bluuebunny/crossref_metadata_2025 huggingface dataset:
Flexibility and Real Options Analysis in Design for Long-Term Generation Expansion Planning of Power Grids
Authors: Rahmat Muhammad , Caunhye Aakil Mohammad , Cardin Michel-Alexandre
Published: November 2017

In recent years, the electricity industry has seen a drive towards the integration of renewable and environmentally friendly generation resources to power grids. These resources have highly variable availabilities. This work proposes a stochastic programming approach to optimize generation expansion planning (GEP) under generator supply capacity uncertainty. To better capture upside opportunities and reduce exposure to downside risks, flexibility is added to the GEP problem through real options on generator addition, which are to be exercised after uncertainty realizations. In addition, with the end goal of providing decision makers with easy-to-use guidelines, a conditional-go decision rule, akin to an if-then-else statement in programming, is proposed whereby the decision maker is provided with a threshold of excess total generator capacity from the previous time period, below which a predetermined generator addition plan (the option) is exercised. The proposed methodology and its decision rule are implemented in a real-world study of Midwest U.S. Comparisons are made to quantify the value of flexibility and to showcase the usefulness of the proposed approach.
Robust Recovery of 3D Geometric Primitives From Point Cloud
Authors: Yang Xiang , Meer Peter , Gea Hae Chang
Published: November 2017

A robust method for surface fitting in 3D point cloud is presented as an application of the robust estimation of multiple in-lier structures algorithm [1]. The geometric primitives such as planes, spheres and cylinders are detected from the point samples in the noisy dataset, without regenerating surface normals or mesh. The inlier points of different surfaces are classified and segmented, with the tolerance of error for each surface estimated adaptively from the input data. From the segmented points, designers can interact with the geometric primitives conveniently. Direct modification of 3D point cloud and inverse design of solid model can be applied. Both synthetic and real point cloud datasets are tested for the use of the robust algorithm.
Vibration of a Tapered Roller Bearing Excited by Localized Damage on a Rotating Cone Raceway
Authors: Li Desheng
Published: November 2017

Localized damages such as spalls, dents and raised metal may develop on bearing raceways and roller bodies in operation for various reasons. They can excite bearings and adjacent mechanical structures into vibration. By measuring machine vibration, it is possible to detect potential bearing damage. However, to do so, it is critical to understand the bearing vibration characteristics that are excited by localized damages.

The vibration of a TRB (tapered roller bearing) excited by a localized damage on a rotating cone (inner ring) raceway was studied using a three-dimensional, non-linear vibration model. Bearing vibration responses were analyzed in three directions. The responses exhibited multiple BPFI (ball passing frequency, inner) harmonics. The spectral envelope is determined by the bearing’s dynamic properties. The vibration characteristics in the axial direction were discovered to be different from those in the radial directions. The reason behind that is revealed in this paper.
Identifying and Managing Dilemmas for Sustainable Development of Rural India
Authors: Yadav Abhishek , Das Ashok K. , Roy Ram Babu , Chatterjee Archana , Allen Janet K. , Mistree Farrokh
Published: November 2017

In this paper, we present a method for identifying conflicts (Dilemmas) that have zero-sum solutions among the three aspects (Drivers) of sustainability, namely, social (people), environment (planet), and economic (profit) values. We develop the value proposition that is anchored in sustainable rural development by converting these zero-sum solutions to positive-sum solutions. Rural development is difficult, and it must be initiated from within the communities with the involvement of local people. We hypothesize that social entrepreneurs can serve as the proverbial lynchpin between the rural population and other agencies (government, non-government, banks, and industry). Hence in this paper, we use the constructs of a dilemma triangle and spheres of sustainability to propose a method to identify and manage dilemmas associated with creating a sustainable eco-system. We use example of a village in India to illustrate the method and to develop the value proposition for the village. The focus in this paper is on the method, rather than the results per se.
A New Locking-Free Formulation of a Three-Dimensional Shear-Deformable Beam
Authors: Fan W. , Zhu W. D.
Published: November 2017

A new locking-free formulation of a three-dimensional shear-deformable beam with large deformations and large rotations is developed. The position of the centroid line of the beam is integrated from its slope that is related to the rotation of a corresponding cross-section and stretch and shear strains. The rotation is parametrized by a rotation vector, which has a clear and intuitive physical meaning. Taylor polynomials are used for certain terms that have zero denominators to avoid singularity in numerical implementation. Governing equations of the beam are obtained using Lagrange’s equations for systems with constraints, and several benchmark problems are simulated to show the performance of the current formulation. Results show that the current formulation do not suffer from shear and Poisson locking problems that the absolute nodal coordinate formulation can have. Results from the current formulation for a planar static case are compared with its exact solutions, and they are in excellent agreement with each other, which verifies accuracy of the current formulation. Results from the current formulation are compared with those from commercial software ABAQUS and RecurDyn, and they are in good agreement with each other; the current formulation uses much fewer numbers of elements to yield converged results.
Part Change Management: A Case Study on Automotive OEM Development and Production Perspectives
Authors: Knackstedt Stephan , Summers Joshua D.
Published: November 2017

Due to interest in aspects such as process, strategies, and tools of engineering changes expressed in a literature review, a case study was done on a major automotive OEM to assess the perceived quality of its part engineering change management process and supporting system through its employees’ eyes. A combination of 12 interviews lasting 12 hours and 46 written surveys was used to capture the views of participants from all major functions found at the research and development (R&D) headquarters of the OEM: Purchasing, Production, Development, and one group consisting of all other functions (“Other”). Statistical analysis was performed to identify statistically significant differences between employee perceptions of an engineering change management system among different departments, amount of use, and years of use. It was found that statistically significant differences exist in terms of understanding the usability of the system between different departments and also between different years of experience.
Real-Time High Bandwidth Feedforward Position Control of Electro-Hydraulic Actuator Using Non-Minimum Phase Inverse Model
Authors: Lee Kyeong Ha , Baek Seung Guk , Koo Ja Choon
Published: November 2017

In this paper, real-time feedfoward position control algorithm of electro-hydraulic actuator (EHA) is proposed. To reduce nonlinearity of EHA, model uncertainty and disturbance, feedback system with proportional-integral-derivative (PID) controller is used. The feedback system is estimated as linear dirsrete time transfer function by recursive least squares algorithm. Feed-forward controller using inverse model generates filtered signals that compensate magnitude and phase of feedback system. For high bandwidth control, fast sample rate is necessary and it causes NMP zeros of estimated transfer function. The NMP transfer function is inversed by zero phase error tracking control (ZPETC) method and the inverse model is used to feedforward controller. The real-time experiment is conducted by NI-CompactRio and Labview, and the simulation is programmed in MATLAB/Simulink. The results of simulation verify the validity of proposed control strategy.
Mesoscale Multi-Physics Simulation of Solidification in Selective Laser Melting Process Using a Phase Field and Thermal Lattice Boltzmann Model
Authors: Liu Dehao , Wang Yan
Published: November 2017

Selective laser melting (SLM) is a powder bed based additive manufacturing process by melting fine-grained metallic powders with a laser heating source. Understanding the solidification of alloys during SLM process is of importance for accurate prediction of microstructures and properties for process design and optimization. In this study, a multi-physics model is developed to simulate evolution of alloy microstructure during solidification, which incorporates heat transfer, fluid dynamics, kinetics of phase transformations, and grain growth. In this integrated simulation framework, the phase field method for the dendritic growth of a dilute binary alloy is coupled with the thermal lattice Boltzmann method for the melt flow and heat transfer. The effects of latent heat, melt flow and cooling rate on solidification process are also investigated. The multi-physics simulation results provide new insight to predict the complex solidification process more accurately than single-physics approaches.
Kinematic Constraint Maps, C-Space Singularities and Generalised Grashof Conditions
Authors: Amirinezhad S. Vahid , Donelan Peter
Published: November 2017

The kinematics of parallel mechanisms are defined by means of a kinematic constraint map (KCM) that captures the constraints imposed on its links by the joints. The KCM incorporates both pose parameters describing the configuration of every link and the design parameters inherent in the mechanism architecture. This provides a coherent approach to determining C-space singularities and generalised Grashof conditions on the design parameters under which these can occur.
A Study of Rapid Tetrapod Running and Turning Dynamics Utilizing Inertial Measurement Units in Greyhound Sprinting
Authors: Hayati Hasti , Eager David , Jusufi Ardian , Brown Terry
Published: November 2017

Understanding the biomechanics of rapid running locomotion plays an important role in comparative biomechanics and bio-inspired engineering and is an integral part of animal welfare.

However, this is not easily achieved using conventional methods of gait analysis: measuring ground reaction forces using a force plate, mainly on irregular granular terrain i.e. greyhounds in racing conditions or in animal’s natural habitats i.e. cheetahs in natural terrain. An alternative to measuring forces externally via force platforms embedded in track ways, we can attach inertial measurement units to agile quadrupeds to measure the effects of rapid running and turning.

Here we deployed an IMU equipped with a tri-axial accelerometer on sprinting greyhounds to analyze rapid locomotion behaviors like dynamic banking and turning in conditions equivalent to racing. High speed videography and paw print analysis of the entire race were used for calibration. The results are beneficial in locomotion analysis and welfare of greyhounds.
On the Existence of Regional Optimal Control for a Class of Fractional Order Differential Inclusion
Authors: He Bin-Bin , Chen YangQuan , Kou Chun-Hai
Published: November 2017

This paper is concerned with the investigation of the regional controllability of the fractional order differential inclusion (FODI). First, some preliminaries and definitions of regional controllability of the system are introduced. Then we obtained some equivalent conditions of regional controllable from the viewpoint of set relations and analyzed the regional controllability with minimum energy of a class of time fractional order differential inclusion.
Frequency Control of Shell Structures With Light-Activated Shape Memory Polymers Based on Isogeometric Analysis
Authors: Guo Yujie , Tzou Hornsen
Published: November 2017

The frequency control of LaSMP laminated shell structures in the framework of isogeometric analysis is presented. LaSMP is a novel smart material which realizes shape memory function and stiffness variation via light exposures. This dynamic properties of stiffness provides a natural way for the noncontact actuation of shell structures. Isogeometric analysis utilizes high order and high continuity NURBS as basis functions which is an ideal candidate for the analysis of shell structures where curved geometries can be captured exactly. A variationally consistent Nitsche’s method is proposed for the coupling between Kirchhoff-Love shell patches to prevent hinge-like motion. The accuracy and efficiency of the proposed isogeometric approach are demonstrated via several numerical examples. The results show that, with LaSMPs, broadband frequency control of shell structures can be realized which further opens a door for the dynamic control of engineering-related LaSMP shell structures.
Topology and Sizing Optimization of Micromixers Using Graph-Theoretical Representation and Genetic Algorithm
Authors: Yoshimura Mitsuo , Shimoyama Koji , Misaka Takashi , Obayashi Shigeru
Published: November 2017

This paper proposes a novel approach for fluid topology optimization using genetic algorithm. In this study, the enhancement of mixing in the passive micromixers is considered. The efficient mixing is achieved by the grooves attached on the bottom of the microchannel and the optimal configuration of grooves is investigated. The grooves are represented based on the graph theory. The micromixers are analyzed by a CFD solver and the exploration by genetic algorithm is assisted by the Kriging model in order to reduce the computational cost. Three cases with different constraint and treatment for design variables are considered. In each case, GA found several local optima since the objective function is a multi-modal function and each local optimum revealed the specific characteristic for efficient mixing in micromixers. Moreover, we discuss the validity of the constraint for optimization problems. The results show a novel insight for design of micromixer and fluid topology optimization using genetic algorithm.
A New Type of NES: Rotary Vibro-Impact
Authors: Saeed Adnan S. , AL-Shudeifat Mohammad A.
Published: November 2017

Rotating and vibro-impact Nonlinear Energy Sinks (NESs) have been employed for rapid and passive Targeted Energy Transfer (TET). Both have been proven to be efficient, shown high energy dissipation and have been tested experimentally. A novel type of NES that combines the two principles of nonlinear TET, rotating inertial coupling and vibro-impact, is numerically investigated on a 2 degree of freedom physical system. Two configurations of the new promising NES are considered via changing the location of the impacts. The optimized parameters of both configurations proved that high amounts of energy can be transferred from the primary system to the new promising type of NESs passively and rapidly.
Comparison of Cyclo-Palloid and Cyclo-Cut Cutting Methods for Generation of Spiral Bevel Gears
Authors: Gonzalez-Perez Ignacio , Fuentes-Aznar Alfonso
Published: November 2017

The face-hobbing cutting method is widely applied for generation of spiral bevel and hypoid gears due to its high productivity. Among face-hobbing processes, Cyclo-Palloid™ system allows either line contact or localized bearing contact through application of a dual head-cutter where two separate rotating centers are considered. Another face-hobbing process known as Cyclo-Cut™ is based on the application of a single and tilted head cutter for localization of the bearing contact. Computerized generation models of spiral bevel gears through the Cyclo-Palloid and the Cyclo-Cut systems are compared here. Application of tooth contact and backlash analyses will bring to light the similarities and differences between both processes, and the possibility to substitute a Cyclo-Palloid gear by a Cyclo-Cut gear in a Cyclo-Palloid spiral bevel gear drive, and viceversa. Several numerical examples are presented.
An On-Line Multi-Fidelity Metamodel Assisted Multi-Objective Genetic Algorithm
Authors: Zhou Qi , Wang Yan , Choi Seung-Kyum , Jiang Ping
Published: November 2017

Multi-objective genetic algorithms, which require a large number of fitness evaluations before obtaining a Pareto set, can become computationally intractable when applied to practical engineering design problems involving computationally expensive simulations. In this work, an on-line multi-fidelity metamodel (MFM) assisted multi-objective genetic algorithm (OLMFM-MOGA) approach is proposed, in which the MFM that can integrate information from both low-fidelity (LF) and high-fidelity (HF) models is constructed to replace the fitness evaluations during the optimization process. Two model management strategies, an individual-based updating strategy considering the interpolation uncertainty from MFM and a generation-based updating strategy considering the discrete degree of the populations, are incorporated in the OLMFM-MOGA. Three numerical examples and an engineering case with different degrees of complexity are used to demonstrate the effectiveness of the proposed approach. Results show that the proposed OLMFM-MOGA is able to obtain similar convergence and diversity of the Pareto frontier to the ones obtained by MOGA with only HF information, while at the same time significantly reducing the number of evaluations of the expensive HF model.
Electrostatically Tunable Nanomechanical Shallow Arches
Authors: Kazmi Syed N. R. , Hajjaj Amal Z. , Costa Pedro M. F. J. , Younis Mohammad I.
Published: November 2017

We report an analytical and experimental study on the tunability of in-plane doubly-clamped nanomechanical arches under varied DC bias conditions at room temperature. For this purpose, silicon based shallow arches are fabricated using standard e-beam lithography and surface nanomachining of a highly conductive device layer on a silicon-on-insulator (SOI) wafer. The experimental results show good agreement with the analytical results with a maximum tunability of 108.14% for 180 nm thick arch with a transduction gap of 1 μm between the beam and the driving/sensing electrodes. The high tunability of shallow arches paves the ways for highly tunable band pass filtering applications in high frequency range.
Theoretical and Experimental Study on Lip Seal Losses in Large High-Speed Rotors
Authors: Bhatia Narayan Jatinder , Missaglia Elia , Previati Giorgio , Mastinu Gianpiero , Ramakrishnan Kesavan , Gobbi Massimiliano
Published: November 2017

This paper is devoted to the theoretical study of rubber-metal friction with particular reference to a lip seal for large high-speed rotor applications.

The paper, starting from previously published mathematical models related to friction estimations, presents a semi-analytical mathematical model to estimate friction loss induced by rubber lip seals. The sliding friction model is formulated on the basis of rubber and metal surface properties. Viscoelastic and hysteretic properties of the rubber are considered as function of temperature and excitation frequency. The metal surface profile is modelled as a superimposition of base ideal peak profiles.

Finally, the friction coefficient is modelled as a function of temperature, frequency and contact pressure. A preliminary validation of the model is achieved by comparing the estimated friction torque provided by the model with the friction torque measured on an actual rotor-stator system at different operating temperatures.
Three-Dimensional Object Realization via Direct Volumetric Activation
Authors: Birnbaum Andrew J. , Iliopoulos Athanasios P. , Steuben John C. , Michopoulos John G.
Published: November 2017

Despite increasing levels of acceptance, traditional additive manufacturing techniques continue to suffer from a number of fundamental drawbacks that act to limit broad adoption. These drawbacks include limits on processable materials, part properties/performance, geometric deviation and repeatability. The vast majority of existing processes also rely on a point-by-point approach to generate parts, resulting in exceedingly long build times and extremely poor scaling behavior. Furthermore, in general, current systems require significant levels of complexity for operation, resulting in the need for considerable upfront capital investment as well as continuing maintenance costs. A new manufacturing approach is presented here, based upon the generation of objects from the direct creation of constituent volumetric sub-regions. This process addresses many of the limitations described above, and has the potential to significantly alter the manner with which three-dimensional objects are realized.
Utilizing Design for Assembly Principles to Predict Product Recyclability
Authors: Yadav Darshan P. , Patel Deep N. , Morkos Beshoy W.
Published: November 2017

Designing products for recyclability is driven by environmental and economic goals. Several Design for Assembly rules and parameters can be used to gauge the recyclability index of product designs. These indices can then be used for comparative analysis of the recyclability of different products. This would assist the designer in making design choices related to the end of the product’s life cycle. Further, such design decisions could be made earlier in the design process, when the design space is less bound. A case study was conducted for different products to compare their recyclability indices. The parameters were obtained from existing Design for Assembly time estimate tables. The results of the study indicated the recyclability of the product, as defined by established recyclability metrics, could be predicted through design for assembly measures. A statistically significant negative correlation was realized between recyclability and insertion time. Effectively, components that required greater time to mate during assembly adversely affected the recyclability of the product. Conversely, handing time was found to have no predictive capability to product recyclability.
A Constitutive Model for Torsional Loads on Fluid-Driven Soft Robots
Authors: Sedal Audrey , Bruder Daniel , Bishop-Moser Joshua , Vasudevan Ram , Kota Sridhar
Published: November 2017

For soft robots to be utilized in medical devices, locomotion, industrial automation, and a number of other fields, they require accurate and computationally efficient models that capture both the kinetic behavior and inherent non-linearity. Fiber reinforcement enables soft robots to create useful motions, such as rotation, but poses additional complexity in modeling. The purpose of this paper is to present a constitutive model that relates the kinematic behaviour of a pneumatic fiber-reinforced soft actuator with its torsional loading. This model has the advantage of requiring minimal experimental parameter determination, being inclusive of torsional loads, without requiring large-scale computing systems. Experimental data in multiple kinematic configurations shows agreement between the models moment prediction and the moments that the actuators generate.
A Multi-Objective and Multi-Level Design Optimization Method for Oil and Gas Ducts
Authors: Cicconi Paolo , Castorani Vincenzo , Germani Michele , Mandolini Marco , Vita Alessio
Published: November 2017

The paper proposes a methodological approach to support the multi-objective (i.e. cost and structural performance) optimization of complex systems, typical of the oil & gas sector. The complexity is managed through a double-level of optimization. The first one, based on simplified product models (1-D and 0-D), considers an analytical approach for the structural behavior and a parametric one for the cost estimation. The second level considers the use of a 3-D FEM solver for structural simulations, and an analytical tool for the cost estimation. As case study, the paper proposes the design optimization of an oil & gas chimney for gas turbines. The workflow analyzed during the case study describes the use of a multi-objective and multi-level approach to optimize cost, weigh, and structural behavior of oil & gas ducts.
Design of Track-Based Climbing Robots Using Dry Adhesives
Authors: Powelson Matthew W. , Canfield Stephen L.
Published: November 2017

This paper focuses on the design of track-type climbing robots using dry adhesives to generate tractive forces between the robot and climbing surface to maintain equilibrium while in motion. When considering the design of these climbing robots, there are two primary elements of focus: the adhesive mechanisms at the track-surface interface and the distribution of these forces over the full contact surface (the tracks). This paper will present an approach to integrate a generic adhesion model and a track suspension system into a complete model that can be used to design general climbing robot systems utilizing a broad range of dry adhesive technologies.
A Systematic Approach to Identifying a Set of Feasible Designs
Authors: Han Hyeongmin , Chang Sehyun , Kim Harrison
Published: November 2017

In engineering design problems, designers set boundaries of design variables and solve the system to find the design variables that satisfy a target performance. Once lower and upper bounds for each performance index are set, the design problem becomes Constraint Satisfaction Problem (CSP). In this paper, CSP problem is transformed into an optimization problem with a penalty function. Also, by applying optimization technique, set of feasible solutions are acquired. The set of solutions and all the function evaluation during the iteration process are stored in database. By utilizing a database query, the best solution among the data points are selected for the design problem. For the numerical experiment, a CSP with three variables and a bicycle model of vehicle design is tested with different scenarios.
Free Dynamics of Multi-Block Rocking Assemblies
Authors: Wiebe R. , Li T.
Published: November 2017

Rocking systems are increasingly being investigated for use as base-isolators in structural engineering applications. Unfortunately these systems present complicated, piecewise defined, kinematic relationships between their generalized coordinates (usually the joint opening angles). This makes it difficult to obtain the governing equations, even for the dynamics between rocking/impact events. This paper seeks to address this through a systematic formulation of the governing equations of rocking post-tensioned assemblies with any number of blocks under base motion. The results are limited to the smooth dynamics between rocking events, and thus, although an important step, they do not give the complete description of rocking systems. The formulation utilizes the Euler-Lagrange equation to model the dynamics, with the constraint that all rocking occurs about the corners of the blocks.
A Life Cycle Model to Assess Costs and Environmental Impacts of Different Maritime Vessel Typologies
Authors: Favi Claudio , Raffaeli Roberto , Germani Michele , Gregori Fabio , Manieri Steve , Vita Alessio
Published: November 2017

Maritime vessels have long service life and great costs of building, manning, operating, maintaining and repairing. Making a consistent lifecycle model among the different vessel typologies, repeatable with the same level of detail and comparable for the implementation of decision-making strategies, remains an open question. This paper aims to define a suitable lifecycle model in the context of maritime vessels to cope with the current limitations of ad-hoc and fragmented methods. The model considers the main aspects involved in the vessel lifecycle such as building materials, manufacturing and assembly, maintenance/service, operational activities, use, etc. The model provides a common structure for the lifecycle assessment (LCA) and lifecycle cost analysis (LCCA) including the way to retrieve and to collect the data necessary for the analysis starting from the available project documentation and the design models. The method is flexible and it is able to cover a large variety of maritime vessel typologies. As example, a luxury yacht has been analysed using the developed method, demonstrating the applicability of the proposed model in one of the most critical vessel typology.
A Generic Method to Generate AS-Curve Profile in Commercial Motion Controller
Authors: Bai Youdun , Chen Xin , Yang Zhijun
Published: November 2017

It is well believed that S-curve motion profiles are able to reduce residual vibration, and are widely applied in the motion control fields. Recently, a new asymmetric S-curve (AS-curve) motion profile, which is able to effectively adjust the acceleration and deceleration periods, is proposed to enhance the performance of S-curve motion profile, and proved to be better than the traditional symmetric S-curve in many cases. However, most commercial motion controllers do not support the AS-curve motion profiles inherently. Special knowledge or expensive advanced controlling systems, such as dSPACE system, are required to generate the AS-curve motion command, which limits the applications of the AS-curve motion profile in many practical applications. In this paper, a generic method based on the Position-Velocity-Time (PVT) mode move supported by most commercial motion controllers is proposed to generate exact AS-curve motion command in real machines. The analytic polynomial functions of AS-curve motion profile are also derived to simplify the further application, and the effectiveness of the proposed method is verified by numerical simulation.
Rigid Foldability of Triangle-Twist Origami Pattern and its Derived 6R Linkage
Authors: Peng Rui , Ma Jiayao , Chen Yan
Published: November 2017

Rigid origami is an important subset of origami with broad engineering applications from space structures to metamaterials. The rigid foldability of an origami pattern is determined by both the geometric parameters and the mountain-valley crease assignment. In this paper, by using the equivalent relationships between origami vertices and spherical linkages, a systematic method was proposed to analyze the motion of the triangle-twist pattern with varying distribution of mountain and valley creases, and its rigid folding types were identified. Moreover, kirigami technology was applied to the rigid folding pattern without changing its degree of freedom, from which a new kind of overconstrained 6R linkage was developed. The theoretical method proposed in this paper can be readily extended to study other types of origami patterns, which will in turn help to design structures with large deployable ratio as well as some new spatial linkages.
Application of Audible Sound Signals for Tool Wear Monitoring and Workpiece Hardness Identification in Gear Milling Using Machine Learning Techniques
Authors: Kothuru Achyuth , Nooka Sai Prasad , Iglesias Victoria Patricia , Liu Rui
Published: November 2017

The machining process monitoring, especially the tool wear monitoring, is very critical in modern automated gear machining environment which needs instant detection of cutting tool state and/or process conditions, quick final diagnosis and appropriate actions. It has been realized that the non-uniform hardness of the workpiece material due to the improper heat treatment can cause expedited tool wear and unexpected tool breakage, which greatly increases difficulties and complexities in monitoring the tool conditions in gear cutting. This paper provides a solution to detect the wear conditions of the gear milling cutter in the cutting of workpiece materials with hardness variations using the audible sound signals. In this study, cutting tools and workpieces are prepared to have different flank wear classes and hardness variations respectively. A series of gear milling experiments are operated with a broad range of cutting conditions to collect sound signals. A machine learning algorithm that incorporates support vector machine (SVM) approach coupled with the application of time and frequency domain analysis is developed to correlate observed sound signals’ signatures to specified tool wear classes and workpiece hardness levels. The performance evaluation results of the proposed monitoring system have shown accurate predictions in detecting tool wear conditions and workpiece hardness variations from the sound signals in gear milling.
Evaluating Assembly Design Efficiency: A Comparison Between Lucas and Boothroyd-Dewhurst Methods
Authors: Dochibhatla Surya Venkata Sumanth , Bhattacharya Manas , Morkos Beshoy
Published: November 2017

DFA principles are widely used to ease the assembly/manufacturing of a design in general. There are various methods which use the DFA principles to quantify design efficiency. The most commonly used industry approved methods are Lucas method and Boothroyd-Dewhurst method. Lucas and Boothroyd methods are both different approaches in DFA; the former is used to analyze product design without need for specific dimensions. On the other hand, to use the Boothroyd method, it is assumed that the designer already has all the dimensions of the part (parametric design). This paper focuses on answering the following research questions-

1. Are there any similarities between the Lucas method and Boothroyd-Dewhurst method?

2. Is there any similarity between the Efficiency index of Lucas method and Design efficiency of Boothroyd method?

3. Can the two methods be integrated and used as one method?

4. After integrating, can the method be coded as computer software?

The research questions will be validated by implementing the DFA methods on a stapler, table fan, and bottle opener. In this paper, the goal is to identify if Boothroyd and Lucas method can work together in product design phase; and if they could be used together, the authors propose a flowchart explaining the process. New DFA techniques are not being investigated/proposed. The Design efficiency of Stapler, Table fan, and Cork opener were 71.4%, 21.05%, and 50% respectively using Lucas method; The corresponding Feeding index was 2.12, 7.7, and 2.17 respectively, and Fitting index was 2.94, 11.25, and 6.93 respectively; And, 63%, 28.86% and 52.7% respectively using Boothroyd method. Design efficiency results indicate that Lucas method and Boothroyd-Dewhurst method are similar analysis and are equally important during the design phase. The above 2 methods can work in tandem with each other to provide insight into: “how many functional parts are there in a product?” and “how long it will take for it to assemble?”
Influence of Distributed Reaction Regime on Fuel Reforming
Authors: Scenna Richard , Gupta Ashwani K.
Published: November 2017

Previous works have demonstrated that the Distributed Reaction regime impact on the reformate product distribution. Using previous works, a theory of how the Distributed Reaction regime influences the reformate product composition is provided. Distributed Reaction regime is achieved by entraining exhaust products into the premixed fuel air mixture. As some steam and carbon dioxide will form in the exhaust, it is theorized that the mixing of the entrained flow (containing heat, carbon dioxide, and steam) into the premixed fuel air mixture will promote dry and steam reforming reactions, improving conversion. As kinetic information on reforming literature is limited, the activity and time scales of these reactions were determined from existing experimental data. This was then used to determine which reactions were active under Distributed Reforming conditions.
In-Plane Dynamic Response Analysis of Hexagonal and Reentrant Honeycombs Under Uniaxial Impact Loading
Authors: Li Zhen , Gao Qiang , Wang Liangmo , Tang Jun
Published: November 2017

To investigate their in-plane dynamic response, a rigid plate with mass was given an initial velocity to impact (square) honeycombs in the X1 and X2 directions, respectively. Firstly, the impact model was built and validated. Then, impact resistance capacity research was conducted. Results showed that each honeycomb performed similarly in X1 and X2 directions, and the reentrant honeycomb usually used smaller displacement and time to absorb the same amount of kinetic energy. Thus, it is better for application if these factors were the main concerns. After that, the nominal stress at the proximal and distal ends were discussed under various impact velocities. It is shown that, under impact loading, the reentrant honeycomb generally showed higher initial peak stress as well as lower plateau stress at both proximal and distal ends. In addition, combining these with the deformation process of honeycombs, it was concluded that the formation of the plateau area of the nominal stress curve is related to the crushing displacement of the impact plate as well as the collapse of cells.
Two Applications of Design As a Sequential Decision Process
Authors: Miller Simon W. , Simpson Timothy W. , Yukish Michael A.
Published: November 2017

A promising approach to overcome the challenges of exploring a design solution space is to employ Set-Based Design tightly coupled to Model-Based Systems Engineering, and to treat the design process formally as a sequential decision process. In such a paradigm, designers start with an initial set of potential solutions, using lower fidelity models and analyses to winnow the set, with the process sequentially advancing through smaller sets of alternatives using models/analyses of ever increasing fidelity. The bounds around a solution are constricted until a candidate is chosen. This sequential decision process can itself be subjected to analysis, and optimized to most efficiently arrive the final choice. We have developed a formal model of Design as a Sequential Decision Process, and we illustrate the process through two examples. The examples are from two different design problem domains (finite element modeling with variable grid fidelity, bi-level optimization with combinatorial kernel) thus demonstrating the broad utility of the method. Ongoing and future work are also discussed.
Flow-Induced Nonlinear Vibration of Non-Uniform Nanotubes
Authors: Mashrouteh Shamim , Barari Ahmad , Esmailzadeh Ebrahim
Published: November 2017

This paper focuses on nonlinear forced vibration analysis of a free-form conveying fluid nanotube. Non-Uniform Rational B-Splines (NURBS) is used to model the free-form curvature of the nanotube, analytically. In order to develop the ordinary differential equations of motion, the Euler-Bernoulli beam theory and Galerkin method are implemented and the frequency response and the primary resonance of the nanotube under a harmonic excitation are studied. The effects of the free-form curvature of the nanotube and its physical characteristic on the nonlinear vibration behavior of the system are discussed as a parametric study.
Transmission Index of Lower-Mobility Parallel Mechanism: Case Study on 3-PRS Mechanism
Authors: Takeda Yukio , Liang Xinghai
Published: November 2017

An extended definition of the transmission index based on the pressure angle was proposed. In order to enable evaluation of motion/force transmissibility and constrainability of parallel mechanism including lower-mobility/hybrid parallel mechanisms, pressure angle of a kinematic structure obtained by blocking all the actuated joints of the original mechanism was defined. In addition to this, an equivalent kinematic model of the original mechanism was introduced, in which the output link is supported by pure forces with the directions determined by the kinematic configuration of the mechanism. With these new ideas, a novel transmission index was proposed, and an illustrative example of 3-PRS mechanism was shown.
Do Technological Advancements Lead to Learning Enhancements?: An Exploration in Virtual Product Dissection
Authors: Starkey Elizabeth M. , Spencer Cailyn , Lesniak Kevin , Tucker Conrad , Miller Scarlett R.
Published: November 2017

Recent shifts into larger class sizes and online learning have caused engineering educators to rethink the way they integrate inductive, or active learning activities into their courses. One way engineering educators have done this is through the integration of new technological environments. However, little is known about how the type of technological environment utilized in active learning exercises impacts student learning and satisfaction. Thus, as a first step to understanding the impact of technological advancements on student learning and satisfaction, a study was conducted with 18 senior level undergraduate engineering students who were asked to perform product dissection, or the systematic disassembly of a product, using three technological interfaces (computer, iPad, immersive virtual reality). Variations in the complexity of the product dissected were also explored. The results of this study indicate that variations in technological interfaces did not impact student learning as assessed by a Student Learning Assessment (SLA). However, the complexity of the product dissected did impact learning, with students scoring significantly lower on the SLA when dissecting the most complex product. The results also indicated that students perceived learning and satisfaction were highest when using the immersive virtual reality system. These results suggest that the costs of investing in more technological advanced systems for product dissection may not yet outweigh the educational benefits. However, the increase in student satisfaction with VR environments has the potential to positively impact student retention in engineering programs.
Application of the POD Method for Cracked Rotors
Authors: Al Mehairi Ayesha , AL-Shudeifat Mohammad A. , Balawi Shadi , Saeed Adnan S.
Published: November 2017

The application of the proper orthogonal decomposition (POD) method to the vibration response of a cracked Jeffcott rotor model is investigated here. The covariance matrices of horizontal and vertical whirl amplitudes are formulated based on the numerical integration response and the experimental whirl response, respectively, for the considered cracked rotor system. Accordingly, the POD is directly applied to the obtained covariance matrices of the numerical and experimental whirl amplitudes where the proper orthogonal values (POVs) and the proper orthogonal modes (POMs) are obtained for various crack depths, unbalance force vector angles and rotational speeds. It is observed that both POVs and their corresponding POMs are highly sensitive to the appearance of the crack and the unbalance angle changes at the neighborhoods of the critical. The sensitivity zones of the POVs and POMs to the crack propagation coincide with the unstable zones of the cracked system obtained by Floquets theory.
Contact-Dependent Balance Stability of Walking Robots
Authors: Mummolo Carlotta , Peng William Z. , Gonzalez Carlos , Kim Joo H.
Published: November 2017

A novel theoretical framework for the identification of the balance stability regions of biped systems is implemented on a real robotic platform. With the proposed method, the balance stability capabilities of a biped robot are quantified by a balance stability region in the state space of center of mass (COM) position and velocity. The boundary of such a stability region provides a threshold between balanced and falling states for the robot by including all possible COM states that are balanced with respect to a specified feet/ground contact configuration. A COM state outside of the stability region boundary is the sufficient condition for a falling state, from which a change in the specified contact configuration is inevitable. By specifying various positions of the robot’s feet on the ground, the effects of different contact configurations on the robot’s balance stability capabilities are investigated. Experimental walking trajectories of the robot are analyzed in relationship with their respective stability boundaries, to study the robot balance control during various gait phases.
Exploring Architecture Selection and System Evolvability
Authors: White Samantha , Ferguson Scott
Published: November 2017

For engineered systems, one of the first decisions a designer must make is the architecture that will solve the established high level function. In most cases, this can be accomplished in a multitude of ways, with each original architecture having strengths and weaknesses. This paper explores how the architecture choice for a system impacts the ability to evolve and meet future needs. The lessons learned from this paper are extracted from a case study where three systems that perform the same task via different architectural solutions are considered. These systems are them compared to understand how well they adhere to, or violate, the Empirically-Derived Principles for Designing Products with Flexibility for Future Evolution introduced by Tilstra et al.
A New Global Spatial Discretization Method for Two-Dimensional Continuous Systems
Authors: Wu K. , Zhu W. D.
Published: November 2017

A new global spatial discretization method is developed to accurately calculate natural frequencies and dynamic responses of two-dimensional continuous systems such as membranes and Kirchhoff plates. The transverse displacement of a two-dimensional continuous system is separated into a two-dimensional internal term and a two-dimensional boundary-induced term; the latter is interpolated from one-dimensional boundary functions that are further divided into one-dimensional internal terms and one-dimensional boundary-induced terms. The two- and one-dimensional internal terms are chosen to satisfy predetermined boundary conditions, and the two- and one-dimensional boundary-induced terms use additional degrees of freedom at boundaries to ensure satisfaction of all boundary conditions. A general formulation of the method that can achieve uniform convergence is established for a two-dimensional continuous system with an arbitrary domain shape and arbitrary boundary conditions, and it is elaborated in detail for a general rectangular Kirchhoff plate. An example of a rectangular Kirchhoff plate that has three simply-supported boundaries and one free boundary with an attached Euler-Bernoulli beam is investigated using the developed method and results are compared with those from other global and local spatial discretization methods. Natural frequencies and dynamic responses that include the displacement, the velocity, rotational angles, a bending moment, and a transverse shearing force are calculated using both the developed method and the assumed modes method, and compared with results from the finite element method and the finite difference method, respectively. Advantages of the new method over local spatial discretization methods are much fewer degrees of freedom and much less computational effort, and those over the assumed modes method are better numerical property, a faster calculation speed, and much higher accuracy in calculation of the bending moment and the transverse shearing force that are related to high-order spatial derivatives of the displacement of the plate with an edge beam.
An Overview of a Connected Autonomous Vehicle Emulator (CAVE)
Authors: Elmquist Asher , Hatch Dylan , Serban Radu , Negrut Dan
Published: November 2017

We discuss an early version of an open-source autonomous vehicle simulation framework whereby piloting control programs (PCPs) and vehicle response can be evaluated and improved in a safe environment. Through the interaction of hundreds of autonomous and avatar agents in a simulated environment, edge cases for self-driving vehicles can be analyzed thus accelerating research, development and technology deployment. The Connected Autonomous Vehicle Emulator (CAVE) builds upon four foundational components: (i) physics engine and dynamic vehicle support using Chrono and Chrono::Vehicle; (ii) virtual sensors support to provide self-driving algorithms with realistic data; (iii) multi-agent and vehicle-to-vehicle simulated communication support through a fast, low-latency server-client model; and, (iv) virtual environment for both physics and sensing to support edge cases for self-driving vehicles where physical testing is not feasible, including varying environmental conditions such as snow, rain, or fog.