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Abstract In this paper, we introduce LINKS, a dataset of 100 million one degree of freedom planar linkage mechanisms and 1.1 billion coupler curves, which is more than 1000 times larger than any existing database of planar mechanisms and is not limited to specific kinds of mechanisms such as four-bars, six-bars, etc. which are typically what most databases include. LINKS is made up of various components including 100 million mechanisms, the simulation data for each mechanism, normalized paths generated by each mechanism, a curated set of paths, the code used to generate the data and simulate mechanisms, and a live web demo for interactive design of linkage mechanisms. The curated paths are provided as a measure for removing biases in the paths generated by mechanisms that enable a more even design space representation. In this paper, we discuss the details of how we can generate such a large dataset and how we can overcome major issues with such scales. To be able to generate such a large dataset we introduce a new operator to generate 1-DOF mechanism topologies, furthermore, we take many steps to speed up slow simulations of mechanisms by vectorizing our simulations and parallelizing our simulator on a large number of threads, which leads to a simulation 800 times faster than the simple simulation algorithm. This is necessary given on average, 1 out of 500 candidates that are generated are valid (and all must be simulated to determine their validity), which means billions of simulations must be performed for the generation of this dataset. Then we demonstrate the depth of our dataset through a bi-directional chamfer distance-based shape retrieval study where we show how our dataset can be used directly to find mechanisms that can trace paths very close to desired target paths. Furthermore, we discuss how we plan to expand LINKS to include more complex mechanical components and expand the dataset in the future. our work is available

The next generation of the manufacturing industry calls for new approaches with smarter functionalities and better/safer working environment for human beings. The Human-Robot Collaboration (HRC) approach provides a feasible solution combing the flexibility and intelligence of a human, together with the accuracy and strength of an industrial robot. However, in the past years, despite the significant development of different HRC approaches, there is still a lack of clear safety strategy for an HRC system. Thus in this paper, the extensive taxonomy of the human-robot relations are first defined to provide a clear classification in different robotic scenarios. Then a comprehensive action strategy is developed toward different scenarios and human stakeholder's roles. A dynamic HRC layout approach is also introduced based on the actual speed of human and robot and the distance between them. The feasibility of the proposed approaches in this paper is then evaluated via the implemenntation in an HRC-based assembly cell. The operator's biometric data is also included in the HRC control loop. It is proven achievable to conduct personalised HRC safety strategy based on the human stakeholder's role, physical conditions, speed and so forth. The future research outlooks and essential considerations are addressed at the end of the paper., QC 20230921

The use of lattice structures in design for additive manufacturing has quickly emerged as a popular and efficient design alternative for creating innovative multifunctional lightweight solutions. In particular, the family of triply periodic minimal surfaces (TPMS) studied in detail by Schoen for generating frame-or shell-based lattice structures seems extra promising. In this paper a multi-scale topology optimization approach for optimal macro-layout and local grading of TPMS-based lattice structures is presented. The approach is formulated using two different density fields, one for identifying the macro-layout and another one for setting the local grading of the TPMS-based lattice. The macro density variable is governed by the standard SIMP formulation, but the local one defines the orthotropic elasticity of the element following material interpolation laws derived by numerical homogenization. Such laws are derived for frame- and shell-based Gyroid, G-prime and Schwarz-D lattices using transversely isotropic elasticity for the bulk material. A nice feature of the approach is that the lower and upper additive manufacturing limits on the local density of the TMPS-based lattices are included properly. The performance of the approach is excellent, and this is demonstrated by solving several three-dimensional benchmark problems, e.g., the optimal macro-layout and local grading of Schwarz-D lattice for the established GE-bracket is identified using the presented approach.

Reliability of electronic drivers, or systems, is crucial for the business of Signify. We manufacture and sell more than a million drivers per year. Field returns taught us what failure modes are important, but this is not sufficient to provide lifetime claims for our products. Being in this business for almost a century, in order to provide detailed lifetime claims, we have established an internal reliability tool. This tool provides our designers the correct information for flawless driver development. The specially developed Electronics Reliability Tool (ERT) uses on the one hand FIT tables provided by handbooks like e.g., Telcordia and on the other hand also considers wear-out mechanisms due to e.g., lightning strikes. Validation and verification of our predictions is performed by collecting sold quantities, field returns, do extensive failure analysis and compare these values with calculated ones. Each internally designed driver is subjected to an ERT calculation. The forecasted lifetime is used as a yard stick to witness the drivers' targeted lifetime. In our presentation we will demonstrate the tool. In this paper, we describe details of how ERT calculates failure rates. We will also present the comparison between field performance and calculated values of our electronic drivers., Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public., Electronic Components, Technology and Materials

The use of lattice structures in design for additive manufacturing has quickly emerged as a popular and efficient design alternative for creating innovative multifunctional lightweight solutions. In particular, the family of triply periodic minimal surfaces (TPMS) studied in detail by Schoen for generating frame-or shell-based lattice structures seems extra promising. In this paper a multi-scale topology optimization approach for optimal macro-layout and local grading of TPMS-based lattice structures is presented. The approach is formulated using two different density fields, one for identifying the macro-layout and another one for setting the local grading of the TPMS-based lattice. The macro density variable is governed by the standard SIMP formulation, but the local one defines the orthotropic elasticity of the element following material interpolation laws derived by numerical homogenization. Such laws are derived for frame- and shell-based Gyroid, G-prime and Schwarz-D lattices using transversely isotropic elasticity for the bulk material. A nice feature of the approach is that the lower and upper additive manufacturing limits on the local density of the TMPS-based lattices are included properly. The performance of the approach is excellent, and this is demonstrated by solving several three-dimensional benchmark problems, e.g., the optimal macro-layout and local grading of Schwarz-D lattice for the established GE-bracket is identified using the presented approach.

The Swedish strategic innovation programme, Produktion2030, is a national long-term effort towards global industrial competitiveness addressing Swedish industry’s transition towards climate goals of the European Green Deal while simultaneously realising smart manufacturing and Industry 4.0 (I4.0). This paper investigated the extent of sustainability implementation and implications of I4.0 technologies through a nation-wide quantitative survey in Produktion2030’s 113 collaborative research projects. The analysis showed that 71% of the assessed projects included environmental aspects, 60% social aspects, and 45% Circular Economy (CE) aspects. Further, 65% of the projects implemented I4.0 technologies to increase overall sustainability. The survey results were compared with literature to understand how I4.0 opportunities helped derive sustainability and CE benefits. This detailed mapping of the results along with eight semi-structured interviews revealed that a majority of the projects implemented I4.0 technologies to improve resource efficiency, reduce waste in operations and incorporate CE practices in business models. The results also showed that Swedish manufacturing is progressing in the right direction of sustainability transition by deriving key resilience capabilities from I4.0-based enablers. Industries should actively adopt these capabilities to address the increasingly challenging and unpredictable sustainability issues arising in the world and for a successful transition towards sustainable manufacturing in a digital future., QC 20220419Part of proceedings: ISBN 9780791885062

Reliability of electronic drivers, or systems, is crucial for the business of Signify. We manufacture and sell more than a million drivers per year. Field returns taught us what failure modes are important, but this is not sufficient to provide lifetime claims for our products. Being in this business for almost a century, in order to provide detailed lifetime claims, we have established an internal reliability tool. This tool provides our designers the correct information for flawless driver development. The specially developed Electronics Reliability Tool (ERT) uses on the one hand FIT tables provided by handbooks like e.g., Telcordia and on the other hand also considers wear-out mechanisms due to e.g., lightning strikes. Validation and verification of our predictions is performed by collecting sold quantities, field returns, do extensive failure analysis and compare these values with calculated ones. Each internally designed driver is subjected to an ERT calculation. The forecasted lifetime is used as a yard stick to witness the drivers' targeted lifetime. In our presentation we will demonstrate the tool. In this paper, we describe details of how ERT calculates failure rates. We will also present the comparison between field performance and calculated values of our electronic drivers., Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public., Electronic Components, Technology and Materials

Origami is traditionally implemented in paper of homogeneous material properties. This research explores the use of material with embedded electronics such as PCB (Printed Circuit Boards) as the medium for origami folding in order to create an interactive folding experience and to generate foldable objects with added functionalities. PCBs are produced as 2D shapes. By folding PCB arrays it is possible to create 3D objects that contain electronic functions. Conductivity, output devices (such as Light Emitting Diodes) and microcontroller computation can create an interactive folding experience, for user guidance and verification of the folding. We call this approach and methodology PCB Origami. The work presented in this paper describes two unique interaction and fabrication techniques for creating and folding electronic materials. We demonstrate prototypes and present verification/evaluation strategies for guiding the user through the folding process. Copyright © 2013 by ASME.

Copyright © 2020 ASME. Cavitation dynamics continue to pose a significant risk in the development and operation of launch vehicle (LV) propulsion systems. In addition to generating unsteady loads that can directly damage turbopump hardware, cavitation dynamics often couple with LV fluid feed systems, producing system wide POGO instability that can cause catastrophic failures. Despite its importance, the current understanding of cavitation dynamics, and especially pump transfer matrices, is limited. Given the relatively sparse amount of inducer transfer matrix data available, there is a critical need for more in-depth characterization of the cavitation dynamics in turbopump inducers to avoid POGO instability. This paper defines and validates a new reduced-order approach to infer key parameters such as cavitation compliance, K, and mass flow gain factor, M, from simple, single sensor unsteady pressure measurements during inducer inlet pressure ramps. The utility of this approach is demonstrated for a range of inducer geometries reported in the literature. The results are in agreement with experimental data and the paper provides a new capability supporting the assessment of launch vehicle POGO instability.

Origami is traditionally implemented in paper of homogeneous material properties. This research explores the use of material with embedded electronics such as PCB (Printed Circuit Boards) as the medium for origami folding in order to create an interactive folding experience and to generate foldable objects with added functionalities. PCBs are produced as 2D shapes. By folding PCB arrays it is possible to create 3D objects that contain electronic functions. Conductivity, output devices (such as Light Emitting Diodes) and microcontroller computation can create an interactive folding experience, for user guidance and verification of the folding. We call this approach and methodology PCB Origami. The work presented in this paper describes two unique interaction and fabrication techniques for creating and folding electronic materials. We demonstrate prototypes and present verification/evaluation strategies for guiding the user through the folding process. Copyright © 2013 by ASME.

Cloud manufacturing is a service-oriented networked manufacturing model that embraces the concept of 'Everything-as-a-Service'. In cloud manufacturing, distributed manufacturing resources encompassed in the product lifecycle are transformed into manufacturing services. Industrial robots are an important category of manufacturing resources in cloud manufacturing. During the past years, robots have been demonstrated to be able to learn various dexterous manipulation skills through training with deep reinforcement learning (DRL). In cloud manufacturing, there are many complex industrial application scenarios that require dexterous robots. Hence, robot training, which enables robots to learn various manipulation skills, becomes an important requirement for cloud manufacturing in the future, leading to the concept of 'Robot Training-as-a-Service'. This paper focuses on industrial robot training in the context of cloud manufacturing. First, related work on cloud manufacturing, DRL, DRL-based robot training, and cloud-edge collaboration is briefly reviewed and analyzed. Then, a framework for industrial robot training in cloud manufacturing with DRL is proposed, and a simplified case study is presented to demonstrate the basic principle of the framework. Finally, possible future research issues are discussed., QC 20230921

This paper presents a solution verification and validation study for an overset mesh based numerical wave tank in OpenFOAM, which considers the coupling between a free-surface hydrodynamic flow model, a rigid body motion model and an overset mesh. The coupling between the rigid body motion solver and the free surface flow solver was achieved in a segregated manner. Free decay of roll motion of a barge was modelled using the numerical wave tank, and the damping coefficient was selected as the target quantity for solution verification. The least square based solution verification procedure was adopted, where one of the four types of error estimators was fit to the data in the least square sense. Both structured and unstructured mesh were tested, and their effects on the convergence order, numerical uncertainty and error were carefully investigated. From the numerical tests, it is found that the numerical wave tank exhibits a very good convergence property for the floating body problems with structured mesh, i.e. nearly second order in space and first order in time. However, when switching the body-fitted mesh to unstructured mesh, the grid convergence is reduced to first order. Unstructured mesh does not significantly affect the convergence order in time domain, but results in a larger uncertainty due to data scattering.

Surplus heat generated from industrial sectors amounts to between 20% and 50% of the total industrial energy input. Smart reuse of surplus heat resulted from industrial sectors and power generation companies is an opportunity to improve the overall energy efficiency through more efficient use the primary energy sources. A potential solution to tackle this issue is through use of thermal energy storage (TES) to match user demand to that of the generated surplus heat. A mobile TES (MTES) concept of transportation of industrial surplus heat from production sites to end customers has shown promising results. One commissioned demonstration project using industrial heat for swimming pool water temperature regulation in Dortmund, Germany proved the interest and attention given to this concept. In this paper, a techno-economic case study in Sweden of transportation of surplus thermal energy to district heating in smart cities is presented. The application consists of heat storage at 110°C- 130°C through the use of phase change materials (PCM) based TES, notably with use of Erythritol (90 kWh/ton) for the considered temperature range, to remote district heating network located at 48 km from the thermal energy generation site. The advantages of using latent heat based PCM are the high enthalpy density per unit volume and per unit mass, as well as the quasi-constant temperature during charging and releasing of heat. The M-TES in this study has a total storage capacity of 2.1 MWh, the optimization of charge/discharge time to the amount of stored/released energy and to that of energy transportation rate is presented in this paper. Contrary to logical thinking, it is shown through this work that under certain conditions, it is more cost-effective to operate at partial load of storage units albeit the increased number of transport trips and charge/discharge cycles., QC 20160204

In low-pressure turbines (LPTs), around 60–70% of losses are generated away from end-walls, while the remaining 30–40% is controlled by the interaction of the blade profile with the end-wall boundary layer. Experimental and numerical studies have shown how the strength and penetration of the secondary flow depends on the characteristics of the incoming end-wall boundary layer. Experimental techniques did shed light on the mechanism that controls the growth of the secondary vortices, and scale-resolving computational fluid dynamics (CFD) allowed to dive deep into the details of the vorticity generation. Along these lines, this paper discusses the end-wall flow characteristics of the T106 LPT profile at Re = 120 K and M = 0.59 by benchmarking with experiments and investigating the impact of the incoming boundary layer state. The simulations are carried out with proven Reynolds-averaged Navier–Stokes (RANS) and large-eddy simulation (LES) solvers to determine if Reynolds-averaged models can capture the relevant flow details with enough accuracy to drive the design of this flow region. Part I of the paper focuses on the critical grid needs to ensure accurate LES and on the analysis of the overall time-averaged flow field and comparison between RANS, LES, and measurements when available. In particular, the growth of secondary flow features, the trace and strength of the secondary vortex system, and its impact on the blade load variation along the span and end-wall flow visualizations are analyzed. The ability of LES and RANS to accurately predict the secondary flows is discussed together with the implications this has on design.

In low-pressure turbines (LPT) at design point, around 60–70% of losses are generated in the blade boundary layers far from end walls, while the remaining 30–40% is controlled by the interaction of the blade profile with the end-wall boundary layer. Increasing attention is devoted to these flow regions in industrial design processes. This paper discusses the end-wall flow characteristics of the T106 profile with parallel end walls at realistic LPT conditions, as described in the experimental setup of Duden, A., and Fottner, L., 1997, “Influence of Taper, Reynolds Number and Mach Number on the Secondary Flow Field of a Highly Loaded Turbine Cascade,” Proc. Inst. Mech. Eng., Part A, 211(4), pp.309–320. Calculations are carried out by both Reynolds-averaged Navier–Stokes (RANS), due to its continuing role as the design verification workhorse, and highly resolved large eddy simulation (LES). Part II of this paper focuses on the loss generation associated with the secondary end-wall vortices. Entropy generation and the consequent stagnation pressure losses are analyzed following the aerodynamic investigation carried out in the companion paper (GT2018-76233). The ability of classical turbulence models generally used in RANS to discern the loss contributions of the different vortical structures is discussed in detail and the attainable degree of accuracy is scrutinized with the help of LES and the available test data. The purpose is to identify the flow features that require further modeling efforts in order to improve RANS/unsteady RANS (URANS) approaches and make them able to support the design of the next generation of LPTs.

Origami-inspired mechanical systems are mostly composed of two-dimensional elements, a feature inherited from paper folding. However, do we have to comply with this restriction on our design space? Would it be more approachable to achieve desired performance by integrating elements of different abstract dimensions? In this paper, we propose an integrated structural system consisting of both two-dimensional and one-dimensional elements. We attach elastic strings onto an origami design to modify its mechanical behavior and create new features. We show that, by introducing elastic strings to the recently proposed Morph pattern, we can obtain bistable units with programmable energy landscape. The behavior of this integrated origami-string system can be described by an elegant formulation, which can be used to explore its rich programmability.

Artificial Intelligence (AI) Support Vector Machine (SVM) learning algorithms have enjoyed rapid growth in recent years with applications in a wide range of disciplines often with impressive results. The present paper introduces this machine learning technology to the field of marine hydrodynamics for the study of complex potential and viscous flow problems. Examples considered include the forecasting of the seastate elevations and vessel responses using their past time records as "explanatory variables" or "features" and the development of a nonlinear model for the roll restoring, added moment of inertia and viscous damping using the vessel response kinematics from free decay tests as "features". A key innovation of AI-SVM kernel algorithms is that the nonlinear dependence of the dependent variable on the "features" is embedded into the SVM kernel and its selection plays a key role in the performance of the algorithms. The kernel selection is discussed and its relation to the physics of the marine hydrodynamic flows considered in the present paper is addressed., United States. Office of Naval Research (Grant N00014-17-1-2985)

Brackish water desalination is crucial to meet basic drinking water needs in rural India. Solar photovoltaic powered electrodialysis (PV-ED) has been justified as a more cost-effective solution than the current dominant reverse osmosis approach for off-grid systems. This paper presents preliminary results from an ongoing field pilot of a village-scale PV-ED system in Chelluru, which is a small village in South India. System performance is compared to predictions of a PV-ED parametric model of local solar irradiance, ED system parameters, power systems parameters, water storage, and cost, validating the model over a single-batch ED operation. An ~88% “solar-to-treated water” conversion efficiency was achieved in a typical ED batch operation, using 2.47±0.27 kWh/m[superscript 3] for brackish desalination in the village. This paper also discusses the difficulties and local constraints encountered during the initial field testing and analyzes system performance in the context of local constraints and availability. Topics: Water, MIT Energy Initiative, Tata Projects Ltd., United States. Bureau of Reclamation

The government has been allocating multi-billion Dollar budgets to STEM (science, technology, engineering and math) education. Several programs aim to educate girls about STEM and STEAM (STEM and arts). It’s a national goal to create equal opportunities for all genders and increase diversity in STEM fields. We propose that the emerging values and social needs of middle school girls must be considered when creating learning experiences for them, and that appropriate design experiences can make engineering problems engaging and relatable. It has been shown that purposefulness is a critical factor for making engineering attractive to girls. Compared to boys, girls initially perceive engineering to be less socially impactful, yet girls place a higher value on social impact at an earlier age. This paper provides a broad review of relevant literature. It is proposed that creative, innovative engineering activities with perceived social impact may motivate middle and high school girls and build their confidence in the ability to impact people’s lives with technology they create. This work tests this hypothesis using different forms of a design activity that enables students to collaboratively build personal and wearable smart devices. Examples of creations based upon this design toolkit include medical bracelets, physical activity monitoring, and other devices. The paper outlines the development of the toolkit and design activity through various stages of abstraction, and provides novel ways of prototyping design experiences. Three stages of development are implemented and tested with adolescent girls, offering new working methods for the human-centered, iterative process of designing such a toolkit. The first stage of toolkit prototypes consists of sketch models with a physical and digital component; focus groups were used to gain in-depth qualitative data. The second stage of toolkit prototypes consists of cardboard prototypes that allow for interaction mimicking the fin

As the propulsor fan pressure ratio (FPR) is decreased for improved fuel burn, reduced emissions and noise, the fan diameter grows and innovative nacelle concepts with short inlets are required to reduce their weight and drag. This paper addresses the uncharted inlet and nacelle design space for low-FPR propulsors where fan and nacelle are more closely coupled than in current turbofan engines. The paper presents an integrated fan-nacelle design framework, combining a splinebased inlet design tool with a fast and reliable body-force-based approach for the fan rotor and stator blade rows to capture the inlet-fan and fan-exhaust interactions and flow distortion at the fan face. The new capability enables parametric studies of characteristic inlet and nacelle design parameters with a short turn-around time. The interaction of the rotor with a region of high streamwise Mach number at the fan face is identified as the key mechanism limiting the design of short inlets. The local increase in Mach number is due to flow acceleration along the inlet internal surface coupled with a reduction in effective flow area. For a candidate short-inlet design with length over diameter ratio L/D = 0.19, the streamwise Mach number at the fan face near the shroud increases by up to 0.16 at cruise and by up to 0.36 at off-design conditions relative to a long-inlet propulsor with L/D = 0.5. As a consequence, the rotor locally operates close to choke resulting in fan efficiency penalties of up to 1.6 % at cruise and 3.9 % at off-design. For inlets with L/D < 0.25, the benefit from reduced nacelle drag is offset by the reduction in fan efficiency, resulting in propulsive efficiency penalties. Based on a parametric inlet study, the recommended inlet L/D is suggested to be between 0.25 and 0.4. The performance of a candidate short inlet with L/D = 0.25 was assessed using full-annulus unsteady RANS simulations at critical design and off-design operating conditions. The candidate design maintains t, Pratt & Whitney Aircraft Company

The present paper describes the application of Proper Orthogonal Decomposition (POD) to Large Eddy Simulation (LES) of the T106A low-pressure-turbine profile with unsteady incoming wakes at two different flow conditions. Conventional data analysis applied to time averaged or phase-locked averaged flow fields is not always able to identify and quantify the different sources of losses in the unsteady flow field as they are able to isolate only the deterministic contribution. A newly developed procedure allows such identification of the unsteady loss contribution due to the migration of the incoming wakes, as well as to construct reduced order models able to highlight unsteady losses due to larger and/or smaller flow structures carried by the wakes in the different parts of the blade boundary layers. This enables a designer to identify the dominant modes (i.e. phenomena) responsible for loss, the associated generation mechanism, their dynamics and spatial location. The procedure applied to the two cases shows that losses in the fore part of the blade suction side are basically unaffected by the flow unsteadiness, irrespective of the reduced frequency and the flow coefficient. On the other hand, in the rear part of the suction side the unsteadiness contributes to losses prevalently due to the finer scale (higher order POD modes) embedded into the bulk of the incoming wake. The main difference between the two cases has been identified by the losses produced in the core flow region, where both the largest scale structures and the finer ones produces turbulence during migration. The decomposition into POD modes allows the quantification of this latter extra losses generated in the core flow region, providing further inputs to the designers for future optimization strategies.

Evaluation of wave loads on a ship translating in water waves is of practical importance in ship hydrodynamics, because it is paramount to the design of ship hull structures and provides essential inputs for ship maneuvering analysis. The linear radiation and diffraction of water waves by a translating ship is studied in this paper. A time-domain Rankine panel method is developed in a non-inertial body-fixed coordinate system, which is able to consider large-amplitude horizontal motions consistently. The double-body flow is used as the basic steady flow model. To ensure numerical stability, an implicit Euler scheme is adopted for time marching, and horizontal derivatives on the free surface are calculated using an upwind-biased finite difference scheme. Numerical examples in comparison with experimental measurements are exhibited to demonstrate the validity of the developed solver.

Advancement of additive manufacturing is driving a need for design tools that exploit the increasing fabrication freedom. Multimaterial, three-dimensional (3D) printing allows for the fabrication of components from multiple materials with different thermal, mechanical, and “active” behavior that can be spatially arranged in 3D with a resolution on the order of tens of microns. This can be exploited to incorporate shape changing features into additively manufactured structures. 3D printing with a downstream shape change in response to an external stimulus such as temperature, humidity, or light is referred to as four-dimensional (4D) printing. In this paper, a design methodology to determine the material layout of 4D printed materials with internal, programmable strains is introduced to create active structures that undergo large deformation and assume a desired target displacement upon heat activation. A level set (LS) approach together with the extended finite element method (XFEM) is combined with density-based topology optimization to describe the evolving multimaterial design problem in the optimization process. A finite deformation hyperelastic thermomechanical model is used together with an higher-order XFEM scheme to accurately predict the behavior of nonlinear slender structures during the design evolution. Examples are presented to demonstrate the unique capabilities of the proposed framework. Numerical predictions of optimized shape-changing structures are compared to 4D printed physical specimen and good agreement is achieved. Overall, a systematic design approach for creating 4D printed active structures with geometrically nonlinear behavior is presented which yields nonintuitive material layouts and geometries to achieve target deformations of various complexities.

Advancement of additive manufacturing is driving a need for design tools that exploit the increasing fabrication freedom. Multimaterial, three-dimensional (3D) printing allows for the fabrication of components from multiple materials with different thermal, mechanical, and “active” behavior that can be spatially arranged in 3D with a resolution on the order of tens of microns. This can be exploited to incorporate shape changing features into additively manufactured structures. 3D printing with a downstream shape change in response to an external stimulus such as temperature, humidity, or light is referred to as four-dimensional (4D) printing. In this paper, a design methodology to determine the material layout of 4D printed materials with internal, programmable strains is introduced to create active structures that undergo large deformation and assume a desired target displacement upon heat activation. A level set (LS) approach together with the extended finite element method (XFEM) is combined with density-based topology optimization to describe the evolving multimaterial design problem in the optimization process. A finite deformation hyperelastic thermomechanical model is used together with an higher-order XFEM scheme to accurately predict the behavior of nonlinear slender structures during the design evolution. Examples are presented to demonstrate the unique capabilities of the proposed framework. Numerical predictions of optimized shape-changing structures are compared to 4D printed physical specimen and good agreement is achieved. Overall, a systematic design approach for creating 4D printed active structures with geometrically nonlinear behavior is presented which yields nonintuitive material layouts and geometries to achieve target deformations of various complexities.

Advancement of additive manufacturing is driving a need for design tools that exploit the increasing fabrication freedom. Multimaterial, three-dimensional (3D) printing allows for the fabrication of components from multiple materials with different thermal, mechanical, and “active” behavior that can be spatially arranged in 3D with a resolution on the order of tens of microns. This can be exploited to incorporate shape changing features into additively manufactured structures. 3D printing with a downstream shape change in response to an external stimulus such as temperature, humidity, or light is referred to as four-dimensional (4D) printing. In this paper, a design methodology to determine the material layout of 4D printed materials with internal, programmable strains is introduced to create active structures that undergo large deformation and assume a desired target displacement upon heat activation. A level set (LS) approach together with the extended finite element method (XFEM) is combined with density-based topology optimization to describe the evolving multimaterial design problem in the optimization process. A finite deformation hyperelastic thermomechanical model is used together with an higher-order XFEM scheme to accurately predict the behavior of nonlinear slender structures during the design evolution. Examples are presented to demonstrate the unique capabilities of the proposed framework. Numerical predictions of optimized shape-changing structures are compared to 4D printed physical specimen and good agreement is achieved. Overall, a systematic design approach for creating 4D printed active structures with geometrically nonlinear behavior is presented which yields nonintuitive material layouts and geometries to achieve target deformations of various complexities.

Advancement of additive manufacturing is driving a need for design tools that exploit the increasing fabrication freedom. Multimaterial, three-dimensional (3D) printing allows for the fabrication of components from multiple materials with different thermal, mechanical, and “active” behavior that can be spatially arranged in 3D with a resolution on the order of tens of microns. This can be exploited to incorporate shape changing features into additively manufactured structures. 3D printing with a downstream shape change in response to an external stimulus such as temperature, humidity, or light is referred to as four-dimensional (4D) printing. In this paper, a design methodology to determine the material layout of 4D printed materials with internal, programmable strains is introduced to create active structures that undergo large deformation and assume a desired target displacement upon heat activation. A level set (LS) approach together with the extended finite element method (XFEM) is combined with density-based topology optimization to describe the evolving multimaterial design problem in the optimization process. A finite deformation hyperelastic thermomechanical model is used together with an higher-order XFEM scheme to accurately predict the behavior of nonlinear slender structures during the design evolution. Examples are presented to demonstrate the unique capabilities of the proposed framework. Numerical predictions of optimized shape-changing structures are compared to 4D printed physical specimen and good agreement is achieved. Overall, a systematic design approach for creating 4D printed active structures with geometrically nonlinear behavior is presented which yields nonintuitive material layouts and geometries to achieve target deformations of various complexities.

Advancement of additive manufacturing is driving a need for design tools that exploit the increasing fabrication freedom. Multimaterial, three-dimensional (3D) printing allows for the fabrication of components from multiple materials with different thermal, mechanical, and “active” behavior that can be spatially arranged in 3D with a resolution on the order of tens of microns. This can be exploited to incorporate shape changing features into additively manufactured structures. 3D printing with a downstream shape change in response to an external stimulus such as temperature, humidity, or light is referred to as four-dimensional (4D) printing. In this paper, a design methodology to determine the material layout of 4D printed materials with internal, programmable strains is introduced to create active structures that undergo large deformation and assume a desired target displacement upon heat activation. A level set (LS) approach together with the extended finite element method (XFEM) is combined with density-based topology optimization to describe the evolving multimaterial design problem in the optimization process. A finite deformation hyperelastic thermomechanical model is used together with an higher-order XFEM scheme to accurately predict the behavior of nonlinear slender structures during the design evolution. Examples are presented to demonstrate the unique capabilities of the proposed framework. Numerical predictions of optimized shape-changing structures are compared to 4D printed physical specimen and good agreement is achieved. Overall, a systematic design approach for creating 4D printed active structures with geometrically nonlinear behavior is presented which yields nonintuitive material layouts and geometries to achieve target deformations of various complexities.

This paper addresses a practical problem: “Under which coverage of buoyancy modules, would the Vortex Induced Vibration (VIV) excitation on buoyant segments dominate the response?” This paper explores the excitation competition between bare and buoyant segments of a 38 meter long model riser. The source of data is a recent model test, conducted by SHELL Exploration and Production at the MARINTEK Ocean Basin in Trondheim Norway. A pipe model with five buoyancy configurations was tested. The results of these tests show that (1) the excitation on the bare and buoyant regions could be identified by frequency, because the bare and buoyant regions are associated with two different frequencies due to the different diameters; (2) a new phenomenon was observed; A third frequency in the spectrum is found not to be a multiple of the frequency associated with either bare or buoyancy regions, but the sum of the frequency associated with bare region and twice of the frequency associated with buoyancy region; (3) the contribution of the response at this third frequency to the total amplitude is small; (4) the power dissipated by damping at each excitation frequency is the metric used to determine the winner of excitation competition. For most buoyancy configurations, the excitation on buoyancy regions dominates the VIV response; (5) a formula is proposed to predict the winner of the excitation competition between bare and buoyant segments for a given buoyancy coverage., DeepStar (Consortium), SHEAR7 JIP

In design, as with many fields, the bases of decisions are generally not formally modeled but only talked or written about. The research problem addressed in this paper revolves around the problem of modeling the direct evaluation of design alternatives and their attributes as they are realized in linguistic communication. The question is what types of linguistic data provide the most reliable linguistic displays of preference and utility. The paper compares two formal methods for assessing a design team’s preferences for alternatives based on the team’s discussion: APPRAISAL and Preferential Probabilities from Transcripts (PPT). Results suggest that the two methods are comparable in their assessment of preferences. This paper also examines the nature of consistency in the way design teams consider the attributes of a design. Findings suggest that assessment of an attribute can change substantially over time., National Science Foundation (U.S.) (Award CMMI- 0900255), Australian Research Council (Discovery Projects funding scheme (project number DP1095601))

This paper describes the development and evolution of research themes in the Design Theory and Methodology (DTM) conference. Essays containing reflections on the history of DTM, supported by an analysis of session titles and papers winning the “best paper award”, describe the development of the research themes. A second set of essays describes the evolution of several key research themes. Two broad trends in research themes are evident, with a third one emerging. The topics of the papers in the first decade or so reflect an underlying aim to apply artificial intelligence toward developing systems that could ‘design’. To do so required understanding how human designers behave, formalizing design processes so that they could be computed, and formalizing representations of design knowledge. The themes in the first DTM conference and the recollections of the DTM founders reflect this underlying aim. The second decade of DTM saw the emergence of product development as an underlying concern and included a growth in a systems view of design. More recently, there appears to be a trend toward design-led innovation, which entails both executing the design process more efficiently and understanding the characteristics of market-leading designs so as to produce engineered products and systems of exceptional levels of quality and customer satisfaction.

Risers are fluid conduits from subsea equipment to surface floating production platforms. The integrity of a riser system plays a very important role in deepwater developments. Riser dynamic analysis is an important part to the system design. This paper investigates riser dynamic analysis using the WKB-Based dynamic stiffness method. This paper first presents a theoretical formulation of the dynamic stiffness method. It then combines the dynamic stiffness method with the WKB theory, which assumes that the coefficients in the differential equation of motion are slowly varying. The WKB-based dynamic stiffness method is derived and a frequency dependent shape function is expressed implicitly. The Wittrick and Williams (W-W) algorithm is further extended to solve eigen value problem for a general non-uniform marine riser. Examples of non-uniform riser are analyzed and the results show the efficiency of this method. In addition, a pipe-in-pipe riser system is analyzed for natural frequencies and mode shapes using the WKB-based dynamic stiffness method with the W-W algorithm. The characteristic of the mode shapes is described for such a riser system., SHEAR7 JIP

This paper presents a mathematical model investigating the physics behind pressure-compensating (PC) drip irrigation emitters. A network of PC emitters, commonly known as drip irrigation, is an efficient way to deliver water to crops while increasing yield. Irrigation can provide a means for farmer to grow more sensitive, and profitable crops and help billions of small-holder farmers lift themselves out of poverty. Making drip irrigation accessible and economically viable is important for developing farmers as most face the challenges of water scarcity, declining water tables and lack of access to an electrical grid. One of the main reasons for the low adoption rate of drip irrigation in the developing world is the relatively high cost of the pumping power. It is possible to reduce this cost by reducing the required activation pressure of the emitters, while maintaining the PC behavior. The work presented here provides a guide of how design changes in the emitter could allow for a reduction in the activation pressure from 1 bar to approximately 0.1 bar. This decrease in the activation pressure of each emitter in turn decreases the system driving pressure. This reduction of driving pressure will decrease the energy need of pumping, making a solar-powered system affordable for small-acreage farmers. This paper develops a mathematical model to describe the PC behavior in a commercially available emitter. It is a 2D model that explains the relationship between the pressure, structural deformation and fluid flow within a PC emitter. A parametric study has been performed to understand the effects of geometric and material parameters with regards to the activation pressure and PC behavior. This knowledge will help guide the designs and prototypes of optimized emitters with a lower activation pressure, while also providing the PC behavior., Jain Irrigation Systems Ltd.

Risers are fluid conduits from subsea equipment to surface floating production platforms. The integrity of a riser system plays a very important role in deepwater developments. A top-tensioned riser generally consists of outer casing, inner casing and tubing. The pipes are coupled either through fluids in the annuli or through intermediate guides (centralizers) or through both. This paper investigates the dynamic analysis for such an internally coupled fluid/ riser system. This paper first presents a theoretical formulation for a general riser system coupled with fluids in the annuli and centralizers between pipes. Hydrodynamic forces associated with the viscous fluid in between concentric cylinders are considered. An effective dynamic stiffness matrix method is then developed to evaluate the added mass and damping influence of the fluid on the natural frequencies and the dynamic response of the coupled riser system. A riser example is used to illustrate the fluid coupling impact on the system’s dynamic performance. The coupling through the fluid and centralizers can be optimally designed such that an inner pipe acts as a vibration absorber to the outer casing., SHEAR7 JIP

This paper proposes a novel method to identify the power-in regions of long flexible cylinders subjected to vortex-induced vibration (VIV). It also attempts to address a practical problem: “Will a secondary power-in region appear after the primary power-in region is covered with suppression devices?” The source of data is a recent model test on a 38 meter long flexible cylinder, densely instrumented with fiber optic strain gauges and accelerometers. For pipes with partial coverage of suppression devices in uniform flow, the bare region would be expected to be a power-in region and the section with suppression devices is expected to be a power-out region. Experimental data from these types of tests are used to benchmark the proposed power-in zone identification method. The method is then used to identify the power-in zones on a bare cylinder in a sheared flow. This paper also explores the occurrence of secondary power-in regions that may exist, when suppression devices are placed in the primary power-in zone. Secondary power-in regions were observed. Lessons learned from the power-in region identification in sheared flows will be a useful tool for designer/engineers choosing where to place suppression devices., DeepStar (Consortium), SHEAR7 JIP

In 2008, King Fahd University of Petroleum and Minerals (KFUPM) in Saudi Arabia and the Massachusetts Institute of Technology (MIT) partnered together to develop project-based curricular material to be tested out in a new undergraduate course offering in KFUPM’s Department of Mechanical Engineering. This paper details some of the unique challenges to collaborating across countries and time zones, and the approaches the KFUPM-MIT team used to address these. These approaches have so far included the establishment of a shared vision for the project and the use of an array of technologies to facilitate distance communication. The paper concludes with a description of lessons learned that might be useful for future programs that plan to engage in international collaboration on design education., Jāmiʻat al-Malik Fahd lil-Batrūl wa-al-Maʻādin

Demand Side Management (DSM) has been recognized for its potential to counteract the intermittent nature of renewable energy, increase system efficiency, and reduce system costs. While the popular approach among academia adopts a social welfare maximization formulation, the industrial practice in the United States electricity market compensates customers according to their load reduction from a predefined electricity consumption baseline that would have occurred without DSM. This paper is an extension of a previous paper studying the differences between the industrial & academic approach to dispatching demands. In the previous paper, the comparison of the two models showed that while the social welfare model uses a stochastic net load composed of two terms, the industrial DSM model uses a stochastic net load composed of three terms including the additional baseline term. That work showed that the academic and industrial optimization method have the same dispatch result in the absence of baseline errors given the proper reconciliation of their respective cost functions. DSM participants, however, and very much unfortunately, are likely to manipulate the baseline in order to receive greater financial compensation. This paper now seeks to study the impacts of erroneous industrial baselines in a day-ahead wholesale market context. Using the same system configuration and mathematical formalism, the industrial model is compared to the social welfare model. The erroneous baseline is shown to result in a different and more importantly costlier dispatch. It is also likely to require more control activity in subsequent layers of enterprise control. Thus an erroneous baseline is likely to increase system costs and overestimate the potential for social welfare improvements.

Advances in cloud-enabled service-oriented architectures (SOA) have caused a resurgence of industry interest in business process catalog as a vehicle for establishing shared references for collaborative business processes. With this paper, we start to explore the state of art and practice in business process catalog and classification scheme (BPCCS) development and use for the manufacturing industry. More specifically, this paper includes two major contributions. First, we identify a set of initial requirements for BPCCS. Second, we provide a use-case analysis based on the identified requirements. We end by comparing our BPCCS requirements with those being developed across other, BPCCS R&D groups.

In recent years, the waste mobile phones are generated in large quantity in China. Those e-wastes gain more and more attention because of both the sharp increase in quantity and the recyclable resources they contain. Furthermore, the mobile phone recycling industry has experienced a trend of rapid growth as well. However, due to the lack of national policies and legislations, the recycling industry is now facing problems in recycling processes. Thus in this paper, mobile phone recycling industry in China is systematically analyzed and a Cloud-based approach is developed which integrates tracking, interaction and coordinator mechanism through the recycling processes. With the integration of various stakeholders, the system can provide integrated data system throughout the whole life cycle of the mobile phones for the policy maker, and provide guidance for the operations during recycling service for the recycling stakeholders., QC 20161222

Hybridization of a vehicle’s drivetrain can in principle help to improve its energy efficiency by allowing for recuperation of kinetic energy and modulating the engine’s load. How well this can be realized depends on appropriate sizing and control of the additional components. The system is typically designed sequentially, with the hardware setup preceding the development and tuning of advanced controller architectures. Taking an alternative approach, component sizing and controller tuning can be addressed simultaneously through simulation-based optimization. The results of such optimizations, especially with standard algorithms with continuous design variable ranges, can however be difficult to realize, considering for example limitations in available components. Furthermore, drive-cycle based optimizations are prone to cycle-beating. This paper examines the results of such simulation-based optimization for a series hydraulic hybrid vehicle in terms of sensitivity to variations in design parameters, system parameters and drive cycle variations. Additional relevant aspects concerning the definition of the optimization problem are pointed out.

This paper shows how the computation of the singularity locus of a 3R robot can be reduced to the analysis of the relative position of two coplanar ellipses. Since the relative position of two conics is a projective invariant and the basic projective geometric invariants are determinants, it is not surprising that, using distance geometry, the computation of the singularity locus of a 3R robot can be fully expressed in terms of determinants. Geometric invariants have the benefit of simplifying symbolic manipulations. This paper shows how their use leads to a simpler characterization, compared to previous approaches, of the cusps and nodes in the singularity loci of 3R robots.

This 8-page paper, provided by the American Society of Mechanical Engineers, discusses teaching perspective free-hand sketching in engineering design courses. "This paper presents the development of a perspective-based sketching curriculum and the study of how this method compares to more traditional methods of teaching sketching to students in a freshman level engineering graphics course." The following sections are included: Abstract, Introduction, Teaching Methods, Methodology, Results, Conclusions, Future Work, Acknowledgments, and References.

Animals are products of nature and have evolved over millions of years to perform better in their activities. Engineering research and development can benefit greatly by looking into nature and finding engineering solutions by learning from animals’ evolution and biological systems. Another relevant factor in the present context is highlighted by the statement of the Nobel laureate Richard Smalley: “Energy is the single most important problem facing humanity today.” This paper focuses on how the research and education in the area of Dynamic Systems can be geared towards these two considerations. In particular, recent advances in self-powered dynamic systems and bio-inspired dynamic systems are highlighted. Self-powered dynamic systems benefit by capturing wasted energy in a dynamic system and converting it into useful energy in the mode of a regenerative system, possibly in conjunction with renewable energies. Examples of solar-powered vehicles, regenerative vibration control, and energy harvesting are presented in the paper. Particularly, development of solar-powered quadrotor, octocopter, and tricopter airships are presented, a self-powered vibration control of a mass-spring system using electromagnetic actuators/generators, and piezoelectric flutter energy harvesting using bi-stable material are discussed. As examples of bioinspired dynamic systems, flapping wing flying robots, vertical axis wind turbines inspired by fish schooling, propulsion inspired by jellyfish, and Psi Intelligent Control are given. In particular, various design and developments of bird-inspired and insect-inspired flapping wings with the piezoelectric and electromagnetic actuation mechanisms, a scaled vertical axis wind turbine farm consist of 4 turbines and the corresponding wind tunnel testing, jellyfish-inspired pulsing jet and experimenting the increase in efficiency of energy consumption, and a multi-agent/robotic based predictive control scheme inspired by Psi precognition (event or s

To extend drain intervals and improve efficiency new engine oils with increased dispersant concentration and reduced viscosity are required. Low viscosity engine oils can increase the prevalence of boundary friction at low temperature and increase its severity at higher temperatures. As a result, combinations of organic and inorganic friction modifiers (FM) will be used to reduce boundary friction across a range of temperatures, also preventing damage to vehicle catalysts. This paper presents an experimental case study of such new generation of fully-formulated engine lubricants with varying concentrations of polyisobutylene succinimide dispersant, organic and inorganic FM. Representative conditions pertaining to those encountered at the top dead centre reversal of the piston compression ring-cylinder liner contact are created, and the generated friction is measured through use of a sliding-strip tribometer. Subsequently, X-Ray Photoelectron Spectroscopy (XPS) is used to determine the composition of the formed surface tribofilms in order to explain the observed frictional characteristics. The key interactions and frictional behaviour of the dispersant and friction modifiers are highlighted across a range of operating temperatures.

New technological developments are changing how the product design community communicates in the workplace and in the classroom. Slack, an online communication application with some project management features, has become a popular communication tool among many workers and students. This paper examines the Slack conversation conducted by 16 student product development teams in a course at the Massachusetts Institute of Technology (MIT), 2.009: Product Engineering Processes. Following a typical product development process, co-located teams of 17-20 students each used the online communication tool in addition to face-to-face meetings to design new products in one semester. The resulting conversations were analyzed for message count over the course of the semester, message count by day of the week and hour of the day, message count by user, and communication organization. It was observed that teams tended to increase their communication right before deadlines and decrease it right after. When viewing teams' communication patterns by day of the week and the hour of the day, it was seen that many teams increased their communication in a short period after team meetings. In both of these cases, successful teams tended to have more consistent communication. There was little correlation (R2=2186) between the number of hours teams reported working on the class and their Slack activity by day. When looking at a team's total volume of communication, high volumes may indicate team members are working well, but it may also indicate they are struggling. Teams with higher levels of success tended to have more organized communication structures than teams with lower levels of success, as assessed by instructors. In addition to the data collected in this work, further research is still needed to understand with more certainty how online communication patterns correlate to teams' levels of success or team behaviors.

Copyright © 2020 ASME. The design of Pressurized Water Reactor (PWR) fuel has to rely on costly prototypical experimental campaigns, due to the inherent limitations of legacy lumped-parameter thermal-hydraulics codes. By resolving the fine spatial scales, computational fluid dynamics (CFD) methods offer the opportunity of delivering improved fuel design, taking full advantage of three-dimensional mixing and turbulence control, but must extend their predictive capabilities to multiphase conditions up to DNB, where the maturity and accuracy of the methods is still developing. In this paper, the closures developed within the Eulerian-Eulerian two-fluid model framework are assembled and extended to a general boiling formulation to deliver prediction of DNB at reactor conditions. The classic heat flux partitioning approach is advanced through selection of optimal closures for interaction length scale, nucleation site density, and bubble departure diameter, and further extended though the addition of a consistent DNB detection criterion, to reflect the near wall two phase characteristics. Assessment is performed at 138 bar against the experimental dataset for vertical pipe, where the inlet subcooling ranges from 1 to 150 K and the mass flux varies from 600 kg/(m2.s) to 2650 kg/(m2.s). The presented closures demonstrate consistent agreement with the experimental data, in particular in light of the calibration free application, while further work is ongoing to close the remaining gap and support the introduction of further modeling improvements.

To extend drain intervals and improve efficiency new engine oils with increased dispersant concentration and reduced viscosity are required. Low viscosity engine oils can increase the prevalence of boundary friction at low temperature and increase its severity at higher temperatures. As a result, combinations of organic and inorganic friction modifiers (FM) will be used to reduce boundary friction across a range of temperatures, also preventing damage to vehicle catalysts. This paper presents an experimental case study of such new generation of fully-formulated engine lubricants with varying concentrations of polyisobutylene succinimide dispersant, organic and inorganic FM. Representative conditions pertaining to those encountered at the top dead centre reversal of the piston compression ring-cylinder liner contact are created, and the generated friction is measured through use of a sliding-strip tribometer. Subsequently, X-Ray Photoelectron Spectroscopy (XPS) is used to determine the composition of the formed surface tribofilms in order to explain the observed frictional characteristics. The key interactions and frictional behaviour of the dispersant and friction modifiers are highlighted across a range of operating temperatures.

[EN] In the present paper, a numerical investigation of a jet-ejector is carried out using a real gas model of R1234yf. The prototype under investigation works with specific operating conditions of a jet-ejector refrigeration system intended for waste heat recovery in an internal combustion engine (ICE). In the first instance, the geometry optimization involving nozzle exit diameter, mixing chamber diameter, and nozzle exit position (NXP) is performed. Once the optimum geometry has been obtained, the jet-ejector prototype is tested with different operating pressure ratios to determine its off-design performance. The flow structure in relevant cases has been examined with an emphasis on critical and subcritical modes. The flow phenomena occurring during expansion, entrainment, and mixing processes are discussed so performance degradation can be directly related to physical processes. The analysis has been completed fitting simulated points to critical and subcritical planar surfaces. The results in terms of goodness of fit are satisfactory so the jet-ejector performance in off-design operating conditions can be reflected through simple mathematic models. When the overall cycle is assessed by using previous computational fluid dynamics (CFD) maps, it is observed that the achievable cooling drops significantly when an ambient temperature of 31 degrees C is exceeded.

A force-limiting buckling flexure has been created which can be used in a wide array of applications where excessive force from an implement can cause harm or damage. The buckling flexure is monolithic, contains no electronics, and can be manufactured using a single shot in an injection molding machine, making it extremely cost effective. In this paper, the design of this flexure is applied to a force-limiting toothbrush as an example of how this buckling flexure may be applied in a real-world technology. An overview of the buckling flexure is presented, and a structural model is shown to predict when the flexure will elastically buckle. This model is compared to data collected from flexures fabricated with varying buckling beam thickness. The data show that the force to buckle the flexure when applied at the tip can be predicted to within 20.84%. Furthermore, a preliminary model is presented which enables design of the buckling beam’s displacement, such that the total breakaway deformation can be maximized, making sensing the sudden deformation easier. As part of the application of the buckling flexure, an ergonomic, injection moldable toothbrush was created with the flexure built into the neck of the brush. When the user applies too much force while brushing, the flexure gives way and alerts the user when they have applied too much force and when the user lets off the force, the brush snaps back to its original shape. This design methodology is generalized and can be utilized in other force limited applications where an injection moldable, pre-set force, purely mechanical breakaway device is desired., 978-0-7918-5180-7

As the worldwide oil and gas market continues to grow and environmental concerns with respect to in-port offloading of gas have increased, there has been a boom of interest in new liquefied natural gas LNG terminals in the past years. Loading - offloading operations at LNG and bulk terminals are generally protected by a breakwater to ensure high operability. For these terminals, caisson breakwaters are generally a preferred solution in water depth larger than 15 m due to its advantages compared to rubble mound breakwaters. The caisson installation is generally planned to be carried out in the period where sea conditions are relatively calm. However, many of these terminal locations are exposed to swell conditions, making the installation particularly challenging and subject to large downtime. There is no clear guidance on the caisson installation process rather than contractors' experiences from different projects/sites. Therefore, studies are required in order to provide general guidance on the range of acceptable wave conditions for the installation operations and to have a better understanding of the influence of the caisson geometry. This paper presents a numerical study to determine the limiting wave conditions for caisson installing operations at larger water depth of 30-35 m for a confidential project along the African coast. Three caisson sizes/geometries are considered in order to assess and compare the wave-structure hydrodynamic interaction. The linear frequency-domain hydrodynamic analysis is performed for various seastates to determine the limiting wave conditions. Viscous effects due to flow separation at the sharp edges of the caisson are considered by using a stochastic linearization approach, where empirical drag coefficients are used as inputs. Parametric studies on caisson size and mooring stiffness are also presented, which can be used as a basis for future optimization. The uncertainty in the applied empirical viscous drag coefficients taken

This paper presents a numerical framework for characterizing fuel injection in modern combustors. The approach utilizes scaling analysis to describe the droplet evaporation in non-dimensional and fluid-independent terms. The results of the model are validated against published experimental data of isolated droplets evaporating at subcritical and near-critical conditions. The model is incorporated in a spray calculation framework and extended to the supercritical regime to assess the impact of different fluid-properties and evaporation models on temperature and fuel vapor distributions. The results suggest that in a non-convective environment the transient and quasi-steady evaporation rates vary exponentially with Lewis number. Furthermore, the results show fluid-independent behavior of the droplet evaporation, indicating that a single-component fluid can potentially be used as a modeling surrogate for jet fuel. The first-principles analysis demonstrates that classical evaporation models overestimate transient evaporation and underestimate quasi-steady evaporation, with discrepancies up to 70% at supercritical conditions. This is due to limitations in fuel-property description and the lack of non-isothermal droplet characterization at near-critical conditions. The temperature profiles are typically under-predicted and fuel vapor concentrations are over-predicted in standard spray calculations with subcritical evaporation models. As such the proposed framework breaks new ground in modeling of supercritical fuel injection. The improved quality in the predicted fuel concentration and temperature distribution can enable more accurate assessment of flame position, improving the estimation of combustion stability margins and NOx emissions. The model can be incorporated in commercial codes to guide the design of combustors operating at supercritical conditions. Keywords: fuels; gas turbines; modeling; evaporation; drops; fluids; combustion chambers; sprays; transients (dyna