bluuebunny/crossref_metadata_2025 huggingface dataset:
A UNITY Sketch Based Modelling Environment for Virtual Assembly and Machining to Evaluate DFMA Metrics
Authors: Read Avery , Ritchie James , Lim Theodore
Published: December 2016

Current tools used to carry out design for manufacture and assembly (DFMA) evaluations are time consuming to use. This increases the cost of bringing a product to market by extending the length of the design process. The steps that comprise the design, analysis and redesign process are typically carried out in series over long periods of time using different tools. Introducing concurrent engineering practices could significantly reduce the time taken to complete this process and improve workplace DFMA learning. An opportunity exists to create and test an integrated real-time DFMA tool using the UNITY game engine, which could potentially address these problems. If this approach can be achieved it has the potential to decrease the time taken for the design process and enable a greater number of solutions to be considered potentially leading to a more optimal design solution. Having a more optimal design could lead to major cost reduction in later stages of product development by reducing the work needed to plan and carry out the manufacturing process and creating a product that is easier and less costly to maintain.

This paper reports on a pilot haptic sketch-based system to investigate its feasibility to conduct concurrent DFMA. .
Reconfiguration Analysis of a Variable Degrees-of-Freedom Parallel Manipulator With Both 3-DOF Planar and 4-DOF 3T1R Operation Modes
Authors: Kong Xianwen
Published: December 2016

Reconfiguration analysis is essential for the design and control of multi-operation-mode parallel manipulators (PMs). This paper deals with the reconfiguration analysis of a variable-DOF (degrees-of-freedom) multi-operation-mode E/PPPR = PM, i.e. a PM with both 3-DOF planar operation mode and 4-DOF 3T1R (or Schönflies motion which has three translational DOF and 1 rotational DOF) operation mode. The axes of rotation of the moving platform in the 3-DOF planar operation mode are not parallel to the axes of rotation of the moving platform in the 4-DOF 3T1R operation mode. In the reconfiguration analysis, the orientation of the moving platform is represented using a Euler parameter quaternion (also Euler-Rodrigues quaternion). The reconfiguration analysis shows that the E/PPPR = PM has two 4-DOF 3T1R operation modes and two 3-DOF planar operation modes, including the two expected operation modes. The transition configurations between each pair of operation modes are also identified.
Exploitation of Nonlinear Dynamics of Buckled Beams
Authors: Wilson James M. , Shukla Amit , Olson William
Published: December 2016

Axially-loaded structures play an integral role in engineering design. Some of these structures exhibit a nonlinear response behavior under harmonic loading. Methods aimed at eliminating these behaviors are often employed in design of such structures. Our hypothesis is that the nonlinear dynamics can be used to optimize desired system response characteristics. In this paper, the dynamic response of a buckled beams under harmonic excitation is considered. An optimization approach is formulated that achieves maximum amplitude, periodic, and stable responses of the beam systems. Case studies are presented that demonstrate the utility of this optimization approach to exploit the nonlinear dynamics to achieve desired responses.
Confidentiality Management in Collaborative Design
Authors: Dachowicz Adam , Chaduvula Siva Chaitanya , Panchal Jitesh H. , Atallah Mikhail
Published: December 2016

The globalization of collaboration in engineering design has raised several new concerns regarding information sharing. In particular, data shared during collaboration has the potential to leak private information through inferences that may be made by another collaborator. Enterprises that must keep certain information confidential, fearing loss of intellectual property, may turn down potential collaborations that would otherwise be mutually beneficial. Thus, there is need for a method to study this tradeoff between confidentiality and value in engineering collaboration. In this paper, a framework for analyzing this tradeoff is proposed, along with an illustrative example of a possible implementation and its effects on the collaborative design process. This framework estimates and quantifies the confidentiality loss and value gain associated with information revelation during design iterations. We believe that such analysis would aid designers in making better decisions about sharing information with their collaborators. Studying this tradeoff may incentivize designers to engage in more frequent, and more secure, collaboration.
On the Linearization of Multibody Dynamics Formulations
Authors: González Francisco , Masarati Pierangelo , Cuadrado Javier
Published: December 2016

The dynamics equations of multibody systems are often expressed in the form of a system of highly nonlinear Differential Algebraic Equations (DAEs). Some applications of multibody dynamics, however, require a linear expression of the equations of motion. Such is the case of the plant representations demanded by a wide variety of control algorithms and the system models needed by state estimators like Kalman filters.

The choice of generalized coordinates used to describe a mechanical system greatly influences the behavior of the resultant linearized models and the way in which they convey information about the original system dynamics. Several approaches to arrive at the linearized dynamics equations have been proposed in the literature. In this work, these were categorized into three major groups, defined by the way in which the kinematic constraints are handled. The properties of each approach and the differences between them were studied through the linearization of the dynamics of a simple example with a method representative of each class.
Time-Dependent Structural Topology Optimization Using a Continuous Adjoint Formulation
Authors: Papadimitriou Dimitrios I. , Mourelatos Zissimos P.
Published: December 2016

A new time-dependent topology optimization methodology is presented based on a time-dependent continuous adjoint approach. The main advantage is its non-intrusiveness which allows us not to interfere with the discretization scheme of the finite-element or finite-volume topology optimization software. The discretization of the differential adjoint equations can be different from the discretization of the structural equations. The objective is to minimize the time-average compliance of a structure subject to a volume-based constraint. A gradient-based optimization algorithm is used. The sensitivity derivatives of a time-average compliance function with respect to the topology design parameters are computed using a time-dependent adjoint formulation. The self-adjoint feature is first presented for discrete time-dependent topology optimization and then extended to the continuous case. The proposed methodology is demonstrated using the topology optimization of a two dimensional and a three dimensional structure under time-dependent excitations.
Experimental Analysis of a Planar Reconfigurable Mechanism With a Variable Joint
Authors: Malak Peter W. , Buchta Anthony J. , Voglewede Philip A.
Published: December 2016

Previously a specific planar reconfigurable mechanism with a variable joint (RRRR1 -RRRP2 Mechanism) was dynamically modeled. The RRRR-RRRP Mechanism functions as a RRRR mechanism in one configuration and as a in RRRP mechanism the other. The kinematics and kinetics of the RRRP and RRRR configurations were previously analyzed with a Lagrangian approach. The developed equations of motion will be validated with a physical prototype in this paper. In addition, a simplified model of the RRRR-RRRP Mechanism is also developed and compared to the experimental results. The experimental angular position of each joint on the RRRR-RRRP Mechanism will be compared to the model position analysis. Particular attention will be given to the transition point when the physical mechanism changes from an RRRR mechanism to RRRP mechanism and vice versa as it is vital to knowing this point for optimal control of the mechanism.
A Null Space Projection Approach for Modally Reduced Flexible Multibody Systems
Authors: Winkler Robert G. , Plakomytis Dimitrios , Gerstmayr Johannes
Published: December 2016

Light-weight structures and high-performance mechanical systems lead to an increasing amount of vibrations. In order to comply with standards in noise and vibration limits, the simulation of flexible multibody systems is inevitable. Due to the size of the finite element models of real-life mechanical systems, a model order reduction is necessary for the efficient simulation of such large scale flexible multibody systems. Currently, the most widely used technique for modelling and simulation of large scale flexible multibody systems is based on the Floating Frame of Reference Formulation (FFRF) of the modally reduced bodies. Recently, alternatives to the FFRF have been proposed, e.g. the Generalized Component Mode Synthesis (GCMS) which uses an absolute or inertial description of the modes. GCMS leads to a concise form of the equations of motion and a constant mass matrix. Within the context of the GCMS method, the rigid body motion is described with twelve coordinates while the deformation of the body is represented with nine coordinates for each flexible mode.

The main drawback of the GCMS method is that the number of flexible coordinates is nine times higher as compared to the classic FFRF and therefore when more modes are needed the efficiency of the method can be impaired. Therefore, the objective of the present paper is the further reduction of the new flexible coordinates by means of a null space projection method. Null space methods have been extensively used in order to develop efficient integration algorithms for rigid bodies, flexible beams and shells; however their applicability to modally reduced flexible multibody systems has not been studied intensively. In the paper herein, we develop a new formulation for modally reduced flexible multibody systems which involves a projection onto the null space of properly defined (internal) constraint conditions imposed to the flexible coordinates. It is important to note that focus is put on the description of the projection in the continuous case rather than the discrete which will be addressed in later developments. The proposed formulation is derived in great detail and it is shown that the simple form of the equations of motion of the GCMS method is almost retained. Finally, the applicability and performance of the method is assessed by means of a numerical example.
Small-Scale Physical Modeling and Testing of a Vehicle Trailer With Onboard Power Supply
Authors: Eisenmann Jesse , Horsley Joshua , Peters Diane L.
Published: December 2016

In typical towing situations, all of the power needed to move the towing vehicle and the towed vehicle (trailer) is supplied by the towing vehicle. This dictates that a person who wishes to tow a trailer must have a vehicle capable of providing enough power to move both the vehicle and the trailer; if they only occasionally tow a trailer, then they either need to rent an appropriately sized vehicle or buy a larger vehicle than is dictated by their everyday needs, which has both financial and environmental consequences. However, if the trailer can provide sufficient power itself to move, then the demands on the towing vehicle are reduced. Such a trailer would be guided by the towing vehicle, but the vehicle would provide very little power to the trailer, and therefore a small car could be used for the towing task, removing the requirement to buy or rent a larger vehicle for occasional towing. This concept has been previously explored theoretically, and was found to be feasible based on dynamic models of the trailer, with the trailer powered by a DC motor; in this paper, it is investigated experimentally, on a small scale. The experiment was conducted on a 1:18 scale remote controlled (RC) car and similarly scaled powered trailer that was constructed for it. The project included the design of an appropriate trailer, integration of a load cell into the trailer hitch, and the design of an appropriate controller. The controller was implemented using National Instruments’ LabVIEW software, running on the NI myRIO controller. The LabVIEW program also saved data from the force sensor and two accelerometers, as well as the controller output to the system, for later analysis. The car was driven around with the assistance of the trailer while data was collected by the affixed sensors. The tests were conducted with different drivers, with the car driven on varying paths that included both straight driving and turns, all on a standard hard indoor floor surface. The goal of this project was to prove out the concept on a small scale, after its feasibility had been shown through modeling and theoretical calculations. The results showed that the concept is feasible and will work in practice on this small scale, although some challenges were seen. Some of these challenges were caused by the limitations of the test setup, such as limited battery capacity and limited space to mount sensors. The success of this test setup, despite these limitations, suggests that a larger-scale model should be constructed and tested, and that in practice the concept will be feasible.
Reduction of System Reliability Model Uncertainty by Considering Dependent Components With Stochastic Process Loading
Authors: Cheng Yao , Du Xiaoping
Published: December 2016

When component dependence is ignored, a system reliability model may have large model (epistemic) uncertainty with wide reliability bounds. This makes decision making difficult during the system design. Component dependence exists due to the shared environment and operation conditions. It is difficult for system designers to model component dependence because they may not have access to component design details if the components are designed and manufactured by outside suppliers. This research intends to reduce the system reliability model uncertainty with a new way for system designers to consider the component dependence implicitly and automatically without knowing component design details. The proposed method is applicable for a wide range of applications where the time-dependent system stochastic load is shared by components of the system. Simulation is used to obtain the extreme value of the system load for a given period of time, and optimization is employed to estimate the system reliability interval. As a result, the epistemic uncertainty in system reliability can be reduced.
An Open Web-Based Repository for Capturing Manufacturing Process Information
Authors: Bernstein William Z. , Mani Mahesh , Lyons Kevin W. , Morris K. C. , Johansson Björn
Published: December 2016

With recent progress in developing more effective models for representing manufacturing processes, this paper presents an approach towards an open web-based repository for storing manufacturing process information. The repository is envisioned to include several new use cases in the context of information use in smart manufacturing. This paper examines several key benefits through usage scenarios engaging existing engineering activities. Based on the scenarios, the desired characteristics of an open web-based repository are presented, namely that it will be (1) complementary to existing practices, (2) open and net-centric, (3) able to enforce model consistency, (4) modular (5) extensible, and (5) able to govern contributions. A repository will support and motivate the ubiquitous and extended use of standardized representations of unit manufacturing processes in order to promote consistency of performance assessments across industries and provide a tangible, data-driven perspective for analysis-related activities. Furthermore, the paper presents additional benefits and possible applications that could result from a shared manufacturing repository.
Multibody-Based Topology Synthesis Method for Large Stroke Flexure Hinges
Authors: Naves M. , Brouwer D. M. , Aarts R. G. K. M.
Published: December 2016

Large stroke flexure mechanisms inherently lose stiffness in supporting directions when deflected due to load components in compliant bending and torsion directions. To maximize performance over the entire range of motion, a topology optimization suited for large stroke mechanisms is required. In this paper a new multibody-based topology synthesis method is presented for optimizing large stroke flexure hinges. This topology synthesis consists of a layout variation strategy based on a building block approach combined with a shape optimization to obtain the optimal design tuned for a specific application. A derivative free shape optimization method is used to optimize high complexity flexure mechanisms in a broad solution space. To obtain the optimal layout, three predefined “building blocks” are proposed which are consecutively combined to find the best layout with respect to a specific design criteria. More specifically, this new method is used to optimize a flexure hinge aimed at maximizing the first disturbing eigenfrequency. The optimized topology shows an increase in frequency of a factor ten with respect to the customary three flexure cross hinge, which represents a huge improvement in performance. The numerically predicted natural frequencies and mode shapes have been verified experimentally.
Free Vibration and Modal Analysis of a Tensegrity-Membrane System
Authors: Yang Shu , Sultan Cornel
Published: December 2016

The growing interest in lightweight, deployable, and adaptive space membrane systems motivates the study of tensegrity-membrane systems. Such systems, which are composed of membranes, bars, and tendons, can be treated as extensions of classical tensegrity systems. Therefore, they inherit typical advantages of tensegrity systems, such as reduced mass, extreme flexibility, and the capacity of shape change. Membranes can be part of a certain device, such as a reflector or solar sail, while also offering opportunities for integrated system design. This paper presents a study in the modal analysis and free vibration analysis of a tensegrity-membrane system. Two mathematical models are used in this analysis: a nonlinear finite element model and a control-oriented model. The nonlinear finite element model is of great generality, while several modeling assumptions are introduced in the control-oriented model to simplify the modeling problem and lead to a model that lends itself to modern control design. Numerical results given by the two models are compared in order to ascertain the extent to which the two models agree. Observations related to system mode shapes, coupled dynamic behavior between system components, and system free vibration responses are discussed.
A Hexagonal Prism Folding for Membrane Packaging Based on Concepts of Finite Rigid Motion and Kinematic Synthesis
Authors: Abdul-Sater Kassim
Published: December 2016

This paper discusses the use of concepts of finite rigid body kinematics as well as kinematic synthesis in non-rigid, engineering folding problems. The exemplary task consists in designing a folding pattern, which allows to fold a circular sheet from a flat unfolded state into a prescribed compact spatial configuration that forms a hexagonal prism. Other two-configuration design problems may be found for instance in space applications where membranes in tensegrity reflector antennas need to be stowed in a spacecraft. The folding motion could be actuated using an appropriately designed linkage mechanism attached to the membrane, which, however, is not considered in this paper. The specific result of this work is a creative but systematic and computational procedure for crease pattern design. The approach is essentially based on the relative kinematics equations of serial kinematic chains and the finite position synthesis of linkage building blocks. These techniques sucessively combine to segment a flat bounded surface, such that it can reach the prescribed spatial configuration.
Modeling of Deformable Tire and Soil Interaction Using Multiplicative Finite Plasticity for Multibody Off-Road Mobility Simulation
Authors: Yamashita Hiroki , Jayakumar Paramsothy , Sugiyama Hiroyuki
Published: December 2016

The objective of this study is to develop a physics-based tire/soil interaction model that can be fully integrated into general multibody dynamics computer algorithms. To this end, a continuum soil model using multiplicative plasticity theory with Drucker-Prager failure criterion is integrated with the high-fidelity flexible tire model developed using the shear deformable laminated composite shell elements for deformable tire/terrain interaction simulation. The element locking of the standard 8-node brick element caused by the tri-linear polynomial can be alleviated by introducing an additional node defining the second derivative of the global position vector at the center of the element, allowing for describing the linear strain distribution over the element volume without introducing enhanced assumed strain (EAS). The benchmark test result indicates that the identical rate of convergence to that of the locking-free 8-node brick element with 9-parameter EAS is obtained using the brick element presented in this study. Since the constitutive equation for soil models is highly nonlinear in nature, involving iterative return mapping algorithm to find the plastic strain every time step, elimination of EAS using the 9-node brick element leads to straightforward implementation for soil model and computationally efficient procedure for tire/soil interaction simulation. Numerical example of deformable tire and terrain interaction simulation is presented to demonstrate the numerical procedure developed in this study.
A Pseudo-Rigid Body Model for Compliant Edge Panels in Origami-Inspired Mechanisms
Authors: Yellowhorse Alden , Howell Larry L.
Published: December 2016

Origami-inspired mechanisms have a variety of potential applications but present many challenges in their design. Problems such as mechanism inflexibility must be considered for any application but may not always be easily resolvable. One option in such a case would be to rely on the inherent flexibility of the origami panels to permit motion. This paper presents a method for increasing the flexibility of a structure and enabling motion in an otherwise immobile origami-inspired mechanism. This method will be derived analytically and then verified through finite-element analysis and experiments.
Topology Optimization Under Independent Multi-Load With Uncertainty
Authors: Gea Hae Chang , Liu Xing , Lee Euihark , Xu Limei
Published: December 2016

In this paper, topology optimization under multiple independent loadings with uncertainty is presented. In engineering practice, load uncertainty can be found in many applications. From the literature, researchers have focused mainly on problems containing only a single uncertain external load. However, such idealistic problems may not be very useful in engineering practice. Problems involving multi-loadings with uncertainty are more commonly found in engineering applications. This paper presents a method to solve a system which contains multiple independent loadings with load uncertainty. First, a two-level optimization problem is formulated. The upper level problem is a typical topology optimization problem to minimize the mean compliance in the design using the worst case conditions. The lower level optimization problem is to solve for the worst loadings corresponding to the critical structure response. At the lower level formulation, an unknown-but-bounded model is used to define uncertain loadings. There are two challenges in finding the worst loading case: non-convexity and multi-loadings. The non-convexity problem is addressed by reformulating the problem as an inhomogeneous eigenvalue problem by applying the KKT optimality conditions and the multi-uncertain loadings problem is solved by an iterative method. After the worst loadings are generated, the upper level problem can be solved by a general topology optimization method. The effectiveness of the proposed method is demonstrated by numerical examples.
Tailoring Plate Thickness of a Helmholtz Resonator for Improved Sound Attenuation
Authors: Kurdi Mohammad , Nudehi Shahin , Duncan Gregory Scott
Published: December 2016

A Helmholtz resonator with flexible plate attenuates noise in exhaust ducts, and the transmission loss function quantifies the amount of filtered noise at a desired frequency. In this work the transmission loss is maximized (optimized) by allowing the resonator end plate thickness to vary for two cases: 1) a non-optimized baseline resonator, and 2) a resonator with a uniform flexible endplate that was previously optimized for transmission loss and resonator size. To accomplish this, receptance coupling techniques were used to couple a finite element model of a varying thickness resonator end plate to a mass-spring-damper model of the vibrating air mass in the resonator. Sequential quadratic programming was employed to complete a gradient based optimization search. By allowing the end plate thickness to vary, the transmission loss of the non-optimized baseline resonator was improved significantly, 28 percent. However, the transmission loss of the previously optimized resonator for transmission loss and resonator size showed minimal improvement.
Design Considerations for Continuum Robot Actuation Units Enabling Dexterous Transurethral Bladder Cancer Resection
Authors: Del Giudice Giuseppe , Sarli Nima , Herrell Stanley D. , Simaan Nabil
Published: December 2016

The last decade has seen rapid growth in exploring the potential of continuum robots for a variety of surgical applications. The design of these robots requires unique electro-mechanical architectures of actuation units that satisfy operational requirements of precision, workspace, and payload capabilities. This paper presents the task-based design process of a compact nine degrees of freedom actuation unit for transurethral resection of bladder tumor (TURBT). This actuation unit has a unique modular architecture allowing partial decoupling of actuation, force and position sensing in a compact modular format. The derivation of task specifications based on kinematic simulations takes into account workspace, accuracy and force application capabilities for TURBT. Design considerations for supporting modularity, serviceability, sterilization, and compactness are presented. The detailed exposition of the design process serves as a case study that will be helpful for other groups interested in the development and integration of surgical continuum robots.
Updating Virtual Fixtures From Exploration Data in Force-Controlled Model-Based Telemanipulation
Authors: Wang Long , Chen Zihan , Chalasani Preetham , Pile Jason , Kazanzides Peter , Taylor Russell H. , Simaan Nabil
Published: December 2016

This paper proposes an approach for using force-controlled exploration data to update and register an a-priori virtual fixture geometry to a corresponding deformed and displaced physical environment. An approach for safe exploration implementing hybrid motion/force control is presented on the slave robot side. During exploration, the shape and the local surface normals of the environment are estimated and saved in an exploration data set. The geometric data collected during this exploration scan is used to deform and register the a-priori environment model to the exploration data set. The environment registration is achieved using a deformable registration based on the coherent point drift method. The task-description of the high-level assistive telemanipulation law (virtual fixture) is then deformed and registered in the new environment. The new model is updated and used within a model-mediated telemanipulation framework. The approach is experimentally validated using a da-Vinci research kit (DVRK) master interface and a Cartesian stage robot. Experiments demonstrate that the updated virtual fixture and the updated model allow the users to improve their path following performance and to shorten their completion time when the updated path following virtual fixture is applied. The approach presented has direct bearing on a multitude of surgical applications including force-controlled ablation.
Approximate Analytical Solutions to Nonlinear Inverse Boundary Value Problems
Authors: Venkataraman P.
Published: December 2016

A nontraditional approach to the nonlinear inverse boundary value problem is illustrated using multiple examples of the Poisson equation. The solutions belong to a class of analytical solutions defined through Bézier functions. The solution represents a smooth function of high order over the domain. The same procedure can be applied to both the forward and the inverse problem. The solution is obtained as a local minimum of the residuals of the differential equations over many points in the domain. The Dirichlet and Neumann boundary conditions can be incorporated directly into the function definition. The primary disadvantage of the process is that it generates continuous solution even if continuity and smoothness are not expected for the solution. In this case they will generate an approximate analytical solution to either the forward or the inverse problem. On the other hand, the method does not need transformation or regularization, and is simple to apply. The solution is also good at damping the perturbations in measured data driving the inverse problem. In this paper we show that the method is quite robust for linear and nonlinear inverse boundary value problem. We compare the results with a solution to a nonlinear inverse boundary value problem obtained using a traditional approach. The application involves a mixture of symbolic and numeric computations and uses a standard unconstrained numerical optimizer.
Linking Properties of Design Problems to Optimal Team Characteristics
Authors: McComb Christopher , Cagan Jonathan , Kotovsky Kenneth
Published: December 2016

A team with the right characteristics can exceed the sum of their individual efforts. However, a team having the wrong characteristics may perform more poorly than the sum of its individuals. Therefore, it is crucial that teams are assembled and managed properly in order to maximize performance. This work examines how the properties of a design problem can be used to select the best values for team characteristics. Two characteristics are considered: team size and interaction frequency. A computational model of design teams that has been shown to effectively emulate human team behavior is leveraged to pinpoint optimized team characteristics for solving a variety of fluid and structural design problems. The nature of each design problem is characterized with respect to local and global behavior of the design space, alignment between objective functions, and the resources allotted for solving the problem. Regression analysis is used to create equations for predicting optimized team characteristics based on problem properties. These equations, which enable the informed design of design teams based on those characteristics, describe statistically significant relationships and are found to have useful levels of accuracy. Further analysis reveals insights about how the properties of a design problem can influence a team’s search for solutions.
Design of Underwater Non-Coaxial Single Beam Scanning Detecting System
Authors: Tan Yayun , Zhang He
Published: December 2016

Aiming at the necessity of torpedo detecting near field target in final stage of guidance, a non-coaxial (transmitter and receiver are not on the same axis) single beam scanning detecting and ranging system has been designed to be applied in torpedo. To study this detection system, this paper proposes a Monte Carlo simulation method for the system. The backscattering signal and target echo signal in seawater is simulated, and then the Signal-to-Backscattering-Noise (SBNR) is calculated. Furthermore, the relationship between maximum detecting distance and system parameters is calculated based on the criterion of minimum SNBR. Finally, the optimal system parameters are determined to get maximum detection range. For verifying the correctness of the theoretical models, underwater laser detection optical simulation system is designed to do target detecting experiment in a basin. The comparative analyses of the simulation and the experimental results show that the simulation results fit the experimental data well, thus the correctness of the semi-analytical Monte Carlo model is verified. The optimal parameters in single beam scanning detecting system can be determined according to the simulation and experimental results. The designed underwater laser detecting system provides a new method for the torpedo to detect underwater target in final stage of guidance.
Effect of Nano-Clays on the Lubricity of Drilling Fluids
Authors: Abdo Jamil , Al-Sharji Hamed
Published: December 2016

In this study, nano-sepiolite (NSP) was synthesized, dispersed and used as a replacement for regular additives in water-based drilling fluids to enhance its lubricity. Due to its structure and morphology the suspended sepiolite nanoparticles is expected to enhance the stability against segmentation along with better thermal, mechanical and electrical properties. The morphology of the nano-modified drilling fluids and the dispersion of the nano-sepiolite are characterized using XRD and SEM. The influences of various sizes and compositions of the NSP on the stability of drilling fluids on HTHP conditions are investigated. Results revealed that the drilling fluids lubricity and the drillstring axial force transfer were significantly improved by using NSP in the base drilling fluids. The investigations showed that the lubricity and rheological properties of the nano-modified drilling fluids depend on the size and composition of the NSP additive. The studies were performed on normal and HTHP conditions.
Non-Ideal System With Quadratic Nonlinearities Containing a Two-to-One Internal Resonance
Authors: Rocha Rodrigo T. , Balthazar Jose M. , Quinn D. Dane , Tusset Angelo M. , Felix Jorge L. P.
Published: December 2016

The dynamical behaviour of a non-ideal three-degrees-of-freedom weakly coupled system associated with the quadratic nonlinearities in the equations of motion is investigated. The main system consists of two nonlinear mechanical oscillators coupling with quadratic nonlinearities and in which possess a 2:1 internal resonance between their translational movements. Under these conditions, we analyzed the response when a DC unbalanced motor with limited power supply (non-ideal system) excites the main system. When the excitation frequency is near to second natural frequency of the main system, saturation and jump phenomena are presented. Then, this work will analyze some torques of the motor, which causes the phenomena, and due to high amplitudes of motion will be possible to look for a way to harvest energy in a future work.
A Quick Method for Assessing Transducer Mass Effects on the Measured FRFs
Authors: Ren Jun , Wang Jun , Zhou Xiaodong , Sun Jinfeng , Wang Quan , Ting Kwun-Lon
Published: December 2016

In modal testing, the measured Frequency Response Functions (FRFs) are often affected by the mass loading of the transducers (such as force transducer and accelerometer) installed on the test structure. This paper proposed a quick method for assessing transducer mass effects on the measured FRFs (including point and transfer FRFs). The assessment method offers some distinct advantages in that very few FRFs measurements are required, and more importantly it does not require calculations involving several measured FRFs, hence avoiding further contaminations of the measured data. In this method, both force transducer and accelerometer masses effects have be considered. And the overall as well as the individual mass effects of the two transducers (force transducer and accelerometer) have been assessed, respectively. A simple numerical example presented illustrates good theoretical performance of the method. To simulate an experimental situation, the same example is extended to incorporate noise, and it is shown that the accuracy of assessment results will be affected to some extent by the noise. A possible solution to this problem is to preprocess the measured FRFs using the curve-fitting procedure before the proposed method is applied.
Design and Analysis of a Robotic Modular Leg Mechanism
Authors: Saab Wael , Ben-Tzvi Pinhas
Published: December 2016

This paper presents the design and analysis of a reduced degree-of-freedom Robotic Modular Leg (RML) mechanism used to construct a quadruped robot. This mechanism enables the robot to perform forward and steering locomotion with fewer actuators than conventional quadruped robots. The RML is composed of a double four-bar mechanism that maintains foot orientation parallel to the base and decouples actuation for simplified control, reduced weight and lower cost of the overall robotic system. A passive suspension system in the foot enables a stable four-point contact support polygon on uneven terrain. Foot trajectories are generated and synchronized using a trot and modified creeping gait to maintain a constant robot body height, horizontal body orientation, and provide the ability to move forward and steer. The locomotion principle and performance of the mechanism are analyzed using multi-body dynamic simulations of a virtual quadruped and experimental results of an integrated RML prototype.
Period-3 Motions in a Two Degree-of-Freedom Nonlinear Oscillator
Authors: Luo Albert C. J. , Yu Bo
Published: December 2016

In this paper, periodic motions of a two-degree-of-freedom nonlinear oscillator are studied by using general harmonic balanced method. Stable and unstable period-3 motions are obtained. The corresponding stability and bifurcations of the period-3 motions are determined through the eigenvalue analysis. Both symmetric and asymmetric period-3 motions are found in the system with a certain set of parameter. Numerical simulations of both stable and unstable period-3 motions in the two degrees of freedom systems are illustrated. The harmonic amplitude spectra show the harmonic effects on periodic motions, and the corresponding accuracy of approximate analytical solutions can be observed.
Solution Space Exploration of the Process Design for Continuous Casting of Steel
Authors: Sabeghi Maryam , Shukla Rishabh , Allen Janet K. , Mistree Farrokh
Published: December 2016

Continuous casting is the process of solidifying molten metal to produce different products such as billet, bloom, or slab. This process can be formulated mathematically in terms of conflicting objectives including productivity, yield, quality and production costs to satisfy sets of constraints such as oscillation mark depth, metallurgical length and center line segregation. The objectives are conflicting in the sense that, if the productivity is increased, there is a reduction in other performance measures. These performance specifications are greatly influenced by operating conditions such as casting speed, superheat, mold oscillation frequency, and secondary cooling conditions. The process of identifying the set points for the continuous casting operation is iterative and expensive. The uncertainties inherent in modeling the phenomena computationally behooves exploration of the solution space to determine the quality of the solution and gain insight.

In this paper, a method to explore the solution space is introduced. The method includes weight sensitivity and constraint sensitivity analysis. This analysis allows a designer to ascertain to what extent the solution is insensitive to uncertainties inherent in the modeling of the decision problem. This is a crucial step towards determining robust solutions for performance measures. The utility of the method is illustrated in providing decision support for the continuous casting operation in presence of variability in the operating parameters and conflicting end requirements, such as productivity and quality parameters.

This method can be instantiated for exploring the solution space for ladle, tundish, rolling and annealing and thereby facilitating the exploration of the solution space for critical unit operations associated with steel product manufacturing. This development has the potential to reduce the number of plant trials necessary to determine the set points for manufacturing a new product mix with a new grade of steel using the existing equipment in a steel mill. The focus in this paper is on the method and not the results per se.
Deep Network-Based Feature Extraction and Reconstruction of Complex Material Microstructures
Authors: Cang Ruijin , Ren Max Yi
Published: December 2016

Computational material design (CMD) aims to accelerate optimal design of complex material systems by integrating material science and design automation. For tractable CMD, it is required that (1) a feature space be identified to allow reconstruction of new designs, and (2) the reconstruction process be property-preserving. Existing solutions rely on the designer’s understanding of specific material systems to identify geometric and statistical features, which could be insufficient for reconstructing physically meaningful microstructures of complex material systems. This paper develops a feature learning mechanism that automates a two-way conversion between microstructures and their lower-dimensional feature representations. The proposed model is applied to four material systems: Ti-6Al-4V alloy, Pb-Sn alloy, Fontainebleau sandstone, and spherical colloids, to produce random reconstructions that are visually similar to the samples. This capability is not achieved by existing synthesis methods relying on the Markovian assumption of material systems. For Ti-6Al-4V alloy, we also show that the reconstructions preserve the mean critical fracture force of the system for a fixed processing setting. Source code and datasets are available.
Using Neuroimaging to Understand Moral Product Preference Judgments Involving Sustainability
Authors: Goucher-Lambert Kosa , Moss Jarrod , Cagan Jonathan
Published: December 2016

Trying to decide whether to purchase or use a sustainable product often puts decision makers in a difficult situation, especially if the more sustainable option provides less desirable features, or costs a premium. These decisions are moral choice scenarios, where benefit to society is weighed against personal gain. Here, it is common for individuals to visualize themselves, and the way that they will be perceived, by choosing whether or not to act sustainably. From an engineering design perspective, trying to model user preferences in this context can be extremely difficult. While several methods exist to assist researchers in eliciting consumer preferences, the vast majority rely on input from the potential consumers themselves. More critically, these methods do not afford researchers the ability to truly understand what someone may be feeling or thinking while these preference judgments are being made. In this work, functional magnetic resonance imaging (fMRI) is used to investigate the neural processes behind multi-attribute product preference judgments. In particular, this work centers on uncovering unique features of sustainable preference judgments; preference judgments which involve products for which the environmental impact is a known quantity. This work builds upon earlier work, which investigated how preference judgments were altered in the context of sustainability. A deeper look at participant decision-making at the time of judgment is examined using neuroimaging with the goal of providing actionable insights for designers and product developers.
Investigation for Industrialization of the Nojima’s Pairing Origami Structure
Authors: Yang Yang , Savchenko Maria , Nara Chie , Hagiwara Ichiro
Published: December 2016

We can see many products with the foldable and deployable function of origami in life, such as solar cell, solar panel and so on. Until now, Nojima has invented a lot of excellent foldable and deployable structures, among which the reversed spiral cylindrical structure (RSC) was parametrically expressed by Hagiwara et al.. The structural shapes of RSC with the maximum absorption energy performance and the minimum absorption energy performance are sought respectively when collapsed under axial loading. The former is studied for the collision strength member of vehicles; and the latter is considered to be applied for the easily folded plastic bottles. Recently, the Tachi-Miura polyhedron (TMP) has been attracting attention for its foldable and deployable properties. On the other hand, Nojima invented an origami shape, can be called Nojima polyhedron (NP). In this study, under the same simulation implementation conditions of RSC, the TMP and the NP are adopted to express the advantages and the disadvantages of diametrical requirements such as the absorbers and the easily folded beverage cans.
A Sequential Robust Approach for Multi-Disciplinary Design Optimization With Uncertainty
Authors: Xia Tingting , Li Mian , Zhou Jianhua
Published: December 2016

The real challenge for multi-disciplinary design optimization (MDO) problems to gain a robust solution is the propagation of uncertainty from one discipline to another. Most existing methods only consider a MDO problem in deterministic manner or find a solution which is robust for a single-disciplinary optimization problem. These rare methods for solving MDO problems under uncertainty are usually computational expensive. This research proposes a robust sequential MDO (RS-MDO) approach based on a sequential MDO (S-MDO) framework. Firstly, a robust solution is obtained by giving each discipline full autonomy to perform optimization. Tolerance range is specified for the coupling variable to model uncertainty propagation in the original coupled system. Then the obtained robust extreme points of global variable and coupling variable are dispatched into subsystems to perform optimization sequentially. Additional constraints are added to keep consistency and guarantee a robust solution. To find a solution with such strict constraints, genetic algorithm (GA) is used as a solver in each optimization stage. Since all iterations in the sequential optimization stage can be processed in parallel, this robust MDO approach can be more time-saving. Numerical examples are provided to demonstrate the availability and effectiveness of proposed approach.
Accelerating Stochastic Dynamics Simulation With Continuous-Time Quantum Walks
Authors: Wang Yan
Published: December 2016

Stochastic diffusion is a general phenomenon observed in various national and engineering systems. It is typically modeled by either stochastic differential equation (SDE) or Fokker-Planck equation (FPE), which are equivalent approaches. Path integral is an accurate and effective method to solve FPEs. Yet, computational efficiency is the common challenge for path integral and other numerical methods, include time and space complexities. Previously, one-dimensional continuous-time quantum walk was used to simulate diffusion. By combining quantum diffusion and random diffusion, the new approach can accelerate the simulation with longer time steps than those in path integral. It was demonstrated that simulation can be dozens or even hundreds of times faster. In this paper, a new generic quantum operator is proposed to simulate drift-diffusion processes in high-dimensional space, which combines quantum walks on graphs with traditional path integral approaches. Probability amplitudes are computed efficiently by spectral analysis. The efficiency of the new method is demonstrated with stochastic resonance problems.