Probabilistic HCF-Investigation of Compressor Blades

2009 ◽  
Author(s):  
Kay Heinze ◽  
Winfried-Hagen Friedl ◽  
Konrad Vogeler ◽  
Matthias Voigt
Keyword(s):  
Design Process ◽  
Optical Measurement ◽  
Measurement Data ◽  
Distribution Functions ◽  
Probabilistic Methods ◽  
Deterministic Models ◽  
Compressor Blades ◽  
Element Mesh ◽  
Hcf Strength ◽  
Detailed Interpretation

During the design process of compressor blades predominantly deterministic models are used for High Cycle Fatigue (HCF) strength investigations. The scatter of HCF that results e.g. through abrasion of the production machines [1] or inhomogeneities of the blade material, is accounted by safety factors and conservative assumptions. A more realistic approach to consider these uncertainties is the application of probabilistic methods. Therefore, further information about HCF and eigenfrequency scatter of the really produced blades can be used for a robust design during the design process. Within a measurement campaign 400 blades of a Rolls-Royce High Pressure Compressor were randomly selected and scanned using an automated process that applies the optical measurement technique of strip projection. The measurement data of the airfoil were subdivided into constant spanwise profile slices. Geometric airfoil parameters were determined on each of the profile slices [2]. Due to the large number of scanned blades each geometric airfoil parameter can be described as a distribution function with corresponding parameters. These distribution functions are the input parameters for the probabilistic investigation — the Monte-Carlo-Simulation (MCS). Within the MCS an automatically transfer process varies at first the profile slices of a CAD-airfoil and in a second step morphs an existent 3D finite element mesh applying the meshmorphing tool of the FE preprocessor Hypermesh. The HCF and eigenfrequency scatter of all blades were calculated with the interpretation of the MCS results and parameters were detected with the largest influence on HCF-strength and eigenfrequencies. A detailed interpretation of the HCF-strength at one example shows the power of the probabilistic investigation. The interpretation helps the engineer to understand the entire system and to design a robust blade.

scholarly journals An uncertainty-based protocol for the setup and measurement of soot/black carbon emissions from gas flares using sky-LOSA

2020 ◽  
Author(s):  
Bradley M. Conrad ◽  
Matthew R. Johnson
Keyword(s):  
Open Source ◽  
Black Carbon ◽  
Open Source Software ◽  
Carbon Emissions ◽  
Climate Models ◽  
Optical Measurement ◽  
Measurement Data ◽  
Software Tool ◽  
Measurement Protocol ◽  
Measurement Uncertainties

Abstract. Gas flaring is an important source of atmospheric soot/black carbon, especially in sensitive Arctic regions. However, emissions have traditionally been challenging to measure and remain poorly characterized, confounding international reporting requirements and adding uncertainty to climate models. The sky-LOSA optical measurement technique has emerged as a powerful means to quantify flare black carbon emissions in the field, but broader adoption has been hampered by the complexity of its deployment, where decisions during setup in the field can have profound, non-linear impacts on achievable measurement uncertainties. To address this challenge, this paper presents a prescriptive measurement protocol and associated open-source software tool that simplifies acquisition of sky-LOSA data in the field. Leveraging a comprehensive Monte Carlo-based General Uncertainty Analysis (GUA) to predict measurement uncertainties over the entire breadth of possible measurement conditions, general heuristics are identified to guide a sky-LOSA user toward optimal data collection. These are further extended in the open-source software utility, SetupSkyLOSA, which interprets the GUA results to provide detailed guidance for any specific combination of location, date/time, and flare, plume, and ambient conditions. Finally, a case study of a sky-LOSA measurement at an oil and gas facility in Mexico is used to demonstrate the utility of the software tool, where potentially small region(s) of optimal instrument setup are easily and quickly identified. It is hoped that this work will help increase the accessibility of the sky-LOSA technique and ultimately the availability of field measurement data for flare black carbon emissions.

scholarly journals Modelling Inhomogeneity of Veneer Laminates with a Finite Element Mapping Method Based on Arbitrary Grayscale Images

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 2993
Author(s):  
David Zerbst ◽  
Christian Liebold ◽  
Thomas Gereke ◽  
André Haufe ◽  
Sebastian Clauß ◽  
...  
Keyword(s):  
Finite Element ◽  
Point Cloud ◽  
Nearest Neighbor ◽  
Measurement Data ◽  
Tensile Tests ◽  
Mapping Method ◽  
Nearest Neighbor Search ◽  
Failure Behavior ◽  
Element Mesh ◽  
Mapping Tool

Failure and deformation behavior of veneer laminates of ring porous wood species vary with the individual arrangement of early- and latewood zones over a veneer sheet. Therefore, a method is presented, where local failure and damage modes are considered for finite element models with respect to forming simulations, during the development process of automotive interior trim parts. Within the mapping tool Envyo, a routine has been realized for the discretization of early- and latewood zones from ash wood veneer surfaces to finite element meshes. The routine performs the following steps: reading a grayscale image of known size and generation of a point cloud based on the number of pixels; transformation and scaling of the generated point cloud to align with a target finite element mesh; nearest neighbor search and transfer of grayscale values to the target mesh element centroids; assigning part and therefore material properties to the target elements based on the mapped grayscale value and user-defined grayscale ranges. Due to the absence of measurement data for early- and latewood, optimization was used to identify locally varying material constants. A set of material input parameters for early- and latewood was created, calibrating the force-displacement response of tensile test simulations to corresponding experimental curves. The numerical results gave a very good agreement to the failure behavior of tensile tests in the loading directions longitudinal and transverse to the fiber orientation. Furthermore, in a stochastic analysis the characteristic distribution of tensile strength and ultimate strain could be verified for the suggested procedure. The introduced modelling approach can be applied for the discrete implementation of inhomogeneity to numerical simulations.

scholarly journals Statistical Analysis of Bistatic Radar Ground Clutter for Different German Rural Environments

Sensors ◽  
2020 ◽  
Vol 20 (11) ◽  
pp. 3311
Author(s):  
Michael Kohler ◽  
Daniel W. O’Hagan ◽  
Matthias Weiss ◽  
David Wegner ◽  
Josef Worms ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Measurement Data ◽  
Distribution Functions ◽  
Statistical Properties ◽  
Cumulative Distribution ◽  
Center Frequency ◽  
Rural Environment ◽  
Bistatic Radar ◽  
Ground Clutter ◽  
Rural Environments

This article presents the statistical analysis of bistatic radar rural ground clutter for different terrain types under low grazing angles. Compared to most state-of-the-art analysis, we present country-specific clutter analysis for subgroups of rural environments rather than for the rural environment as a whole. Therefore, the rural environment analysis is divided into four dominant subgroup terrain types, namely fields with low vegetation, fields with high vegetation, plantations of small trees and forest environments representing a typical rural German environment. We will present the results for both the summer and the winter vegetation. Therefore, bistatic measurement campaigns have been carried out during the summer 2019 and the winter of 2019/20 in the aforementioned four different rural terrain types. The measurements were performed in the radar relevant X-band at a center frequency of 8.85 GHz and over a bandwidth of 100 MHz according to available transmit permission. The distinction of the rural terrain into different subgroups enables a more precise and accurate clutter analysis and modeling of the statistical properties as will be shown in the presented results. The statistical properties are derived from the calculated clutter amplitudes probability density functions and corresponding cumulative distribution functions for each of the four terrain types and the corresponding season. The data basis for the clutter analysis are the processed range-Doppler maps from the bistatic radar measurements. According to the authors’ current knowledge, a similar investigation based on real bistatic radar measurement data with the division into terrain subgroups has not yet been carried out and published for a German rural environment.

Experimental Study of Moderator Circulation in CANDU6 Calandria Tank

2014 ◽  
Author(s):  
Hyoung Tae Kim ◽  
Han Seo ◽  
Sunghyuk Im ◽  
Bo Wook Rhee ◽  
Jae Eun Cha
Keyword(s):  
Heat Sink ◽  
Optical Measurement ◽  
Cooling System ◽  
Safety Concern ◽  
Measurement Data ◽  
Validation Data ◽  
3 Dimensional ◽  
Loss Of Coolant Accident ◽  
Piv Measurement ◽  
Accident Conditions

As a CANDU6 reactor has a high pressure primary cooling system and an independently cooled moderator system, the moderator in the calandria would act as a supplementary heat sink during a loss of coolant accident (LOCA) if the primary cooling and emergency coolant injection systems fail to remove the decay heat from the fuel. For the safety concern it is required to predict the 3-dimensional velocity and temperature distribution of moderator fluid to confirm the effectiveness of moderator heat sink. Korea Atomic Energy Research Institute (KAERI) is carrying out a scaled-down moderator test program to simulate the CANDU6 moderator circulation phenomena during steady state operation and accident conditions. This research program includes the construction of the Moderator Circulation Test (MCT) facility, production of the validation data for self-reliant CFD tools, and development of optical measurement system using the Particle Image Velocimetry (PIV). In the present work the PIV technique is used to measure the velocity distributions in the scaled moderator tank of MCT under iso-thermal test conditions. The preliminary PIV measurement data are obtained and compared with CFX code predictions.

Efficient Adaptive Meshing of Parametric Models

2001 ◽  
Vol 1 (4) ◽  
pp. 366-375 ◽  
Author(s):  
Alla Sheffer ◽  
Alper U¨ngo¨r
Keyword(s):  
Finite Element ◽  
Design Process ◽  
Parametric Model ◽  
Parametric Modeling ◽  
Boundary Representation ◽  
Finite Element Mesh ◽  
Parametric Models ◽  
Adaptive Meshing ◽  
Element Mesh ◽  
Parametric Change

Parametric modeling is becoming the representation of choice for most modern solid modelers. However, when generating the finite-element mesh of the model for simulation and analysis, most meshing tools ignore the parametric information and use only the boundary representation of the model for meshing. This results in re-meshing the model basically from scratch each time a parametric change is instantiated, which happens numerous times throughout the design process. In this paper we look at ways to use the parametric information during the meshing procedure to prevent unnecessary re-meshing. The paper examines existing meshing techniques developed for other purposes, which can be applied to this problem. It also suggests several new mesh modification techniques specifically designed for efficient mesh adjustment after parametric model changes.

Analyzing wind speed data and wind power density of Tetouan city in Morocco by adjustment to Weibull and Rayleigh distribution functions

2017 ◽  
Vol 41 (3) ◽  
pp. 174-184 ◽  
Author(s):  
Mohamed Hatim Ouahabi ◽  
Farid Benabdelouahab ◽  
Abdellatif Khamlichi
Keyword(s):  
Wind Speed ◽  
Measurement Data ◽  
Rayleigh Distribution ◽  
Distribution Functions ◽  
Statistical Distributions ◽  
Energy Potential ◽  
Distribution Models ◽  
Wind Speed Data ◽  
Resource Characteristics ◽  
Wind Resource

Several statistical distributions have been considered to model wind speed data. However, Weibull and Rayleigh statistical distributions are the most widely used methods for analyzing wind speed measurements and determining wind energy potential. In this work, these statistical distributions were applied in order to evaluate the wind resources in the northern Moroccan city of Tetouan. Adjustment of wind measurement data was performed. Then, the obtained results were compared with the provided wind data to test their accuracy based on common statistical indicators for performance. It was found that the Weibull and Rayleigh distribution models provide adequate description of the frequencies of actual wind records in Tetouan. They can be advantageously used to assess wind resource characteristics in this region.

Tool path adaption based on optical measurement data for milling with industrial robots

2012 ◽  
Vol 6 (4-5) ◽  
pp. 459-465 ◽  
Author(s):  
E. Abele ◽  
K. Schützer ◽  
J. Bauer ◽  
M. Pischan
Keyword(s):  
Tool Path ◽  
Optical Measurement ◽  
Measurement Data ◽  
Industrial Robots

Geometrical Shape Analysis for Investment Casting Turbine Blade Based on Optical Measurement

2013 ◽  
Vol 365-366 ◽  
pp. 716-719 ◽  
Author(s):  
Yun Yong Cheng ◽  
Zhen Zhen Zhu ◽  
Ding Hua Zhang
Keyword(s):  
Turbine Blade ◽  
Shape Analysis ◽  
Optical Measurement ◽  
Measurement Data ◽  
Geometrical Shape ◽  
Shape Deviation ◽  
Fast Calculation ◽  
Optical Scanning ◽  
Blade Model ◽  
Structure Light

Turbine blade is one of the key components of the aero engine. It needs to be inspected comprehensively and carefully during its production stage. The methods for investment turbine blade geometrical shape analysis based on optical scanning measurement were presented, including optical measurement data collection, blade model reliable alignment and geometrical shape deviation fast calculation and visualization. Real measurement data from a structure light measurement device for a turbine blade was used to validate the discussed methods.

Processing of multiple-site optical measurement data

2000 ◽  
Vol 67 (7) ◽  
pp. 634
Author(s):  
V. F. Fateev ◽  
A. P. Aleshkin
Keyword(s):  
Optical Measurement ◽  
Measurement Data ◽  
Multiple Site

scholarly journals Performance based approach in design of freeform space structures

2017 ◽  
Vol 15 (2) ◽  
pp. 153-166
Author(s):  
Miodrag Nestorovic ◽  
Predrag Nestorovic ◽  
Jelena Milosevic
Keyword(s):  
Design Process ◽  
Rational Design ◽  
Optical Measurement ◽  
Digital Fabrication ◽  
Digital Design ◽  
Physical Models ◽  
Design Solution ◽  
Roof Structure ◽  
Cad Cam ◽  
Context Specific

This paper is related to the fact that use of computational tools for form generation, analysis and digital fabrication (CAD/CAM/CAE) in an efficient way enables accurate representation of ideas, simulation of diverse impact and production of rational design solutions. Application of geometrical and numerical computational methods and adoption of performance based priorities enables formal exploration in constrained conditions and improvement of architectural engineering design process. Implementation of advanced technologies in 3D digital design process facilitates production of unconventional complex designs, their verification by construction of physical models and experimental diagnostics, as phase preceding construction of real structure. Within this work concept that provides design of non-standard, context-specific, freeform structure using rapid prototyping technology and 3D optical measurement will be reviewed. The analyzed design solution of roof structure above atrium of National Museum in Belgrade has a function to demonstrate the effectiveness of this approach.

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