bluuebunny/crossref_metadata_2025 huggingface dataset:
Automating Parametric Redesign of Structural Thin-Walled Frames
Authors: Wang Lyang Suan , Haghighi Payam , Ramnath Satchit , Horner Kurtis , Detwiler Duane , Shah Jami J.
Published: November 2019

Thin walled frames are prevalent in automotive body structures as they provide lower vehicle weight to meet strength and stiffness requirements for different type of loading cases. Reducing body weight improves fuel efficiency. The inner and outer styling surfaces drive the shape of the design space which constrains structural configurations and size of parts. Although automotive structural engineers have been using thin walled frames for years, they are keen on getting improvements through topology optimization. This paper focuses on development of a set of methods that automate the process of creating hollow cross-sections for body components inside the design space. Lofting these cross-sections along the load path of each component results in a surface model which can be used in FEA for verification and later in designing joints between different components. The starting point of this methodology is the curve skeleton, which is a 1D representation of the load paths within the design space. By analyzing the load paths, planes normal to the curve can be created to cut the design space to obtain the 2D wireframe of the boundaries. Predefined parameterized cross-sections created based on experiential knowledge that are stored in our cross-section tutor, can then be mapped to reside inside the design space boundaries at these different cutting locations. Several test cases are presented to discuss the capabilities and limitations of the tool. Future work on expanding the software to include more functions is also presented.
Customized PEEK Implants With Microporous and Surface Modification Using 3D Printing
Authors: Liao Chao-Yaug , Wu Po-Lun , Lee Chao-Yu
Published: November 2019

Polyetheretherketone (PEEK) is a high-performance, semi-crystalline thermal polymer with medical advantages such as biocompatibility and radiolucency. PEEK has an elastic modulus comparable to that of human cortical bone, so it can effectively reduce the stress shielding effect caused by the mismatch between the mechanical properties of an implant and human bone tissue. However, PEEK is biologically inert, and its use typically relies on a variety of surface modification methods, such as surface coatings of bio-ceramic materials, enhancing the surface bioactivity, and osseointegration. Compared to thermal spray or plasma spray technologies, the cold spray is carried out at relatively low temperatures, retaining the original properties of the material. This research establishes an open-source three-dimensional printer compatible with PEEK and also develops a powder-spray module based on the cold spray technology that can coat the surfaces of PEEK printings with hydroxyapatite (HA) to improve its bioactivity. This paper discusses the best parameter selection for PEEK printing, a thermal history analysis of the printing process, and the adhesion of HA powder coated on PEEK specimens with different porosities. Finally, the PEEK implant is printed to measure its performance under a vertical load.
Design Principle Cards: Toolset to Support Innovations With Additive Manufacturing
Authors: Lauff Carlye A. , Perez K. Blake , Camburn Bradley A. , Wood Kristin L.
Published: November 2019

Additive manufacturing (AM) continues to play an important role in product development, and many companies are searching for how to best integrate AM into their products, business models, and design processes. Often, AM is integrated into later stages of the design process for products during manufacturing and production. However, there is an opportunity to introduce AM in early-stage design, which could spark new business models and services in addition to re-thinking manufacturing for products. The central research question for this paper is what is an appropriate and useful tool to support innovations with AM early in the design process? Prior work has extracted and validated AM design principles. This paper describes the strategic development of AM Principle Cards from these design principles. The cards are a vehicle for codified AM design principles to be shared and understood in a way that inspires learning, creativity, and AM considerations during the early stages of the design process. They implement a number of best-known practices from an inductive principle-extraction study and literature related to the use of design stimuli, learning theory, design by analogy, and creativity. The AM cards were awarded a Singapore Good Design Award (SG Mark) for 2019. The AM Principle Cards were validated in two studies. In this paper, an ideation study is conducted with 85 designers to elicit feedback about the cards’ effectiveness to explain concepts related to AM and their ability to inspire creativity and new innovations. An additional ideation study was conducted with 61 participants that showed significant improvement in quality and novelty of ideas. The full deck of the final 27 AM Principle Cards is shared for design educators and practitioners to use.
Augmented Reality Interface: Guidelines for the Design of Contrast Ratios
Authors: Koreng Regina , Krömker Heidi
Published: November 2019

As part of the quality assurance process in industrial production, employees make hundreds of decisions every day based on their experience and the given inspection specifications. The detection of quality deviations currently depends on the individual competence of the persons involved in the production process. With the automatic recognition of textured surfaces in camera images, valuable information can be given to support these persons in their decisions. For the design of augmented reality systems, the cognitive decision-making processes are first described in a model-based way and the requirements for design of the decision-making process are defined. The different lighting environments in the industrial process represent one of the important requirements of the augmented reality system, to function independently of the lighting. The good perceptibility of the information is the basic requirement for the recognition of contents. When implementing an augmented reality system, it is problematic to consider the different illuminance levels in a room. Depending on the task at hand, usually, the light at a machine is weaker and brighter in the quality control area. It is important that user-centered implementation is observed. Manual intervention by the end user in the augmented reality system is necessary to compensate for differences in brightness. This paper examines different lighting environments and the degree to which the user can clearly see content. An empirical evaluation is conducted to examine the clarity of content in AR. The aim is to find out how the difference in contrast at different lighting situations influences the differences in brightness of colors. The colors are chosen to display content but also to emphasize content. As a result, a usage recommendation can be made for grey values as well as for different color values. The consequence of this investigation is then used for the further development of sample solutions for the design of an augmented reality system. The focus lies on the user-centered development process and thus the integration of user requirements into the technical implementation should be ensured. The perceptibility of the information in an augmented reality system should not only play a role technically, but also physically. The perception of information is omnipresent, so one can perceive our environment. With the help of the study, a natural and easy perception of information should take place, which supports the recognition of important information in the everyday working environment.
Inverse Thermo-Mechanical Processing (ITMP) Design of a Steel Rod During Hot Rolling Process
Authors: Nellippallil Anand Balu , Mohan Pranav , Allen Janet K. , Mistree Farrokh
Published: November 2019

The production of steel products involves a series of manufacturing processes. The material Thermo-Mechanical Processing (TMP) history at each process affects the final properties and performances of the product. Experiments and plant trials to predict these properties and performance of steel products are expensive and time consuming. This has resulted in the need for computational design methods and tools that support a human designer in realizing such complex systems involving the material, product and manufacturing processes from a simulation-based design perspective.

In this paper, we present a Goal-oriented Inverse Design method to achieve the integrated design exploration of materials, products and manufacturing processes. The key functionality offered is the capability to carry out a microstructure-mediated design satisficing specific processing requirements and performance goals of the product. Given models to establish the information flow chain, a designer can use the method for the decision-based design exploration of material microstructure and processing paths to realize products in a manufacturing process chain. The efficacy of the method is tested using an industry-inspired hot rolling problem to inversely design the thermo-mechanical processing of a steel rod. The focus here is the method and associated design constructs which are generic and support the formulation and decision-based design of similar problems involving materials, products and associated manufacturing processes.
Applicability of an Oil Based Calculation Approach for Wear Risk and Wear Lifetime to Grease Lubricated Gear Pairings
Authors: Siewerin Benedikt J. , Dobler Andreas , Tobie Thomas , Stahl Karsten
Published: November 2019

Gear pairings often run under very high loads. That can result in different kinds of failure modes limiting their lifetime. Many of the known gear failure modes are tribologically influenced. Especially for gear pairs running with lower circumferential speeds or with different surface hardness, (continuous or slow speed) wear is often the lifetime limiting factor. Slow speed wear appears continuously over a longer period of runtime. In many cases, such applications are lubricated with greases. Since the standardized calculation methods (e.g. ISO 6336) do not cover any determination of wear, one common way to predict the wear lifetime is the calculation method according to Plewe. In the associated Plewe diagram the worn off amount of material is correlated to the minimal lubricant film thickness in the tooth contact. The wear intensity decreases for higher film thicknesses. However, this method has certain limits for greases, because the film thickness of a grease, its bleed oil and the base oil is not necessarily the same. Additionally, the consistency and the flow properties have to be considered, because they influence the lubrication supply mechanism (circulating or channeling). Under certain circumstances channeling could be predominant. Although in theory a grease should build a thicker lubricating film than its base oil, experimental investigations have shown higher wear rates in comparison to oil lubrication.
Decomposing Incentives for Early Resilient Design: Method and Validation
Authors: Hulse Daniel , Hoyle Christopher , Tumer Irem Y. , Goebel Kai
Published: November 2019

Due to the expansive, time-consuming nature of risk analyses, it is important to be able to assign the minimization of risk (and, in general, optimization of resilience) to responsible teams that can work in parallel. However, while methods exist for minimization of risk in conventional design processes, research has not yet shown how it should be performed in a model-based design context in early design phase, when the design representation is relatively high-level and there are uncertainties in parameter values. This paper presents a value-driven design approach to minimize risk by decomposing the design, operational, and expected failure costs to individual functions in a system failure model. This process is demonstrated in a case study considering the redundancy of components to fulfill overall functions in an electric power system, where it is shown to increase design value significantly. An uncertainty-based process is additionally provided to enable the designer to test the sensitivity of the chosen design solution to uncertain parameter values. In this limited case study it is shown that the sensitivity of the choice to parameter value uncertainty is low, provided the range of uncertainty for each parameter is within a reasonable range. In situations like this, presented expected cost metrics provide meaningful information to justify system-architectural design decisions made on the basis of resilience.
Decision-Making in the Prescription of Orthotics and Prosthetics for Partial-Foot Amputees
Authors: Saravanan Pratima , Hipple Charity , Wang Jingxin , McComb Christopher , Menold Jessica
Published: November 2019

Prosthetists face a daunting number of decisions that directly affect an amputee’s ability to walk and indirectly affect the overall quality of life of that amputee. In addition, the lack of resources in low-income countries provides a barrier to receive care after an amputation, and approximately 80% of amputees in low-income countries lack appropriate prosthetic care. In this research, we are motivated to understand what factors affect the decision-making strategies of prosthetists and podiatrists when prescribing prosthetics and orthotics to partial foot amputees. This work establishes a decision-making framework as a step towards automated methods that may reduce the complexities and decision-making burden of prosthetic prescription, ultimately increasing the efficiency of prosthetic prescription in low-resourced areas. A decision-making model is proposed based on an extensive literature review of over 100 papers. The proposed model is compared to qualitative data regarding decision-making strategies during prosthetic or orthotic prescription collected from nine prosthetists, surgeons, and other healthcare professionals directly involved in amputee care. Changes to the proposed model are described and future work exploring the role of automated methods to support decision-making in the context of prosthetics is discussed.
Antecedents and Outcomes of Designer Empathy: A Retrospective Interview Study
Authors: Surma-aho Antti , Chen Claudia , Hölttä-Otto Katja , Yang Maria
Published: November 2019

A growing body of research suggests that to uncover key needs and create successful designs, designers must holistically and empathically understand end-users. However, despite the existence of empathy frameworks and guides in design, little empirical work has investigated what influences and results from empathy, i.e. its antecedents and outcomes, at the project level. Further, the distinct roles of affective and cognitive empathic processes are rarely recognized in design, even though they are commonly addressed in psychology research. To begin filling these research gaps, this paper presents a thematic analysis of 10 semi-structured interviews with product and service designers. The designers described a variety of techniques and situations that had enabled them to cognitively understand their users’ perspectives and that had caused affective reactions, ranging from consciously searching for analogous experiences in the designer’s own life to feeling concern for users after observing difficulties in their everyday lives. While cognitive empathy and the resulting accuracy of user understanding was perceived to motivate design changes and thus the creation of more beneficial designs, affective empathy was connected to increased acknowledgement of user problems and motivation to help users. The results describe empathy in a design context and highlight differences between distinct components of empathy.
Simulation-Based Process Optimization of Metallic Additive Manufacturing Under Uncertainty
Authors: Wang Zhuo , Liu Pengwei , Hu Zhen , Chen Lei
Published: November 2019

The presence of various uncertainty sources in metal-based additive manufacturing (AM) process prevents producing AM products with consistently high quality. Using electron beam melting (EBM) of Ti-6A1-4V as an example, this paper presents a data-driven framework for process parameters optimization using physics-informed computer simulation models. The goal is to identify a robust manufacturing condition that allows us to constantly obtain equiaxed materials microstructures under uncertainty. To overcome the computational challenge in the robust design optimization under uncertainty, a two-level data-driven surrogate model is constructed based on the simulation data of a validated high-fidelity multi-physics AM simulation model. The robust design result, indicating a combination of low preheating temperature, low beam power and intermediate scanning speed, was acquired enabling the repetitive production of equiaxed-structure products as demonstrated by physics-based simulations. Global sensitivity analysis at the optimal design point indicates that among the studied six noise factors, specific heat capacity and grain growth activation energy have largest impact on the microstructure variation.
Manufacturing Processes Re-Engineering for Cost Reduction: The Investment Casting Case Study
Authors: Mandolini Marco , Campi Federico , Favi Claudio , Germani Michele
Published: November 2019

The production cost is one of the most important drivers for product competitiveness. For increasing profits, a manufacturing process re-engineering is mandatory. This practice passes through systematic procedures for process selection, cost estimation and results analysis.

This paper presents a method for evaluating different manufacturing alternatives for cost reduction. This method, composed of eight steps (most of them retrieved from the scientific literature), permits engineers to consider important aspects, such as the choice of cost estimation tools, the collection of data related to production processes, the impact related to the introduction of new production processes and the interpretation of results. Authors adopted such method for evaluating economic benefits of introducing a new manufacturing technology (i.e. investment casting) for three components of a food packaging machine.

The adoption of the proposed method leads to compare investment casting vs. machining. The paper presents a detailed discussion of the economic benefits (return on investment, cash flows and manufacturing cost breakdown) related to the introduction of the investment casting technology.
Should it Stay or Should it Go?: A Case Study of Concept Screening in Engineering Design Industry
Authors: Zheng Xuan , Miller Scarlett R.
Published: November 2019

While we know that poor decisions during concept screening can lead to great expenses including redesign costs, production postponement, and even product failure, little is known about what factors influence professional concept screening. Previous research in this area has mostly been conducted with students or used hypothetical design challenges with professionals. This is problematic because such research methods are based on challengeable assumptions leaving out the risks and consequences that professionals face in their daily work. Hence, the purpose of the current study was to investigate the process of professionals making screening decisions in situ and identify the impact of the perceived properties of ideas (i.e., riskiness, originality, and feasibility) and the role of the professionals (idea generators versus executives) in this process. Specifically, a mixed method in-situ study was conducted in a small electromechanical company which included shadowing a research and development team from the conceptual stage to a final pitch meeting to senior executives. In addition, surveys and interviews were conducted to identify what factors were impacting concept screening. The results showed both idea generators and executives were able to distinguish and move ideas with relatively high market potential forward and avoided taking risks during concept screening. However, the idea generators did not show any preferences on the originality or feasibility of the ideas, while the executives preferred to invest in ideas with high feasibility. The findings of this study drew a distinction between professional design studies solving real design problems in a naturalistic, collocated team environment and those in a laboratory setting and added to the understanding of factors that influence the decisions made during professional concept screening. They also provide a much-needed insight into how engineering design professionals screen ideas.
Do Students Want to Dissect?: A Survey of Student Opinions on the Use of Product Dissection in the Classroom
Authors: Riegel Carolyn , Starkey Elizabeth M. , Hunter Samuel T. , Miller Scarlett R.
Published: November 2019

Product dissection has the ability to create an engaging and active learning environment for engineering students. The purpose of this paper was to further investigate students’ perceptions on product dissection in the classroom. This paper was developed to provide an examination of the usefulness of product dissection for idea generation and how product dissection modules might aid in students’ understanding of the module. The findings of this paper conclude that students felt that the product dissection module was useful, valuable, and enjoyable and that students had a positive sentiment towards the designed aspects of the dissection module. Through the use of content analysis, areas for improvement in these modules are identified.
Robust Observer-Based Load Extenuation Control for Wind Turbines
Authors: Do M. Hung , Söffker Dirk
Published: November 2019

Wind energy is currently the fastest growing electricity source. To meet the output demand, wind turbines are becoming larger and more flexible leading to the problems of structural load especially in case of offshore turbines. Advanced control algorithms are developed to reduce the load, allowing to build larger turbines, and expand their lifetime. Observer-based control algorithms such as Linear-Quadratic-Gaussian LQG control which uses LQR to calculate the optimal observer and controller gains are commonly applied to wind turbines in literature. However the approach requires to calculate the observer and control gains separately. In addition, linear models used for parameter calculation may have errors with respect to the nonlinearities of wind turbines and induced to unmodeled dynamical properties. These modeling errors need to be considered to to guarantee the stability of the controlled system. Alternatively a robust design assuming bounds and limits of models have to be realized to guarantee stability while ignoring details of modeling. This paper proposes an optimal robust observer-based state feedback controller for large-scale wind turbines to realize multi objectives, including structural load mitigation and rotor speed regulation. The novel contribution is that the observer gain parameters, control gains, and integral action are optimized at the same time within H∞ mixed sensitivity framework to achieve desired performance with respect to power regulation, structural load mitigation, and also robustness for the wind turbine control system. The control performances have been verified by a high fidelity simulation software and are compared to those of a classical baseline controller.
Word-of-Mouth Recommendations in an Automobile Market System
Authors: Zadbood Amineh , Russo Nicholas , Hoffenson Steven
Published: November 2019

Improving design in the context of market systems requires an understanding of how consumers learn about and evaluate competing products. Marketing models frequently assume that consumers choose the product with the highest utility, which provides businesses insights into how to design and price their products to maximize profits. While recent research has shown the impacts of consumer interactions within social networks on their purchasing decisions, they typically model market systems using a top-down approach. This paper applies an agent-based modeling approach with social network models to investigate the extent to which word-of-mouth (WOM) communications are influential in changing consumer preferences and producer market performance. Using a random network, we study the effects of the number of referrals for a product and the degrees of similarity between the senders and receivers of referrals on purchase decisions. In addition, the eigenvector centrality metric is used to analyze the spread of WOM referrals. The simulation results show that the most influential consumers in the network can create significant shifts in the market share, and a statistical analysis reveals a significant change in the system-level metrics of interest for the competing firms when WOM recommendations are included. The findings incentivize producers to invest in supporting their product development efforts with rigorous social networks analysis so as to increase their market success.
A Framework for Automating Maynard Operation Sequence Technique Studies
Authors: Renu Rahul Sharan
Published: November 2019

This research proposes a framework for automating Maynard Operation Sequence Technique (MOST) studies. This is done by using data available in assembly work instructions, plant layouts and Product Data Management systems. Specifically, an investigation into the information flow requirements for the automated system is performed. One aspect of the information flow is investigated — mapping assembly work instruction to MOST activities and sequence models. A software is developed from the mapping, which acts as a demonstrator to show the usefulness of decision support during MOST analyses. The demonstrated efficacy warrants future efforts towards implementing the remaining facets of the information flow identified.
Characteristics of Truss Core Created by Origami Forming Method
Authors: Abe Aya , Terada Kosuke , Yashiro Haruki , Hagiwara Ichiro
Published: November 2019

The truss core surpasses the honeycomb core depending on the tasks. The height of core is limited by press forming and so on. Therefore, we developed a method by folding mountain / valley lines like origami. The origami forming method has the feature that it can be done from paper to metal by the same method. By examining three-point bending tests, drop tests, and analyzing them, we show that the structure that space-filled with cores obtained by the origami forming method called ATCP will be a box for both excellent cushioning material and transporting. Moreover, we also show that the core structure obtained by this has excellent sound insulation performance.
A Cloud Computing Architecture to Map Trawling Activities Using Positioning Data
Authors: Galdelli A. , Mancini A. , Tassetti A. N. , Ferrà Vega C. , Armelloni E. , Scarcella G. , Fabi G. , Zingaretti P.
Published: November 2019

Descriptive and spatially-explicit information on fisheries plays a key role for an efficient integrated management of the maritime activities and the sustainable use of marine resources. However, this information is today still hard to obtain and, consequently, is a major issue for implementing Marine Spatial Planning (MSP). Since 2002, the Automatic Identification System (AIS) has been undergoing a major development allowing now for a real time geo-tracking and identification of equipped vessels of more than 15m in length overall (LOA) and, if properly processed, for the production of adequate information for MSP. Such monitoring systems or other low-cost and low-burden solutions are still missing for small vessels (LOA < 12m), whose catches and fishing effort remain spatially unassessed and, hence, unregulated. In this context, we propose an architecture to process vessel tracking data, understand the behaviour of trawling fleets and map related fishing activities. It could be used to process not only AIS data but also positioning data from other low cost systems as IoT sensors that share their position over LoRa and 2G/3G/4G links. Analysis gives back important and verified data (overall accuracy of 92% for trawlers) and opens up development perspectives for monitoring small scale fisheries, helping hence to fill fishery data gaps and obtain a clearer picture of the fishing grounds as a whole.
A Novel Reconfigurable Wheel-Legged Mobile Mechanism
Authors: Zhang Hongchuan , Zhang Xianmin , Huang Yanjiang , Du Junjie , Zhu Benliang
Published: November 2019

This paper presents a novel wheel-legged mobile robot with a reconfigurable frame, which uses a compliant kaleidocycles inspired spring-hinged eight-bar mechanism. The kinematic model of the mechanism is established and the relationships between actual rotation angle and the joint angles is thoroughly obtained in the spherical coordinate system. According to the analysis of the multivariable potential energy surface, the relationship among multistable performance, under-actuated behavior and potential mechanism energy is studied. On account of under-actuated kinematic relationship and multistability of the proposed mechanism, a cable-driven approach is used and its feasibility is finally verified by the experiment of the prototype robot.
Conversion Model for the Design of Steel and Polymer S-Gears
Authors: Zorko Damijan , Černe Borut , Duhovnik Jože , Žavbi Roman , Tavčar Jože
Published: November 2019

The existing models for the conversion and design of polymer gears are only valid for involute gears. This research was focused on S-gears, a specific type of gear profile which has more favorable contact conditions and greater root thickness when compared to involute gears. S-gears design is currently based on tests, experience, and the use of numerical simulations. Due to the lack of a simple calculation model for designing S-gears, there is a limited number of applications in practice. The goal was to set up a model for the evaluation of the root and flank load-carrying capacity of polymer S-gears. The VDI 2736 guideline was taken as the basis of our conversion model for polymer S-gears. With the introduction of new factors for the calculation of root and flank stress, the VDI 2736 model was upgraded to take into account the specific shape of the S-gear profile. In addition, a model for designing steel S-gears was set up.
Fire Detection Using Both Infrared and Visual Images With Application to Unmanned Aerial Vehicle Forest Fire Surveillance
Authors: Yuan Chi , Liu Zhixiang , Hossain Anim , Zhang Youmin
Published: November 2019

Forest fires are a universal problem that destroy a large amount of natural resources and creates environmental pollution. Forest firefighting is one of today’s most important events for natural and environmental resources protection and conservation. Unmanned aerial vehicle (UAV) with remote sensing system can offer a rapid, safe and low-cost approach for effective forest fire detection which have attracted researchers attention worldwide. In this paper, automatic detection of fire regions using both visual and infrared images is investigated. In order to improve the computational performance to satisfy the requirement of real-time processing, a reduced complexity fusion method is adopted in this research. Through testing the proposed approach on real video sequences, good detection performance is achieved and it is indicated that using multi-modal camera system to detect forest fire with application to firefighting UAV is very promising.
Graded Origami Honeycomb Tube for Energy Absorption
Authors: de Waal Leo , You Zhong
Published: November 2019

When loaded parallel to the prismatic cells (out-of-plane), honeycombs and re-entrant honeycombs exhibit high initial stiffness and peak force, followed by a force reduction as progressive failure occurs. The high initial peak force and large post-peak force reduction are undesirable for energy absorption purposes. In this study a graded honeycomb structure based on origami is proposed in an effort to lower the peak force, increase the energy absorption capacity and tune the stiffness throughout the loading process. The grading is achieved through a developable origami crease pattern that utilises the typical honeycomb expansion manufacturing technique. The crease pattern has one degree of freedom and is constructed from a repetition of a modified Miura-ori unit. A kinematic study of the crease pattern is completed, highlighting the simple geometric parameters that can be altered to tune the structure. Quasi-static numerical simulations are then used to investigate the interaction between these simple geometric parameters, the energy absorption capacity and the stiffness throughout the loading process. Compared to honeycomb and re-entrant honeycomb tubes, it has been found that a reduction in the peak force, increase in energy absorption capacity and tunable stiffness can be achieved.
Simulation of a Micro-Electro-Mechanical System for Generating Electrical Power From Pressurized Gas
Authors: Cunningham Andrew , Jensen Brian D.
Published: November 2019

This paper presents a novel approach to energy scavenging for a micro-electro-mechanical system (MEMS) device to convert the energy stored in pressurized gas into electrical power. The proposed design uses input pressure to move a piston and magnet through a set of coils while pulling on another mass through non-linear springs to open and close the input air valve. The model demonstrates that the design is capable of staying in motion with continual input pressure (up to at least a time stamp of 1 second), and that an average power output of 9.47 μW over 5 ms can be achieved. We suggest that further research be done to optimize the design parameters and that the optimized design be used to the test the system.
Theoretical Study on the Influence of Planet Gear Rim Thickness and Bearing Clearance on Calculated Bearing Life
Authors: Fingerle Andreas , Hochrein Jonas , Otto Michael , Stahl Karsten
Published: November 2019

Planetary gearboxes are becoming more popular due to their high power density and potentially high efficiency. When the planet bearings are internally mounted, the body of the planet gear has to be hollow. The demand for large outer diameters due to high load requirements might result in a small planet rim thickness. Depending on the rim thickness, its rigidity may become very low. Due to the low stiffness and the special load conditions caused by the double meshing, the deformation of the planet and its bearings are unique. In this paper, the influence of rim thickness on bearing load and lifetime are examined. The analysis is performed with an FEM model of a planet rim with a built-in cylindrical roller bearing. With the resulting planet deformation from the FEM calculation, the load distribution on the rolling elements in the bearing and the bearing lifetime according to ISO/TS 16281:2008 have been evaluated.
Optimal Design of Thermo-Compression Bonding for Advanced Packaging System Under Uncertainty
Authors: Hwang Sungkun , Choi Seung-Kyum
Published: November 2019

As the trend of miniaturization of electronic components has grown, demands for advanced microelectronics packaging development have also increased. At the same time, however, this trend raises concerns of unreliable assembly processes that are caused by defective packaging interconnections. In particular, the defects can be induced by non-coplanarity and unpredictable structural deformation of interconnections. When a slope of the die exceeds a certain degree, connectivity between components in the package may fail, which results in warpage or electrical power loss. To control this issue, thermo-compression bonding has been developed to globally apply heat and pressure into the die while the substrate is maintained at a low stage temperature. Therefore, in order to effectively handle these issues, strongly coupled thermal and structural analysis is inevitable. In this research, a simulation-based optimal design of thermo-compression bonding is developed to achieve better packaging reliability in the time transient domain. The proposed framework clearly demonstrates how the multivariate uncertain parameters can be generated. Also, it suggests how the multivariate uncertainty can be propagated through the classification approach, i.e., artificial neural network. The classification approach is then utilized to estimate the reliability of the system. The efficacy of the proposed framework is demonstrated with a practical example of an advanced packaging system which is utilized in actual commercial products. Ultimately, this study demonstrates how the strong coupling optimization method can be utilized in the actual packaging system.
Quantum Mechanical Perspectives in Reliability Engineering and System Design
Authors: Pandey Vijitashwa
Published: November 2019

Engineering design under uncertainty is an established field. Attempts to extricate the human decision maker from the process generally do not succeed. Surprisingly, even the determination of system parameters and their admissible values needs as many interventional steps from human designers and operators, as the selection of final attributes of the system that the human end user is expected to only interact and be concerned with. In this light, it becomes important to consider the mathematical models that would explain and model the decision making behavior of human beings. Concerningly, this behavior has been seen to violate common sense probability axioms. In this paper, we propose an earnest look at the mathematics of quantum mechanical theory in modeling and manipulating the uncertainties involved in engineering systems. We propose that the state of a system be modeled as a point in an abstract complex vector space as in quantum mechanics. Additionally, at a given point in time it can be interpreted as a superposition of multiple pure states. This change in perspective allows explanation of many commonly observed behaviors, least of which is the inconsistencies in defining what constitutes the failure of a system. We present our approach in the context of reliability engineering as it sees some of the most prevalent use of uncertainty modeling and propagation techniques. However, the implications on design and design theory are also evident. Some motivating examples are provided and directions for future work are identified.
IISC DBox: A Game for Children to Learn Design Thinking
Authors: Bhatt Apoorv Naresh , Bhaumik Rahul , Moothedath Chandran Kumari , Chakrabarti Amaresh
Published: November 2019

Design thinking (DT) can be a valuable tool for nurturing problem-solving abilities in school children. The objective of the paper is two-fold. The first is to evaluate the effectiveness of the DT process as a potential tool for open-ended problem-solving for school children; the second is to test the effectiveness of gamification of the DT process in terms of the extent of comprehension and learning of the process enabled by gamification. The paper presents a framework for IISC, a Design Thinking Process developed by the authors, and compares two gamified models of the DT process against one another using empirical studies that involved school children in the age-range of 14 to 18 (8th to 12th years of their twelve years of school education) playing the games. Feedback from the students and their mentors during the game was used as data for evaluation. The paper also discusses the limitations identified and suggested improvements of the two gamified models, and implications of these for designing more effective games.
Development of Three-Nozzle Extrusion System for Conformal Multi-Resolution 3D Printing With a Robotic Manipulator
Authors: Yoon Yeo Jung , Yon Minsok , Jung Sung Eun , Gupta Satyandra K.
Published: November 2019

Using a 6-DOF robotic manipulator for material extrusion additive manufacturing (AM) enables conformal printing onto complex surfaces while orienting material fibers at desired directions. Compared to a traditional 3D printer, conformal printing can produce parts with good surface finish, less number of layers and enhanced mechanical properties. In this paper, we present a three-nozzle extrusion system which can be attached to a robot. This system allows the robot to achieve conformal 3D printing with multi-resolution. One extruder is for printing support materials and the other two extruders are for fabricating structural material with different resolutions. The interior regions of the part are fabricated with a bigger diameter nozzle and the surface of the part is printed with a smaller diameter nozzle. This multi-resolution printing not only speeds up the build times but also produces the good surface finish. In previous work, we demonstrated multi-resolution 3D printing using two robots. The contributions of this paper are design and fabrication of a three-nozzle extrusion system, calibration process for the system, and its validation. The validation of the calibration was done by printing linear and circular patterns using different nozzles, and evaluating relative dimensional accuracy. This work will enable a single robot to perform multi-resolution conformal 3D printing.
Piezoelectric Subordinate Oscillator Arrays: Performance Recovery and Robustness to Uncertainty
Authors: Sterling John , Paruchuri Sai Tej , Tarazaga Pablo , Vignola Joseph , Kurdila Andrew , Malladi Vijaya V. N. Sriram , Ryan Teresa
Published: November 2019

Prior work demonstrates that an attached subordinate oscillator array (SOA) can attenuate vibration of a host structure. The distribution of masses and stiffnesses of the attached oscillators can craft a flat frequency response over a desired band. This response modification can be a significant improvement over classical dynamic vibration absorbers (DVA) that attenuate response at one target frequency while increasing the frequency response amplitude at nearby side frequencies. Performance of the SOA can be highly sensitive to the uncertainty or disorder in the mechanical properties of the system. This paper shows that use of piezolectric SOAs (PSOAs) has the potential to address and ameliorate such sensitivity to off-design situations. It is important to note that the design strategy is simple and effective: it can be carried out without optimization techniques by choosing simple or well-known distributions of electromechanical properties.
Implications of Competitor Representation on Optimal Design
Authors: Yip Arthur H. C. , Michalek Jeremy J. , Whitefoot Kate S.
Published: November 2019

We investigate the effect of competitor product representation on optimal design results in profit-maximization studies. Specifically, we study the implications of replacing a large set of product alternatives available in the marketplace with a reduced set of selected competitors or with composite alternatives, as is common in the literature. We derive first-order optimality conditions and show that optimal design (but not price) is independent of competitors under the logit and nested logit models (where preference coefficients are homogeneous), but optimal design results may depend on competitor representation in latent class and mixed logit models (where preference coefficients are heterogeneous). In a case study of automotive powertrain design using mixed logit demand, we find some change in the optimal acceleration performance value when competitors are modeled using a small set of alternatives rather than the larger set. The magnitude of this change depends on the specific form and parameters of the cost and demand functions assumed, ranging from 0% to 3% in our case study. We find that the magnitude of the change in optimal design variables induced by competitor representation in our case study increases with the heterogeneity of preference coefficients across consumers and changes with the curvature of the cost function.
Effects of Surface Condition on Traction of Two-Wheeled Inverted-Pendulum Transporters
Authors: Castro Arnoldo , Adams Christopher , Singhose William
Published: November 2019

Self-balancing transporters apply wheel torque in order to accelerate, turn, and regain balance. However, these control efforts require sufficient traction between the wheels and the ground so that appropriate wheel-ground forces are generated. When this is not the case, the stability is compromised and machine behavior can be unexpected and destabilizing. Experiments were performed to quantify the reduction in wheel-ground friction that can occur in common real-life conditions, such as on wet surfaces or surfaces with debris. A simulation has been developed to show that common transporter motions that are safe on dry surfaces lead to unstable or unpredictable behavior when the available wheel-ground friction is reduced by amounts similar to those seen in the experiments.
Periodic-Doubling Bifurcation of a Circuit With a Fractional-Order Memristor
Authors: Yu Yajuan , Chen Yangquan
Published: November 2019

A new fractional-order current-controlled memristor is proposed by the fact of the memory loss. Excited by sinusoidal current, the generalized hysteresis loops of the new fractional-order memristor are no longer symmetrical to the origin and the time to reach the steady state is longer than the integer-order memristor’s. The dynamical behaviors of a new fractional-order memristive circuit system whose state variables have different derivation orders are investigated by theoretical analyses and simulated numerically. It is shown that the new fractional-order memristive circuit system goes into chaos by period-doubling bifurcation; the periodic windows are induced by the discontinuous change of derivative order between variables.
Effect of Structural Nonlinearity on a Piecewise Linear Aeroelastic System
Authors: Lelkes János , Kalmár-Nagy Tamás
Published: November 2019

Aeroelasticity is the study of the interaction of aerodynamic, elastic and inertia forces. When flexible structures, such as an airfoil, undergo wind excitation, divergence or flutter instability may arise. We study the dynamics of a two-degree-of-freedom (pitch and plunge) aeroelastic system with cubic structural nonlinearities. The aerodynamic forces are modeled as a piecewise linear function of the effective angle of attack. Stability and bifurcations of equilibria are analyzed. The effect of the structural nonlinearity is investigated. We find border collision, rapid, Hopf, saddle-node and pitchfork bifurcations. Bifurcation diagrams of the system were calculated utilizing MatCont and Mathematica.
Maximizing the Power Extraction From Train Suspension Energy Harvesting System
Authors: Costanzo Luigi , Vitelli Massimo , Pan Yu , Zuo Lei
Published: November 2019

In this paper, an equivalent electric model for railway vehicle suspension harvester is proposed. With reference to the maximization of the extracted power, the open issues for such kinds of systems are reviewed. In particular, it is evidenced that the use of passive diode bridge rectifiers unavoidably leads to a reduction of power with respect to both the resistive load case and the theoretical optimal load case. Therefore, suitable average power maximization techniques and power electronics architectures are needed. In this paper, two techniques are proposed. The first technique is based on the adoption of additional passive components and, in the considered test cases, it allows the increase of the power output up to 45%. The second technique is based on the adoption of a properly controlled active power electronic interface and it is much more efficient since, in the considered test cases, it allows the increase of the power output up to 135%.