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Design and Experimental Verification of a High Force Density Tubular Permanent Magnet Linear Motor for Aerospace Application

Daido University-Yoshiaki Kano
  • Technical Paper
  • 2019-01-1911
To be published on 2019-09-16 by SAE International in United States
This paper presents the design and construction of a high force density tubular permanent-magnet (PM) linear motor. A strut structure of a tubular PM linear motor developed to improve resistance to impurities and structural rigidity is described. In the design, computationally efficient two-dimensional finite-element analysis is used to estimate the motor force density. The motor’s design is optimized for the major pole number/slot number combinations of 8/24, 16/24, 20/24, 28/24, 32/24, and 40/24. The optimized motor design of a three-phase 16/24 combination with one-layer winding achieved the highest force-to-mass density. The force-to-mass density of the designed motor is higher than that of the first prototype motor by a factor of 5. The validity of the proposed design method and the expected drive characteristics are experimentally verified using the prototype.
 
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Measured Interfacial Residual Strains Produced by In-Flight Ice

Connecticut Reserve Technologies-Eric Baker
NASA John Glenn Research Center-Jonathan Salem, Richard Kreeger
Published 2019-06-10 by SAE International in United States
The formation of ice on aircraft is a highly dynamic process during which ice will expand and contract upon freezing and undergoing changes in temperature. Finite element analysis (FEA) simulations were performed investigating the stress/strain response of an idealized ice sample bonded to an acrylic substrate subjected to a uniform temperature change. The FEA predictions were used to guide the placement of strain gages on custom-built acrylic and aluminum specimens. Tee rosettes were placed in two configurations adjacent to thermocouple sensors. The specimens were then placed in icing conditions such that ice was grown on top of the specimen. It was hypothesized that the ice would expand on freezing and contract as the temperature of the interface returned to the equilibrium conditions. While results from the aluminum specimens matched this hypothesis, results from the acrylic specimens show a short period of contraction followed by a much larger expansion at the interface, indicating more complex ice growth thermodynamics than anticipated. Some samples were observed to delaminate, suggesting that the residual strain is significant to the shedding…
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Characterization of Mode-II Interfacial Fracture Toughness of Ice/Metal Interfaces

Iowa State University-Denizhan Yavas, Ashraf Bastawros, Bishoy Dawood, Christopher Giuffre
Published 2019-06-10 by SAE International in United States
Airborne, marine and ground structures are vulnerable to atmospheric icing in cold weather operation conditions. Most of the ice adhesion-related work have focused on the mechanical ice removal strategies because of practical considerations, while limited literature is available for fundamental understanding of the ice adhesion process. Here, we present a fracture mechanics-based approach to characterize interfacial fracture parameters for the shear behavior of a typical ice/aluminum interface. An experimental framework employing two complementary tests (1) lap shear and (2) shear push-out tests was introduced to assess the mode-II fracture parameters for the selected aluminum/ice interface. Both analytical (shear-lag analysis) and numerical (finite element analysis incorporating cohesive zone method) models were used to evaluate shear fracture parameters. The combined experimental and numerical results, as well as surveying published results for lap shear and 0° cone tests showed that mode-II interfacial strength and toughness can be significantly affected by the method of testing geometry due to geometrically induced interfacial residual stress. As a result, the apparent toughness (or strength) obtained by 0° cone test could reach an…
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Utilization of Single Cantilever Beam Test for Characterization of Ice Adhesion

Iowa State University-Bishoy Dawood, Denizhan Yavas, Christopher Giuffre, Ashraf Bastawros
Published 2019-06-10 by SAE International in United States
Many engineering systems operating in a cold environment are challenged by ice accretion, which unfavorably affects their aerodynamics and degrades both their performance and safety. Precise characterization of ice adhesion is crucial for an effective design of ice protection system. In this paper, a fracture mechanics-based approach incorporating single cantilever beam test is used to characterize the near mode-I interfacial adhesion of a typical ice/aluminum interface with different surface roughness. In this asymmetric beam test, a thin layer of ice is formed between a fixed and elastically deformable beam subjected to the applied loading. The measurements showed a range of the interfacial adhesion energy (GIC) between 0.11 and 1.34 J/m 2, depending on the substrate surface roughness. The detailed inspection of the interfacial ice fracture surface, using fracture surface replication technique, revealed a fracture mode transition with the measured macroscopic fracture toughness. The higher level of fracture toughness was associated with cohesive-type interfacial failure. The lower level of fracture toughness on smoother surfaces was associated with adhesive interface failure.
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Modeling and Validation for the Hysteretic Behavior of an Automatic Belt Tensioner

BYD Auto Industry Company Limited-Pu Xu
South China University of Technology-Shangbin Long, Xuezhi Zhao
Published 2019-06-05 by SAE International in United States
An automatic tensioner used in an engine front end accessory drive system (EFEADS) is taken as a study example in this paper. The working torque of the tensioner, which consists of the spring torque caused by a torsional spring and the frictional torques caused by the contact pairs, is analyzed by a mathematic analysis method and a finite element method. And the calculation and simulation are validated by a torque measurement versus angular displacement of a tensioner arm. The working torques of the tensioner under a loading and an unloading process are described by a bilinear hysteretic model, and are written as a function with a damping ratio. The rule of the action for the damping devices is investigated based on the simulation and a durability test of the tensioner. A finite element method for the tensioner without damping device is established. Then the radial deformation for the torsional spring under an unconstrained state is obtained. The analysis results have a good correlation with the measurements. The method presented in this paper is beneficial for…
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A New Method for Mid- to High-Frequency Vibration Analyses of Beam Structures

University of Southern California-Bingen Yang, Yichi Zhang
Published 2019-06-05 by SAE International in United States
Vibrations of complex flexible structures at mid- to high- frequencies have important applications in automotive, aerospace and ship engineering, as well as in high-tech developments. In this paper, a new method is proposed for mid- and high-frequency vibration analyses of complex flexible beam structures. In this method, the vibration of a multi-body beam structure is modeled by an augmented formulation of the Distributed Transfer Function Method (DTFM). This formulation does not rely on discretization, treats beam members, different types of connection, and general boundary conditions in a unified manner, and does not need to adjust algorithms of calculation as the excitation frequency varies from low to high. A highlight of the new method is that it delivers frequency response solutions with detailed information on local displacement, slope, bending moment and shear force in mid- to high-frequency regions, which otherwise might be difficult to obtain by conventional analyses. The proposed method is illustrated on two-dimensional Euler-Bernoulli beam frames in numerical simulation. The new method is validated with the finite element analysis (FEA), the statistical energy analysis…
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Power Electronic Noise-Simulation Measurement Comparison

AVL LIST GmbH-Markus Resch, Thomas Resch, Stephan Brandl
AVL Software and Functions Gmbh-Peter Olbrich, Hartwig Reindl
Published 2019-06-05 by SAE International in United States
A growing development of hybrid or fully electrical drives increases the demand for an accurate prediction of noise and vibration characteristics of electric and electronic components. This paper describes the numerical and experimental investigation of noise emissions from power electronics, as one of the new important noise sources in electric vehicles.The noise emitted from the printed circuit board (PCB) equipped with multi-layer ceramic capacitors (MLCC) is measured and used for the calibration and validation of numerical model. Material properties are tuned using results from experimental modal analysis, with special attention to the orthotropic characteristic of the PCB glass-reinforced epoxy laminate sheet (FR-4). Electroacoustic excitation is pre-calculated using an extension of schematic-based EMC simulation and applied to the structural model. Structural vibrations are calculated with a commercial FEM solver with the modal frequency response analysis. Sound radiation is simulated using the wave-based approach (WBT). Simulation and experimental results are compared in a frequency range up to 10 kHz.The developed simulation methodology can successfully identify the main noise sources from the equipped PCB. Critical peak noise responses…
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Numerical Modeling of Internal Helmholtz Resonators Created by Punching Small Holes on a Thin-Walled Tube

University of Kentucky-Hao Zhou, T. W. Wu
Published 2019-06-05 by SAE International in United States
Helmholtz resonators are normally an afterthought in the design of mufflers to target a very specific low frequency, usually the fundamental firing frequency of the engine. Due to space limitations in a complex muffler design, a resonator may have to be built by punching a few small holes on a thin-walled tube to create a neck passage into a small, enclosed volume outside the tube. The short neck passage created by punching a few small holes on a thin-walled tube can pose a great challenge in numerical modeling, especially when the boundary element method (BEM) is used. In this paper, a few different BEM modeling approaches are compared to one another and to the finite element method (FEM). These include the multi-domain BEM implemented in a substructure BEM framework, modeling both sides of the thin-walled tube and the details of each small hole using the Helmholtz integral equation and the hypersingular integral equation, and modeling just the mid surface of the thin-walled tube. The FEM and BEM solutions are used to estimate the effective neck…
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Early Research on Additively Manufactured Sound Absorbers

University of Kentucky-Weiyun Liu, David Herrin
Published 2019-06-05 by SAE International in United States
Additive manufacturing is slowly changing how components are developed and manufactured. As the technology develops over time, it is anticipated that industry will 3D print sound absorbers in production. Configurations may be considered that would be difficult to manufacture in another way. For exploratory purposes, several designs were 3D printed and positioned in an impedance tube for testing. Though the absorbers developed are based on well-established strategies, the absorbers considered are either difficult to manufacture by another means or take advantage of the unique features of 3D printed parts. The samples measured include long perforations, lightweight panels, and Helmholtz resonators with spiral wound necks. Selected results are compared with acoustic finite element analysis.
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Structural-Acoustic Modeling and Optimization of a Submarine Pressure Hull

Michigan Engineering Services, LLC-Geng Zhang
University of Michigan-James Spain, Nickolas Vlahopoulos
Published 2019-06-05 by SAE International in United States
The Energy Finite Element Analysis (EFEA) has been validated in the past through comparison with test data for computing the structural vibration and the radiated noise for Naval systems in the mid to high frequency range. A main benefit of the method is that it enables fast computations for full scale models. This capability is exploited by using the EFEA for a submarine pressure hull design optimization study. A generic but representative pressure hull is considered. Design variables associated with the dimensions of the king frames, the thickness of the pressure hull in the vicinity of the excitation (the latter is considered to be applied on the king frames of the machinery room), the dimensions of the frames, and the damping applied on the hull are adjusted during the optimization process in order to minimize the radiated noise in the frequency range from 1,000Hz to 16,000Hz. Constraints on the total amount of damping that can be used are considered (resource driven constraints) and structural collapse constraints are also taken into account in order to avoid…
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