bluuebunny/crossref_metadata_2025_split huggingface dataset:
Non-Rigid Variation Simulation for Ready-to-Assemble Furniture
Authors: Wärmefjord Kristina , Söderberg Rikard , Lindkvist Lars , Dagman Andreas 
Published: January 2020

Abstract
Ready-To-Assemble (RTA) furniture is becoming increasingly popular due to attractive pricing compared to standard furniture. However, for this kind of furniture to be attractive to the customer, the assembly process must be smooth. If the assembly requirements are fulfilled or not is, for this kind of assembly, ruled by the tolerances on part level. In this paper, a methodology for variation simulation of RTA furniture is presented. By predicting the fulfillment of requirement on assembly level, reasonable tolerances on part level can iteratively be set, to guarantee a smooth assembly process. The methodology includes material models, flexibility and bending during assembly, contact modeling and modeling of fastener elements between parts. Variation simulation is commonly used in the automotive industry and a comparison of variation simulation methodologies between the two kinds of industries is conducted. A major difference between RTA furniture business and automotive industry is that no fixtures are used for RTA furniture. This must be reflected in the simulation procedure. Furthermore, the results from the variation simulation need to be evaluated, and the results are dependent on the context of the assembled product. Both the assemblability and esthetical requirements, like flush, gap, and parallelism, need to be evaluated.
The methodology is illustrated on a case study and future development and research needed to adapt variation simulation to furniture industry are discussed.
Low-Order Representation of Manufacturing Variations Based on B-Spline Morphing
Authors: Urbano Jose , Bestle Dieter , Gerstberger Ulf , Flassig Peter 
Published: January 2020

Abstract
Even small surface deviations arising from manufacturing may lead to critical performance losses of mechanical components as e.g. blade shape deviations in aeroengines. Supposed that such deviations are often associated with complex geometries, the nominal parametrization of the part may be inadequate to correctly describe them. Therefore, this paper proposes to re-parametrize the surface of interest as a B-spline surface with a higher number of control points to allow accurate coverage of surface deviations. Further, it is demonstrated how such a B-spline surface may be fitted to surface measurements by B-spline morphing and how manufacturing uncertainties may be described statistically by a few manufacturing modes only. Such a small data characterization may be used as an excellent basis for performing robust design. The proposed procedures are validated by an application to the hub endwall of a high-pressure turbine blade.
Mechanical Properties of 3D Printed Fiber Reinforced Thermoplastic
Authors: Sanei Seyed Hamid Reza , Lash Zack , Servey Josh , Gardone Frank , Nikhare Chetan P. 
Published: January 2020

Abstract
3D printed composites is a relatively new and untested market in the composites industry. 3D printing in general is becoming a widely used manufacturing method because of its ease, versatile capabilities, and consistency. Recent improvement in 3D printing enables 3D printing of composites fibers in any given direction. In this study, continuous carbon fiber onyx samples were manufactured using Markforged X7 3D printers. Samples with three different fiber orientations were manufactured to determine all elastic properties. The results show that while the properties are lower than high strength CFRPs, there is high potential for the use of 3D printed composites upon improving the matrix properties as well as the bonding between fiber and matrix.
Anisotropy Oriented Tolerance Analysis of Composite Assembly With T-Maps Method
Authors: Wang Hua , Yan Chen , Yu Junyang 
Published: January 2020

Abstract
Anisotropy is an outstanding characteristic of the composite parts, and should be considered during the course of the tolerance analysis. The paper presents a tolerance analysis method for composite elevator assembly using T-Maps method, mainly concerning the variations originated from the anisotropy of the composite materials. The composite elevator is composed of the forward spar, the skin panels, and the ribs. Variations of the composite forward spar and the composite panels in different directions are represented by the T-Maps. Mating clearances of the composite spar and the metallic joints are mapped to the hypothetical Euclidean space. Since the different axial deviations are represented in the same Euclidean point-space, anisotropy oriented tolerance analysis of the composite parts assembly could be conducted with more accurate results. This procedure is found to be effective for anisotropy oriented tolerance analysis. The assembly of the composite elevator is investigated intensively by the proposed method. The procedures outlined in the paper are quite general and can be used for tolerance analysis of any anisotropic parts assembly process.
In-Situ Fatigue Prediction of Direct Laser Deposition Parts Based on Thermal Profile
Authors: Seifi Seyyed Hadi , Tian Wenmeng , Yadollahi Aref , Doude Haley , Bian Linkan 
Published: January 2020

Abstract
Additive manufacturing (AM) is a novel fabrication technique which enables production of very complex designs that are not feasible through conventional manufacturing techniques. However, one major barrier against broader adoption of additive manufacturing processes is concerned with the quality of the final products, which can be measured as presence of internal defects, such as pores and cracks, affecting the mechanical properties of the fabricated parts. In this paper, a data-driven methodology is proposed to predict the size and location of porosities based on in-situ process signatures, i.e. thermal history. Size as well as location of pores highly affect the resulted fatigue life where near-surface and large pores, compared to inner or small pores, significantly reduces the fatigue life. Therefore, building a model to predict the porosity size and location will pave the way toward building an in-situ prediction model for fatigue life which would drastically influence the additive manufacturing community. The proposed model consists of two phases: in Phase I, a model is established to predict the occurrence and location of small and large pores based on the thermal history; and subsequently, a fatigue model is trained in Phase II to predict the fatigue life based on porosity features predicted from Phase I. The model proposed in Phase I is validated using a thin wall fabricated by a direct laser deposition process and the Phase II model is validated based on fatigue life simulations. Both models provide promising results that can be further studied for functional outcomes.
Design and Modeling of Semi Compliant Prosthetic Knee Joint
Authors: Warnix Trevor , Lin Hongkuan , Lowder M. Loraine , Tekes Coskun , Tekes Ayse 
Published: January 2020

Abstract
This paper presents the design phases and modeling of multi axial compliant prosthetic knee joint comprised of rigid and flexible members providing a better performance than traditional spring-loaded rigid multilink joints. Mechanism consists of monolithic compliant five bar incorporating large deflecting flexure hinges, two rigid body representing the upper and lower legs, translational spring and flexure joints simulating ankle motion. Dynamical modeling is studied by integrating pseudo rigid body modeling of small-length flexure hinge method and Lagrange equations under the assumption that link 2 (left base link) is fixed and link 3 is rotated quasi-statically at constant speed. Torsional stiffness of ankle springs is obtained by using MSC Adams simulations. Initial prototype is built by 3D printing the parts using polylactic acid (PLA) filament. Mechanism is potentially suitable for pediatric prosthetic knee systems due to its simple design, versatility and light weight.
High-Cycle Fatigue Behavior of Type 4340 Steel Pressurized Blocks Including Mean Stress Effect
Authors: Badr Elie A. , Ishak Joanne 
Published: January 2020

Abstract
Mean stress effects in pressurized steel blocks were examined under constant amplitude fatigue loading. The tests were performed to provide experimental data needed to study the effect of mean stress on fatigue lives of subject specimen, and to substantiate the use of analytical expressions to account for the mean stress. The mean stress was the result of subjecting the specimens to an autofrettage pressure which induced compressive residual stresses at the crossbore intersection of the specimens. Fatigue tests were carried out under both tensile and compressive mean stress levels. Test results were compared to several mean stress accounting relationships such as the Smith-Watson Topper, Bergmann and Seeger, modified Goodman, Gerber and Soderberg. Test results indicated that the modified Goodman equation is favorable in accounting for the effect of both tensile and compressive mean stresses on fatigue life (up to a compressive mean stress to ultimate stress ratio of −0.2). The behavior under compressive mean stress to ultimate stress ratio of less than −0.2 indicated that a linear correction relationship was required.
Optimization of Fixed PV Panel “Tilt” Angles for Maximal Energy Harvest Considering Year-Around Sky Coverage Conditions
Authors: Gwesha Ammar Omar , Alfulayyih Yasir Mohammed , Li Peiwen 
Published: January 2020

Abstract
In order to maximize the electrical energy harvested by photovoltaic panels in a setup with fixed angles, it is important to get the angle optimized. In the present work, sunlight availability or sky coverage conditions of year-long period based on ten years’ data are counted in the modeling to optimize the PV panel tilt angles targeting for the maximal energy in a year. The analysis uses precise sunray calculation models. The energy harvested in every 6 minutes by a PV panel is summated for the daily time period from sunrise to sunset when the sun elevation angles are above 5 degree, with the sky-coverage factor multiplied. The results show that the annual solar energy received by a PV solar panel tilted with a fixed angle equal to the local latitude (at Tucson AZ, USA) could reach 2297 kWh/m2 under 10-year averaged sky coverage conditions. However, the gain in the yearly solar energy harvest is expected to be about 4.28%, 7.06%, and 8.42% higher if a PV panel is inclined optimally according to two-season, four-season, and monthly adjustments, respectively, compared to the optimized life-long fixed angle.
Design of a Free Piston Stirling Engine Power Generator
Authors: Li Ruijie , Gao Yuan , Yanaga Koji , Qiu Songgang 
Published: January 2020

Abstract
Free Piston Stirling Engine is an external combustion engine, which can use diversified energy resources, such as solar energy, nuclear energy, geothermal energy, biomass, industrial waste heat etc. and is suitable for the remote area power generation due to the advantage of robustness, durability, reliability, and high efficiency. In this work, a Free Piston Stirling Engine has been designed based on the numerical simulation results and previous experimental experience. Direct Metal Laser Sintering method has been adopted for the manufacturing of the key components including the displacer cap, displacer body, piston housing, cold heat exchanger, and regenerator. One dimension analysis using Sage software has been conducted. The designed engine has a power output of 65W with the hot and cold end temperature is 650°C and 80°C respectively, and charge pressure is 1.35 MPa. Finite Element Method has been used to analyze the structural stress of the engine, which is operated at the high temperature and high pressure, to determine if it is able to tolerate the operating condition designed by the Sage according to the Section VIII Division 2 of the ASME Boiler and Pressure Vessel (BPV) Code.
In addition, Computational Fluid Dynamics (CFD) method has been used to investigate the flow distribution in heat exchangers (heat acceptor, regenerator, and heat rejecter), as the heat exchanger performance affect the engine performance greatly. Considering the large mesh number, a quarter of the heat exchangers have been investigated, in order to reduce the mesh numbers and accelerate the calculation speed.
A Methodology for Modelling Tugger Train Systems Using Modelica
Authors: Veiga João , Sousa João , Machado José , Silva João , Machado Toni , Silva Pedro 
Published: January 2020

Abstract
In this paper, the authors present a methodology to develop a modular model of a tugger train system using Modelica language. The presented system is composed by a tugger and three passive trolleys. The model allows to estimate the path of the trolleys relative to the path of the tugger vehicle and it can be used to estimate the maximum velocities when in a curve.
A review of common vehicle models from the literature is presented. Some concepts of the Modelica language are introduced in order to support the model of the shown system.
The presented model is a simplified representation of the system for planar motion developed in Modelica language using the Open Modelica OMEdit software2. The vehicle models are modelled by custom classes and linked with the aid of blocks from the Open Modelica standard library. This model was mainly used to understand the behavior of the vehicles during U-turns, estimate the minimum turning radius and maximum velocities during the turn.
The methodology allows a modular approach combining vehicle and multibody modelling.
Assessment of Eddy-Viscosity Turbulence Models on Flow in a Wheelhouse
Authors: Nabutola Kaloki L. , Boetcher Sandra K. S. 
Published: January 2020

Abstract
Six different turbulence models were used to simulate the flow within the wheelhouse of a simplified body. The performance of each model was evaluated by comparing the results to data collected from wind tunnel experiments. The performance of large eddy simulation (LES) and detached eddy simulation (DES) is largely dependent on the time step and grid size to accurately resolve turbulent eddies. The standard k–ω and k–ω SST models deviated the most from the experimental data. The standard k–ε model was found to produce the most consistent results which matched experimental data for the simplified body and wheel.
Drag Reduction of Ground Vehicles Using Air-Injected Wheel Deflectors
Authors: Nabutola Kaloki L. , Boetcher Sandra K. S. 
Published: January 2020

Abstract
Numerical simulations of flow modification devices on a simplified ground vehicle are conducted. A parametric study on the size and distance upstream of conventional wheel deflectors is conducted on a simplified body at a Reynolds number of 1.6 × 105 to observe the impact on drag coefficient. Results show that wheel drag is decreased as the height of the conventional wheel deflector is increased. Additionally, the further the conventional wheel deflector is from the wheelhouse, the more sensitive the wheel is to changes in drag coefficient. The conventional wheel deflectors are then replaced by air-jets which are used to manipulate the flow field in and near the wheelhouse to reduce the wheel drag of the simplified body. The air-jet successfully decreases the wheel drag and it is observed that the closer the air-jet is to the wheelhouse the less impact it has on the single wheel drag, but the greater the impact on the overall drag of the simplified body.
High-Power Fuel Cell Systems Fueled by Recycled Aluminum
Authors: Godart Peter , Fischman Jason , Hart Douglas 
Published: January 2020

Abstract
Presented here is a novel system that uses an aluminum-based fuel to continuously produce electrical power at the kW scale via a hydrogen fuel cell. This fuel has an energy density of 23.3 kWh/L and can be produced from abundant scrap aluminum via a minimal surface treatment of gallium and indium. These additional metals, which in total comprise 2.5% of the fuel’s mass, permeate the grain boundary network of the aluminum and disrupt its oxide layer, thereby enabling the fuel to react exothermically with water to produce hydrogen gas and aluminum oxyhydroxide, an inert and valuable byproduct. To generate electrical power using this fuel, the aluminum-water reaction is controlled via water input to a reaction vessel in order to produce a constant flow of hydrogen, which is then consumed in a fuel cell to produce electricity. As validation of this power system architecture, we present the design and implementation of two example systems that successfully demonstrate this approach. The first is a 3 kW emergency power supply and the second is a 10 kW power system integrated into a BWM i3 electric vehicle.
3D Printing and Stretching Effects on Alignment Microstructure in PDMS/CNT Nanocomposites
Authors: Herren Blake , Gu Tingting , Tang Qinggong , Saha Mrinal , Liu Yingtao 
Published: January 2020

Abstract
The alignment of high aspect ratio reinforcing nanoparticles within a polymer matrix can have significant effects on the mechanical, electrical, and thermal properties of the nanocomposite. Therefore, in order to tailor the properties of the composite, it is imperative to develop novel methods to control the alignment of these filler particles in various polymeric matrices. This paper reports a unique approach to alter the alignment of carbon nanotubes (CNT) within polydimethylsiloxane (PDMS) nanocomposites using 3D printing technology. A line of the reinforced PDMS resin is printed on a PDMS substrate using direct ink writing technology, which can produce alignment in the print direction depending on printing parameters, the loading of the reinforcing particle, and the rheology of the ink. Then, the substrate is stretched and placed in an oven to cure the printed nanocomposites line with increased alignment in the stretch direction. These two techniques have the advantage of simplicity over other techniques and can efficiently manufacture nanocomposites with the alignment of nanoparticles. Optical microscopy will be used to quantify the alignment within the printed line. Electrical and mechanical properties will be tested to determine the effects of the different alignments within the elastomer. The ability to control the alignment of elastomeric CNT composites is advantageous for the growing field of polymer-based electronics.
Highly Porous Shape Memory Nanocomposites for Applications in Biomedical Devices
Authors: Luo Jishan , Kunkel Robert , Wang Jingyu , Bohnstedt Bradley N. , Saha Mrinal , Liu Yingtao , Lee Chung-Hao 
Published: January 2020

Abstract
This paper presents the novel development of highly porous carbon nanotube (CNT)/shape memory polymer (SMP) nanocomposites for potential endovascular treatment of intracranial aneurysms (ICAs). Intracranial aneurysm is a cerebrovascular disorder that can significantly weaken the wall of a brain artery, resulting in a localized dilation of the blood vessel with risk of rupture and subarachnoid bleeding. Current therapeutic options include surgical clipping and endovascular coil embolization. Clipping of intracranial aneurysms is invasive, and, therefore, it has gradually been replaced by non-invasive endovascular embolization. Recent studies have shown that aneurysmal recanalization and incomplete occlusion are still emerging clinical challenges in endovascular coil embolization. Therefore, there is an urgent need to develop new medical devices and surgical procedure to treat intracranial aneurysms with improved long-term outcomes.
CNT/SMP nanocomposites are fabricated by directly coating CNTs on sugar particles before fabricating the sugar template for porous nanocomposites. Pristine SMP prepolymer is infiltrated into the pores of sugar template. All the sugar is dissolved in water after the fully curing of PDMS, resulting in SMP based nanocomposites with well dispersed CNTs. The porous nanocomposites are characterized to identify key parameters, such as electrical resistivity and shape memory capability. A resistive-heating mechanism is developed to trigger shape recovery of the nanocomposites. The results of this work will lay a solid foundation for our subsequent development of new personalized biomedical devices to treat ICAs using a catheter-based endovascular embolization procedure.
Computational Design of Microstructures With Stochastic Property Closures
Authors: Acar Pınar 
Published: January 2020

Abstract
The present work addresses a stochastic computational solution to define the property closures of polycrystalline materials under uncertainty. The uncertainty in material systems arises from the natural stochasticity of the microstructures and the variations in deformation processes, and impacts the performance of engineering components by causing unanticipated anisotropy in properties. We utilize an analytical uncertainty quantification algorithm to describe the microstructural stochasticity and model its propagation to the volume-averaged material properties. The stochastic solution will be integrated into linear programming to generate the property closure that shows all possible values of the volume-averaged material properties under the uncertainty. We demonstrate example applications for stiffness parameters of a-Titanium, and multi-physics parameters (stiffness, yield strength, magnetostrictive strain) of Galfenol. Significant differences observed between stochastic and deterministic closures imply the importance of considering the microstructural uncertainty when modeling and designing materials.
Effect of Phase Change Material on Temperature in a Room Fitted With a Windcatcher
Authors: Abdo Peter , Huynh B. Phuoc , Braytee Ali , Taghipour Rahil 
Published: January 2020

Abstract
Global warming and climate change have been considered as major challenges over the past few decades. Sustainable and renewable energy sources are nowadays needed to overcome the undesirable consequences of rapid development in the world. Phase change materials (PCM) are substances with high latent heat storage capacity which absorb or release the heat from or to the surrounding environment. They change from solid to liquid and vice versa. PCMs could be used as a passive cooling method which enhances energy efficiency in buildings. Integrating PCM with natural ventilation is investigated in this study by exploring the effect of phase change material on the temperature in a room fitted with a windcatcher. A chamber made of acrylic sheets fitted with a windcatcher is used to monitor the temperature variations. The dimensions of the chamber are 1250 × 1000 × 750 mm3. Phase change material is integrated respectively at the walls of the room, its floor and ceiling and within the windcatchers inlet channel. Temperature is measured at different locations inside the chamber. Wind is blown through the room using a fan with heating elements.