bluuebunny/crossref_metadata_2025 huggingface dataset:
Planar Cable-Direct-Driven Robots: Part II — Dynamics and Control
Authors: Gallina Paolo , Rossi Aldo , Williams Robert L.
Published: November 2020

A hybrid parallel/serial manipulator architecture was introduced in a companion paper where the translational freedoms are provided by a cable-direct-driven robot (CDDR) and the rotational freedoms are provided by a serial wrist mechanism. While the companion paper presents kinematics and statics, the current paper presents a dynamics model and simulated control for planar CDDRs. Examples are presented to compare the planar 3-cable CDDR with one degree of actuation redundancy and the 4-cable CDDR with two degrees of actuation redundancy. It was found that the 4-cable tracking error was worse than for the 3-cable case, due to increased inertia with an additional actuator. Also, the controller architecture considers including and not including a feedforward reference acceleration term with the overall mass matrix; the performance of the controller with the feedforward term is clearly preferable.
Chinese Natural Language Oriented Dynamic Knowledge Extraction: A Case Study of Intelligent Design
Authors: Xiao Renbin , Chang Ming , Zhan Hongbin , Su Mu
Published: November 2020

In view of the existed problems of knowledge acquisition in intelligent systems, a dynamic knowledge extraction method based on Chinese natural language sentence-clustering is put forward, and the corresponding software prototype system is implemented. First of all, the proposed method is introduced in the paper by the way to give its outline. In order to demonstrate an important role of the proposed method, we make a complete case study via the intelligent design of certain machine tool. The design background of such a product is presented and the implementation steps is given in detail to show the whole design process. Through the practical case, we have succeeded in extracting knowledge from natural language text and the effectiveness of the proposed method is verified.
Proposal of an Integrated Design Support Environment Based on the Model of Synthesis
Authors: Yoshioka Masaharu , Nomaguchi Yutaka , Tomiyama Tetsuo
Published: November 2020

We propose a new integrated computational environment, called a Knowledge Intensive Engineering Framework (KIEF), to support design object modeling, during engineering design process that requires a variety of design object models, such as a geometric model, a control model, and a finite element model. KIEF is capable of guiding designers with design process knowledge based on a model of synthesis, of integrating multiple design object models, and of maintaining consistency among these models. The design process knowledge is a result of a research project we conduct to establish a model of synthesis. This model formalizes design process knowledge in a design process as operations to a multiple model-based reasoning system, such as KIEF, and from a language of synthesis. We describe a prototype system that incorporates design process knowledge to KIEF and illustrate an example design on it.
Fluid Mechanics of Slot Coating in Layered Manufacturing
Authors: Haberer M. , Zak G. , Park C. B. , Paraschivoiu M. , Benhabib B.
Published: November 2020

This paper addresses the fluid mechanics of the slot-coating process within the context of the layered manufacturing system. The investigation was carried out to assist with the design of a novel slot-coating-based liquid-layer-formation subsystem. This subsystem, when used as a part of a lithography-based Rapid Layered Composite parts Manufacturing (RLCM) system, successfully solves some of the difficulties encountered in the formation of thin layers from a highly viscous fibre-photopolymer composite liquid.

In addition to an analytical model, the paper presents a numerical model based on a volume of fluid (VOF) algorithm. The algorithm allows (1) solution of non-steady-state problems, (2) tracking of the free surface of the fluid undergoing large deformations, and (3) easy modification of model’s domain to facilitate experimentation with coater geometry. Results from a set of simulated experiments are reported which show the relationship between the liquid coat height and several design and process parameters. Examination of cross-sections of test parts built on an RLCM prototype system confirmed the ability of the new coater design to form solid layers of good quality.
Fuzzy Reform and Optimization of Design Task in Concurrent Engineering
Authors: Zhao Yong , Cha Jianzhong , Zhang Junfeng
Published: November 2020

With the increasing of global market competition and dynamic change of market environment, consumer needs are more personal and diversified, enterprise production is more flexible. At present, the production cycle period of traditional manufacturing industry is long, delivering goods is not in time, product quality is not good and resource are not used in reason. Because of the phenomena, products are not met the requirements of market and lack of market competition ability. For changing the situation, the development direction is building concurrent agility dynamic alliance of product development. So this paper puts forward an improved fuzzy reform optimization method of design task in Concurrent engineering (CE). Using this method, enterprise can develop product rapidly to satisfy consumer requirements and have high quality, low cost, reasonable price and good service, that is because it can assign right task to right person in right time for shortening development time of product.
Conflict Elimination of Product Concurrent Design Based on Blackboard Model
Authors: Zhao Yong , Cha Jianzhong , Zhang Junfeng
Published: November 2020

As to product design itself has quite complexity and many domain influence factors are integrated in concurrent design (CD), conflict phenomena exists in any process of carrying out CD. Conflict elimination is an important key to carrying out CD effectively. Conflict usually relates to many members in multifunction group of CD. Negotiation that is a process of multiple iteration and repeated alternation is utilized in CD conflict elimination. Many objects and constraints are considered in the process of negotiation and it is very hard to have no problem in the process of calculation, reasoning, evaluation and decisionmaking. As to the updating error is a tracing process and a lot of work done before is needed to repeat, efficiency of conflict elimination is very low. In this paper, a method of conflict elimination of product CD based on blackboard model is put forward. Design conflict producing, system and mechanism of conflict elimination based on blackboard model are analyzed and described. It takes gear CD conflict elimination as an example to illustrate the concrete application of the method and system.
Qualitative Reasoning for Decision Synthesis
Authors: Kazmer David , Zhu Liang
Published: November 2020

A qualitative reasoning approach is presented for decision support. This approach is initiated with the generation and normalization of a qualitative model including relationship matrix, importance weightings, control limits for decision variables, and specification limits for performance attributes. An extensive Simplex method is then utilized for mapping the global feasibility of the decision problem. Finally, the approach interprets and simplifies the results from the multi-dimensional feasibility space back to the qualitative model. The paper also presents application of the approach to process tuning of multilayer sheet extrusion and concept development of a 2nd generation reusable launch vehicle to orbit.

The results indicate that the developed approach is a viable alternative to currently practiced decision analysis methods. Specifically, the approach uses: 1) tightened specification limits rather than a weighted multi-attribute objective relationship, 2) determines global system feasibility from active constraints rather than local parametric optimization, and 3) establishes correlations based on dynamic Pareto-optimal frontiers rather than manual estimations. While the approach is potentially useful, further research is required to extend the methods to non-linear, stochastic, and uncharacterized engineering systems.
Using Yielded Cost As a Metric for Modeling Manufacturing Processes
Authors: Becker Daniel V. , Sandborn Peter
Published: November 2020

Yielded cost is defined as cost divided by yield and can be used as a metric for representing an effective cost per good (non-defective) assembly for a manufacturing process. Although yielded cost is not a new concept, it has no consistent definition in engineering literature, and several different formulations and interpretations exist in the context of manufacturing and assembly.

In manufacturing, yield is the probability that an assembly is non-defective. To find the effective cost per good assembly that is invested in the manufacturing or assembly process, cost is accumulated and divided by yield.

This paper reviews and correlates existing yielded cost formulations and presents a new method that enables consistent measurement of sequential process flows. This new method views the yielded cost associated with an individual process step (step yielded cost) as the change in the process’s yielded cost when the step is removed from the process. This approach is preferred because it incorporates upstream and downstream information and because it provides a specific process step’s effective cost per good assembly that is independent of step order between steps that scrap defective product (i.e., test steps).

Conventional wisdom dictates that the best way to improve a process is to increase the yield of the lowest yield step. The new approach developed in this paper produces an auxiliary cost that can be used to determine the best method of improving processes that, for complex processes, does not always correspond to improving the lowest yield step.

Simple and complex assembly process examples are presented to demonstrate the interpretation of yielded cost. The new approach is applied to a microwave module (MWM) manufacturing and assembly process example.
Assembly Redesign for Rapid Prototyping
Authors: Wu J. , Tan S. T. , Sze W. S.
Published: November 2020

Reducing cost and increasing productivity is always the goal of the industry. In traditional manufacturing, considerable cost is consumed on assembly. With the emergence of rapid prototyping (RP), product development shows a new way and assembly process is possible to be eliminated. In this paper, the possibility is investigated and a scheme based on assembly CAD solid model is proposed. Assemblies after redesign have simplified structures and less number of parts and can be fabricated in one go in a RP machine. Multiple material issue is also addressed in this paper.
Feature-Based, Design-Concurrent Cost Calculation Using Case-Based Reasoning (CBR)
Authors: Layer Alexander , Haasis Siegmar , van Houten Fred
Published: November 2020

For the successful launch of a product, the product costs are just as important as product quality and functionality. This paper gives an overview about recent work in the field of cost estimation and process planning and derives the requirements of a cost calculation system for design-concurrent use, because up to now there is no such system that has widespread application within the industry. For this reason the paper presents a concept for design-concurrent cost calculation, using feature-technology and case-based reasoning. This concept overcomes the shortcomings of existing methods and applications and fulfils the targets to be met for a generic cost calculation method.
Towards Massively Parallel MEMS Assembly
Authors: Abbott Mark W. , Sturges Robert H.
Published: November 2020

Microelectromechanical System (MEMS) are miniaturized sensor and actuator systems built with mechanical and/or electrical components. Applications for MEMS devices range from optical switches to biomedical devices and microrobots. Fabrication of MEMS is dominated by bulk micromachining techniques with an additional enhancement of wafer-to-wafer bonding. These combined techniques use lithography to selectively etch substrates and bond dissimilar types of parts and substrates together to fabricate MEMS parts. However, the difficulties in compatible process requirements for the different technologies, e.g. CMOS, gallium arsenide, polysilicon, or silicon nitride, has resulted in the design and implementation of hybrid MEMS devices, those devices that use more than one technology. This paper presents a starting point to explore the possibilities of assembling hybrid MEMS devices on a wafer-to-wafer scale. Assembly will be broken down into two categories, serial and parallel, that will be discussed in two scenerios and considered with regard to gripper technologies and possible applications. This new assembly approach is a topic for the Design for Manufacturing community to consider for translating their knowledge of macroscopic assembly into the micro domain. We believe that a successful investigation into the tolerances and techniques required for the massively parallel assembly of MEMS scale devices will result in a smaller number of fabrication steps and a high yield of increasingly complex MEMS devices.
Design of an Evaluative Tool for a Multi-Station Injection Molding System Using an Evolutionary Algorithm
Authors: Wolf A. R. , Shu L. H. , Venter R. D.
Published: November 2020

A tool to facilitate the feasibility study of a newly proposed multi-station injection molding system is developed. The conceptual design and proposed embodiment of the new system are geared toward the development of a system flexible enough to handle multiple part types and production volumes. A comprehensive design model is used to structure the problem by identifying the desired design objectives and the effect the system variables have on the final design. An Evolutionary Algorithm optimization is used to find the combination of system variables that yields optimal system outputs. The algorithm uses a number of components customized to suit the design requirements of the proposed system. This optimization and evaluation process provides a basis by which the new system can be compared with traditional injection molding practices. Results confirm that the new multi-station system is less affected by the degree of product variety than traditional molding machines.
Transformation Invariant Shape Similarity Comparison of Solid Models
Authors: McWherter David , Peabody Mitchell , Regli William C. , Shokoufandeh Ali
Published: November 2020

This paper presents two complementary approaches to comparing the shape and topology of solid models. First, we develop a mapping of solid models to Model Signature Graphs (MSGs) — labeled, undirected graphs that abstract the boundary representation of the model and capture relevant shape and engineering attributes. Model Signature Graphs are then used to define metric spaces over arbitrary sets of solid models. This paper introduces two such metric spaces: first, a mapping of MSGs to a high-dimension vector space where euclidean distance measures are applied; second, a distance computation performed between graph spectra constructed from MSGs using spectral graph theoretic techniques.

In practice, exact computation of the edit distance between model signature graphs is believed to be an NP-hard problem. We show that properties of the design signature graph’s spectra, derived from the eigenvalues of its adjacency matrix, can be used as a efficient and tractable approximation of the edit distance.

Lastly, we provide empirical results using real test data from the National Design Repository (http://www.designrepository.org) to validate our approach. We argue comparisons among solid models in these metric space are immune to problems caused by inexactness and ambiguity arising from basic modeling transformations (scale, translation, rotation, sheer, etc.). It is our belief that this work contributes to a growing body of techniques for comparing models and indexing CAD media types in database systems.
Concurrent Product Development Across the Supply Chain: Development of Integrator/Supplier Risk and Coupling Indices
Authors: Esterman Marcos , Ishii Kosuke
Published: November 2020

This paper develops the fundamental requirements, definitions and metrics that will serve as a foundation for a method to aid in concurrent product development (CPD) across the supply chain. A case study at HP validated nine sources of CPD uncertainty and identified four new important ideas that led to five key requirements for CPD across the supply chain. The concepts of degree of design customization and degree of coupling are introduced as a framework by which to evaluate the risk introduced into the product development process by suppliers. The engineering metric supplier coupling, the engineering metric deviation from target and the degree of design customization indices are defined and integrated into a process to facilitate risk assessment from the integrator’s perspective both at the system-level and supplier-level. The paper concludes by presenting the future research agenda.
Void Elimination Algorithm for Extrusion-Based Layered Manufacturing
Authors: Qiu Dan , Langrana Noshir A.
Published: November 2020

For extrusion based multi-material layered manufacturing (LM) processes, a CAD system has been developed which generates high quality toolpath for part fabrication. This closed loop CAD system includes solid model design & slicing, single-material toolpath generation, multi-material toolpath generation and virtual simulation modules. The solid model is sliced equally. Intelligent features and adaptive roadwidth optimum toolpath generation algorithm computes void sizes & their location and generates void free toolpath. The virtual simulation visualizes and validates the toolpath generated for the part. When the computed toolpath quality is acceptable, it is sent to the in house hardware Fused Deposition of Multiple Ceramics (FDMC) machine for fabrication.
Application of a Genetic Algorithm for Segmentation of a Ship Hull for FF-TLOM and for 3-Axis Milling
Authors: Koelman Herbert J. , Horváth Imre
Published: November 2020

Physical concept modeling and pre-manufacturing prototyping of ship hulls are becoming more and more important due to the strong need for better quality ships, for optimization of the global performance, and for involving the customers in the development process. Physical models are typically scale models, which are used during and after design for various purposes such as shape presentation, arrangement investigation, and hydrodynamic testing. Due to their large size, single piece prototyping of ship hulls is usually not possible. The large-scale models have to be decomposed to manufacturable elements, for example, segments, layers and sectors. This paper presents a genetic algorithm-based decomposition for two specific manufacturing technologies: free-form thick-layered object manufacturing and three-axis high-speed milling. The fabrication tools used in these technologies require an unobstructed access to the cut surface. The proposed segmentation technique allows decomposition of the CAD model of a ship hull into manufacturing segments. The decomposition has been considered a non-gradient optimization problem, for which the developed genetic algorithm can be applied effectively. Examples for segmentation to support FF-TLOM and TA-HSM are presented.
Visualization of Milling Processes on Internet
Authors: Sormaz Dusan N. , Borse Prashant A.
Published: November 2020

In current environment of simultaneous product development, the Internet is being recognized as the best platform for implementation of virtual manufacturing organization located at different global places. This paper represents a step towards the integration of product development teams and introduces a novel method for visualization of manufacturing processes in order to verify the process plans generated. The paper presents the pilot implementation in VRML with JavaScript as a scripting language for dynamic nature of the program. Using the concepts of Geometric representation of the Manufacturing processes a program in C++ language is developed, which supplies data for animation. The results are presented on Internet by developing a web page for Visualization of Manufacturing Processes.
A Mixed Integer Programming Formulation for Generating Shared Press-Brake Setups
Authors: Gupta Satyandra K. , Rajagopal Deepak
Published: November 2020

To enable cost-effective small batch manufacturing, we need to eliminate unnecessary setup operations, improve tool utilization, and thereby increase throughput. In sheet metal bending, the time taken for the actual process of bending is significantly less compared to the time taken for setup and tool changes. Press-brakes for sheet metal bending can be setup to produce more than one type of parts without requiring a setup change. To exploit this flexibility, we need setup planning techniques so that press-brake setups can be shared among many different parts. In this paper, we describe an approach based on mixed integer programming to generate a shared setup for a set of parts. We expect that by producing many different types of parts on the same setup, we can significantly reduce the number of setups required and enable cost-effective small-batch manufacturing.
Possible Sources of Sub-Optimisation in Design for Manufacture: An Initial Survey
Authors: Gregory M. J. , Fan I.-S.
Published: November 2020

This paper surveys the human and technical problems that may occur in manufacturing and how they may be prevented in design. Advice and guidance on Design for Manufacture was sought from textbooks, journal articles and conference papers that aim to improve the process or report on difficulties. Potential problems are classified and related to the sources of knowledge available to prevent these problems reaching the shop floor. The detail analysis is presented in this paper. This structured approach could assist in planning CE processes, especially communications and teamworking, so that potential problems are addressed in a comprehensive manner so as to minimise the costs, effort and delay needed to avoid them.
Designing a Requirement Driven Product Development Process
Authors: Dong Qi , Whitney Daniel E.
Published: November 2020

This paper presents a technique to obtain a Design Structure Matrix (DSM) from a Design Matrix (DM). This technique enables us to obtain the design information flow pattern at early stage of the design, and apply the DSM system analysis and management techniques at the time when the most important decisions about the system and the design are made. The validity of this method is proven using a case study on the design integration process of an electrostatic chuck used in semiconductor wafer processing. The algorithm underlying this technique is also proven logically and mathematically to be valid.
A Methodology for Reusing Freeform Shape Content
Authors: Vergeest Joris S. M. , Horváth Imre , Spanjaard Sander
Published: November 2020

The reuse of precedent designs is a significant profit factor in new product development. In industry there is a tendency to enhance the reuse process by applying digital scanning of 3D parts, sampling imported, normative CAD models or by deploying a digital library of design concepts. The data thus obtained should be inserted into the design model. The available techniques typically originate from reverse engineering applications. However, to support shape reuse during conceptual design a dedicated methodology and workflow are needed. Using our methodology, the designer selects existing products, or parts, or portions of them. Then he/she specifies where and how the selected portion should be inserted into the new design. The key issue of the methodology is the explicit distinction between the variables that the designer does or does not wants to control. The underlying technology, including shape matching, shape parameter fitting and shape merging must be mostly invisible to the user, except for those controls that intrinsically affect the resulting shape. One application of the methodology is a freeform feature copy-and-paste facility based on 3D scanning and fitting of existent designs. The technical feasibility of such an approach will be addressed.
Identifying Shared Understanding in Design Using Document Analysis
Authors: Hill Andrew , Song Shuang , Dong Andy , Agogino Alice
Published: November 2020

Design as a social activity characterized by information exchange, compromise and negotiation frames much of out understanding of the design process. At the heart of this social activity is the development of a shared understanding of the design problem. The design stakeholders jointly form a shared understanding through a process of defining the problem, exploring the space of solutions and searching for information. A shared understanding is a critical element in successful, collaborative design. This paper describes a formal approach for identifying shared understanding in design by analyzing the documentation. By mining the documentation for signatures of a shared understanding, specifically a common frame of reference and a similar voice, a shared language and vocabulary of the design could emerge. Information management tools built around the shared understanding would be more effective in directing and alerting the design team of relevant information.
Platform Product Development: Product Model — A System Structure Composed of Configurable Components
Authors: Claesson Anders , Johannesson Hans , Gedell Stellan
Published: November 2020

This paper describes how the functional behavior and embodiment of design solutions can be modeled using configurable components. The concept of a system structure composed of configurable components is defined and put in context of business requirements as well as in context of design theory and more specifically the chromosome model and function-means-trees. The paper contends that this kind of product description is necessary from a business perspective in order to successfully manage development of derivative products and product variants based on a product platform concept. The concepts presented in this paper is currently being deployed at Saab Automobile as the next logical evolution of product description systems necessary in order to maintain competitiveness in the automotive business.
Transformation of an EGT Grammar: New Grammar, New Designs
Authors: Li Xin , Schmidt Linda , He Weidong , Li Lixing , Qian Yuanmei
Published: November 2020

Grammars generate design options through the application of predefined rules that transform collections of symbols into more meaningful expressions. Research on the nature of grammars tells us that writing the rules is where the fundamental design activity occurs. Using the grammar rules allows us to explicitly articulate one design at a time. We can exploit the design power of grammars further by modifying a grammar to describe new languages of designs. Here we examine an existing grammar to demonstrate how modifying its rule base to relax an assumption can expand the space of solutions it generates significantly. We show that investing our design attention on the grammar itself can yield dramatic results.
Longitudinal Design Teams: Students Teaching Students
Authors: Rice Janet M. , Allen Robert H. , Shoukas Artin A.
Published: November 2020

We report on the characteristics of our year-long Longitudinal Design Team (LDT) courses, which have been taught since Fall 1998. Our main goal in these courses is to have teams of undergraduates at all educational levels work together solving problems that involve design in biomedical engineering.

Consisting of about ten students, each team is composed mostly of freshmen, who, with the help of upperclassmen mentors and an upperclassman Team Leader, are able to use the knowledge they have gained in their introductory courses and from their life experiences and apply it to biomedical engineering problems. In the Fall semester, teams work on one or two projects, where they design, perform, measure and apply principles of physics to develop an understanding of a bio-mechanical event. In the spring, teams work on individual design projects proposed by “customers.” Faculty mentors interact with the team leaders and they decide how to proceed with their respective projects. Because the course is open to all educational levels, freshman students often reregister for the course as more upper level students. In addition to a learning environment, the design team is also a place for underclassmen to develop relationships with upperclassmen and vice versa. These relationships have proved particularly useful to the freshmen in choosing their courses, as well as in deciding summer and research plans. The upperclassmen are also learning how the knowledge they have gained in their coursework applies to solving practical problems. Although only in operation for three years, others perceive tangible results as well. In particular, the majority of customers are satisfied with the prototypes they receive. These preliminary results indicate that this unique program helps our students become acclimated to our curriculum and in preparing them for their profession.
Maximising Opportunities for Collaboration Between Universities and Small to Medium Size Enterprises
Authors: Burvill Colin R. , Lewis William P.
Published: November 2020

This paper is about collaborative relationships between manufacturing industry and universities in Australia, with particular reference to small to medium size enterprises (SME’s) because of their prevalence and their importance to the economies of industrialised countries. To put local conditions in perspective, it should be recorded that the annual output of Australian manufacturing industry currently is in excess of $100 billion (Australian dollars) of which 30% is exported [1]. The role of the Government in promoting collaboration between industry and universities, and the associated knowledge transfer, is exemplified by a senior body sponsored by the Australian Commonwealth Government.
Experiences in Integrating the Product Realization Process Into the Design Curriculum
Authors: Doepker Philip E. , Murray Andrew P.
Published: November 2020

This paper outlines many of our experiences in the implementation of the Product Realization Process (PRP) in industry sponsored team design projects. There are three areas of emphasis. The first part reviews the Product Realization Process as implemented in our senior design courses. The second part presents and evaluates the data for the time spent on project phases and the total project. This aspect has been studied previously with industry projects and was found to be a useful way of evaluating projects as related to the PRP. The paper concludes with the lessons learned after 5 years of implementing these projects.
Emphasizing Decision Analysis Techniques in the Design Curriculum
Authors: Bailey Reid , Doepker Phil
Published: November 2020

Theoretically strong decision approaches such as utility theory are currently being researched for use in engineering design. Countless ad hoc decision tools have preceded this recent work, yet only a handful of these tools are used by industry or taught in universities. Reasons for the emergence of such a small number of acceptable decision tools are not known. In this paper, the opinions of undergraduate engineering students in an industry-sponsored senior design class and their sponsor mentors are studied to identify reasons why some decision tools are more popular than others. Two established decision tools were introduced to the class and used in the projects. A survey was used to gather student and sponsor opinions about the two tools and important aspects of decision tools. Results indicate a variety of factors influencing the students’ preference of one decision tool, including simplicity, clarity of results, the ability to give more emphasis to certain criteria, and ease of communication of results to their sponsors. Other results from the study include information about strategies for integrating decision tools into a design process and the role of projects in promoting reflection and learning by students.
Early Lessons in Executing Distributed Collaborative Student Design Projects
Authors: Murray Andrew P. , Stevens Jon M. , Smari Waleed W. , Kremer Gregory G. , Marquart Jed E.
Published: November 2020

In this paper we review two student design projects executed under a geographically distributed protocol. Our pilot design project occurred at the University of Dayton between the 5th and 14th of July, 2000. We assembled a small group of students into a distributed design team and assigned a rudimentary project via an audio chat session. Most team members were prohibited from face-to-face interaction during the ten-day period. To communicate and share data, they were required to use either the set of collaborative tools installed on each member’s personal computer or a telephone. The second project occurred from January to May 2001, involving students from Ohio University, Ohio Northern University and the University of Dayton. There were no artificial restrictions on the interactions amongst the team members as in the pilot project. However, the distance between the students made collaborating in a distributed fashion a necessity. This paper presents an overview of the design projects and the collaborative tools used, observations about our experiences executing design under this protocol, and future directions for this work.
Application of Double Impact Oscillator in Forming
Authors: Peterka František
Published: November 2020

The double impact oscillator represents two symmetrically arranged single impact oscillators. It is the model of a forming machine, which does not spread the impact impulses into its neighborhood. The anti-phase impact motion of this system has the identical dynamics as the single system. The in-phase motion and the influence of asymmetries of the system parameters are studied using numerical simulations. Theoretical and simulation results are verified experimentally.
Modeling for Optimization (MO-OP): Tools for Manufacturing and Design Engineering Problems
Authors: Gadallah Mohamed H. , El-Mounayri Hazim
Published: November 2020

In this paper, a new statistical optimization technique is proposed. The technique employs new variance reduction schemes (VRTs). The performance of three standard designs: L27/L27 OA, L54/L27 OA and L243 / L27 OA are studied. These designs, although both orthogonal and balanced, exhibit high variance reduction properties with questionable convergence in very short number of iterations. Four new composite designs are developed, implemented and compared with the standard ones. These designs are known as: 5-, 7-, 9- and 11-point composite L27 OA. The problem of tolerance allocation with optimal process selection is revisited as a case study for simulation. Results indicate the efficiency of these new designs to reduce variances to lower levels than standard designs and better convergence in fraction of experiments. These designs are then integrated in an optimization algorithm previously developed (Gadallah, M.H., 2000). The algorithm is then modified to deal with the least sensitive optimal solutions for standard and composite designs. Particularly, the parameters that affect the algorithm are varied and their effects on performance of algorithm are studied. A standard manufacturing case study is used for analysis and simulation results for the composite designs are also given.
Development and Validation of a S-N Based Two Phase Bending Fatigue Life Prediction Model
Authors: Singh Avinash
Published: November 2020

The stress-life (S-N) method along with the Palmgren-Miner cumulative damage theory is the simplest and the most commonly used fatigue life prediction technique. Its main advantage is that the material properties needed are easy to collect and life calculation is simple. However under many variable amplitude loading conditions, life predictions have been found to be unreliable. Various modifications have been proposed to the Palmgren-Miner theory, but they have not lead to more reliable life predictions.

In this paper, a two-stage cumulative damage model will be developed and validated. This model divides fatigue life into two phases — a crack initiation phase and a crack propagation phase. It will be shown that the proposed method results in greatly improved life prediction capabilities. Also, the proposed method retains the simplicity of the S-N based approach in that the material data is still relatively simple to generate and the calculations are straightforward.
A Procedure for Fast Evaluation of High-Cycle Fatigue Under Multiaxial Random Loading
Authors: Li Bin , de Freitas Manuel
Published: November 2020

This paper presents a fast evaluation procedure for high-cycle fatigue (HCF) under multiaxial random loading. The recent multiaxial cycle counting method of Wang and Brown is used to identify the loading reversals. For each identified reversal, the effective shear stress amplitude is directly calculated from the component stress ranges by an equation derived from the MCE approach, which is a newly developed method to account for non-proportional loading effect. This shear stress amplitude and the maximum hydrostatic stress during the time period of an identified reversal are used to evaluate the fatigue damage for that reversal by Crossland’s criterion. The fatigue damage of the loading block is then calculated by summing the damages of all the identified reversals by Miner’s rule. Comparisons with other multiaxial HCF approaches show that the procedure is a computationally efficient and conservative engineering approach.
Study of Thin Film-Edge Induced Stresses in Silicon Substrates by Infrared Photoelasticity
Authors: Peng H. J. , Wong S. P. , Zhao Shounan
Published: November 2020

In this work, we shall report the direct observation of the stress field in the silicon substrate induced by an oxide thin film edge using the infrared (IR) photoelastic (PE) method. Our experimental results showed that the earlier analytical solutions cannot give a satisfactory description of the observed IR PE stress fringe patterns. A simple model is developed to treat the stress field under the film edge as a superposition of two contributions. One term is as described by the concentrated force model proposed by Hu which is singular at the thin film edge. The other term is non-singular corresponding to the contribution as described by the bimetallic strip theory. The simulation images of stress fringe patterns are obtained according to this model. Good agreement is found between the simulated and experimental stress fringe patterns. In addition, the effects of film thickness and substrate thickness on the stress distribution in this structure were also investigated.
Comparative Study Between CWT and STFT for On-Line Health Monitoring Applications in Systems Under Random Excitation
Authors: Alonso Raul J. , Noori Mohammad , Masuda Arata , Hou Zhikun
Published: November 2020

Two time-frequency signal analysis methods, based on results of Continuous Wavelet Transform, and the Short Time Fourier Transform are compare for the purpose of on-line health monitoring application in systems subjected to random loads. A classic example with a simple signal is used to differentiate the characteristics of the two transforms suggesting the possible preference of a Wavelet Transform based approach over the Short Time Fourier Transform. Another example including a single degree of freedom system subjected to random loads proves how the inherent variable window capabilities on the Wavelet Transform perform better than the constant window length nature of the Short Time Fourier Transform for on-line health monitoring application.
Application of Harmonic Wavelet Analysis to Soil Motion Data
Authors: Teymur Berrak , Madabhushi S. P. Gopal
Published: November 2020

This paper presents techniques which employ frequency response and wavelet analysis to identify damage in soils. Experimental data is obtained by dynamic centrifuge modeling. Dynamic centrifuge model experiments generate complex data. Harmonic wavelet analysis provides a good way to analyse them. In this paper the experimental technique will be explained along with typical time-frequency maps. With harmonic wavelet analysis, the signal features that cannot be observed from classical Fourier analysis were seen. Harmonic wavelet analysis provide a new insight into the boundary effects in the Equivalent Shear Beam (ESB) model container used in the experimental work.
Non-Stationary Response of Non-Linear SDOF Systems by Perturbation of Wavelet Coefficients
Authors: Chatterjee Pranesh , Basu Biswajit
Published: November 2020

A wavelet based random vibration theory has been developed for the non-stationary seismic response of single degree of freedom (SDOF) systems with cubic type non-linearity in the spring force. The ground motion process has been characterized by statistical functionals of wavelet coefficients. The wavelet transformed coefficient of the displacement response of the oscillator has been perturbed to obtain a series of wavelet domain algebraic equations. The stochastic response of the system has been obtained by using these sets of wavelet domain equations. The root mean square (r.m.s.) displacement response has been obtained in terms of the functionals of the input wavelet coefficients. Parametric variations are carried out to observe the effects of variation of the magnitudes of non-linear spring stiffness on the temporal variation of instantaneous r.m.s. values of oscillator displacements.
Modeling of Track-Wheel-Terrain Interaction for Dynamic Simulation of Tracked Vehicles: Numerical Implementation and Further Results
Authors: Ma Zheng-Dong , Perkins N. C.
Published: November 2020

This paper extends the methods and results of a previous paper (Ma and Perkins, 1999) on simulating track-wheel-terrain interaction for tracked vehicle dynamics. A new solution algorithm is described that includes an adaptive finite element method for remeshing the track model during simulation. Doing so produces a track model that more accurately describes the mechanics of a track as the vehicle negotiates rough terrain. The model and solution algorithm are illustrated using a full vehicle model of an M1A1 tank.
Multibody Systems With Distributed Piezoelectric Actors and Sensors in Flexible Bodies
Authors: Rose Michael , Sachau Delf
Published: November 2020

Efficiency in high speed mechanism can be further increased by use of lightweight construction. But quite often these structures have the drawback of being susceptible to vibrations. This can be overcome by applying the technology of smart structures. Here distributed actuators and sensors made from piezoceramic (PZT) material are capable to actively reduce the unwelcome vibrations if implemented within a control loop. For the optimal design of such kind of mechanism up-to-date simulation tools have to be developed further. To simulate the dynamic behavior of lightweight structures undergoing large motions the multi-body approach is a suitable tool. The necessary parameters in the equations of motion for the flexible body can be calculated from the output of a finite element code. The large number of variables from the finite element model have to be reduced to only a few generalized coordinates. Therefore a modal reduction is applied in combination with the introduction of a moving frame of reference. Beyond this technique so called active modes are introduced to represent the impact of the active strain by the PZT patches. These active modes combined with natural modes represent the body deformation within the multibody model. As an example the slider/crank mechanism with actively controlled PZT patches on the crank is simulated.
A Unified Development of Basis Reduction Methods for Rotor Blades
Authors: Ruzicka Gene C. , Hodges Dewey H.
Published: November 2020

The axial foreshortening effect plays a key role in rotor blade dynamics, but approximating it accurately in reduced basis models has long posed a difficult problem for analysts. Recently, though, several methods have been shown to be effective in obtaining accurate, reduced basis models for rotor blades. These methods are the axial elongation method, the mixed finite element method, and the nonlinear normal mode method. The main objective of this paper is to demonstrate the close relationships among these methods, which are seemingly disparate at first glance. First, the difficulties inherent in obtaining reduced basis models of rotor blades are illustrated by examining the modal reduction accuracy of several blade analysis formulations. It is shown that classical, displacement-based finite elements are ill-suited for rotor blade analysis because they cannot accurately represent the axial strain in modal space, and that this problem may be solved by employing the axial force as a variable in the analysis. It is shown that the mixed finite element method is a convenient means for accomplishing this, and the derivation of a mixed finite element for rotor blade analysis is outlined. A shortcoming of the mixed finite element method is that it increases the number of variables in the analysis. It is demonstrated that this problem may be rectified by solving for the axial displacements in terms of the axial forces and the bending displacements. Effectively, this procedure constitutes a generalization of the widely used axial elongation method to blades of arbitrary topology. The procedure is developed first for a single element, and then extended to an arbitrary assemblage of elements of arbitrary type. Finally, it is shown that the generalized axial elongation method is essentially an approximate solution for an invariant manifold that can be used as the basis for a nonlinear normal mode.
A Proposal of Advanced Modeling for Motion and Vibration in Flexible Structures
Authors: Sagane Takahito , Shono Takashi , Adachi Kazuhito , Kinoshita Takao , Tajima Hiroshi , Seto Kazuto
Published: November 2020

This paper proposes a modeling technique for motion and vibration in flexible structures. We call this technique ‘extended reduced order physical model’. Because vibration is generally influenced by motion, it is necessary to analyze vibration together with motion. New modeling technique can be used to represent both motion and vibration. Effectiveness of this technique is confirmed by characteristics of vibration of a flexible rectangular plate with free support through simulation in this study. Target modes, the first bending and the first torsional modes of the structure reappeared.
A Recursive Implementation Method With Implicit Integrator for Multibody Dynamics
Authors: Cho H. J. , Ryu H. S. , Bae D. S. , Choi J. H. , Ross B.
Published: November 2020

A recursive implementation method for the equations of motion and kinematics is presented. Computational structure of the kinematic and dynamic equations is exploited to systematically implement a dynamic analysis program RecurDyn. A differential algebraic equation solution method with implicit numerical integrators is discussed. Virtual body concept is introduced for the flexible body dynamics. The accuracy of the flexible body solutions is estimated by an error measure and is improved by the dynamic correction mode method. Several examples are solved to demonstrate the efficiency of the proposed methods.