021

This paper provides a rigorous statistical analysis of the educational effectiveness of a curriculum module pertaining to direct current (DC) motors and motorized systems. Educational interactive multimedia software played an important role in the module, which also included lectures, a design project and other more traditional pedagogics. Pre- and post-tests were administered to measure learning during the module and individual test questions targeted specific areas of the curriculum to determine the contribution of the various resources to the entire learning environment. The data indicate that the module was indeed educationally successful and that the software contributed to the curriculum’s success. The module was particularly effective for promoting learning by female engineering students in the course and mitigated some discrepancies in prior knowledge. Students were also grouped into four preference groups based on analysis of students’ preference questionnaire responses. The data indicate that each preference group responded differently to the various teaching techniques employed in the curriculum.
A Framework for Modelling and Analysis of Engineering Information Management Systems
Authors: Svensson Daniel , Malmström Johan , Pikosz Peter , Malmqvist Johan
Published: February 2021

This paper presents a framework for modelling and analysing complex Engineering Information Management systems (EIM systems1). Using the framework, a “holistic” model of an EIM system is constructed by four basic interrelated aspect models, respectively describing the process, the information, the role and the computer systems aspects of the EIM system. The framework further provides several methods for analysing the aspect models and the relationships between the models. The paper shows one example of such an EIM system model and discusses results from case studies in which the framework has been applied.
Global New Product Development Strategies and I.T. Applications
Authors: Balbontin Alejandro , Yazdani Baback
Published: February 2021

This report presents the results of the 1998 Global New Product Development Survey, carried-out by the Warwick Manufacturing Group at the University of Warwick (UK). The survey is based on a questionnaire addressed to 637 firms with turnover greater than £ 30 million ($ 45 million), operating in the UK across key industrial sectors and engaged in New Product Development (NPD). Response rate was of 8%.

Global NPD practices include product standardization, the strategy used to allocate NPD centers (related to business units and geographically), the level of centralization of tasks, the level of NPD outsourcing, the use of external collaboration and the use of Information Technology (IT) applications to support the NPD process. It was found that firms with products designed for global markets have about an 8 times greater potential to export than those firms who only standardize core components. Firms that collaborate more with external entities implement universal products more easily. Based on the “pretax profit in the last four years of business activity”, the respondent firms with losses have an average of 7 business sectors, whereas the top ten profitable firms have an average of only 4 business sectors, this relationship also applies to NPD activities. It was found that firms manage the collaborative ventures through either team members or team leaders and that top management involvement is only on a small scale. IT communication tools (e-mail and video-conferencing), followed by administration tools (project-planning and presentation software) are the main priorities in firms with widely distributed teams.
XML and Java: Engineering Software Development Meets Internet Technologies
Authors: Hagemann Dirk
Published: February 2021

XML and Java show vast potential to improve software interoperability and to facilitate data exchange across applications from various disciplines and vendors — a pivotal prerequisite for effectivity and efficiency in computer-aided collaborative product development. The paper dicusses aspects of software and data integration with regard to computer-aided engineering tools and introduces main characteristics of XML and Java. Examples of engineering software developed at IKMF employing XML and Java accompany the discourse.
Agent-Based Knowledge Management for Collaborative Engineering
Authors: Jin Yan , Zhou Weihua
Published: February 2021

Collaborative engineering is knowledge work in the sense that engineers and managers must apply their knowledge to solve their problems and proceed with their work. The knowledge that is applied spans from the basic knowledge they learned from schools, application knowledge acquired from the industry, and experiential knowledge obtained from years of working experience. Most of the current research on collaborative engineering support focuses on providing communication and data sharing support for effective coordination. We argue that in order to increase the productivity of current practice of collaborative engineering, we need mechanisms that can not only facilitate information flow, but also provide active knowledge level support for engineers. Our research on KICAD — a Knowledge Infrastructure for Collaborative and Agent-based Design — attempts to develop a network of intelligent agents that capture knowledge from their associated human engineers and provide knowledge level support to them when needed. Among the issues involved in developing such a framework is the issue of knowledge management — how can we model knowledge, how can agents capture, update, manage, and utilize the knowledge for human support? In this paper, we first briefly introduce the KICAD research program and describe the issue of knowledge management in KICAD. After that we present a general knowledge application model (GKAM), the basic conceptual framework of knowledge management in KICAD. An example of applying GKAM in a prototype system will also be discussed.
Integrated Product and Production Data Management Based on Generic Bill of Materials and Operations to Support Mass Customization Production
Authors: Jiao Jianxin , Tseng Mitchell M. , Ma Qinhai , Zou Yi
Published: February 2021

This paper discusses the integrated product and production data management for mass customization production which is characterized by a large number of variety. A data structure, called Bill-of-Materials-and-Operations (BOMO), is proposed for the purpose of unifying BOMs and routings in order to facilitate better production planning and control, as well as order processing and engineering change control. To deal with variety effectively, a generic BOMO concept is put forward based on an understanding of a generic variety structure developed in the paper for characterizing variety. The merits of the generic BOMO for integrated product and production data management are detailed in terms of customer order processing, engineering change control, production job planning, costing, and integrated material and capacity planning. A prototype implementation of the proposed generic BOMO methodology in souvenir clock manufacturing is also reported.
Structural Damage Detection and Identification Using Learning Vector Quantization Neural Network
Authors: Shi Qinzhong , Hagiwara Ichiro , Sekine Toshiaki
Published: February 2021

This research deals with the structural damage detection by experimental measured modal parameters, such as the modal frequencies and the modal shapes. Changes of local structural parameters, induced by damage, will affect the local stiffness and cause the change of modal frequencies and modal shapes of structure. Use of these observable values to detect the damage of the structure is feasible and implement. Learning Vector Quantization (LVQ) Neural Network based on pattern classifier is used to detect the location of damage, and a method of releasing the dense of input vector to neural network is proposed to increase the accuracy of detection. Several numerical examples show the proposed method is effective to increase the rate of damage detection. Finally, a practical application example of damage detection for a turbine blade is used to demonstrate and verify the approach developed.
Self-Powered Active Vibration Control With Continuous Control Input: Application to a Cab Suspension of a Heavy Duty Truck
Authors: Nakano Kimihiko , Suda Yoshihiro , Nakadai Shigeyuki
Published: February 2021

Active vibration control using regenerated vibration energy, i.e., self-powered active control, is proposed. In the self-powered active control system, vibration energy is regenerated by an electric generator, which is called an energy regenerative damper, and is stored in the condenser. An actuator achieves active vibration control using the energy stored in the condenser. The variable-value resistance whose value can be controlled by a computer is utilized to control output force of the actuator. The authors examine the performance of the self-powered active vibration control on experiments and propose to apply this system to cab suspensions of a heavy duty truck. Through experiments, it is shown that the self-powered active vibration control system has better isolation performance than a semi-active and a passive control system. Numerical simulations demonstrate better isolation performance of the self-powered active vibration control in cab suspensions of a heavy duty truck.
Development of a Pipe Positioning System Using a 5-DOF Suspension Mechanism
Authors: Hayatsu Masaki , Imaoka Shizuo , Tagawa Yasutaka
Published: February 2021

Decreasing the number of skilled workers and utilization of automated machines is becoming a general trend at plant construction sites. For this reason, an automated pipe positioning system using a 5-DOF suspension mechanism has been developed as an important automated tool for power plant construction sites. This device is expected to be used for not only assisting less skilled operators, but also making operations more efficient at plant construction sites.

This paper mainly focuses on the control system design and the control performance of the proposed positioning system. The controller is designed based on the disturbance observer concept. The pipe positioning system has a 5-DOF suspension mechanism which consists of five stepping motors and chains. A relationship between the actuator space (chain length) and the task space (position and attitude of the pipe center of gravity) is expressed using the Jacobian matrix, and each element of this Jacobian matrix is generally a nonlinear function in space. Therefore the plant in this system is nonlinear. In this study, a disturbance observer concept is used to remove this nonlinearlity, then a conventional linear feedback control low is applied to the control system. The control performance is verified through experiments using a pipe with a diameter of 0.3m. In the experiments, trajectories of the pipe center of gravity with the Jacobian nonlinearly compensation is compared to the trajectories without Jacobian compensation case, and the effectiveness of this pipe positioning system is shown.
Simultaneous Optimization of a Flexible Robot Arm
Authors: Zhu Ye , Qiu Jinhao , Tani Junji
Published: February 2021

Integrated structure/control design of a one-link flexible robot arm is investigated in this paper. The arm consists of a tip mass, a flexible link and a hub and is driven by the hub motor to reach pre-defined tip position and suppress residual flexural vibrations. The arm is modeled using finite element method and the cross-sectional dimensions of the beam elements are used as structural design variables. A sliding mode controller and a linear stabilizer are used to regulate the arm position. The structural and control parameters are optimized simultaneously using genetic algorithm and the simulation results show the advantages of the new design method: faster regulation and less weight for the optimized arm than a uniform arm.
Control System Design of a Repulsive Magnetic Bearing Stabilized by the Motion Control of Permanent Magnets
Authors: Mizuno Takeshi , Hara Yusuke , Araki Kenji
Published: February 2021

The control system of a magnetic bearing system using forces of repulsion between permanent magnets was designed on a state-feedback basis. In the treated magnetic bearing, the radial motions of the rotor were passively supported by repulsive forces and the axial motion was stabilized by active control. Stabilization was achieved by using the motion control of the permanent magnets for passive radial suspension; these magnets were driven by voice coil motors in the axial direction. Experimental results showed that the designed controllers achieved contactless levitation and adjusted the levitation characteristics effectively by the assignment of closed-loop poles.
Mass Measurement System With Dual Reaction-Mass Type Actuators
Authors: Mizuno Takeshi , Negishi Takeshi
Published: February 2021

A mass measurement system using two reaction-mass type actuators as a vibration generator and a vibration absorber were studied both theoretically and experimentally. In the system, a measurement object is attached to one reaction mass. The principles and features of the measurement system were described. An experimental apparatus was developed in which bimorph-type piezoelectric actuators were used to drive the masses. The experimental results demonstrated that the developed system could measure mass accurately.
Determination of the Transfer Function for the Mechanical Objects Along Transitional Response
Authors: Rimantas Dapkus , Kastytis Sarkauskas , Stanislovas Bartkeyicius
Published: February 2021

The paper deals with the mechanical object’s transfer function determination using theoretical presumption, which earlier practically was not possible apply because of large error of the calculations. The determination of the transfer function could be carried out along transitional response of the mechanical object, by implementation of the proposed new mathematical method and using new created software.
High-Speed Driving of a Lateral Guided Vehicle With Sensor Steering Mechanism
Authors: Takita Yoshihiro
Published: February 2021

This paper proposes a simple relation of the lateral guidance mechanism for automatic, guided vehicles and Dual Mode Trucks, and named it SSM (Sensor Steering Mechanism). SSM consists of a guide bar and deceleration gear which reduces the bar angle to one-second. In order to demonstrate the effectiveness of this relation, this paper examines the stability of the dynamic behavior of the front wheel steering of the vehicle. These results show that there is no limitation of the moving speed unless without a slip of the tire. For the test, a self-standing mobile robot, reduced to a scale of one-twentieth of the real car, is developed. Experimental results show that high-speed automatic moving is realized by using this relation.
Active Reduction of Sound Transmission Through a Double Panel Partition
Authors: De Fonseca P. , Sas P. , Van Brussel H.
Published: February 2021

The paper addresses the active control of the sound transmission through a double panel partition. A literature survey indicates that active cavity control is much more efficient than active structural control. The vibro-acoustic behaviour of the double wall is analysed in light of this observation. This analysis shows that the sound transmission through the double panel is larger than that through a single panel at the resonances of the coupled eigenmodes with the strongest vibro-acoustic coupling between the plate motion and the pressure in the cavity. At frequencies where the double panel radiates much sound energy, the acoustic energy in the cavity is also high. Active control simulations illustrate that the cavity control approach, reducing not only the uncoupled (0,0,0) mode, achieves a considerable reduction of the sound transmission over a large frequency band. Depending on the desired noise reduction, the complexity and the cost of the control system can be reduced by a proper diagonalisation of the controller and by a clustering of the sensors and the actuators.
Design of a Highly Integrated Active Magnetic Bearing With Six Coupled Actuators for High Precision Rotation Applications
Authors: Kümmerle M. , Aeschlimann B. , Zoethout J. , Belfroid T. , Vuillemin R. , Bleuler H.
Published: February 2021

This paper presents the design and the implementation of a contact free Active Magnetic Bearing (AMB) for high precision rotation applications. For controlling five Degrees of Freedom (DOF) of the rotor six coupled reluctance force actuators (creating radial and axial forces at the same time) are used. A method for designing the actuators in order to meet the specifications is described.

Two different controller schemes using different sensor configurations have been implemented on a functional prototype: On the one hand a conventional decentralized PID controller, on the other hand a more centralized structure.
Acceleration Feedback for Suppression of Friction Induced Limit Cycles in Direct Drives
Authors: Babinski Alexander , Tsao Tsu-Chin
Published: February 2021

This paper presents describing function analysis and control solution for a friction related problem encountered during the development of a voice coil actuated direct drive for use in turning of automotive camshafts. It is observed that the addition of a high accuracy tracking (repetitive) controller results in a system that is susceptible to limit cycle oscillations induced by Coulomb friction. A local acceleration feedback loop is utilized to shape the system response to disturbance forces and is shown to improve the drive stiffness and prevent performance deterioration due to friction.
Modal Actuators and Sensors
Authors: Gawronski Wodek
Published: February 2021

The paper introduces a method of determination of locations and gains of actuators and sensors that excite and measure a single mode, or a set of selected modes with assigned amplitudes. The method is illustrated with the clamped beam example, where a single (second) mode is excited and measured, all 9 modes are excited and measured, and all 9 but the second modes are excited and measured.
Application of the Physics of Failure Approach to Reliability Prediction for Design Guidance of Commercial Appliance Components
Authors: Steiner Mark W. , Zagray Ken , Ganti Surya , Hasan Omar
Published: February 2021

The physics of failure approach to reliability prediction considers fundamental failure mechanisms such as fatigue, wear, corrosion and creep that can shorten the useful life of a product. The work described here uses this approach for commercial appliance components and presents three examples. This paper also outlines a methodology for developing rate modification factors. These rate modification factors can be used for evaluating design changes, early estimation of failure rates, planning accelerated life tests and assessing risks in component application alternatives. Although the physics of failure approach is not new, the application to relatively inexpensive light service commercially based components extends the application beyond the realm of military and heavy industrial equipment. Simplifying assumptions and the use of manufacturer’s material properties are utilized to create a “cookbook” approach for development of design charts useful for improving product reliability. The principal objective of the work presented here is to demonstrate the development of the design charts and their application to commercially based products.
Removal of Chromium From Contaminated Water
Authors: Jahanian Shariar , Rostami Hossein
Published: February 2021

Over the past 15 years, about one half million sites with potential contamination have been reported to federal or state authorities. Of these, about 217,000 sites still need remediation (1) and new contaminated sites continue to appear each year. The most common type of contaminants are metals, solvents and petroleum products. Heavy metals are present in two thirds of DOD and superfund sites and about 50% of DOE and RCRA sites.

AAM is a new material that possesses the ability to remove heavy metal from conaminated water. AAM consists of fly ash activating chemicals and fillers. AAM barrier material was used to remove Cr from contamination water. Fly ash from three different sources were used to produce reactive barrier of different permeability. AAM materials with permeability 10−2 to 10−1 was created. Only highest permeability proved to be viable for reactive barrier material. AAM barrier from three ash sources with permeability of 10−1 was produced and crushed into pelletized form. To determine effectiveness of the various barriers batch test was performed, based on that result the column test was conducted.

In this work contamination barrier with controled permeabilty was tested to determine its ability to remove Cr from contaminated water. AAM barrier material was used in column test to remove Cr from 1000 ppm and 10 ppm solution. The results show that AAM barrier is very effective in removing Cr from highly contaminated water (up 99% efficiency).
The Design of a Universal Autonomous Power Tray
Authors: Choi Jin , Lai Yuk , Harrison Nathan , Curiel Robert
Published: February 2021

Several accessories have been developed to aid the wheelchair-confined individual in retaining their social independence. However, after a comprehensive study it was determined that a device, which would automatically extend the immediate reach of the handicapped individual, could not be easily added to such currently existing wheelchairs. We proposed a device that could easily be attached to the back of the electric wheelchair. This unit contains all necessary hardware to support the movement of an actuating arm whose intent is to automatically deliver and retrieve objects outside the person’s immediate reach. In addition, the unit does not significantly exceed the dimensions of the chair so as to not obstruct its normal use. To maximize our efforts, we re-evaluated the creativity of its construction: This was done to optimize its durability, reliability, and ultimately lower its construction cost. The ease of its manufacturing supports our intent for a universal application so that all handicapped individuals could benefit from this device as an after-market electric wheelchair accessory.

Achieving these types of functions required the development of two pneumatic telescoping arms that can match and overcome its maximum load of 15 lb., and an electrical control system that both develops arid defines all object motions. A comprehensive static and dynamic analysis was performed to, determine the forces governing the motion of the arm as well as to predict its operating speed and direction. This analysis also tests the boundaries of our control system. This information allowed us to determine the range and limitations that defined the electrical as well as mechanical components of this system.
Chipper/Shredder: The Pull-in Hypothesis
Authors: Barnett Ralph L. , Brickman Dennis B.
Published: February 2021

On rare occasions, a portion of an uncut fiber will exit the discharge chute of a consumer hammer mill type chipper/shredder and remain at rest with its inboard portion in the neighborhood of the rotating elements. Disturbing the fiber may cause it to commit to the rotating flails and be pulled instantaneously back into the machine. A number of investigators have postulated that an operator who grasps a fiber that subsequently experiences this pull-in phenomenon cannot release it fast enough to avoid being dragged into the flails. This hypothesis is discredited by both analytical and experimental analyses.
Nonlinear Dynamics of Coupled Nonlinear Oscillators: Using of Complex Variables
Authors: Manevitch L. I.
Published: February 2021

We present an asymptotic approach to the analysis of coupled nonlinear oscillators with asymmetric nonlinearity based on the complex representation of the dynamic equations The ideas of the approach are previously given on the example of the system with two degrees of freedom. The special attention is paid to the study of localized normal modes in the chain of weakly coupled nonlinear oscillators. We discuss also certain peculiarities of the localization of excitations in the case of strong coupling between oscillators.
Hamiltonian Systems, Pseudo-Poisson Brackets and Their Scattering Representation for Physical Systems
Authors: Maschke B. M. J. , van der Schaft A. J.
Published: February 2021

This paper is concerned with the definition of the geometric structure of Hamiltonian systems associated with energy–conserving systems in relation with an interconnection topology of their network model. It is also presented how the symplectic structure of standard Hamiltonian systems has to be extended to pseudo–Poisson tensors in order to cope with invariants, equilibria and constraints. Finally a scattering representation of these pseudo–Poisson tensors is defined.
Nonlinear Dynamics of the Bombardier Beetle
Authors: Rand Richard H. , Wirkus Erika T. , Cooke J. Robert
Published: February 2021

This work investigates the dynamics by which the bombardier beetle releases a pulsed jet of fluid as a defense mechanism. A mathematical model is proposed which takes the form of a pair of piece wise continuous differential equations with dependent variables as fluid pressure and quantity of reactant. The model is shown to exhibit an effective equilibrium point (EEP). Conditions for the existence, classification and stability of an EEP are derived and these are applied to the model of the bombardier beetle.
Steady-State Non-Synchronous and Localized Responses of Tuned Pendulum Vibration Absorbers
Authors: Al-suwaiyan Abdallah S. , Shaw Steven W.
Published: February 2021

Previous analytical studies of Centrifugal Pendulum Vibration Absorber (CPVA) systems have focused on the dynamics of either a single absorber mass or multiple absorber masses moving along very special paths. In this paper, an approach is taken that allows one to investigate the dynamics of multi-absorber systems that have quite general paths for the absorber masses, including those used in practice. Of particular interest here are the existence and stability of certain classes of non-unison responses, including those in which the amplitude of a sub-group of absorbers is larger than the expected unison response. It is shown via the method of averaging that these steady state responses may exist and be stable for certain types of paths, including the commonly-used mistuned circular path. Furthermore, it is shown that these responses can co-exist with a stable unison response, even for very small torque levels. The analytical results are compared with numerical simulations and good agreement is found.
Nonlinear Dynamics of Orthogonal Metal Cutting: Experimental Studies
Authors: Foong Chee-Hoe , Wiercigroch Marian , Deans William F.
Published: February 2021

The elimination of chatter is one of the major aims in machining to improve geometrical accuracy and surface finish. In this study, occurrence of chatter was investigated experimentally using a specially designed rig by examining time histories of the cutting and thrust force components. A broad experimental study was conducted using brass, cast iron and aluminium samples. It was found that by changing the horizontal stiffness of the rig, the thrust force variations (in the vertical direction) were completely eliminated for the cast iron samples. A systematic analysis of the chip formation for the aluminium alloy is presented.
Computer Based Model of Vibro-Impact Driving
Authors: Lok Howe Ping , Neilson Richard D. , Rodger Albert A.
Published: February 2021

A computer based model of a novel vibro-impact ground moling system is presented as an aid to designing such systems. The equations of motion governing the system are presented and a corresponding laboratory model is described. The model includes elasto-plastic modelling of the end resistance and Coulomb terms for side resistance between the soil and the body of the moling system. Results for both penetration time histories and end resistance time histories from both the model and the rig are presented which show that the model can adequately predict the motion of the mole for design purposes.
Estimation of the Largest Lyapunov Exponent of Discontinuous Systems Using Chaos Synchronization
Authors: Stefanski Andrzej , Wojewoda Jerzy , Kapitaniak Tomasz , Brindley John
Published: February 2021

Properties of chaos synchronization have been used for estimation of the largest Lyapunov exponent of a discontinuous mechanical system. A method for such estimation is proposed and an example is shown, based on coupling of two identical systems with dry friction which is modelled according to the Popp-Stelter formula.
Nonlinear Dynamics in the Estimation of Rotor-Bearing Dynamic Properties in Large Hydro-Units*
Authors: Zhang X. Z. , Liu B. G.
Published: February 2021

This paper describes a method with which the nonlinear dynamic response and the natural features of rotor-bearing systems in large hydro-units can be estimated on a personal computer. The key step of this process is to estimate the dynamic eccentricity of the journal center in every guide bearing when the system is subjected to dynamic loads. As an example, the nonlinear dynamic responses, the natural frequencies and the critical speeds of the rotor-bearing system of a 240MW hydro-unit are calculated. The calculated dynamic responses agree well with the ones measured in the field.