bluuebunny/crossref_metadata_2025 huggingface dataset:
Toolbox for User-Centered Specification of VR Systems
Authors: Liebal Andreas , Krömker Heidi , Mahboob Atif , Weber Christian
Published: November 2019

Breaking into the consumer market, Virtual Reality (VR) has now penetrated wide areas of the industrial market. Rapidly developing technologies are opening up new application possibilities with low cost and high quality solutions. Although VR has been used exclusively as a marketing tool in companies up to now, it is still being extended to support all areas of the complete product development process.

However, this is also accompanied by the difficulty to manage the amount of functionalities and design options associated with VR. Developers of such VR systems must nevertheless maintain an overview of the multitude of technological and content-related possibilities and bring them in line with the requirements of VR customers or VR users. At the same time, VR customers must also have an idea of the technological possibilities and formulate their vision of a VR system as precisely, completely and goal-oriented as possible. In the end, both sides must find a common level of communication in order to record the characteristics of the VR system in the form of a requirement specification or an offer. Factors such as different terminologies and different views about the product development process along with the diverse knowledge about VR functionalities on both sides complicate this process.

This article is intended to show the concept for a toolbox that supports the definition of a customer-specific VR solution. This shall exploit the full potential of VR for the customer’s specific product development process in VR. The generic product development process will be studied and the VR application areas will be located. In this regard, a classification of the main components of VR systems is performed. The goal of such a classification is to establish a relationship between the product model (along with product specific properties and relationships) and the VR system components.

As the field of VR does not yet have an established set of standardized terms, a definition of all terms in this context can help to improve communication between customer and developer. This article shows how a toolbox for agencies and development departments must be structured so that the VR developer can design, evaluate, calculate and develop a complex VR system in a customer-oriented way. Furthermore, the vision of the toolbox presented in this paper also has the goal that the VR customer can specifically formulate his/her requirements in a customer-specific way that leads to an easier understanding for VR developer and eventually to a VR solution.

Finally, the possibility of extension of the presented toolbox structure is discussed to automatically generate specification proposals and suitable technology recommendation based on the problem at hand.
Determining the Number of Distinct Solutions in Planar Mechanism Design
Authors: Funke Lawrence , Raney Jonathan , Caldwell Cyler
Published: November 2019

This work investigates two novel approaches to sorting solutions to planar-mechanism-synthesis problems. The examples contained herein are specific to planar morphing mechanisms, but the procedure is general and can easily be extended to any planar-mechanism-synthesis problem. The results indicate that the two approaches, namely self-organizing map (SOM) neural network and modal assurance criterion (MAC), can be used to sort a set of solution mechanisms into a reduced set of distinct solution groups. Additionally two sorting approaches (inclusive and exclusive) were investigated. This process can be used to take the initial set of solution mechanisms, often numbering in the hundreds, and pare it down to a significantly smaller set of substantially different designs. For the two case studies presented herein, one set was reduced by a factor of ten and the other by a factor of five. This means that a designer has fewer mechanisms to look through and that the differences in these mechanisms are clearer so that considerations such as size and joint locations may more easily be considered. It was found that the MAC method with inclusive sorting is generally a better starting point because it runs quickly and gives a more compact set of distinct solution mechanisms. The paper concludes with some recommendations for best practices for sorting solutions for a general mechanism-design problem.
Classification and Execution of Coupled Decision Problems in Engineering Design for Exploration of Robust Design Solutions
Authors: Sharma Gehendra , Allen Janet K. , Mistree Farrokh
Published: November 2019

Decision Support Problems (DSPs) are used to model design decisions involving multiple trade-offs. In practice, such design decisions are also coupled, that is, these decisions must be modelled by identifying and addressing the influence they exert on one another. Hence, we need to classify coupled decision problems and to introduce methods for managing uncertainty for such problems. Classification of coupled decision problems allows for the development and execution of decision templates to effect design and to archive design-related knowledge on a computer. Incorporating robustness metrics allows for the exploration of robust design solutions for coupled decision problems by managing uncertainty.

In this paper, we present a classification scheme for coupled decisions using DSPs, called the Decision Scenario Matrix and we illustrate its utility by solving a coupled problem using DSPs. The design of a beam to be used as a fender is used to illustrate the efficacy of the formulation of coupled problems. In the first example, we determine a robust design, that is, determine the dimensions of the fender and simultaneously design the material recognizing that the computational models are incomplete and inaccurate. In the second example, we determine robust design solutions when design decisions are coupled, that is, determine the dimensions of the fender and select the material concurrently. Our focus, in this paper, is on illustrating the efficacy of the method rather than on the results.
Designing the Customer Order Decoupling Point to Facilitate Mass Customization
Authors: Guo Lin , Chen Suhao , Allen Janet K. , Mistree Farrokh
Published: November 2019

As globalization continues, manufacturing enterprises need to do mass customization with a short lead-time, to satisfy evolving market demands in different regions. One challenge of mass customization is to fulfill orders swiftly at an acceptable cost, meanwhile maintaining the service quality. To do this, the customer order decoupling point – CODP, where the value-adding activities take place, should be designed and adapted to the changing market demands.

In this paper, we propose a Formulation-Exploration method to make decisions on CODP positioning and improve the supply chain to support mass customization. A test problem of auto parts manufacturing is used to establish the efficacy of our method. The Formulation-Exploration method can be used to design supply chains to manage mass customization of products, especially when information is incomplete and inaccurate, goals conflict and multiple types of uncertainty add complexity. In this paper, we focus on the method rather than the results per se.
Design Innovation With Additive Manufacturing: A Methodology
Authors: Perez K. Blake , Lauff Carlye A. , Camburn Bradley A. , Wood Kristin L.
Published: November 2019

Additive manufacturing (AM) has matured rapidly in the past decade and has made significant progress towards a reliable and repeatable manufacturing process. The technology opens the doors for new types of innovation in engineering product development. However, there exists a need for a design process framework to efficiently and effectively explore these newly enabled design spaces. Significant work has been done to understand how to make existing products and components additively manufacturable, yet there still exists an opportunity to understand how AM can be leveraged from the very outset of the design process. Beyond end use products, AM-enabled opportunities include an enhanced design process using AM, new business models enabled by AM, and the production of new AM technologies. In this work, we propose the use, adaptation and evolution of the SUTD-MIT International Design Centre’s Design Innovation (DI) framework to assist organizations effectively explore all of these AM opportunities in an efficient and guided manner. We build on prior work that extracted and formalized design principles for AM. This paper discusses the creation and adaptation of the Design Innovation with Additive Manufacturing (DIwAM) methodology, through the combination of these principles and methods under the DI framework to better identify and realize new innovations enabled by AM. The paper concludes with a representative case study with industry that employs the DIwAM framework and the outcomes of that project. Future studies will analyze the effects that DIwAM has on designers, projects, and solutions.
ARCHIE: An Automated Data Collection Method for Physical Prototyping Efforts in Authentic Design Situations
Authors: Nelson Jacob , Berlin Andrew , Menold Jessica
Published: November 2019

Effective data collection can be one of the most challenging aspects of engineering design research. Design projects often occur over periods of weeks, months, or years, making continuous data collection a time-intensive task. Further, interrupting the design process to collect data can be intrusive and disrupt the flow of design. ARCHIE is a system designed to take photos of designers’ physical prototypes, link them to designer perceptions of the design, and maintain a record of design evolution over time. This device will allow researchers to collect data on physical prototyping efforts in design environments without researcher intervention, reducing the burden of data collection in authentic design settings. The device provides designers with an easier way to document physical prototyping efforts and record the evolution of their design with photos and descriptions and promises to allow for researchers to leverage machine learning to automatically analyze aspects of the prototype such as geometric complexity or material choice by facilitating the creation of databases of design artifacts. This work describes the rationale, method, implementation, and testing of ARCHIE using student design projects.
A Comparison of Numerical Optimizers in Developing High Dimensional Surrogate Models
Authors: Xu Yanwen , Wang Pingfeng
Published: November 2019

The Gaussian Process (GP) model has become one of the most popular methods to develop computationally efficient surrogate models in many engineering design applications, including simulation-based design optimization and uncertainty analysis. When more observations are used for high dimensional problems, estimating the best model parameters of Gaussian Process model is still an essential yet challenging task due to considerable computation cost. One of the most commonly used methods to estimate model parameters is Maximum Likelihood Estimation (MLE). A common bottleneck arising in MLE is computing a log determinant and inverse over a large positive definite matrix. In this paper, a comparison of five commonly used gradient based and non-gradient based optimizers including Sequential Quadratic Programming (SQP), Quasi-Newton method, Interior Point method, Trust Region method and Pattern Line Search for likelihood function optimization of high dimension GP surrogate modeling problem is conducted. The comparison has been focused on the accuracy of estimation, the efficiency of computation and robustness of the method for different types of Kernel functions.
Unsteady Aerodynamic Modeling and Prediction of Loads for Rotary Wings in Forward Flight
Authors: Dayhoum Abdallah , Zakaria Mohamed Y. , Abdelhamid Omar E.
Published: November 2019

In this effort, a new approach in aerodynamic modeling that accounts for unsteady wake effects as well as viscous friction drag, Leading edge suction effect and post stall behavior for rotary wings in forward flight is proposed. The adopted approach commingles the unsteadiness with the problem of helicopter rotor blade in forward flight. The results of the local normal force coefficients were compared with experimental results of the 7A rotor case study in high speed test point 312 at five non-dimensional radial positions. A CFD solver, HOST/elsA, results are compared with the obtained results at five radii locations. The results show a good agreement between the experimental results and the proposed model preserving the same pattern of variation along the azimuth angle with a slight discrepancy for amplitude and phase angle. Of particular interest, the presented model showed better agreement with the experimental for higher radii locations.
Resonance Responses and Bifurcations of Circular Mesh Antenna in Thermal Environment
Authors: Liu Tao , Zhang Wei , Guo Xiangying , Zheng Yan
Published: November 2019

In this paper, resonance responses and bifurcations of the circular mesh antenna with 1:3 internal resonance in thermal environment are studied. Considering this internal resonance, based on the equivalent circular mesh antenna model, which is a composite laminated circular cylindrical shell clamped along a generatrix and with the radial pre-stretched membranes at both ends in thermal environment, we obtain the amplitude-frequency response curves of the system in the state-parameter space by using the prediction-correction continuation algorithm in order to study the bifurcation characteristics of the equivalent circular mesh antenna model. Meanwhile, the fold bifurcation points and Antronov-Hopf bifurcation points are detected and located on these resonance response curves. We find that the nonlinear vibrations of the equivalent circular mesh antenna model have the hardening characteristics, and the temperature excitation has noticeable effects on the stabilities and bifurcations of this system.
Modelling and Evaluation of the Friction in Robotic Joints Considering Thermal Effects
Authors: Legnani Giovanni , Incerti Giovanni , Pagani Roberto , Gheza Matteo
Published: November 2019

The paper presents a second order friction model for the joints of industrial robot manipulators that takes into account temperature effects. A solution based on a polynomial description of the friction is proposed. The theoretical analysis and the experimental measurements have shown that friction decreases with increasing temperature, which in turn depends on the working cycle of the manipulator. The mathematical model here proposed allows to foresee the friction variation during extensive working cycles and it does not require the use of a transducer for the measurement of the joint internal temperature; therefore it is well suitable for low-cost industrial applications, to improve the control performance or to predict the energy consumption. Experimental tests performed on a commercial 6 DOF manipulator show that the model is effective in estimating the joint temperature and the friction torque during the robot operations.
Deployable Euler Spiral Connectors (DESCs)
Authors: Ynchausti Collin , Magleby Spencer P. , Bowden Anton E. , Howell Larry L.
Published: November 2019

Deployable Euler Spiral Connectors (DESCs) are introduced as a way to use compliant flexures that lay flat when under strain in a stowed position. This paper presents the design of DESCs using the Euler spiral equations. An application of a spinal device is presented as a proof-of-concept of the use of DESCs.
A Fourier Descriptor Approach to Integrated Type and Dimensional Synthesis of Coupled Serial Mechanism for Motion Generation
Authors: Lv Hao , Han Yuanfei , Li Xiangyun , Zhu Liuxian
Published: November 2019

Coupled serial mechanism is a class of mechanisms that couple the relative rotation of successive links utilizing gears or cable-pulley systems. They can be used to generate complex end-effector trajectories or motions with a single actuator. With the employment of Fourier descriptors, a novel approach to integrate type synthesis and dimensional synthesis of such mechanisms is proposed in this paper. Through the Fourier analysis of two arbitrary trajectories from the given motion, the simplest trajectory that contains the least number of harmonic components is identified. Then, characteristic information of those harmonics such as their numbers, amplitudes and initial phases are used to determine the topology and dimensions of the corresponding coupled serial mechanism, thus effectively solving the motion synthesis problem of this type of mechanisms. Finally, three examples are given to demonstrate the validity of the proposed method.
Research on an Intelligent Diagnostic Equipment Suitable for Rail Traffic Braking System
Authors: Fang Changzheng , Yang Jing , Liu Quan , Feng Furen , Zuo Jianyong
Published: November 2019

In order to meet the increasing requirements of train safety in the rail transit industry, it is important for the operators to monitor the running status and health status of the train in real time. Based on train on-broad data, using big data analysis method for data mining to study the health status of trains and change rules, it will be helpful to realize the informationization and intelligence of train operation.

This paper designs and introduces a smart device for the brake system of rail transit trains. It reads the required data through the train CAN Bus network, and uses the wireless transmission device DTU to remotely send the analysis result to the cloud server. The user can easily browse the train’s device status and system health analyzed by the server through the webpage anytime and anywhere, which is helpful for the health operations and management of trains. The equipment passed the relevant tests of the Changsha subway train in China, which can meet the needs of functional design.
Digital Design Automation to Support In-Situ Embedding of Functional Components in Additive Manufacturing
Authors: Malviya Manoj , Sinha Swapnil , Meisel Nicholas A.
Published: November 2019

Additive manufacturing (AM) offers access to the entire volume of a printed artifact during the build operation. This makes it possible to embedding foreign components (e.g. sensors, motors, actuators) into AM parts, thus enabling multifunctional products directly from the build tray. However, the process of designing for embedding currently requires extensive designer expertise in AM. Current methods rely on a designer to select an orientation for the embedded component and design a cavity such that the component can be successfully embedded without compromising the print quality of the final part. For irregular geometries, additional design knowledge is required to prepare a shape converter: a secondary piece to ensure a flush deposition surface on top of the embedded component. This research aims to develop a tool to automate these different design decisions for in-situ embedding, thus reducing the need for expert design knowledge. A three-stage process is proposed to 1) find the optimum orientation based on cavity volume and cross-section area, 2) create the necessary cavity geometry to successfully insert the component, and 3) perform a Boolean operation to create the digital design for any requisite shape converter. Performance of the tool is demonstrated with four test cases with varying levels of geometric complexity. These test cases show that the proposed process successfully handles arbitrary embedded geometries, though several limitations are noted for future work.
Rigidly Foldable Thick Origami Using Designed-Offset Linkages
Authors: Lang Robert J. , Brown Nathan , Ignaut Brian , Magleby Spencer , Howell Larry
Published: November 2019

We present new families of thick origami mechanisms that achieve rigid foldability and parallel stacking of panels in the flat-folded state using linkages for some or all of the hinges between panels. A degree-four vertex results in a multi-loop eight-bar spatial mechanism that can be analyzed as separate linkages. The individual linkages are designed so that they introduce offsets perpendicular to the panels that are mutually compatible around each vertex. This family of mechanisms offers the unique combination of a planar unfolded state, parallel-stacked panels in the flat folded state, and kinematic single-degree-of-freedom motion from the flat-unfolded to the flat-folded state.
Distributed Design of Two-Scale Structures With Unit Cells
Authors: Liu Xingchen
Published: November 2019

The use of unit cell structures in mechanical design has seen a steady increase due to their abilities to achieve a wide range of material properties and accommodate multi-functional requirements with a single base material. We propose a novel material property envelope (MPE) that encapsulates the attainable effective material properties of a given family of unit cell structures. The MPE interfaces the coarse and fine scales by constraining the combinations of the competing material properties (e.g., volume fraction, Young’s modulus, and Poisson’s ratio of isotropic materials) during the design of coarse scale material properties. In this paper, a sampling and reconstruction approach is proposed to represent the MPE of a given family of unit cell structures with the method of moving least squares. The proposed approach enables the analytical derivatives of the MPE, which allows the problem to be solved more accurately and efficiently during the design optimization of the coarse scale effective material property field. The effectiveness of the proposed approach is demonstrated through a two-scale structure design with octet trusses that have cubically symmetric effective stiffness tensors.
On the Kinematic Performance of a Novel 5-DOF Reconfigurable Hybrid Manipulator With Ultra Large Workspace for Automatic Perfusion of a Large-Scale Spherical Honeycomb Structure
Authors: Yang Hui , Fang Hairong , Ge Qiaode Jeffrey , Fang Yuefa
Published: November 2019

A conventional parallel manipulator consists of a moving platform, a fixed base platform, as well as several serial chains that connect the two platforms. This paper presents a novel five degree-of-freedom (DOF) hybrid manipulator such that its base platform itself is movable and thus reconfigurable. This hybrid structure greatly expands the workspace of the end-effector platform so that it can reach and perform tasks over a large-scale spherical honeycomb structure. First, the inverse kinematics as well as the Jacobian matrix is developed. Then, the workspace and singularity of the hybrid manipulator are studied for four different positions of the reconfigurable base platform to show the enlarged singularity-free workspace. For a large-scale honeycomb structure with prefusion requirements, which is placed within the workspace of the hybrid manipulator, the minimum and maximum limit positions of the reconfigurable base are obtained. Finally, a simulation model for the hybrid manipulator is developed using Mathematica and Adams and numerical simulations are conducted to evaluate the kinematic performance and verify the effectiveness of the hybrid manipulator.
Investigation on Influence of Tooth Precision on Meshing Noise of Planetary Gear Train
Authors: Hamada Seiya , Nakagawa Masao , Fukuda Tomoki , Hirogaki Toshiki , Aoyama Eiichi
Published: November 2019

Noise is one of the major serious issues for planetary gear trains (PGTs). This noise is regarded as a noise hazard in certain cases such as helicopter cabins where the sound level reaches 100dB. Herein, planet gears of several precisions are combined to investigate the influence of tooth precision on meshing noise of PGT. The meshing noise of PGTs is generated by stiffness coefficient excitation and error excitation forces; however, the stiffness coefficient excitation is assumed to be constant in this paper because a slight error on the tooth surface does not affect the meshing stiffness. It was found that maintaining the same precision for all planet gears is the best. If one of the planet gears has a precision that is significantly different from that of the others, the sound pressure level increases. The deviation for the maximum error among all meshing pairs, should be restricted to no more than 3μm in case of module one spur gear.
Confidence-Based Design Optimization Under Data Uncertainty Using Most Probable Point-Based Approach
Authors: Jung Yongsu , Cho Hyunkyoo , Lee Ikjin
Published: November 2019

An accurate input statistical model has been assumed in most of reliability-based design optimization (RBDO) to concentrate on variability of random variables. However, only limited number of data are available to quantify the input statistical model in practical engineering applications. In other words, irreducible variability and reducible uncertainty due to lack of knowledge exist simultaneously in random design variables. Therefore, the uncertainty in reliability induced by insufficient data has to be accounted for RBDO to guarantee confidence of reliability. The uncertainty of input distributions is successfully propagated to a cumulative distribution function (CDF) of reliability under normality assumptions, but it requires a number of function evaluations in double-loop Monte Carlo simulation (MCS). To tackle this challenge, reliability measure approach (RMA) in confidence-based design optimization (CBDO) is proposed to handle the randomness of reliability following the idea of performance measure approach (PMA) in RBDO. Input distribution parameters are transformed to the standard normal space for most probable point (MPP) search with respect to reliability. Therefore, the reliability is approximated at MPP with respect to input distribution parameters. The proposed CBDO can treat confidence constraints employing the reliability value at the target confidence level that is approximated by MPP in P-space. In conclusion, the proposed method can significantly reduce the number of function evaluations by eliminating outer-loop MCS while maintaining acceptable accuracy.
Study on the Mixed Method of Transfer Matrix Method and Finite Element Method for Vibration of Multibody System
Authors: Lu Hanjing , Rui Xiaoting , Zhang Jianshu , Ding Yuanyuan
Published: November 2019

The mixed method of Transfer Matrix Method for Multibody System (MSTMM) and Finite Element Method (FEM) is introduced in this paper. The transfer matrix and transfer equation of multi-rigid-body subsystem are deduced by MSTMM. The mass matrix and stiffness matrix of flexible subsystem are calculated by FEM and then its dynamics equation is established. The connection point relations among subsystems are deduced and the overall transfer matrix and transfer equation of multi-rigid-flexible system are established. The vibration characteristics of the system are obtained by solving the system frequency equation. The computational results of two numerical examples show that the proposed method have good agreements with MSTMM and FEM. Multi-rigid-flexible-body system with multi-end beam can be solved by proposed method, which extends the application field of MSTMM and provides a theoretical basis for calculating complex systems with multi input end flexible bodies of arbitrary shape.
Optimization of Edge Geometry of Cylindrical Milling Tools to Enhance Dynamic Stability
Authors: Dombovari Zoltan , Bachrathy Daniel , Stepan Gabor
Published: November 2019

Tool geometry directly influences the dynamic performance of milling operations. Both surface properties and stability behavior are significantly influenced by the regeneration effect. The regeneration phenomenon is modelled by delay differential equations with delays originated from the time passed between consecutive flute passes. This work presents the implementation study of a constrained general optimization scheme for cutting edges of cylindrical milling cutters based on functional minimization principle. Mathematically, this leads to the determination of the corresponding weight function of a distributed delay differential equation. The presented semi-analytical methodology is based on the general milling model implemented in the semidiscretization framework.
An Improved Unified Solution for a Vibration Equation of Tension-Stiffening Beam Using Extended Rayleigh Energy Method
Authors: Yang Zhijun , Li Ruiqi , Bai Youdun
Published: November 2019

The tension-stiffening effect is very important for physical science, which has been widely used in MEMS, sensors and micro-motion stages. The analytical solutions of the tension-stiffening beam are extremely significant, in consideration of the inefficiency of finite element analysis (FEA) for the design and optimization. Commonly, there are three typical types of boundary conditions for tension-stiffening (or stress-induced) beams, i.e., clamped-clamped, clamped-hinged, and hinged-hinged. But only the hinged-hinged beam has an analytical solution. Therefore, a method based on extended Rayleigh energy method is proposed in this paper to deduce the analytical solutions of three boundary conditions. The predictions are verified to be in good agreement with FEA and experiment results.
Modal Analysis to Interpret Localization Phenomena of Harmonic Oscillations in Nonlinear Oscillator Arrays
Authors: Harata Yuji , Ikeda Takashi
Published: November 2019

This paper investigates localization phenomena in a nonlinear array with N Duffing oscillators connected by weak, linear springs when the array is subjected to harmonic excitation. In the theoretical analysis, the equations of motion are derived for: (1) the physical coordinate system, and (2) modal coordinate system. The modal equations of motion form an autoparametric system, i.e., the excitation acts directly on the first mode of vibration, and the other modes are indirectly excited because they are nonlinearly coupled with the first mode. Van der Pol’s method is employed to obtain the solutions of the harmonic oscillations, and then the expressions of the frequency response curves are given. In the numerical calculations, the frequency response curves of the amplitudes and phase angles in the cases of N = 2 and 3 are presented. The frequency response curves, obtained in the modal coordinate system, demonstrate that localization phenomena occur in the physical coordinate system when multiple vibrational modes simultaneously appear. When imperfections exist in the N Duffing oscillators, the modal equations of motion do not form an autoparametric system because the external excitation directly acts on all modes. Instead, internal resonances may occur in such systems.
Assessment of Shoulder and Chest Protection of Wearable Motorcycle Airbags
Authors: Girardi Davide , Marconi Edoardo , Massaro Matteo
Published: November 2019

The application of numerical simulation to wearable airbags for motorcyclists is relatively recent and only few works about this topic can be found in the literature. This research uses multi-physics simulation to analyse a new wearable airbag geometry, primarily designed to protect the shoulders of motorcycle riders, with the aim of assessing the effect of inflation pressure on the protection performance. The finite element model of the airbag employs a simple linear-isotropic material model, calibrated though the comparison between experimental and numerical outcomes of a drop test, together with the analysis of the airbag inflated geometry. The finite element model of the wearable device is then fitted to a dummy model and a human body model, in order to be used in a parametric analysis. Two set-ups are considered. The first is a thorax impact test, used to assess the effect of inflation pressure on chest protection. A modification to the bag geometry is also proposed and tested on this configuration. The second set-up is a shoulder impact test, used to assess the effect of inflation pressure on shoulder protection. In both tests an optimal inflation pressure can be found, but the maximization of shoulder protection proved more critical and should therefore drive the choice of this parameter.
Hypocycloid Gear Mechanism Versus Slider-Crank Mechanism in Engines
Authors: ElBahloul Mostafa A. , Aziz ELsayed S. , Chassapis Constantin
Published: November 2019

This effort investigates the feasibility of using the Hypocycloid Gear Mechanism (HGM) as an alternative to the conventional slider-crank mechanism for Internal Combustion Engine (ICE) applications. Engines incorporating the conventional slider-crank mechanism are subjected to high frictional power losses mainly due to the piston-rod assembly and the associated complex motion of the connecting rod. The unique HGM engine provides the means for the piston-rod assembly to reciprocate in a straight-line motion along the cylinder axis, thus eliminating the piston side-thrusting into the cylinder wall. To analyze the performance advantages of the HGM engine, a Matlab/Simulink model is developed for the simulation of a single-cylinder HGM engine from the throttle to the crankshaft output. The model integrates several sub-models for combustion, gas flow, heat transfer, and friction power loss of the internal gear train meshes, rolling bearings, and sliding bearings. The design of the planetary crank gearing system to satisfy the design specifications of ICE, has been derived using standard design procedures provided by AGMA. Calculated efficiency and power diagrams are plotted and compared with the performance of conventional engines in the literature. The results show that the HGM can satisfy modern ICE design requirements, achieve better engine performance characteristics, and minimize the frictional power losses. The HGM engine achieved lower frictional power losses by an average 33% of the conventional engine losses while its mechanical efficiency is enhanced by up to +24% with respect to the conventional engine.
Level Set Topology Optimization for Design Dependent Hydrostatic Loading Using the Reproducing Kernel Particle Method
Authors: Neofytou Andreas , Picelli Renato , Chen Jiun-Shyan , Kim Hyunsun Alicia
Published: November 2019

Level set topology optimization for the design of structures subjected to design dependent hydrostatic loads is considered in this paper. Problems involving design-dependent loads remain a challenge in the field of topology optimization. In this class of problems, the applied loads depend on the structure itself. The direction, location and magnitude of the loads may change as the shape of the structure changes throughout optimization. The main challenge lies in determining the surface on which the load will act.

In this work, the reproducing kernel particle method (RKPM) is used in combination with the level set method to handle the dependence of loading by moving the particles on the structural boundary throughout the optimization process. This allows for the hydrostatic pressure loads to be applied directly on the evolving boundary. One-way fluid-structure coupling is considered here. A hydrostatic pressure field governed by Laplace’s equation is employed to compute the pressure acting on linear elastic structures. The objective in this optimization problem is to minimize compliance of these structures. Numerical results show good agreement with those in the literature.
Novel State Estimation Method of Surface Chatter Pattern via Image Processing After End Milling
Authors: Ozaki Nobutoshi , Matsui Shota , Hirogaki Toshiki , Aoyama Eiichi
Published: November 2019

We studied a new analytical method for determining self-excited chatter vibration at an end mill processing site. When chatter vibration occurs, cutting marks with periodic features called “chatter marks” are generated on the processed surface. We focused on the relationship between the vibration generated during cutting and the roughness of the processed surface. We developed a method to analyze such vibrations, based on the roughness of the finished surface. Instead of using a roughness meter and laser-measuring instrument, which are often used for measuring the contours of a processed surface, we presumed the roughness of the processed surface from image data obtained using a digital camera. As a comparative experiment to verify the proposed method, side cutting with an end mill was performed. Chatter vibrations occurring during the cutting were measured using a displacement sensor and microphone, and compared with the vibration of the tool edge as determined from the processed surface. The chatter frequency read from the processed surface was close to that obtained from the displacement sensor and microphone. Thus, the proposed method can be used to analyze the information of chatter vibration inexpensively and easily. It can serve as a substitute for displacement and acceleration sensors.
Engineering Design Concept Generation: The Effect of Concept Combination and Classification
Authors: Deo Saurabh , Hölttä-Otto Katja , Bhalerao Yogesh , Malge Abhijeet
Published: November 2019

World economic forum reported that creativity is one of the most sought after skills by employers globally. Preliminary research lead to multiple initiatives on enhancing creativity and innovation. To contribute in this field, we investigated the effect of two interventions on the creativity of undergraduate engineering students, particularly on engineering design concept generation. The primary focus of this investigation was on assessing the effect of two interventions, combining and classifying concepts, on the originality and quantity of the concepts produced.

In this research, we used the Decision Tree for Originality Assessment in Design (DTOAD) as a measure of concept originality. Statistical analysis showed that both the combine and the classify interventions lead to concept generation with higher originality. We also found that students produced higher number of the radically different concept, i.e. concepts with originality score 7.5 and above, however this effect was observed in all the test groups.

These interventions made improvements and thus can be encouraged as a part of an ideation or an engineering problem solving task in the undergraduate engineering education to help the students develop creative skills.
Machine Learning-Augmented Stochastic Search for the Automated Synthesis and Optimization of Cooling Channels
Authors: Schwarz Jonas , Shea Kristina
Published: November 2019

Stochastic search methods are widely used when it comes to design synthesis and optimization of response-based objective functions. In engineering applications, the objective function is typically expensive to evaluate, and stochastic search methods lack efficiency, resulting in the necessity of extensive design evaluations. In order to improve stochastic search methods, we propose a Machine Learning (ML)-based augmentation, consisting of three modules: a design archiver, a data modeler, and a modification advisor. These three modules cooperatively work together to store the gathered data during the design process, build up a representative model of the observations made, and advise the search for further sequences of modifications to apply. The proposed method is benchmarked against its unaugmented parent method in placing cooling channels in a die casting mold. The results show that the efficiency of the method is significantly improved when augmented with ML, i.e. similar results are obtained with 25–50% fewer evaluations. Additionally, the robustness and reliability of the optimization process is improved with a standard deviation of the obtained results that is 60–85% smaller. It is shown that the search strategy can be significantly improved with the proposed method, resulting in shorter running times and more reliable convergence behavior.
Additive Manufacturing of a Bistable Mechanism Using Fused Deposition Modeling: Experimental and Theoretical Characterization
Authors: Ben Salem Mouna , Aiche Guillaume , Haddab Yassine , Rubbert Lennart , Renaud Pierre
Published: November 2019

Bistable mechanisms can be used for performing specific functions such as locking or negative stiffness generation. These compliant structures are then of interest at different scales, with different corresponding manufacturing technologies. One of them is additive manufacturing, which is interesting for the integration of such structures. Although this technology has undergone a revolution with the development of high-accuracy machines, the manufacturing of small-sized compliant structures is still quite a challenge especially for bistable mechanisms, which was not yet finely characterized. This is the focus of this paper, with presentation of an experimental and analytical confrontation in the case of Fused Deposition Modeling (FDM).
Internal Resonance of Plane Waves in Nonlinear Lattices
Authors: Fronk Matthew D. , Leamy Michael J.
Published: November 2019

Recent studies have employed perturbation techniques to derive amplitude-dependent band structures in nonlinear periodic materials. The associated applications include amplitude-dependent filters, waveguides, and diodes. However, for a range of frequencies and wavenumbers, perturbation-based dispersion corrections for a single wave break-down due to internal resonance between the primary wave and its nonlinearity-induced higher-harmonics. This work presents a perturbation analysis of one-dimensional plane waves in lattices with internal resonances. The exchange of energy between propagating modes within the same branch of the lattice’s band structure is considered, and the stability of the energy exchange is assessed through a local analysis. Direct numerical integration of the lattice equations of motion validates the analytical expressions for energy exchange. These findings can be used to resolve discontinuities in band diagrams that do not account for internal resonances and may inspire new technology that enables long-range coherent signal transmission in nonlinear media.
Molding Parameters Design for Meso and Micro Components Using Polylactic Acid (PLA)
Authors: Surace Rossella , Bellantone Vincenzo , Fassi Irene
Published: November 2019

Currently, the increasing interest in the study of Polylactic acid (PLA) polymer has been motivated by the potential of such material for consumer and biomedical applications. PLA is a thermoplastic polymer, biodegradable, compostable and deriving from renewable natural sources as starch and sugar. Injection molding is the most widely used process for thermoplastic micro-featured parts for to its capacity to manufacture low-cost and high repeatable micro-parts. The use of PLA for injection molded micro components is still not well stabilized due to the slow crystallization kinetics, not suitable for high performance applications. In this work, preliminary experimental studies have been performed to analyze the filling ability of PLA in a meso and a micro parts using different molding conditions to evaluate process parameters influence. The experiments results are discussed in the paper and show that injection molding proved to be suitable for meso-micro PLA product manufacturing.
Analysis of a Multibody Elastodynamic Model for Closed-Loop Kinematic Mechanisms
Authors: Carbonari Luca , Brillarelli Stefano , Palpacelli Matteo-Claudio , Callegari Massimo
Published: November 2019

This paper is focused on the analysis of an elastodynamic model, typically referred to single-link flexible manipulators, when it is extended to multibody systems with closed-loop kinematic chains subject to vibrations, caused by the slenderness of their mechanical structure together with severe dynamic working conditions. The work is aimed at analyzing the relationship between the degree of accuracy of the proposed elastodynamic model, compared with more complete but time consuming models developed with software, and the time required for its computation, with the final aim of guiding its implementation in real-time control algorithms. Notwithstanding the study is proposed for parallel kinematic machines, the results are also valid for serial kinematic chains.
An Optimal Quantity of Scheduling Model for Mass Customization-Based Additive Manufacturing
Authors: Oh Yosep , Behdad Sara
Published: November 2019

The purpose of this study is to optimize production planning decisions in additive manufacturing for mass customization (AMMC) systems in which customer demands are highly variable. The main research question is to find the optimal quantity of products for scheduling, the economic scheduling quantity (ESQ). If the scheduling quantity is too large, the time to collect customer orders increases and a penalty cost occurs due to the delay in responding to consumer demands. On the other hand, if the scheduling quantity is too small, the number of parts per jobs decreases and parts are not efficiently packed within a workspace and consequently the build process cost increases. An experiment is provided for the case of stereolithography (SLA) and 2D packing to demonstrate how the build time per part increases as the scheduling quantity decreases. In addition, a mathematical framework based on ESQ is provided to evaluate the production capacity in satisfying the market demand.
Combined Lane Keeping and Longitudinal Speed Control for Autonomous Driving
Authors: Feraco Stefano , Bonfitto Angelo , Amati Nicola , Tonoli Andrea
Published: November 2019

This paper presents a technique for the lane keeping and the longitudinal speed control of an autonomous vehicle with the combination of an MPC and a PID control. The goal of the proposed control method is to minimize the lateral deviation and relative yaw angle with respect to the planned trajectory, while driving the vehicle at the highest acceptable longitudinal speed. The reference profile of the longitudinal speed is computed considering both the lateral and longitudinal dynamic of the vehicle. The vehicle is represented by means of a linear 3-DoF bicycle model. The control algorithm takes the road lane boundaries as the only external input. The proposed strategy is validated in simulation on three distinct driving scenarios.
Collaborating With Style: Using an Agent-Based Model to Simulate Cognitive Style Diversity in Problem Solving Teams
Authors: Lapp Samuel , Jablokow Kathryn , McComb Christopher
Published: November 2019

Collaborative problem solving can be successful or counterproductive. The performance of collaborative teams depends not only on team members’ abilities, but also on their cognitive styles. Cognitive style measures differences in problem-solving behavior: how people generate solutions, manage structure, and interact. While teamwork and problem solving have been studied separately, their interactions are less understood. This paper introduces the KAI Agent-Based Organizational Optimization Model (KABOOM), the first model to simulate cognitive style in collaborative problem solving. KABOOM simulates the performance of teams of agents with heterogeneous cognitive styles on two contextualized design problems. Results demonstrate that, depending on the problem, certain cognitive styles may be more effective than others. Also, intentionally aligning agents’ cognitive styles with their roles can improve team performance. These experiments demonstrate that KABOOM is a useful tool for studying the effects of cognitive style on collaborative problem solving.
Pilot-Induced-Oscillations Issue in Driverless Car Age
Authors: Yuan Jie , Wu Zhenlong , Fei Shumin , Chen YangQuan
Published: November 2019

As driverless vehicles becoming more and more popular due to the development of artificial intelligence, human beings will gradually get free from the vehicle driving. However, unexpected oscillations may happen due to the unfamiliarity of the vehicle configuration when humans want to drive themselves, even the vehicle itself is stable. These driver-induced-oscillations are similar with the pilot-induced-oscillations (PIO) which is generally related with actuator rate limit in the aircraft systems. Thus, this study attempts to review the PIO issue briefly and provide a guidance to solve the potential human-in-the-loop unmanned driving challenge associated with rate limit effect.