scholarly journals Investigation of wear mechanics and behaviour of NiCr metallic foam abradables

2021 ◽  
pp. 095440622110553
Author(s):  
Allan Liu ◽  
Matthew Marshall ◽  
Eldar Rahimov ◽  
Julian Panizo
Keyword(s):  
High Speed ◽  
Load Transfer ◽  
Measurement Techniques ◽  
Image Correlation ◽  
Metallic Foam ◽  
Filler Materials ◽  
Nicr Alloy ◽  
Speed Test ◽  
Aero Engine ◽  
Sealing Materials

Current aero-engine sealing materials are reaching their operating limit, as manufacturers seek more efficient engines with longer service lives. Even when utilised in optimum conditions, current materials have inconsistencies in performance due to variabilities in their microstructure, which lead to undesirable responses and events. As such, a new generation of sealing materials is required. Metallic foams are one such material, given the opportunities that exist to both engineer material properties, and achieve relatively consistent microstructures when compared to the current class of thermally sprayed abradable materials. In this study, the abradability of a nickel (70%)–chromium (30%) (NiCr) alloy foam is investigated, with the role of cell size and filler material considered. Tests are performed on a representative high-speed test rig, where a flat blade is used to simulate an aero-engine incursion event. A series of in situ measurement techniques, such as force, temperature and stroboscopic wear measurements are used to characterise the incursion, with DIC (Digital Image Correlation) techniques also employed to investigate breakdown of the foam. Unfilled foams were shown to lead to high blade wear, with the inclusion of filler materials leading to load transfer and collapse of the foam away from the incursion site, along with improved fracture. Both load transfer and ligament collapse mechanisms were found to promote more favourable rub mechanics at all incursion rates tested.

Investigating the Flexural Behaviour of Foams at High Strain Rate Using Optical Measurement Techniques

2013 ◽  
Vol 569-570 ◽  
pp. 799-804
Author(s):  
Duncan A. Crump ◽  
Janice M. Dulieu-Barton
Keyword(s):  
High Speed ◽  
Optical Measurement ◽  
Measurement Techniques ◽  
Maximum Load ◽  
Image Correlation ◽  
Test Machine ◽  
Full Field ◽  
Closed Cell ◽  
Load To Failure ◽  
Point Bend

Polymer closed cell foam beam specimens manufactured from H100 Divinycell (Diab) are tested in four point bend at three loading speeds using a specially designed rig and an Instron VHS test machine. Synchronised high speed images are captured using white light and infra-red thermography (IRT) to obtain the mid-point full-field deflection and strains using digital image correlation (DIC) along with the temperature evolutions. There is a marked increase in the maximum load to failure with loading rate and the optical techniques provide an opportunity to analyse the strain and temperature evolution within the specimens.

Strain distribution and load transfer in the polymer-wood particle bond in wood plastic composites

Holzforschung ◽  
2015 ◽  
Vol 69 (1) ◽  
pp. 53-60 ◽  
Author(s):  
Matthew Schwarzkopf ◽  
Lech Muszynski
Keyword(s):  
Quantitative Measurement ◽  
Load Transfer ◽  
Optical Measurement ◽  
Measurement Techniques ◽  
Wood Particle ◽  
Image Correlation ◽  
Wood Particles ◽  
The Matrix ◽  
X Ray Computed ◽  
Structured Approach

Abstract The load transfer between wood particles and the matrix was analyzed by observation of the strain patterns in thin films of high density polyethylene (HDPE) with embedded wood particles subjected to tensile loading. Optical measurement techniques based on the digital image correlation (DIC) principle were employed for quantitative measurement of strain distributions on the surfaces of the specimens. Interpretation of these measurements in terms of load transfer between the particle and the matrix below the surface proved challenging and required a structured approach. In this paper, quantitative descriptors were selected as synthesized metrics to support the quantitative interpretation of the measured strains. X-ray computed tomography (XCT) scans were used to assess the effect of the position of the particles in the film specimens on the strains patterns observed on the surface.

Application of High Speed Image Correlation for Measurement of Mode Shapes of a Car Bonnet

2011 ◽  
Vol 70 ◽  
pp. 45-50
Author(s):  
Thorsten Siebert ◽  
Wei Zhuo Wang ◽  
John E. Mottershead ◽  
Andrea Pipino
Keyword(s):  
High Speed ◽  
Speckle Pattern ◽  
Measurement Techniques ◽  
Image Correlation ◽  
Mode Shapes ◽  
Analysis Tool ◽  
Full Field ◽  
Digital Speckle Pattern Interferometry ◽  
Full Field Measurement ◽  
Wide Range

For the analysis of vibrations and mode shape extraction in particular the use of optical full-field measurement techniques has grown during the last years. Beside techniques like Digital Speckle Pattern Interferometry, Moiré, Thermography or Photoelasticity the Digital Image Correlation techniques have already been successfully proven to be an accurate displacement analysis tool for a wide range of applications.

Experimental Measurement of In-Plane Rolling Nonpneumatic Tire Vibrations Using High-Speed Imaging

2019 ◽  
Vol 47 (3) ◽  
pp. 196-210
Author(s):  
Meghashyam Panyam ◽  
Beshah Ayalew ◽  
Timothy Rhyne ◽  
Steve Cron ◽  
John Adcox
Keyword(s):  
High Speed ◽  
Image Correlation ◽  
Dynamic Mode Decomposition ◽  
Dynamic Mode ◽  
High Speed Imaging ◽  
Correlation Algorithm ◽  
Mode Decomposition ◽  
Series Of Experiments ◽  
Plane Deformations ◽  
Dominant Frequencies

ABSTRACT This article presents a novel experimental technique for measuring in-plane deformations and vibration modes of a rotating nonpneumatic tire subjected to obstacle impacts. The tire was mounted on a modified quarter-car test rig, which was built around one of the drums of a 500-horse power chassis dynamometer at Clemson University's International Center for Automotive Research. A series of experiments were conducted using a high-speed camera to capture the event of the rotating tire coming into contact with a cleat attached to the surface of the drum. The resulting video was processed using a two-dimensional digital image correlation algorithm to obtain in-plane radial and tangential deformation fields of the tire. The dynamic mode decomposition algorithm was implemented on the deformation fields to extract the dominant frequencies that were excited in the tire upon contact with the cleat. It was observed that the deformations and the modal frequencies estimated using this method were within a reasonable range of expected values. In general, the results indicate that the method used in this study can be a useful tool in measuring in-plane deformations of rolling tires without the need for additional sensors and wiring.

scholarly journals Full-Field Operational Modal Analysis of an Aircraft Composite Panel from the Dynamic Response in Multi-Impact Test

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1602
Author(s):  
Ángel Molina-Viedma ◽  
Elías López-Alba ◽  
Luis Felipe-Sesé ◽  
Francisco Díaz
Keyword(s):  
Modal Analysis ◽  
Energy Absorption ◽  
High Speed ◽  
Operational Modal Analysis ◽  
Modal Identification ◽  
Image Correlation ◽  
Composite Panel ◽  
Impact Excitation ◽  
Full Field ◽  
The Impact

Experimental characterization and validation of skin components in aircraft entails multiple evaluations (structural, aerodynamic, acoustic, etc.) and expensive campaigns. They require different rigs and equipment to perform the necessary tests. Two of the main dynamic characterizations include the energy absorption under impact forcing and the identification of modal parameters through the vibration response under any broadband excitation, which also includes impacts. This work exploits the response of a stiffened aircraft composite panel submitted to a multi-impact excitation, which is intended for impact and energy absorption analysis. Based on the high stiffness of composite materials, the study worked under the assumption that the global response to the multi-impact excitation is linear with small strains, neglecting the nonlinear behavior produced by local damage generation. Then, modal identification could be performed. The vibration after the impact was measured by high-speed 3D digital image correlation and employed for full-field operational modal analysis. Multiple modes were characterized in a wide spectrum, exploiting the advantages of the full-field noninvasive techniques. These results described a consistent modal behavior of the panel along with good indicators of mode separation given by the auto modal assurance criterion (Auto-MAC). Hence, it illustrates the possibility of performing these dynamic characterizations in a single test, offering additional information while reducing time and investment during the validation of these structures.

scholarly journals The Influence of the Axial Rub Added in the Radial Rub on the Wear of the Seal Fins during the High Speed Rub of Labyrinth-Honeycomb Seal

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1997
Author(s):  
Bin Lu ◽  
Haijun Xuan ◽  
Xiaojian Ma ◽  
Fangjun Han ◽  
Weirong Hong ◽  
...  
Keyword(s):  
Wear Rate ◽  
High Speed ◽  
State Of The Art ◽  
Negative Influence ◽  
Axial Thrust ◽  
Cross Sectional ◽  
Honeycomb Seal ◽  
Aero Engine ◽  
Honeycomb Seals ◽  
Clearance Change

Labyrinth-honeycomb seals are a state-of-the-art sealing technology commonly used in aero-engine interstage seal. The undesirable severe rub between the seal fins and the honeycomb due to the clearance change may induce the cracking of the seal fins. A pervious study investigated the wear of the seal fins at different radial incursion rates. However, due to the axial thrust and mounting clearance, the axial rub between the seal fins and the honeycomb may occur. Hence, this paper focuses on the influence of the axial rub added in the radial rub on the wear of the seal fins. The rub tests results, including rubbing forces and temperature, wear rate, worn morphology, cross-sectional morphology and energy dispersive spectroscopy results, are presented and discussed. Overall, the participation of the axial rub leads to higher rubbing forces, temperature, and wear rate. The tribo-layer on the seal fin is thicker and the cracks are more obvious at high axial incursion rate. These phenomena indicate the axial rub has a negative influence on the wear of the seal fins and should be avoided.

scholarly journals An Improved Lagrangian-Inverse Method for Evaluating the Dynamic Constitutive Parameters of Concrete

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1871
Author(s):  
Xinlu Yu ◽  
Yingqian Fu ◽  
Xinlong Dong ◽  
Fenghua Zhou ◽  
Jianguo Ning
Keyword(s):  
High Speed ◽  
Inverse Method ◽  
Image Correlation ◽  
Analysis Method ◽  
Stress Strain ◽  
Optical Techniques ◽  
Element Simulation ◽  
Non Linear ◽  
Constitutive Parameters ◽  
Inverse Analysis Method

The dynamic constitutive behaviors of concrete-like materials are of vital importance for structure designing under impact loading conditions. This study proposes a new method to evaluate the constitutive behaviors of ordinary concrete at high strain rates. The proposed method combines the Lagrangian-inverse analysis method with optical techniques (ultra-high-speed camera and digital image correlation techniques). The proposed method is validated against finite-element simulation. Spalling tests were conducted on concretes where optical techniques were employed to obtain the high-frequency spatial and temporal displacement data. We then obtained stress–strain curves of concrete by applying the proposed method on the results of spalling tests. The results show non-linear constitutive behaviors in these stress–strain curves. These non-linear constitutive behaviors can be possibly explained by local heterogeneity of concrete. The proposed method provides an alternative mean to access the dynamic constitutive behaviors which can help future structure designing of concrete-like materials.

The Use of Modan 3D in Experimental Modal Analysis

2013 ◽  
Vol 486 ◽  
pp. 36-41 ◽  
Author(s):  
Róbert Huňady ◽  
František Trebuňa ◽  
Martin Hagara ◽  
Martin Schrötter
Keyword(s):  
Modal Analysis ◽  
Vibration Analysis ◽  
High Speed ◽  
Mechanical Vibration ◽  
Steel Sample ◽  
Experimental Modal Analysis ◽  
Image Correlation ◽  
Optical Methods ◽  
Mode Shapes ◽  
Vibration Modes

Experimental modal analysis is a relatively young part of dynamics, which deals with the vibration modes identification of machines or their parts. Its development has started since the beginning of the eighties, when the computers hardware equipment has improved and the fast Fourier transform (FFT) could be used for the results determination. Nowadays it provides an uncountable set of vibration analysis possibilities starting with conventional contact transducers of acceleration and ending with modern noncontact optical methods. In this contribution we mention the use of high-speed digital image correlation by experimental determination of mode shapes and modal frequencies. The aim of our work is to create a program application called Modan 3D enabling the performing of experimental modal analysis and operational modal analysis. In this paper the experimental modal analysis of a thin steel sample performed with Q-450 Dantec Dynamics is described. In Modan 3D the experiment data were processed and the vibration modes were determined. The reached results were verified by PULSE modulus specialized for mechanical vibration analysis.

Wind-Induced Vibration Analysis and Remote Monitoring Test of Wind Turbine Power Tower

2013 ◽  
Vol 639-640 ◽  
pp. 293-296 ◽  
Author(s):  
Ai Jun Chen ◽  
Guo Jing He
Keyword(s):  
Wind Power ◽  
Electromagnetic Interference ◽  
High Speed ◽  
Measurement Techniques ◽  
Dynamic Monitoring ◽  
Leading Role ◽  
Tower Structure ◽  
Monitoring Test ◽  
Major Loss ◽  
Wind Induced Vibration

The major loss of the hurricane was damage and collapse of structures, In particular, wind power tower wich requires both the use of wind, wind on the structure plays a leading role in the tall slender flexible structure.In this paper, tests of remote sensing dynamic monitoring of tower structure with wind power are carried out, using measurement techniques of high-frequency and high-speed electromagnetic interference.

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