bluuebunny/crossref_metadata_2025 huggingface dataset:
Multi-Direction Slicing for Layered Manufacturing
Authors: Singh Prabhjot , Dutta Debasish
Published: December 2020

Parts made by Layered Manufacturing (LM) have a limited surface accuracy and their build time is often long due to the deposition of sacrificial support structure. However, LM machines with an ability to deposit along multiple directions can improve upon the surface quality and reduce the support volume. In this paper we consider multi-directional slicing, present algorithms and implemented examples.
ASUPPA: A Framework for Interactive and Iterative Synthesis and Improvement of Process Plans
Authors: Li Xiaomin , Kambhampati Subbarao , Shah Jami
Published: December 2020

The limited success and acceptance of automated process planning methods in the industry can be traced to the fact that most existing approaches aim at complete automation. We believe that the quest for complete automation is flawed, both because in practice optimality metrics for process plans are context-sensitive, and because there is significant organizational resistance to approaches that completely eliminate humans from the process planning framework. In this paper, we present an interactive and iterative planning framework, called ASUPPA, which focuses instead on providing intelligent assistance to a human process planner. After generating a “good” default process plan, ASUPPA engages in a “present – elicit criticism – revise” loop with an expert process planner. To operate successfully, ASUPPA needs access to the full search space of process plans, and have the ability to incrementally modify plans in response to expert criticism. The former is provided by basing ASUPPA on ASU Features Testbed, a comprehensive and systematic framework for recognizing and reasoning with features in machinable parts. To support the latter, the system is equipped with an iterative and interactive search mechanism. We will discuss the operational details of the resultant system, called ASUPPA.
Agent-Based NC Process Planning for Complete Machining on Turning Centers
Authors: Storr Alfred , Li Rui , Stroehle Hansjoerg
Published: December 2020

The application of turning centers for complete machining greatly increases production efficiency by means of introducing new machining possibilities. At the same time, it makes the generation of NC process plans more complicated and as a result the current process planning methods often fail in dealing with the new requirements. Based on agent theory this paper presents a new strategy for distributing a complex planning task to different relatively small planning units, so-called agents, which are defined considering both machine and workpiece structure. Instead of a central algorithm the agent based planning method generates NC process plans through some cooperative activities between different agents. The activity model and the cooperation rule are also discussed in detail.
Generation of Robust Error Recovery Logic in Assembly Systems Using Multi-Level Optimization and Genetic Programming
Authors: Baydar Cem M. , Saitou Kazuhiro
Published: December 2020

Automated assembly lines are subject to unexpected failures, which can cause costly shutdowns. Generally, these errors are handled by human experts or logic controllers. However, these controller codes are based on anticipated error scenarios and are deficient in dealing with unforeseen situations. In our previous work (Baydar and Saitou, 2000a), an approach for the automated generation of error recovery logic was discussed. The method is based on three-dimensional geometric modeling of the assembly line to generate error recovery logic in an “off-line” manner using Genetic Programming. The scope of our previous work was focused on finding an error recovery algorithm from a predefined error case. However due to the geometrical features of the assembly lines, there may be cases which can be detected as the same type of error by the sensors. Therefore robustness must be assured in the sense of having a common recovery algorithm for similar cases during the recovery sequence. In this paper, an extension of our previous study is presented to overcome this problem. An assembly line is modeled and from the given error cases optimum way of error recovery is investigated using multi-level optimization. The obtained results showed that the infrastructure is capable of finding robust error recovery algorithms and multi-level optimization procedure improved the process. It is expected that the results of this study will be combined with the automatic error generation, resulting in efficient ways to automated error recovery logic synthesis.
Deviplan: A Bid Preparation System for Mechanical SMEs
Authors: Kiritsis Dimitris , Xirouchakis Paul
Published: December 2020

The problem under consideration is the cost estimation and consequent bid preparation for machined parts subcontracted to mechanical small and medium enterprises (SME). This activity, i.e. cost estimation and corresponding bid preparation, becomes more and more important due to the increasing and globalized competition in this market. There is, therefore, a clear need for precise and accurate cost estimation of machined parts in order for a small company to justify its prices. The proposed prototype software system is based (i) on a manufacturing feature based product description of the part to be machined and (ii) on a non-linear model of its process plan using Petri nets, taking into consideration processing alternatives and precedence constraints, which allows a heuristic based best search of the process plan and, consequently, the corresponding machining time and cost. Product description is done interactively through user friendly interfaces and the corresponding process planning model is constructed automatically in the form of a Petri net. Machine tools and their characteristics are selected from a customized database. Tools and machining parameters are selected through a link with the tool management software TOOL Light©. Minimum time or cost process plans and corresponding bids are reported using the Petri net model of the machined part under consideration and using machining heuristics. The type of parts that are considered in our application are rotational or prismatic parts that are used as components in complex machines like machine tools or automatic assembly machines.
A Decomposition Methodology for Machining Feature Extraction
Authors: Ramesh Madhumati M. , Yip-Hoi Derek , Dutta Debasish
Published: December 2020

Many applications such as computer aided process planning require an interpretation of the complex geometry of a mechanical part in terms of simpler local shapes such as machining features. Decomposition of non-polyhedral parts is difficult as compared to that of polyhedrons, but mechanical parts are seldom polyhedral. A decomposition method that makes use of primitives for planar and cylindrical faces of parts is presented in this paper. A semi-automatic method for mapping the resulting shapes to library-features is also presented. The proposed method for decomposition and mapping is simple, intuitive and easy to implement using standard geometric and solid modeling operators.
Robustness in Optimum Design of Freeform Mechanical Parts
Authors: Cholaseuk Dulyachot , Srinivasan Vijay , Modi Vijay
Published: December 2020

A method to identify robust designs of mechanical parts with free-form shapes is proposed. For each design, the geometry and operating conditions represent one design point in the design space, with noise altering the design point leading to a change in performance. A shape optimization process is conducted for each example problem. Each successive iteration during the process produces an iterative design point with the final one being the optimum design. Once the process is completed, a design of experiment approach is used to apply noise in order to generate samples around each and every iterative design point. Then a simple statistical method is utilized to analyze the samples in order to evaluate the robustness of each iterative design. The results show that an optimum design is not necessarily robust.
DoE Study in Building Surrogate Models for Complex Systems
Authors: Ge Ping , Wang Nanxin
Published: December 2020

Surrogate models are used as a substitute for sophisticated system analysis in engineering design in order to improve efficiency, enhance understanding of problem domains and facilitate multidisciplinary design trade-offs. However, the cost of acquiring knowledge and information needed to build high-quality surrogate models may greatly undermine the advantages of using them. This is particularly significant for building surrogate models in complex system design where collection of necessary modeling data can be extremely expensive. In the existing researches, though different Design of Experiment (DoE) techniques are proposed to reduce the cost of data collection, general guidelines are absent in applying these methods into different design scenarios in industrial practice. In our work, a study is conducted to investigate different DoE methods and their impact on building high-quality surrogate models for complex systems. Several DoE methods are studied and their effectiveness in highly nonlinear engineering domains are compared through case studies of a vehicle system design problem. This paper summarizes the study results and attempts to provide valuable knowledge for the related research and applications of DoE methods in building surrogate models for complex system designs.
Modified Hysteresis Model With New Energy Index
Authors: Zhang Haochuan , Ma Fai
Published: December 2020

A guideline for modifying the energy dissipation index used in the Bouc-Wen hysteresis model is given in order to overcome the fluctuation problem caused by the original index. The resulting energy dissipation index is a physically correct, non-decreasing function of time. A numerical example is also provided to demonstrate the performance of the new index.
Acoustic Emission: Data Analysis and Applications
Authors: Zheng Gangtie , Ma Fai
Published: December 2020

Some applications and state-of-art of acoustic emission techniques are introduced in the present paper through an overview of publications in acoustic emission techniques. Attention is given to applications of acoustic emission techniques to the condition monitoring and damage feature extractions of reinforced concrete structures. With the use of numerical examples, major acoustic emission signal processing methods such as the wavelet transform, the Gabor transform, the bilinear time-frequency distribution, and the cepstral analysis are discussed.
Fuzzy Quality Measures for Use in a Hierarchical Fuzzy Controller
Authors: Carlson Alan , Edwards Dean B. , Anderson Michael J.
Published: December 2020

This paper presents a control strategy that uses a hierarchical structure to arbitrate between recommendations from lower level modules. The lower level modules represent lower level tasks or behaviors. Each lower level module provides its own control recommendation based on its limited perception of the environment.

We introduce the concept of a fuzzy quality measure that may be used by the hierarchical controller to determine how best to fuse the individual recommendations. The Quality Measure provides an approximate determination of each control recommendations potential value.

The hierarchical partitioning reduces the cardinality of the rule base and decreases the number of system parameters, as compared to a monolithic structure. Optimization of the reduced parameter set is simpler and requires less time.
An Improvement of Phone-Based Interfaces System
Authors: Huang Yuan Mao , Ho Hsin-Ni
Published: December 2020

Applications of the interactive voice response system (IVRS) have been increased rapidly. However, deficiencies of phone-based interface systems (PBIS) suggest human factors considerations can improve design structures of the systems. To improve the existing phone-based interface systems, this study proposes an new interface style, which is based on the ‘standard-with-skips’ and the ‘hierarchy’ styles. This improved interface style can assist in saving time for both the novices and the experienced users and allows users to have more control. A new kind of identifier is also developed to facilitate procedures for reaching user goals. To reduce the workload in the working memory, a marking function is presented to give the users memory aids and prevent them from making errors. With consideration of these factors, an ideal modal is constructed and compared with existing systems.
Design and Implementation of High-Level Numerical Analysis Functions Based on Computational Arrays for Applications in Engineering
Authors: Cheng Harry H. , Hu Xudong , Lin Bin
Published: December 2020

This paper presents the design and implementation of high-level numerical analysis functions in CH, a superset of C language developed for the convenience of scientific and engineering computations. In CH, complex number is treated as a built-in data type, so that the syntaxes of complex arithmetic, relational operations, and built-in mathematical functions are the same as those for real numbers. The variable number of arguments is used in the built-in mathematical functions to simplify the computation of different branches of multi-valued complex functions. The computational arrays are introduced to handle the arrays in the numerical computations. Passing arrays of variable length by arrays of deferred-shape and arrays of assumed-shape to functions are discussed. These methods allow the arrays to be passed with their rank, dimensions and data types. A list of high-level numerical functions and two examples of the applications in the scientific and engineering are given in the paper.
Numerical Simulation and Experimental Validation on the Particle Trajectory in a Solid Propellant Rocket Chamber
Authors: Xiao Yumin , Amano R. S. , Cai Timin , Li Jiang
Published: December 2020

In solid rocket motors (SRMS) using aluminized composite solid propellants and submerged nozzles a two-phase flow pattern is one of the main flow characteristics needs to be investigated. The modeling and validation of two-phase flow are the focus in this research field. In this paper the authors first traced the particle trajectory in a SRM chamber by using numerical method, and then developed a new experimental method to measure the particle trajectory in a SRM chamber to validate the numerical results. The experimental method was based on the RTR (X-ray Real-time Radiography) technique and high-speed motion analyzer. A special method was developed to imitate the particle injection on the propellant surface. The calculation results and measurement data show that the trajectory obtained by numerical simulation was in good agreement with the measured one by imposing proper boundary conditions. For particles with diameter of 75μm, the initial velocity factor of particle is approximately 0.4, and the particles pass through the centerline in both calculation and experiment. The present method can be extended to study the impingement of particles on the wall and other related two-phase flow patterns.
Characterization of Cofficient of Friction in Dry Contact for Control of Vibrations in Machine Systems
Authors: Abdo Jamil , Farhang Kambiz , Meinhardt Glenn
Published: December 2020

A 2k factorial experiment is performed to ascertain the effect of four factors and their cross influence on friction between dry surfaces. The factors in this study include materials Young’s modulus, applied normal load, surface roughness and relative surface speed. For each combination of factors four replicates in addition to two center points are used to obtain an average coefficient of friction for dry contact. In the experiment 304 Stainless Steel and Alloy 6061 Aluminum are employed to provide the high and low levels of Young’s modulus. Results suggest that Young’s modulus has the most significant influence followed by velocity/modulus cross-coupling, surface roughness, load, and modulus/roughness. Analyses are carried out separately for the 304 Stainless Steel and alloy 6061 Aluminum to remove the effect of Young’s modulus. The results are used to obtain iso-friction curves that serve to establish force-speed control for prevention of stick-slip vibration.
Direct-Insertion Realization of Linear Modular Models of Engineering Systems Using Fixed Input-Output Structure
Authors: Byam Brooks P. , Radcliffe Clark J.
Published: December 2020

Computer modeling of engineering systems with a large number of interconnected multi degree of freedom (DOF) subsystems requires flexible modeling tools. Flexible modeling tools with arbitrary input-output structure formulate equations to fit the input-output structure of specific engineering systems at the cost of globally reformulating equations with every model change. Each equation formulation requires experimental performance verification. This can be particularly cumbersome in the design, development, and refinement of large models. In previous work Byam and Radcliffe designed modular modeling, a flexible modeling method that eliminates equation reformulation and enhances model experimental performance verification in large models. A fixed input-output structure for all multi DOF modular modeling elements eliminates equation reformulation. The cost is a connector constraint to assemble elements, thereby adding complexity to the global model. Solving linear modular models is a systematic realization of compatible standardized modular elements and connectors. In this work, a modular solution to linear models of engineering systems is defined. Structural and automotive examples are given.
Design of a Multi-Axis Diamond Wire Cutting Machine
Authors: Huang Jung-Tang , Cheng Yi-Sheng , Shih Sheng-Hsiung
Published: December 2020

This study attempts to develop a machine tool to let its cutting function and precision be able to compare with the counterpart of the wire-cut electrical discharge machine, and also can cut non-conducting materials. This machine tool is numerically controlled by a PC-based controller to cut some projected shapes defined on a single axis, dual axes or multiple axes. This machine is to use one diamond wire loop with motion in direction of Z-axis or a certain direction, to attain the function of cutting. The wire could be kept as straight as possible at the cutting zone and not to shift laterally from the feeding direction. Besides, a tension sensor based on CCD cameras is also installed to know the cutting force and reactions of the workpiece against the diamond wire so as to adjust the wire travelling speed and feedrate of the workpiece to cut the corner precisely.
Uncertainty Management in Automotive Crash: From Analysis to Simulation
Authors: Marczyk J. , Hoffmann R. , Krishnaswamy P.
Published: December 2020

The paper discusses automotive crash simulation in a stochastic context, whereby the uncertainties in vehicle properties, boundary and initial conditions are taken in to account by means of Monte Carlo simulation techniques. It is argued that, since crash is a non-repeatable phenomenon, qualification for crashw orthinessbased on a single test is not meaningful neither from a physical nor from a conceptual standpoint, and should be replaced by stochastic simulation in which the mentioned uncertainties are taken into account. In addition, a broad spectrum of impact angles and velocities should be considered in each scenario (frontal, rear, side, etc.). The advocated approach, due to the fact that it addresses a sample of the population of the to-be-manufactured cars, instead of a single idealized nominal car, possesses built-in robustness and therefore enables the entire problem to be viewed with a high level of confidence. Finally, it is shown that based on today’s deterministic CAE techniques, validation of numerical models via a single test is impossible.
A Generic Cooling Schedule for Simulated Annealing
Authors: Cantelmi Frank J. , Pelz Richard B. , Ogot Madara M.
Published: December 2020

Discrete-State Simulated Annealing (DSSA) is a version of Simulated Annealing (SA) having a generic cooling schedule which is totally independent of the problem being optimized. By employing a generic cooling schedule, DSSA does not incur the overhead computational costs associated with the tuning of the parameters that make up the cooling schedule. DSSA introduces a single parameter that sets the total number of discrete states available. This paper summarizes the algorithm and presents results for two studies. First, the performance of the DSSA algorithm is compared to that of a parameter-tuned SA algorithm. The DSSA algorithm is able to provide similar results without any parameter tuning. Second, a parameter study is undertaken to determine the effect of varying the total number of discrete states. The results suggest that the performance of the algorithm is insensitive to the total number of states.
A New Mathematical Model for Geometric Tolerances As Applied to Round Faces
Authors: Davidson J. K. , Mujezinovic A. , Shah J. J.
Published: December 2020

A new mathematical model is presented for the tolerances of planar surfaces. The model is compatible with the ASME Standard for geometric tolerances. Central to the new model is a Tolerance-Map, a hypothetical volume of points which corresponds to all possible locations and variations of a segment of a plane which can arise from tolerances on size, form, and orientation. Every Tolerance-Map®2 is a convex set. This model is one part of a bi-level model that we are developing for geometric tolerances. The new model makes stackup relations apparent in an assembly, and these can be used to allocate size and orientational tolerances; the same relations also can be used to identify sensitivities for these tolerances. Stackup relations are developed for parts where the centers of faces are offset laterally. All stackup relations can be met for 100% interchangeability or for a specified probability. Methods are introduced whereby designers can identify trade-offs and optimize the allocation of tolerances. Examples are presented that illustrate important features of the new model.
Effective Product Family Design Using Physical Programming and the Product Platform Concept Exploration Method
Authors: Messac Achille , Martinez Michael P. , Simpson Timothy W.
Published: December 2020

In an effort to produce more variety for today’s highly competitive market, companies are designing and developing families of products — groups of related products derived from common product platforms — to simultaneously satisfy multiple customer requirements. After reviewing the state of the art in product family and product platform design, we describe the Product Platform Concept Exploration Method (PPCEM) for designing common product platforms that can be scaled or “stretched” into a suitable family of products. This paper extends previous work by the authors through the novel integration of physical programming within the PPCEM to enable the product family design problem to be formulated using physically meaningful terms and preferences. The design of a family of universal electric motors is presented to demonstrate the effectiveness of the proposed approach. Performance gains are achieved in the motor family by utilizing physical programming within the PPCEM when compared to previous results.
Domain Independent Characterization of Parametric and Geometric Problems in Embodiment Design
Authors: Bettig Bernie , Shah Jami J. , Summers Joshua D.
Published: December 2020

In embodiment and detailed design one is often concerned with sizing and geometric arrangement. Constraint problems of satisfying certain relationships in feasible designs are often solved by domain specific procedures in design and manufacturing applications. This paper shows that a variety of such problems are reducible to a small set of generic problems solvable by domain-independent procedures. A taxonomy of constraint problem types is developed. The taxonomy is based on the types of entities, constraints, and tasks (reasoning or inquiry) that are to be performed. The “exemplar” is introduced as a new concept for describing complex situational patterns and extracting information of interest. Such a canonical representation of parametric problems is needed for designing cleaner interfaces between applications and generic solvers, as a basis for standardized data exchange between future CAD systems, and for providing the foundations for domain independent shells for parametric design.
Using a Multiple Concurrent Design Views Interface to Enhance Design Complexity Management
Authors: Baker Benjamin A. , Fish Russell D. , Cohen Elaine
Published: December 2020

Modern product design complexity is a problem faced by designers of complex geometric products. It is very difficult for a designer to assimilate the vast amounts of data necessary to produce and understand such complex designs in their totality. Recently, research has been done to better manage design complexity, but little or no work has been done with respect to user interfaces for complexity management tools.

In this research, we present a concurrent design views interface to enhance design complexity management. This user interface assists the designer in creation and visualization of complex design frameworks. These design views support different levels of design detail and complexity, and also provide hierarchical design decomposition of complex design frameworks. Concurrency between design views is maintained, thus increasing the overall power of the system. To demonstrate the validity and applicability of this approach in solving complexity management issues, a prototype system implementation of an intuitive user interface built upon an existing complexity management framework is presented.
A Variation-Based Methodology for Product Family Design
Authors: Nayak Raviraj U. , Chen Wei , Simpson Timothy W.
Published: December 2020

In recent years, considerable research has been directed towards the development of methods for designing families of products. In this paper, we present a Variation-Based Platform Design Methodology (VBPDM), which aims to satisfy a range of performance requirements using the smallest variation of the product designs in the family. In the first stage of the VBPDM, the common product platform around which the product family is to be developed is identified. A ranged set of solutions is found, represented by the mean and standard deviation of the input design variables, to meet a range of the different performance requirements for the product family. During this first stage, a compromise Decision Support Problem (DSP) is used to optimize the commonality goal that seeks to minimize the deviation of the input design variables, while satisfying the range of performance requirements. Those design variables that show small deviations are held constant to form the product platform. In the second stage of the VBPDM, each individual product is designed around the common platform such that the functional requirements of the product are best satisfied. As an example, the proposed method is used to develop a family of universal electric motors designed to meet a range of torque requirements. The results are compared against previous work.
Integrated Aerodynamic and Geometric Modeling for Hypersonic Vehicle Design
Authors: Bhungalia Amarshi A. , Zweber Jeffrey V. , Stevenson Mark D.
Published: December 2020

In the past, hypersonic aircraft and space launch vehicle designs were dependent on empirical methods that were developed and verified using wind tunnel testing. This process was time consuming and extremely expensive. The vehicle designers were forced to look for improved ways to assess the design because they needed to cut the design costs. This led to the development of high-speed aerodynamic analysis codes. These codes cut the design costs by reducing the number of wind tunnel tests that were required (and eliminating the associated time and expense). Currently, there are many different aerodynamic analysis codes, of different fidelities, available for use in the design process. One of these codes is the Supersonic/Hypersonic Arbitrary Body Program (S/HABP). Versions of S/HABP are implemented with varying pre and post-processing applications. Two of the common ones are the Aerodynamic Preliminary Analysis System (APAS) and Viscous Effects on Complex Configurations (VECC). Both APAS and VECC are stand-alone specialized codes that are not well integrated into the design process. This paper documents an application that was developed to improve the process of generating an aerodynamic analysis mesh for S/HABP from the geometric modeling activities that are needed for the overall vehicle design process.
Design Potential Concept for Reliability-Based Design Optimization
Authors: Choi Kyung K. , Tu Jian , Park Young H.
Published: December 2020

This paper presents a design potential concept for reliability-based design optimization by integrating the probability analysis into the design optimization process. The reliability-based system parameter design is illustrated by the design potential concept in a unified system space, where design potential surfaces are derived from first-order reliability methods and an adaptive strategy is developed for robust and more efficient probabilistic constraint evaluation. More important, the design potential concept provides an in-depth understanding of reliability-based design optimization and leads to a design potential method that can significantly accelerate the process of robust system parameter design optimization.
Parametric Engineering Design Tools and Applications
Authors: Rohm Tapie , Jones Chris L. , Tucker Scott S. , Jensen C. Greg
Published: December 2020

Recent collaborations with graduate students in Mechanical Engineering at Brigham Young University and industry, such as United Technologies (OTIS and Pratt & Whitney) and Honeywell (AlliedSignal) have resulted in significant advancements to the interactive and programmatic parametric design methodologies. This paper presents the basics of interactive parametric CAD design as a point-of-departure for our discussion of the programmatic approach. Further it will discuss the advantages and problems of using a programmatic parametric design approach to reduce design cycle time. This programmatic parametric approach involves the combination of vendor provided interactive CAD parametrics and native CAD toolkit development and customization. Finally it will focus on the advantages and drawbacks of this schema by using joint educational/ industrial examples. These advantages include improvements in the design/analysis/ manufacture process as well as in the overall communication between different engineering load centers.

The time and resource commitment to custom CAD development has haunted industry for decades. However, through new techniques and interfaces being explored and developed at BYU we propose a new graphical user interface for custom programming of CAD. This paper discusses the advantages that such an interface would have in reducing programming time and allowing the program to interoperate between multiple CAD packages with varying graphic kernels.
Interval Methods for B-Rep Model Verification and Rectification
Authors: Shen Guoling , Sakkalis Takis , Patrikalakis Nicholas M.
Published: December 2020

Boundary representation (B-rep) models often have geometric specifications inconsistent with their topological structures due to numerical errors. In this paper, we verify the geometric consistency of B-rep models and evaluate existing inconsistencies of such models using interval arithmetic. Moreover, we convert conventional B-rep models into interval solid models to correct them. An interval solid is defined as a collection of non-degenerate boxes whose union covers the intended exact boundary and is guaranteed to be gap-free. An example illustrates our method for model conversion.
Kinematic Approximation of Ruled Surfaces Using NURBS Motions of a Cylindrical Cutter
Authors: Xia J. , Ge Q. J.
Published: December 2020

This paper deals with the problem of 5-axis machining of ruled surfaces. It is well known that a ruled surface may be efficiently machined with a cylindrical cutter using the side milling process. This paper studies the problem of planning the tool motion for side milling of ruled surfaces as a kinematic approximation problem. The goal is to develop a new method for synthesizing a Non-Uniform Rational B-Spline (or NURBS) motion such that the swept surface of such a motion with a cylindrical cutter closely approximates a given ruled surface. First a NURBS motion is used to interpolate or approximate a set of discrete cutter locations for the side milling of a given ruled surface. Then the deBool control positions of the NURBS motion is fine-tuned to minimize the error between the swept surface of the cylindrical cutter under the NURBS motion and the desired ruled surface. In this way, the tool motion is represented by the set of deBoor control positions and associated knot sequence as opposed to a huge set of discrete cutter locations.
Experimental Design Issues for Simultaneous Fitting of Forward and Inverse Metamodels
Authors: Barton Russell R. , Meckesheimer Martin , Simpson Timothy W.
Published: December 2020

In engineering design, approximations to engineering simulation or analysis models can provide quick, approximate predictions of system or part performance as a function of system/part design parameters. There are often preliminary requirements for performance, which can be mapped to specific values of design parameters via an inverse model. Typically, only forward models exist explicitly, but an inverse approximation can be fitted. The quality of an approximation depends on the set of runs (the experiment design) used to fit the approximation. This paper examines experiment design construction strategies for simultaneously fitting forward and inverse approximation models, using the commonly applied measure of D-optimality.
Layered Manufacturing of Thin-Walled Parts
Authors: McMains Sara , Smith Jordan , Wang Jianlin , Séquin Carlo
Published: December 2020

We describe a new algorithm we have developed for making partially hollow layered parts with thin, dense walls of approximately uniform thickness, for faster build times and reduced material usage. We have implemented our algorithm on a fused deposition modeling (FDM) machine, using separate build volumes for a loosely filled interior and a thin, solid, exterior wall. The build volumes are derived as simple boolean combinations of slice contours and their offsets. We make use of an efficient algorithm for computing the Voronoi diagram of a general polygon as part of the process of creating offset contours. Our algorithm guarantees that the surface of the final part will be dense while still allowing an efficient build.
Interval Method for Interrogation of Implicit Solid Models
Authors: Chang Jack , Ganter Mark , Storti Duane
Published: December 2020

Computer-aided design/manufacturing (CAD/CAM) systems intended to support automated design and manufacturing applications such as shape generation and solid free-form fabrication (SFF) must provide not only methods for creating and editing models of objects to be manufactured, but also methods for interrogating the models. Interrogation refers to any process that derives information from the model. Typical interrogation tasks include determine surface area, volume or inertial properties, computing surface points and normals for rendering, and computing slice descriptions for SFF.

While currently available commercial modeling systems generally employ a boundary representation (B-rep) implementation of solid modeling, research efforts have considered implicit modeling schemes as a potential source of improved robustness. Implicit implementations are available for a broad range of modeling operations, but interrogation operations have been widely considered too costly for many applications.

This paper describes a method based on interval analysis for interrogating implicit solid models that aims at achieving both robustness and efficiency.
Can Finite Element Models Be Used to Aid in Calibrating a Crash Sensing System?
Authors: Lin Chin-Hsu , Neal Mark , Wang J. T.
Published: December 2020

A study is presented to address the question “Can finite element models be used to aid in calibrating a crash sensing system?” Details that are crucial for using a single vehicle model to simulate multiple testing conditions were identified and incorporated in a chosen vehicle model. The vehicle model was then used to simulate a set of no-deployment and all-deployment calibration events. The simulated results were compared with test data to assess the capability of the existing nonlinear finite element analysis in aiding sensing system calibration.
Application of Topological Optimization Program to the Danner Test Simulation
Authors: Mayer Robert R. , Maurer Detlev , Bottcher Curd
Published: December 2020

This study used a topological optimization program, TOPOPT, to optimize the crashworthiness performance of a small vehicle in a Danner test simulation. The Danner test is a low-speed test used by insurance companies to help set insurance premiums. New designs with added holes were developed using TOPOPT, and a procedure for applying the program to future vehicle programs was established.
Efficient Use of Finite Element Analysis in Early Design Phases
Authors: Eriksson Martin
Published: December 2020

The utilization of analytical/numerical techniques and methodologies within product development and design is seldom discussed in the literature. This leads to a loss of a holistic perspective on product development and design. The exclusion of analysis methods and techniques implies that their impact on the development/design procedures is considered negligible and is not regarded as a constituent part in the establishment of a generic product development procedure model.

The overall focus of the work presented in this paper has been to show how extensions and adaptations of available techniques can be introduced in the mechanical engineering design process, or design process for short, to promote the general holistic perspective of product development. The example presented emphasizes the value of combining Design of Experiments (DOE) and Finite Element (FE) analysis into an effective tool to be used in the early phases of the design process to predict, at least to some extent, the final behavior of the product-to-be.
Rapid Systematic Product Design
Authors: Grote Karl-H. , Torby Bruce J. , Kimura Ikuo
Published: December 2020

This paper proposes a design methodology to develop better quality, less expensive products in the shortest possible product development cycle, focusing on prototyping issues such as rapid prototyping (RP) and virtual prototyping (VP). Along with details of the proposed design methodology, brief overviews of the conventional product development, concurrent engineering, each stage of the product development cycle, RP and VP are described. Moreover, to make use of both RP and VP in the course of product development, their advantages and disadvantage are discussed.
“Intelligent” Optimal Design of Materials and Structures What Does it Mean?
Authors: Zarka Joseph
Published: December 2020

The engineers have to face very important problems in the design, the test, the survey and the maintenance of their structures. These problems did not yet get full answer even from the best people in the world. Usually in these problems (such as no satisfactory constitutive modeling of materials, no real control of the accuracy of the numerical simulations, no real definition of the initial state and/or the effective loading of the structure), there is no solution and the experts do not understand the problem in its whole. Moreover, the available data may be not statistically representative (i.e. are in limited number), fuzzy, qualitative and missing in part.

We propose a practical solution the «Intelligent Optimal Design of Materials and Structures» where the actual best knowledges of the researchers/experts are intelligently mixed to the results of experiments or real returns. Several examples of applications are given in this serial set of papers to explain the real meaning and power of this approach.
Tool for Assembly Locating Scheme Definition
Authors: Lindkvist Lars , Söderberg Rikard
Published: December 2020

Locating schemes control the stability of a system, which has a major impact on the way variation propagates through that system and affects overall critical dimensions. The definition of the locating scheme should be made early in the design process in order to eliminate the need for costly modifications later on. This paper presents a tool that aids the designer in selecting the optimal locating scheme definition. It requires only the basic geometry of the components and is therefore easy to use early in the design process. The tool graphically indicates in which way the locating scheme should be modified to increase the stability of the system. The objective function for the stability of the system can be a number of defined critical dimensions or the general stability of all the components. The tool can be used for single part fixturing as well as for complete assemblies. Color coding is used to quickly identify sensitive areas of the assembly and as an easy way to compare different concepts. The use of the tool is shown in a number of examples.
A Team-Based Design for Manufacture Methodology
Authors: Appleton E. , Garside J. A.
Published: December 2020

It is now widely accepted that the majority of the cost involved in manufacture is determined in the design stage. Although it is obviously important to keep assembly and manufacturing costs as low as possible, by the effective and efficient use of operators and automation, in many ways, attempting cost saving at the production stage is equivalent to ‘closing the stable door after the horse has bolted’. Design for manufacture has existed since manufacture began. Indeed, much of the skill of the early craftsmen was based upon a knowledge of how to use processes efficiently. As design and production evolved into separate functions within manufacture the knowledge about efficient use of processes was retained by designers because of their shop floor experience. As design has become more complex, specialised function knowledge about how to design to make manufacture efficient has manifested itself in case material and hints on what not to do. Generally these hints are focused on particular processes. More recently these hints and guides have been collected together in a systematic way. Pioneers such as Boothroyd and Dewhurst (1) have been educating industry on the matter of Design for Manufacture and Assembly (DFMA) for many years and a considerable awareness has been created. At the present time DFMA is widely recognised but take up of the methods has been less than necessary if the full benefit is to be achieved.
An Open Model Updating Software: Application to Car Suspension Model Updating
Authors: Abouelainine Abderrahim , Morelle Patrick
Published: December 2020

The open model updating software described here is built on a quadratic programming method with a sensitivity analysis, for constrained optimization problem with bounded variables. The updating software is tested here with a numerical car suspension model in the objective to minimize the deviation between measures and simulations. The appropriate results obtained here show the efficiency of the updating software.
A Study on Computer Aided Bionic Design System Based on Self-Organization of Modelons
Authors: Wu Yizhong , Xiao Renbin , Zhong Yifang , Shi Hanmin
Published: December 2020

All the design activities of new products are top-down processes, in turn, conceptual design, functional design, structural design and detailed design. Unfortunately, design activity under the most traditional CAD systems belongs to a bottom-up process that has many disadvantages such as low efficiency, difficulty of modification and limitation of original thoughts of designers.

This paper will describe a new approach for product design, i.e., computer aided bionic design (CABD), integrating both top-down and bottom-up process, which imitates partible attribute of functional structure and self-organization mechanism of cells of organism. Bionic design includes constructing of modelons that constitute a product through computer aided conceptual design (CACD) and structural design, building of product’s local structural gene and global structural gene through self-organization planning of constraints, generating of modelons and automatic assembling of modelons based on the self-organization mechanism under the control of product structural gene. A prototype system based on this approach has been implemented and an example will be presented in this paper.
Multidisciplinary Design Optimization of Link Mechanisms by Combining Decomposition and Mini-Max Relaxation
Authors: Fujita Kikuo , Hirokawa Noriyasu , Inoue Masafumi
Published: December 2020

This paper proposes an efficiency improvement method for the multidisciplinary design optimization of link mechanisms. While behavior of a link mechanism is dominated by kinematic relationships, it is restricted under various other conditions such as structural strength, etc. Thus, the design problem of a link mechanism is obviously multidisciplinary. Further, since the motion of a link mechanism is sequentially time-dependent, the optimization problem can be formulated as a mini-max type one. Under these characteristics, this paper proposes a design optimization method of link mechanisms by combining non-hierarchic coupled system decomposition and mini-max relaxation. Then, after the multidisciplinary design problem of a link mechanism used in hydraulic shovels is modeled and formulated based on skeleton based kinematic analysis and beam-theory based strength analysis, its design optimization with the proposed method is demonstrated. The numerical results show more than about four times of speedup and robust performance as compared with a conventional optimization method.
On the Interaction Between the Dynamic Contact Load and the Surface Wear of a Plastic Gear Pair
Authors: Kuang J. H. , Lin A. D.
Published: December 2020

Due to the merits, for example, silent operation, self-lubrication, and light weight, etc., the demand for plastic gears increases tremendously. The purpose of this paper is to investigate the interaction between the dynamic contact loads and the sliding wear depths of a meshing plastic gear pair. Parameters, such as time-varying mesh stiffness, damping ratio, tooth errors, etc., are included in the gear dynamic model presented. As to the mesh stiffness, finite element results will be used to curve fit the flexible stiffnesses at different contact points. The values of the damping ratio and the friction coefficient are referenced to the experimental results in the papers cited. In addition to the studies of the parameters involved in the dynamic model, the wear equation proposed by Archard is used to calculate the wear depths of the running gear pair. With the gear dynamic model and the wear model developed, a computation algorithm is designed to simulate the interaction of the sliding wears and the dynamic contact loads.
The Disassembly Matrix for Computer-Aided Disassembly
Authors: Huang Yuan Mao , Huang Chun-Ting
Published: December 2020

This study proposes an effective and feasible method that improves the existing methods for disassembly. The elements of three dimensional interference matrices in the directions of x, y and z axes are considered as the low bit, middle bit and high bit, respectively, for the elements of the proposed disassembly matrix in the binary system. By using the Boolean operation and the deep-first-search method, the algorithm is developed and a software program is generated to create all of the possible disassembly sequences and directions of components in the tree diagram. With the grades for change of the disassembly directions, the optimum disassembly sequences can be determined. This disassembly matrix not only can help disassemble the disposed devices but also can evaluate the potential products during design.