Wing profile performance variations influenced by manufacturing tolerances.

2013 ◽  
Author(s):  
Tomas Melin ◽  
Christopher Jouannet ◽  
Petter Krus
Keyword(s):  
Wing Profile ◽  
Manufacturing Tolerances ◽  
Performance Variations

Photon Emission Spectral Signatures of AlGaN/GaN HEMT for Functional and Reliability Analysis

2008 ◽  
Author(s):  
Arkadiusz Glowacki ◽  
Christian Boit ◽  
Richard Lossy ◽  
Joachim Würfl
Keyword(s):  
Reliability Analysis ◽  
Gate Voltage ◽  
Near Infrared ◽  
Photon Emission ◽  
Electrical Characterization ◽  
Spectral Signatures ◽  
Operating Modes ◽  
Gan Hemt ◽  
Spectrally Resolved ◽  
Performance Variations

Abstract Non-degraded and degraded AlGaN/GaN HEMT devices have been characterized electrically and investigated in various operating modes using integral and spectrally resolved photon emission (PE). In degraded devices the PE dependence on the gate voltage differs from the non-degraded devices. Various types of dependencies on the gate voltage have been identified when investigating local degradation sites. PE spectroscopy was performed at various bias conditions. For both devices broad spectra have been obtained in a wavelength regime from visible to near-infrared, including local performance variations. Signatures of the degradation have been determined in the electrical characterization, in integral PE distribution and in the PE spectrum.

Electric Vehicle Charger Placement Optimization in Michigan Considering Monthly Traffic Demand and Battery Performance Variations

2021 ◽  
pp. 036119812098195
Author(s):  
Fatemeh Fakhrmoosavi ◽  
MohammadReza Kavianipour ◽  
MohammadHossein (Sam) Shojaei ◽  
Ali Zockaie ◽  
Mehrnaz Ghamami ◽  
...  
Keyword(s):  
Optimal Allocation ◽  
Critical Factor ◽  
Cold Weather ◽  
Contributing Factors ◽  
Modeling Framework ◽  
Long Distance ◽  
Charging Infrastructure ◽  
Traffic Demand ◽  
Adverse Weather ◽  
Performance Variations

Limited charging infrastructure for electric vehicles (EVs) is one of the main barriers to adoption of these vehicles. In conjunction with limited battery range, the lack of charging infrastructure leads to range-anxiety, which may discourage many potential users. This problem is especially important for long-distance or intercity trips. Monthly traffic patterns and battery performance variations are two main contributing factors in defining the infrastructure needs of EV users, particularly in states with adverse weather conditions. Knowing this, the current study focuses on Michigan and its future needs to support the intercity trips of EVs across the state in two target years of 2020 and 2030, considering monthly traffic demand and battery performance variations. This study incorporates a recently developed modeling framework to suggest the optimal locations of fast EV chargers to be implemented in Michigan. Considering demand and battery performance variations is the major contribution of the current study to the proposed modeling framework by the same authors in the literature. Furthermore, many stakeholders in Michigan are engaged to estimate the input parameters. Therefore, the research study can be used by authorities as an applied model for optimal allocation of resources to place EV fast chargers. The results show that for charger placement, the reduced battery performance in cold weather is a more critical factor than the increased demand in warm seasons. To support foreseeable annual EV trips in Michigan in 2030, this study suggests 36 charging stations with 490 chargers and an investment cost of $23 million.

scholarly journals Vibro-Acoustical Sensitivities of Stiffened Aircraft Structures Due to Attached Mass-Spring-Dampers with Uncertain Parameters

Aerospace ◽  
2021 ◽  
Vol 8 (7) ◽  
pp. 174
Author(s):  
Johannes Seidel ◽  
Stephan Lippert ◽  
Otto von Estorff
Keyword(s):  
System Response ◽  
Fuzzy Arithmetic ◽  
Parameter Uncertainties ◽  
Excitation Spectra ◽  
Radiated Noise ◽  
Linking Elements ◽  
Manufacturing Tolerances ◽  
Suitable Framework ◽  
Mass Spring ◽  
The Impact

The slightest manufacturing tolerances and variances of material properties can indeed have a significant impact on structural modes. An unintentional shift of eigenfrequencies towards dominant excitation frequencies may lead to increased vibration amplitudes of the structure resulting in radiated noise, e.g., reducing passenger comfort inside an aircraft’s cabin. This paper focuses on so-called non-structural masses of an aircraft, also known as the secondary structure that are attached to the primary structure via clips, brackets, and shock mounts and constitute a significant part of the overall mass of an aircraft’s structure. Using the example of a simplified fuselage panel, the vibro-acoustical consequences of parameter uncertainties in linking elements are studied. Here, the fuzzy arithmetic provides a suitable framework to describe uncertainties, create combination matrices, and evaluate the simulation results regarding target quantities and the impact of each parameter on the overall system response. To assess the vibrations of the fuzzy structure and by taking into account the excitation spectra of engine noise, modal and frequency response analyses are conducted.

The Influence of Manufacturing Tolerances on Swirler Durability

2014 ◽  
Author(s):  
Nagaraja S. Rudrapatna ◽  
Richard R. Bohman ◽  
Jonathan K. Anderson ◽  
Rudolph Dudebout ◽  
Richard Hausen
Keyword(s):  
Damage Mechanism ◽  
Jet Fuel ◽  
Combustible Mixture ◽  
Fuel Injector ◽  
Component Level ◽  
Pareto Chart ◽  
Flow Features ◽  
Manufacturing Tolerances ◽  
Oxidation Damage ◽  
Component Assembly

Jet fuel flowing through the fuel injector is atomized and then mixed with high temperature compressed air flowing through the swirler to create a combustible mixture inside a gas turbine combustor. Individual geometric and flow features are carefully tuned at a component level to deliver optimum combustion performance. In a critical interface such as the fuel injector and swirler, manufacturing tolerances not only have an impact on combustor performance and operability but also on durability, as the relative position of the fuel injector to the swirler significantly impacts the swirler temperature. This paper studies the influence of manufacturing tolerances on component assembly and the resulting impact on swirler temperature. The oxidation damage mechanism of the swirler is used as a measure to assess swirler durability. A Pareto chart of the effect of manufacturing tolerances on metal temperature is used to highlight the key influencing parameters. Probability distribution associated with manufacturing tolerances is gathered with Monte Carlo simulation to guide the design.

scholarly journals Direct numerical simulation of TS-waves over suction panel steps from manufacturing tolerances

2021 ◽  
Author(s):  
H. Lüdeke ◽  
R. von Soldenhoff
Keyword(s):  
Numerical Simulations ◽  
Linear Stability ◽  
Direct Numerical Simulations ◽  
Linear Stability Theory ◽  
High Fidelity ◽  
Order Method ◽  
Direct Simulation ◽  
High Order Method ◽  
Manufacturing Tolerances ◽  
Tollmien Schlichting

AbstractTo determine allowable tolerances between successive suction panels at hybrid laminar wings with suction surfaces, direct numerical simulations of Tollmien–Schlichting waves over different steps are carried out for realistic suction rates on a wind tunnel configuration. Simulations at given suction panel positions over forward and backward facing steps are carried out by the use of a high-order method for the direct simulation of Tollmien–Schlichting wave growth. Comparisons between high-fidelity direct numerical simulations and quick linear stability calculations have shown capabilities and limits of the well-validated linear stability theory design approach.

scholarly journals Electrophysiological and performance variations following driving events involving an increase in mental workload

2019 ◽  
Vol 11 (1) ◽  
Author(s):  
Hugo Loeches De La Fuente ◽  
Catherine Berthelon ◽  
Alexandra Fort ◽  
Virginie Etienne ◽  
Marleen De Weser ◽  
...  
Keyword(s):  
Mental Workload ◽  
And Performance ◽  
Performance Variations

Quantification of uncertainties due to manufacturing tolerances using deterministic sampling methods

2021 ◽  
Vol 382 ◽  
pp. 111399
Author(s):  
Elias Y. Garcia Cervantes ◽  
Bernard Erasmus ◽  
Steven van der Marck ◽  
Christian Fedon
Keyword(s):  
Sampling Methods ◽  
Deterministic Sampling ◽  
Manufacturing Tolerances

A Probabilistic Approach to Engine Balance

1999 ◽  
Vol 122 (4) ◽  
pp. 526-532 ◽  
Author(s):  
Dinu Taraza
Keyword(s):  
Internal Combustion Engines ◽  
Probabilistic Approach ◽  
Rayleigh Distribution ◽  
Statistical Characteristics ◽  
Balance Model ◽  
Combustion Engines ◽  
Normal Distributions ◽  
First Order ◽  
Rayleigh Law ◽  
Manufacturing Tolerances

The paper presents an original probabilistic model of the balance of internal combustion engines. The model considers the manufacturing tolerances and predicts the most probable value of the first-order residual unbalance for engines that—theoretically—have the first order forces and moments balanced. It has been found that, assuming normal distributions of the geometric and mass parameters of the reciprocating mechanisms of a multicylinder engine, the unbalancing forces and moments are statistically distributed according to a Rayleigh law. The mode of the Rayleigh distribution, which represents the most probable value of the residual unbalance, is expressed in terms of the statistical characteristics of the parameters subjected to manufacturing tolerances. In this way, the tolerances and, especially the ones admitted for the reciprocating masses, are directly correlated to the expected value of the residual unbalance making it possible to establish reasonable limits for these tolerances. Validation of the probabilistic balance model is demonstrated by computer simulation. [S0742-4795(00)01704-X]

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